Thermohydraulic analysis of nanofluid flow in tubular heat exchangers with multi-blade turbulators: The adverse effects

Based on the significance of heat transfer in tubular flows, various methods of heat transfer enhancement have been developed by scholars. The use of turbulator inserts like twisted tapes is widely discussed and suggested by researchers, and many studies have concentrated on the positive influence of these devices. However, the question is whether these devices always positively impact heat transfer and fluid flow. In this study, efforts were made to find possible adverse impacts of using twisted tapes on the average Nusselt number (Nu), friction factor (f), flow behavior, and performance evaluation criterion (PEC) of water-titania nanofluid. Three-dimensional (3D) numerical methods were used to assess a combination of three different configurations of 156 cases with/without turbulators with different numbers of blades and pitch ratios (PR). Results suggest that at Reynolds number (Re) = 4000, 6000, and 8000, only 25 %, 25 %, and 22.9 % of the examined cases led to PEC values over 1. Based on the results, while twisted tapes raised the Nu by up to 65.1 %, the f can be increased by up to more than six times. Furthermore, streamlines and velocity magnitude contours were employed to discuss the fluid flow behavior in the presence of the turbulators. According to the findings, while with the best turbulator, the PEC value was increased by only 6.3 %, some of the turbulators reduced this parameter by up to 11.8 %, which is more severe. The worst performance was observed with the Case C (three-bladed) turbulator at a PR value of 11, which reduced the PEC by 11.8 %.

Potable water production through a low-cost single chamber solar still in north India

The main aim of this study is to evaluate the performance of a single slope solar still and to assess the effect of nanofluid on its performance. A single basin single slope solar still was designed and fabricated at the Department of Chemical Engineering, IET Lucknow. Its performance was assessed in terms of the yield of potable water. The effect of various climatic parameters was also studied. Al2O3 nanofluid was used to enhance the yield of the solar still. In the presence of nanofluid, the total yield of the solar still improved by 16.6%. Its economic feasibility was analyzed and reported. The portability of the small size of solar stills, its better economics, easy fabrication, and good performance make them very useful for industrial as well as household purposes.

Sensitivity analysis of natural convection in a porous cavity filled with nanofluid and equipped with horizontal fins using various optimization methods and MRT-LB

In the present study, natural convection heat transfer is investigated in a porous cavity filled with Cu/water nanofluid and equipped with horizontal fins. Optimization and sensitivity analysis of the fin's geometry, porous medium and nanofluid properties to maximize heat transfer rate is the aim of this work. To achieve this purpose, a design space is created by input parameters which include length, number of fins, distance between fins, porosity, Darcy number and volumetric fraction of the nanoparticles. Several tools have been used to implement optimization methods including the Taguchi method (TM) for design points generation, sensitivity analysis of design variables by using signal-to-noise ratio (SNR) and analysis of variance (ANOVA), response surface method (RSM) for interpolation and regression by using nonparametric regression, and genetic algorithm (GA) for finding optimum design point. The double multi-relaxation time lattice Boltzmann method (MRT-LBM) is used to analyze and simulate the flow field and heat transfer in each design point. The results show that the optimal configuration leads to an average Nusselt number of 5.56. This optimal configuration is at the length of fins L/2, the number of fins 2, the distance between fins L/12, porosity 0.8, Darcy number 0.1, and the volumetric fraction of the nanoparticles 0.02. By using the SNR results, the Darcy number and the number of fins have the most and the least effect in maximizing the average Nusselt number, respectively. The ANOVA results and global sensitivity analysis (GSA) findings further validated this conclusion.

Analysis for bioconvection due to magnetic induction of Casson nanoparticles subject to variable thermal conductivity

Owing to valuable significance of bioconvective transport phenomenon in interaction of nanoparticles, different applications are suggested in field of bio-technology, bio-fuels, fertilizers and soil sciences. It is well emphasized fact that thermal outcomes of nanofluids can be boosted under the consideration of various thermal sources. The aim of current research is to test the induction of induced magnetic force in bioconvective transport of non-Newtonian nanofluid. The rheological impact of non-Newtonian materials is observed by using Casson fluid with suspension of microorganisms. The chemical reaction effected are interpreted. The thermal conductivity of material is assumed to be fluctuated with temperature fluctuation. The flow pattern is endorsed by stretching surface following the stagnation point flow. Under the defined flow assumptions, the problem is formulated. A computational software with shooting technique is used to present the simulations. A comprehensive analysis for problem is presented. It is claimed that the interpretation of induced magnetic force exclusively enhanced the thermal phenomenon.

Pulsatile nanofluid flow with variable pressure gradient and heat transfer in wavy channel

This research contributes to the comprehension of nanofluid behaviour through a wavy channel, emphasizing the significance of considering diverse influences in the modelling process. The study explores the collective influence of pressure gradient variation, magnetic field, porosity, channel waviness, nanoparticle concentration, and heat transfer on nano-blood flow in a two-dimensional wavy channel. In contrast to prior research assuming a constant pulsatile pressure gradient during channel waviness, this innovative study introduces a variable pressure gradient, significantly influencing several associated parameters. The mathematical model characterizing nano-blood flow in a horizontally wavy channel is solved using the perturbation technique. Analytical solutions for fundamental variables such as stream function, velocity, wall shear stress, pressure gradient, and temperature are visually depicted across different physical parameters values. The findings obtained for differing parameter values in the given problem demonstrate a significant influence of the amplitude ratio parameter of channel waviness, Hartmann number of the magnetic field, permeability parameter of the porous medium, volume fraction of nanoparticles, radiation parameter, Prandtl number, and the suction/injection parameter on the flow dynamics. The simulations provide valuable insights into the decrease in velocity with increasing magnetic field and its increase with higher permeability. Additionally, the temperature is observed to escalate with a rising nanoparticle volume fraction and radiation parameter, while it declines with increasing Prandtl number.

Enhanced Stability, Superior Anti-Corrosive, and Tribological Performance of Al2O3 Water-based Nanofluid Lubricants with Tannic Acid and Carboxymethyl Cellulose over SDBS as Surfactant

In this research work, the stability, tribological, and corrosion properties of a water-based Al2O3 nanofluid (0.5 wt%) formulated with tannin acid (TA) and carboxymethyl cellulose (CMC) as dispersants or surfactants were investigated. For comparative purposes, sodium dodecylbenzene sulfonate (SDBS) was also incorporated. The stability of the nanofluid was assessed through zeta potential measurements and photo-capturing, revealing the effectiveness of TA and CMC in preventing nanoparticle agglomeration. Tribological properties were examined using a pin-on-disk apparatus, highlighting the tribofilm of Al2O3 that enhanced lubricating properties of the nanofluid by the SEM, resulting in reduced friction and wear of the contacting surfaces. Sample with the addition of both TA and CMC exhibited the best tribological performance, with a ~ 20% reduction in the friction coefficient and a 59% improvement in wear rate compared to neat nanofluid without TA and CMC. Additionally, the corrosion resistance of the nanofluids were evaluated via weight loss and electrochemical impedance spectroscopy. The nanofluid sample containing both TA and CMC exhibited the lowest corrosion rate, with 97.6% improvement compared to sample without them. This study provides valuable insights into the potential applications of TA and CMC-based Al2O3 nanofluids as effective and environmentally friendly solutions for coolant or lubrication in cutting processes.

Comparative simulation of nonlinear radiative nano casson and maxwell fluids with periodic magnetic force and sensitivity analysis

This study investigated cyclic magneto-hydrodynamic radiative effects in Casson and Maxwell fluids, including nonlinear radiation and Arrhenius activation energy. It promotes non-Newtonian fluid use in diverse fields like industry, manufacturing, sciences, medicine, and engineering. Using boundary layer approximations, non-dimensional equations are formulated. For numerical solutions, widely recognized explicit finite difference method (EFDM) has been utilized. To ensure the robustness of EFDM results, stability and convergence tests are performed. Exploration involve a detailed sensitivity analysis by using RSM, offering a thorough understanding of influential parameters. These analyses explore complex interactions among physical parameters, affecting Nusselt number, skin friction, and Sherwood number. Maxwell fluid's velocity is more affected by periodic magnetic force than Casson fluid, during the presence of nonlinear radiation. Additionally, nonlinear thermal radiation has a greater impact on temperature and concentration profiles compared to linear radiation for both fluids. Moreover, Casson fluid has a stronger influence on the average heat transfer rate compared to Maxwell fluid with nonlinear thermal radiation which is 8.6 % greater than the Maxwell fluid. On the other hand, at constant thermal radiation (Ra), due to decrease of Brownian motion (Nb), the rate of heat transfer is reduced by 1.2 % and 0.3 % respectively for Maxwell and Casson fluid. Also, for thermophoresis parameter (Nt), this rate is reduced by 2 % and 1.6 % respectively. The investigation also revealed that the Ra exhibits a positive sensitivity towards average Nusselt number, while Nb and Nt are displayed a negative sensitivity.

Ozone degradation of tetracycline hydrochloride enhanced by magnetic nanofluid composed of Fe3O4 nanoparticles

Magnetic Fe3O4 nanoparticles were added into the aqueous phase to form nanofluid systems, in which ozone was used for the oxidation of tetracycline hydrochloride (TC) in the solution. The nanomaterials were characterized using SEM, XRD, EDS, and FT-IR. The effects of nanoparticles size, addition ratio, and number of cycles on the process of ozone oxidation of TC were investigated. The results indicated that the addition ratio of nanoparticles have a certain impact on the performance of ozone oxidation. When the addition ratio increased from 0.02% to 0.4%, the removal rate of TC in the solution was improved significantly. Besides, the particle size of nanoparticles showed a greater impact on ozone oxidation. At the nanoscale, Fe3O4 nanoparticles exhibited significant strengthening properties, which is attributed to the construction of nanofluid systems. The removal rate of TC in solution decreased obviously with the increase of nanoparticles size. The Fe3O4 nanoparticles with particle size of 20 nm showed the most significant effect on TC degradation. The recycling experiment showed that magnetic Fe3O4 nanoparticles had stable regeneration performance. For three times of recycling treatment, with a Fe3O4 addition ratio of 0.4%, the removal rate of TC reached 98.7%, 97.21%, and 96%, respectively. Based on the characterization results, the strengthening mechanism was analyzed. The experimental results indicated that construction of nanofluids systems could improve the utilization rate of ozone, and Fe3O4 nanoparticles were reusable and easily recyclable.

Enhancement of solar evacuated tube unit filled with nanofluid implementing three lobed storage unit equipped with fins

This study discusses an evacuated tube collector-type solar water heater (ETCSWH) using a phase change material (PCM) chamber with fins, nanofluid, and nano-enhanced phase change material (NEPCM). First, the charging phenomena in a horizontal triplex tube heat exchanger (TTHX) equipped with fins, natural convection, and an ETCSWH system without PCM is simulated to validate the solution. The impact of adding fins and nanoparticles with a volume fraction of 3% of Al2O3 and Cu to paraffin wax and water-based fluid, respectively, on the unit's efficiency has been examined. The proposed system for the PCM melting process, heat storage, fluid flow behavior in the system, and velocity distribution and temperature contour in the storage tank and three parts of the absorber tube have been evaluated using ANSYS FLUENT software in a three-dimensional and transient simulation. The results show that Case 8 has improved by 39.7% compared to Case 1 and Case 4 by 5.2% compared to Case 1 within 4 h of the melting process. Also, Case 8 with a 43% and 6.4% shorter melting time than Cases 1 and 5 has the best performance and the greatest heat transfer rate. The productivity of the ETCSWH system is considerably enhanced by the use of fins, NEPCM, and nanofluid.

Instability analysis for MHD boundary layer flow of nanofluid over a rotating disk with anisotropic and isotropic roughness

The study focuses on the instability of local linear convective flow in an incompressible boundary layer caused by a rough rotating disk in a steady MHD flow of viscous nanofluid. Miklavčič and Wang's (Miklavčič and Wang, 2004) [9] MW roughness model are utilized in the presence of MHD of Cu-water nanofluid with enforcement of axial flows. This study will investigate the instability characteristics with the MHD boundary layer flow of nanofluid over a rotating disk and incorporate the effects of axial flow with anisotropic and isotropic surface roughness. The resulting ordinary differential equations (ODEs) are obtained by using von Kàrmàn (Kármán, 1921) [3] similarity transformation on partial differential equations (PDEs). Subsequently, numerical solutions are obtained using the shooting method, specifically the Runge-Kutta technique. Steady-flow profiles for MHD and volume fractions of nanoparticles are analyzed by the partial-slip conditions with surface roughness. Convective instability for stationary modes and neutral stability curves are also obtained and investigated by the formulation of linear stability equations with the MHD of nanofluid. Linear convective growth rates are utilized to analyze the stability of magnetic fields and nanoparticles and to confirm the outcomes of this analysis. Stationary disturbances are also considered in the energy analysis. The investigation indicates the correlation between instability modes Type I and Type II, in the presence of MHD, nanoparticles, and the growth rates of the critical Reynolds number. An integral energy equation enhances comprehension of the fundamental physical mechanisms. The factors contributing to convective instability in the system are clarified using this approach.

Thermal performance augmentation in a pipe employing hybrid nanofluid and a plate as turbulator with V-shaped double-winglet ribs

This article employs a plate with V-shape ribs inside a tube as turbulator to augment the heat transfer rate. The utilized vortex generators are double-winglets arranged in a V-shape placed on both sides of the plate. The proposed system's suggested working fluids are water-based hybrid nanofluids, including Al2O3-Cu/water, Cu-CuO/water, and Cu-TiO2/water. This work involves a numerical evaluation of the effects of the type and volume concentration of the examined hybrid nanofluids on the enhancement of heat transfer. The experimental results are used to validate the numerical model. It is worth mentioning that all the obtained numerical results are compared with the simple tube, without any turbulator (vortex generator) and in the presence of water instead of the hybrid nanofluids. Based on the numerical results, it can be concluded that all employed hybrid nanofluids showed improved thermal performance compared to pure water. Furthermore, the differences between the models are more substantial for higher Reynolds numbers than for lower Reynolds numbers. In Re = 30,000, the Cu-TiO2/water exhibits the lowest thermal performance improvement (augmentation of about 0.3%), while the Cu-CuO/water at Re = 50,000 exhibits the largest thermal performance improvement (augmentation of approximately 5.7%), in the case of ∅1 = ∅2 = 0.5%. For ∅1 = ∅2 = 1%, the Cu-TiO2/water at Re = 30,000 has the lowest thermal performance improvement (augmentation of around 1.1%), while the Cu-CuO/water at Re = 50,000 has the most thermal performance improvement (augmentation of roughly 8.7%). According to the augmentation of around 2.8% at Re = 30,000 for Cu-TiO2/water and approximately 10.8% at Re = 50,000 for Cu-CuO/water, the thermal performance increase in the scenario of ∅1 = ∅2 = 1.5% is the lowest. In Conclusion, the Cu-CuO/water hybrid nanofluid with a volume concentration of ∅1 = ∅2 = 1.5% has the greatest thermal performance value of all the hybrid nanofluids studied.

Numerical entropy analysis of MHD electro-osmotic flow of peristaltic movement in a nanofluid

The present study investigates the MHD electro-osmotic flow of entropy generation analysis for peristaltic movement in a nanofluid with temperature-dependent viscosity. Long wavelengths, i.e., The magnitude of a wave's energy corresponds directly to its frequency while being inversely related to its wavelength in terms of velocity, temperature, and concentration, govern and confine the flow stream in the laminar region. Ohmic heating and hall effects are also included. Graphs are used to obtain and examine numerical solutions for axial velocity, temperature, concentration, Bejan number, and entropy generation. The effects of this research can help to improve pumping and gastrointestinal movements in different engineering devices. Debye-Huckel and lubrication approximations are studied to access the Boltzmann distribution of electric potential across an electric double layer. The investigations of an existing model are important in illuminating the microfluidics machinery used at the micro level for various transport phenomena in which fluids as well as particles are transported together. The current study has many applications and can be further extended to a three-dimensional profile with appropriate modifications and assumptions. When studying entropy generation, it is essential to examine the irreversible factors, while also taking into account the velocity and thermal slip conditions at channel boundaries. Moreover, the concept of entropy generation holds significant importance in comprehending various biological phenomena. Hence, the current research holds promising implications for both industrial and medical fields. The entropy generation is minimum at left wall of the channel for negative values of Helmholtz-Smoluchowski velocity.

Revisiting thermo-physical property models of Al2O3-Water nanofluid for natural convective flow

One of the comprehensive ways of heat transport performance augmentation of thermo-fluid systems is to use nanofluid over base fluid. This study mainly scrutinizes several existing models of thermal conduction coefficient and absolute viscosity of Al2O3-water nanofluid with the experimental data. A benchmark problem of natural convective flow is selected to test the performance of the available nanofluid models. The Rayleigh number varies between 103 and 109, while the solid-volume proportion (φ) changes from 0 to 4%. The governing mathematical model is numerically discretized via the Galerkin finite element procedure under appropriate auxiliary conditions. The results produced by the models are verified with the existing experimental findings based on the evaluation of the Prandtl number and average Nusselt number. It has been confirmed that the AH model (Azmi's viscosity and Ho's conductivity models) is suitable for lower nanoparticle concentration (φ = 0.01), the AM model (Azmi's viscosity and Maxwell's conductivity models) for moderate concentration (0.01 < φ < 0.04), and the NH model (Ngueyn's viscosity and Ho's conductivity models) for higher value of the solid-volume proportion (φ = 0.04).

The significance of chemical reaction, thermal buoyancy, and external heat source to optimization of heat transfer across the dynamics of Maxwell nanofluid via stretched surface

Energy loss during the transportation of energy is the main concern of researchers and industrialists. The primary cause of heat exchange gadget inefficiency during transportation was applied to traditional fluids with weak heat transfer characteristics. Instead, thermal devices worked much better when the fluids were changed to nanofluids that had good thermal transfer properties. A diverse range of nanoparticles were implemented on account of their elevated thermal conductivity. This research addresses the significance of MHD Maxwell nanofluid for heat transfer flow. The flow model comprised continuity, momentum, energy transport, and concentration equations in the form of PDEs. The developed model was converted into ODEs by using workable similarities. Numerical simulations in the MATLAB environment were employed to find the outcomes of velocity, thermal transportation, and concentration profiles. The effects of many parameters, such as Hartman, Deborah, buoyancy, the intensity of an external heat source, chemical reactions, and many others, were also evaluated. The presence of nanoparticles enhances temperature conduction. Also, the findings are compared with previously published research. In addition, the Nusselt number and skin friction increase as the variables associated with the Hartman number and buoyancy parameter grow. The respective transfer rates of heat are 28.26 % and 38.19 % respectively. As a result, the rate of heat transmission increased by 14.23 % . The velocity profiles enhanced while temperature profiles declined for higher values of the Maxwell fluid parameter. As the external heat source increases, the temperature profile rises. Conversely, buoyancy parameters increase as it descends. This type of problem is applicable in many fields such as heat exchangers, cooling of electronic devices, and automotive cooling systems.

Sandstone chemical consolidation and wettability improvement using furan polymer-based nanofluid

The oil and gas industry faces a challenge in meeting global energy demand due to sand production in unconsolidated or semi-consolidated reservoirs, leading to equipment wear, production instability, and significant financial burdens. Mechanical and chemical sand control methods are being used among which chemical sand consolidation techniques have emerged as a promising solution. In this research, furan polymer-based nanofluid is investigated as a chemical consolidant to explore its intriguing properties and characteristics and how the quantity of nanoparticles influences the fundamental properties of curing resin and wettability while pioneering a groundbreaking approach to enhancing regaining permeability. According to the findings, a substantial boost in core compressive strength has been achieved as well as an impressive increase in re-permeability, especially for the foam injection case, by the meticulous optimization of nanofluid composition. The results include a remarkable regain permeability of 91.37%, a robust compressive strength of 1812.05 psi, and a noteworthy 15.32-degree shift towards water-wet wettability. Furthermore, silica nanoparticles were incorporated to enhance the thermal stability of the fluid, rendering it more adaptable to higher temperatures. Therefore, Furan polymer-based nanofluid is not only expected to present a solution to the challenge of sand production in the oil and gas industry but also to provide operational sustainability.

Using of artificial neural networks and different evolutionary algorithms to predict the viscosity and thermal conductivity of silica-alumina-MWCN/water nanofluid

This study predicts the parameters such as viscosity and thermal conductivity in silica-alumina-MWCN/water nanofluid using the artificial intelligence method and using design variables such as solid volume fraction and temperature. In this study, 6 optimization algorithms were used to predict and numerically model the μnf and TC of silica-alumina-MWCNT/water-NF. In this study, six measurement criteria were used to evaluate the estimates obtained from the coupling process of GMDH ANN with each of these 6 optimization algorithms. The results reveal that the influence of the φ is notably higher on both μnf and TC with values of 0.83 for μnf and 0.92 for TC, while Temp has a relatively weaker impact with -0.5 for μnf and 0.38 for TC. Among various algorithms, the coupling of the evolutionary algorithm NSGA II with ANN and GMDH performs best in predicting μnf and TC for the NF, with a maximum margin of deviation of -0.108 and an R2 evaluation criterion of 0.99996 for μnf and 1 for TC, indicating exceptional model accuracy. In the subsequent phase, a meta-heuristic Genetic Algorithm minimizes μnf and TC values. Four points (A, B, C, and D) along the Pareto front are selected, with point A representing the optimal state characterized by low values of φ and Temp (0.0002 and 50.8772, respectively) and corresponding target function values of 0.9988 for μnf and 0.6344 for TC. In contrast, point D represents the highest values of φ and Temp (0.49986 and 59.9775, respectively) and yields target function values of 2.382 for μnf and 0.8517 for TC. This analysis aids in identifying the optimal operating conditions for maximizing NF performance.

Thermal and hydraulic performance of ZnO/EG based nanofluids in mini tubes of different diameters: An experimental investigation

The present experimental study investigates the thermal and hydraulic performance of Ethylene Glycol (EG)-based ZnO nanofluids (NFs) in circular minichannel test sections, each of 330 mm in length and 1.0-2.0 mm inner diameters. The experiments were conducted under steady-state constant heat flux and laminar flow conditions. The stable ZnO/EG-based NFs were synthesized using a standard two-step method in varying nanoparticles (NPs) loadings (0.012-0.048 wt%). The morphological characteristics, crystal structure, and specific surface area (SSA) showed that the NPs were sized in nm, possessing excellent crystal structure and enhanced surface area. Thermal conductivity (TC) and viscosity (VC) of the NFs were examined in the 20-60 °C temperature range. Both TC and VC possessed an increasing trend with the rise in concentration of the NPs. However, with the temperature rise, TC increased while the VC decreased and vice versa. The highest enhancements in TC and VC were 14.38 % and 15.22 %, respectively, at 40 °C and 0.048 wt% of NPs loading. The highest enrichment recorded in the local and average heat transfer coefficient (HTC) were 14.80 % and 13.48% in a minichannel with 1.0 mm inner diameter, respectively. It was directly proportional to the NPs loading and volume flow rate of the NFs. The friction factor was also directly proportional to the test section's inner cross-sectional area, while the pressure gradient showed an inverse behavior. An inverse relationship was recorded for the volume flow rate of the NFs and vice versa. Maximum friction factor and the pressure drop for all three minichannel test sections were recorded as 34.58 % and 32.16 %, respectively. The well-known Shah correlation predicted the local and average HTC within ±15.0 %, while the friction factor and the pressure gradient were well predicted by the Darcy correlation within the ±10.0 % range.

Numerical modeling of a MHD non-linear radiative Maxwell nano fluid with activation energy

The present research explores linear as well as nonlinear radiation patterns based on the MHD non-Newtonian (Maxwell) nanofluid flow having Arrhenius activation energy. This study's core focus is MHD properties in non-Newtonian fluid dynamics and boundary layer phenomena analysis. It initiates with time-dependent equations, employing boundary layer approximations. Extensive numerical computations, executed with custom Compact Visual Fortran code and the EFD method, provide profound insights into non-Newtonian fluid behavior, revealing intricate force interactions and fluid patterns. To check the stability of the solution, a convergence and stability analysis is performed. With the values of ΔY = 0.25, Δτ = 0.0005, and ΔX = 0.20; it is found that the model convergence occurs to the Lewis number, Le > 0.016 as well as the Prandtl number, Pr > 0.08. In this context, investigating non-dimensional results that depend on multiple physical factors. Explanation and visual representations of the effects of different physical characteristics and their resultant temperatures, concentrations, and velocity profiles are provided. As a result of the illustrations, the skin friction coefficient and Sherwood number, which are calculated, as well as Nusselt values, have all come up in discussion. Additionally, detailed representations of isothermal lines and streamlines are implemented, and it is pointed out that the development of these features occurs at the same time as Brownian motion. Furthermore, the temperature field for Maxwell fluid is modified due to the impression of chemical reaction as well as the Dufour number (Kr and Du). Our research demonstrates the superior performance of non-Newtonian solutions, notably in cases involving activation energy and nonlinear radiation. This paradigm shift carries significant implications. In another context, the interplay between Maxwell fluid and nonlinear radiation is notably affected by activation energy, offering promising applications in fields like medicine and industry, particularly in groundbreaking cancer treatment approaches.

Energy and exergy studies on the receiver models with materials and heat transfer fluids

This work focuses on meeting the growing demand in solar energy conversion for small-scale applications. In this regard, experimental and CFD research has been done to examine the thermal performance (energy and exergy efficiencies) of a dish collector (reflector and receiver) system with different receiver models. In this work, receivers with uniform absorber cavity areas having cylindrical and hemispherical shapes were modeled for length-to-diameter ratios (L/D) of 1.5, 1, and 0.75. The modeled receivers having coil tube configurations concerning the geometrical shape of the models were tested with two different materials of aluminum and copper. The performance of the receiver models was compared by experimental and CFD methods for the average solar direct normal irradiations of 860 W/m2 by the dish reflector area of almost 12 m2. The supplied average heat flux by the dish reflector was 7 kW/m2 at the absorbing area of the cavity receivers. The energy and exergy efficiencies from the experimental and CFD analyses on the models were determined based on the cavity surface temperature distribution of receiver walls, and heat gain for different mass flow rates by the heat transfer fluid water. The receiver with copper material and L/D ratio of 0.75 has been found as the optimized one among all other models with the maximum obtained energy and exergy efficiencies of 73.64 and 7.31% when water is used as the heat transfer fluid. The performance of the optimized receiver model was also validated with a few other heat transfer fluids such as SiC + water nanofluid and therminol VP1.

Numerical study for bioconvection peristaltic flow of Sisko nanofluid with Joule heating and thermal radiation

Present work describes the peristaltic flow of Sisko nanomaterial with bioconvection and gyrotactic microorganisms. Slip conditions are incorporated through elastic channel walls. Additionally, we considered the aspects of thermal radiation and viscous dissipation. Further ohmic heating features are also present in the thermal field. Buongiorno's nanofluid model comprising thermophoresis and Brownian movement is taken. The lubrication approach is utilized for the simplification of the problem. Being highly coupled and nonlinear, the resulting system of equations must be solved numerically using the NDSolve technique and bvp4c via Matlab. Velocity, concentration, thermal field and motile microorganisms. are addressed graphically.

Three dimensional study for entropy optimization in nanofluid flow through a compliant curved duct: A drug delivery and therapy application

This research explores the three-dimensional characteristics of nanofluid dynamics within curved ducts, in contrast to earlier studies that mainly focus on two-dimensional flow. By using this ground-breaking method, we can capture a more accurate depiction of fluid behavior that complies with the intricate duct design. In this study, we investigate the three dimensional flow and entropic analysis of peristaltic nanofluid flows in a flexible curved duct, comparing the effects of silver and copper nanoparticles. To obtain accurate results, we assume physical constraints such as long wavelength and low Reynolds number and used a perturbation technique through NDSolve commands for finding exact solutions of the obtained differential equations. A comprehensive error analysis is provided through residual error table and figures to estimate a suitable range of the physical factors. Our findings indicate that the velocity of the nanofluid is directly proportional to the elasticity of the walls, while the mass per unit volume inversely affects velocity. We show that reducing the aspect ratio of the duct rectangular section can decrease entropy generation by raising magnitudes of damping force exerted by to the flexible walls of the enclosure. Additionally, using a larger height of the channel than the breadth can reduce stream boluses. The practical implications of this study extend beyond turbines and endoscopy to biomedical processes such as drug delivery and microfluidic systems.

Analysis of the mechanism of enhanced heat transfer by nanofluids

CONTEXT

Industrial production and humans cannot exist without energy, but the low efficiency of the heat transfer in the excessive use of energy is the most significant aspect of energy saving and emission reduction. Molecular dynamics simulation methods are devoted to simulate the heat transfer efficiency of a nanofluid system with different particle sizes, and the heat transfer enhancement mechanism of the nanofluid is simulated and studied from a microscopic perspective. The analysis showed that as nanoparticle size increases, the thermal conductivity of the Al-Ar nanofluid tends to decrease, but all of them are still higher than the thermal conductivity of the liquid argon system. According to the findings of the density and radial distribution function analyses, it can be seen that the microstructure of the system changes after putting solid nanoparticles to the original fluid. This alteration in the system's microstructure is the primary component responsible for the increased heat transfer efficiency of nanofluids.

METHODS

In this paper, based on the theory of molecular dynamics, the simulation calculations were mainly performed using LAMMPS software, which is a commonly used open source computational program in the field of MD simulation research. VMD is used for visualization and analysis. The Lennard-Jones potential function was used in the simulation to accurately describe the forces acting between the atoms.

Melting heat transfer analysis in magnetized bioconvection flow of sutterby nanoliquid conveying gyrotactic microorganisms

In biotechnology and biosensors bioconvection along with microorganisms play a important role. This article communicates a theoretic numerical analysis concerning the bioconvective Sutterby nanofluid flow over a stretchable wedge surface. Bioconvection is a remarkable occurrence of undercurrents fluid that is produced owing to the turning of microbes. It is considered for hydrodynamics unsteadiness and forms classified in interruption of inclined swimming microbes. Bioconvection is perceived practically in many uses for example pharmaceutical products, bio sensing applications, biomedical, bio-micro systems, biotechnology advancements and refining of mathematical models. Additionally, unsteady parameter influences are taken into account. Furthermore, no mass flux as well as heat sink/source consequences are measured in existing analysis. The similarity transformation are established for the non-linear PDEs of microorganism's field, nanofluid concentration, energy, momentum and mass for bioconvection flow of Sutterby nanofluid. Then, altered non-linear ODEs are resolved by utilizing the bvp4c technique. Moreover, nanofluids are declining in thermal and concentration fields and the greater number of Peclet number declines the field of microorganisms. Acquired numerical data displays that temperature field of nanofluid increases for more thermophoretic and unsteady parameters.

An experimental investigation on the nanofluids in a cavity under natural convection with and without the rotary magnetic field

This experimental study involves the use of two distinct categories of nanofluids, namely ferromagnetic and non-magnetic, within a square cavity that facilitates natural convection. There are five distinct concentrations associated with each nanofluid. Natural convection arises as a consequence of the thermal gradient between the opposing surfaces of the copper cavity, which has a thickness of 18 gauge. The purpose of utilizing the constructed electro-magnet assembly is to investigate the impact of the rotational magnetic field on the process of heat transfer. The manipulation of magnetic strength can be achieved by regulating the magnetic power and direct current (DC) power. The manipulation of the electromagnet's spin can also be regulated. In the context of a rotational magnetic field, it is seen that the magnetic flux undergoes a transition from a positive value to an almost identical negative value throughout a full rotation. The optimal heat transfer performance is observed at a nanoparticle concentration of 0.1% by volume (φ) for both nanofluids. In the absence of a rotating magnetic field, the ferromagnetic nanofluid exhibited superior performance. When the Rayleigh number (Ra) is one order smaller than the critical Rayleigh number value, the heat transfer performance is often superior with nanofluid compared to demineralized water.

Recent progress on flat plate solar collectors equipped with nanofluid and turbulator: state of the art

This paper reviews the impacts of employing inserts, nanofluids, and their combinations on the thermal performance of flat plate solar collectors. The present work outlines the new studies on this specific kind of solar collector. In particular, the influential factors upon operation of flat plate solar collectors with nanofluids are investigated. These include the type of nanoparticle, kind of base fluid, volume fraction of nanoparticles, and thermal efficiency. According to the reports, most of the employed nanofluids in the flat plate solar collectors include Al2O3, CuO, and TiO2. Moreover, 62.34%, 16.88%, and 11.26% of the utilized nanofluids have volume fractions between 0 and 0.5%, 0.5 and 1%, and 1 and 2%, respectively. The twisted tape is the most widely employed of various inserts, with a share of about one-third. Furthermore, the highest achieved flat plate solar collectors' thermal efficiency with turbulator is about 86.5%. The review is closed with a discussion about the recent analyses on the simultaneous use of nanofluids and various inserts in flat plate solar collectors. According to the review of works containing nanofluid and turbulator, it has been determined that the maximum efficiency of about 84.85% can be obtained from a flat plate solar collector. It has also been observed that very few works have been done on the combination of two methods of employing nanofluid and turbulator in the flat plate solar collector, and more detailed work can still be done, using more diverse nanofluids (both single and hybrid types) and turbulators with more efficient geometries.

Dynamics of chemically reactive Carreau nanomaterial flow along a stretching Riga plate with active bio-mixers and Arrhenius catalysts

Nanomaterial flow has fascinated the concern of scientists across the globe due to its innovative applications in various manufacturing, industrial, and engineering domains. Bearing aforementioned uses in mind, the focal point of this study is to examine the Carreau nanofluid flow configured by the Riga surface with Arrhenius catalysts. Microorganisms are also suspended in nanofluid to strengthen the density of the regular fluid. Time-dependent coupled partial differential equations that represent the flow dynamics are modified into dimensionless patterns via appropriate non-dimensional variables, and handled through an explicit finite difference approach with stability appraisal. The performances of multiple flow variables are examined graphically and numerically. Representation of 3D surface and contour plots for heat transportation and entropy generation are also epitomized. The findings express that the modified Hartmann number strengthens the motion of nanomaterial. Reverse outcomes for heat transport rate and entropy are seen for the radiation variable. Concentration diminishes for chemical reaction variable. Activation energy enhances the concentration of nanomaterial, whereas reduction happens in the movement of microbes for bio-Lewis number. Greater Brinkman variable heightens the entropy.

Effervescent tablet-assisted deep eutectic solvent based on magnetic nanofluid for liquid phase microextraction of tyrosine kinase inhibitors in plasma samples by high-performance liquid chromatography

BACKGROUND

Tyrosine kinase inhibitors (TKIs) are efficient anti-cancer drugs. The analysis of TKIs in the treatment of cancer is important to achieve the highest anti-cancer effects with minimal toxicities. Herein, we report an efficient effervescent tablet-assisted deep eutectic solvent based on nanofluid (ETA-DES-NF) combined with HPLC-UV for the determination of three anti-cancer drugs (erlotinib, imatinib, and nilotinib) in human plasma samples.

METHODS

In this method, a magnetic nanofluid composed of deep eutectic solvent (DES) and Fe3O4@SiO2 nanoparticles was used as an extraction solvent. The deep eutectic solvent acted as a carrier and stabilizer for Fe3O4@SiO2 nanoparticles. A tablet was used in the nanofluid for dispersion. The effervescent tablet was implemented to generate in situ CO2 and provide the effective dispersion of the sorbent into the sample solution for diminishing the extraction time and improving the extraction efficiency. Moreover, the magnetic nanofluid enhanced phase separation efficiency without centrifugation to collect the organic solvent.

RESULTS

The synthesized nanofluid was characterized by Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), energy-dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), and vibrating sample magnetometry (VSM). The impact of main parameters, including the type and volume of DES, the composition of the tablet, the composition of the nanofluid and the composition of eluent, were optimized. According to the optimized conditions, the limits of detection (LODs) and the limits of quantitation (LOQs) were from 0.5-0.8 to 1.5-2.4 μg L-1 for imatinib, erlotinib, and nilotinib, respectively. The intra-day and inter-day relative standard deviations (RSD% n = 5) were determined to be 3.1-5% and 6.4-7.5%, respectively.

CONCLUSIONS

The developed method displayed high sensitivity, low consumption of solvent, low cost, simplicity, high recoveries, short extraction time, and good repeatability for determination of three anti-cancer drugs in human plasma samples.

Heat and mass transfer by stirring nanofluids with the presence of renewable solar rays, Joule heating, and entropy procreation

Renewable solar radiation is the foremost energy source because of its accessibility, natural replication, and sustainability in an environmentally safe manner. Here, researchers intended to inspect the heat and mass transfer via nanofluid transported on an inclined permeable expanded sheet in the presence of solar thermal radiation without any barrier. Mainly, the formation of non-recovery energy called entropy and Joule heating are also weighed. The guiding non-linear partial differential equations were transformed into systems of non-linear higher-order ordinary differential equations by felicitous similarity transformation. They are solved by the prevalent technique called the Homotopy Analysis Method, which is executed by the BVPh2.0 package in Mathematica 12.1 software. Comparisons with preceding published articles confirm the method's validity and accent its admirable uniformity. Afterward, the magnetic field interaction delays the mobility of nanofluid while increasing the magnitude of local skin friction and temperature distribution. By intensifying the thermal radiation parameter and Eckert number, the temperature and entropy production escalated. Furthermore, the heat transfer by convective surpasses that of conductive owing to the particles' Brownian motion. Thermophoresis established surplus tiny-particles concentration. Heat transfer from solar radiation in moving nanofluids has been applicable for cooking, heating water, and producing electricity.

Insight into the enhancement effect of amino functionalized carbon nanotubes on the H2S removal performance of nanofluid system

By constructing nanofluid system, trace functionalized nanoparticles can significantly enhance the absorption performance of basic liquid. In this work, amino functionalized carbon nanotubes (ACNTs) and carbon nanotubes (CNTs) were introduced into alkaline deep eutectic solvents to build nanofluid systems and used for the dynamic absorption of H2S. The experiment results showed that the introduction of nanoparticles can significantly enhance the H2S removal performance of original liquid. When performing H2S removal experiments, the optimal mass concentrations of ACNTs versus CNTs were 0.05 % and 0.01 %, respectively. The characterization showed that the surface morphology and structure of the nanoparticles unchanged significantly during the absorption-regeneration process. A double mixed gradientless gas-liquid reactor was used to explore the gas-liquid absorption kinetics characteristics of the nanofluid system. It was found that the gas-liquid mass transfer rate increased significantly after the addition of nanoparticles. The highest total mass transfer coefficient of the nanofluid system of ACNTs was increased to more than 400 % of the value before the addition of nanoparticles. The analysis showed that the shuttle effect and hydrodynamic effect of nanoparticles play important role in the process of enhancing gas-liquid absorption, and the amino functionalization enhanced the shuttle effect of nanoparticles significantly.

Heat transfer study and optimization of nanofluid triangular cavity with a pentagonal barrier by finite element approach and RSM

Nowadays, several engineering applications and academic investigations have demonstrated the significance of heat transfers in general and mixed convection heat transfer (MCHT) in particular in cavities containing obstacles. This study's main goal is to analyze the MCHT of a nanofluid in a triangular cavity with a pentagonal barrier using magneto hydrodynamics (MHD). The cavity's-oriented walls are continuous cold temperature, whereas the bottom wall of the triangle and all pentagonal obstacle walls are kept at a constant high temperature. For solving governing equations, we utilized the Galerkin's finite element approach. Four dimensionless factors, Richardson number (0.01 ≤ Ri ≤ 5), Reynolds number (10 ≤ Re ≤ 50), Buoyancy ratio (0.01 ≤ Br ≤ 10) and Hartmann number (0 ≤ Ha ≤20) are examined for their effects on streamlines, isotherms, concentration, velocity, and the Nusselt number. Also, with the help of Taguchi method and Response Surface Method (RSM) the optimization of the studied dimensionless parameters has been done. The optimum values of Ri, Re, Ha and Br are obtained 4.95, 30.49,18.35 and 0.05 respectively. Ultimately, a correlation has been extracted for obtaining the optimum average Nusselt number (Nu) in mentioned cavity.

A critical review of concentrating and nanofluid-based hybrid PV/T systems utilizing beam splitting technique: Progress, challenges, and way forward

The utilization of nanofluids and concentrating techniques in solar photovoltaic/thermal (PV/T) systems, to enhance the overall system performance, have been analysed explicitly in the last few years. More recently, nanofluid-based optical filters were integrated with photovoltaic (PV) systems for the effective utilization of solar spectrum, i.e. below and beyond the band-gap of PV cells. Therefore, to quantify the recent progress of spectral beam splitting-based hybrid PV/T systems (BSPV/T), a systematic review has been presented therein. The study highlights the technological and scientific advancement in BSPV/T in last two decades. Linear Fresnel mirror-based BSPV/T showed significant enhancement in the overall performance of hybrid PV/T system. Recently developed nanoparticle-laden BSPV/T system shows significant improvement in overall thermal efficiency of BSPV/T system, thanks to decoupling of thermal system and PV cell. Further, economic analysis, carbon footprint, and environmental assessment of BSPV/T are also discussed briefly. At the last, the authors have made an effort to identify the challenges, limitations, and prospective paths for future research in BSPV/T systems.

Advances of nanofluid in food processing: Preparation, thermophysical properties, and applications

Nanofluids (NFs) are homogenous mixes of solid nanoparticles as well as base fluid in which the size of the solid nanoparticles (NPs) is smaller than 100 nm. These solid NPs are intended to enhance the thermophysical characteristics and heat transmission attributes of the base fluid. The thermophysical characteristics of nanofluids are influenced by their density, viscosity, thermal conductivity and specific heat. These colloidal solutions of nanofluids include condensed nanomaterials such as nanoparticles, nanotubes, nanofibers, nanowires, nanosheets, and nanorods. The effectiveness of NF is significantly influenced by temperature, shape, size, type, as well as the concentration of NPs or the thermal characteristics of the base fluid. Compared to oxide NPs, metal NPs have superior thermal conductivity. Many of these investigations revealed that hybrid NFs had enhanced thermal conductivity than traditional ones. Thermal conductivity values are reduced by the formation of clusters in nanofluid. When compared to spherically formed nanoparticles, cylindrically shaped nanoparticles produced superior outcomes. In food industries, NFs could be used in various unit operations where heat needs to be transported from a heating or cooling medium to food product using a heat exchanger, as in freezing, pasteurization, refrigeration, drying, thawing, sterilization, and evaporation. The objective of this review is to analyze the recent developments in the research of nanofluids including innovative production methods, stability assessment, enhancement approaches, and thermophysical properties of nanofluids.

Recent advancements in flat plate solar collector using phase change materials and nanofluid: a review

Solar energy has emerged as one of the most promising sources of renewable energy to replace the current energy market. Flat plate solar collectors (FPSC) not only are one of the easiest collectors to produce and work with but also are cheap and economical. Due to this, extensive research has been done on FPSC to improve its efficiency and reliability. Some of the methods include using nanofluids to improve the heat transfer process, phase change materials to increase and maintain stable temperatures, or integrating the collector with additional components. This review article focuses on analyzing the recent improvements in FPSC, with a particular emphasis on the achieved efficiencies and temperatures in the studies. Additionally, it is aimed at updating the information in the current field, providing a comprehensive overview of the advancements in FPSC technology. Furthermore, the article explores the combined effects of nanofluids and phase change materials in photovoltaic/thermal (PVT) collectors, considering the resulting temperature enhancements. By critically evaluating the efficiency improvements and temperatures achieved through these approaches, this article is aimed at providing valuable insights into the state-of-the-art of FPSC and their potential for advancing solar energy utilization.

Analysis of the Time-Dependent magnetohydrodynamic Newtonian fluid flow over a rotating sphere with thermal radiation and chemical reaction

This article presents the magnetohydrodynamic (MHD) flow of a nanoliquid due to a rotating sphere at a stagnation point. The flow is considered to be influenced by the magnetic field, dissipative, thermally radiative, and chemically reactive. Also, the thermophoretic and Brownian motion influences are taken into consideration. Some restrictions in the present analysis are taken: like there is no-slip and convective conditions, joule heating, Hall effects and buoyancy-driven. The solution of the present analysis is derived through the homotopy analysis method (HAM). The significance of several physical parameters on velocities, thermal and concentration profiles are shown with the help of Figures. Also, the significance of different physical factors on skin frictions, local Nusselt number and Sherwood number are demonstrated with the help of Tables. The outcomes show that the Nusselt number is lower for the larger Brownian motion parameter, Eckert number, and thermophoretic parameter, while the increment in the thermal radiation parameter augmented the Nusselt number. It is established that the increasing rotation, magnetic and positive constant parameters have increased the velocity profiles along the x-direction while reducing the velocity profiles along the z-direction of the nanoliquid flow. The increasing positive constant parameter reduces the thermal graph of the nanoliquid flow. Furthermore, the intensifying Eckert number, thermophoresis, Brownian motion, and thermal radiation factor have escalated the thermal profiles of the nanoliquid flow.

Evaluation of AGM and FEM method for thermal radiation on nanofluid flow between two tubes in nearness of magnetism field

The nanofluid flow through two orbicular cylinders is explored utilizing the overall Koo-Kleinstreuer-Li (KKL) model within the nearness of a magnetic field. The impact of thermal radiation is considered in the energy equation. The novelty of this study is examining convective heat transfer for nanofluid flow between two flat tubes with the Akbari-Ganji method and Finite Element Techniques to examine the heat flux field by implies of 2D forms of temperature and velocity at unprecedented Reynolds numbers. The approaches for solving ODEs are AGM and FEM. Semi-analytical methods are assessed for specific parameters of aspect ratio, Hartmann number, Eckert number, and Reynolds quantity with various values. Adding Ha, Ec, and G causes the temperature gradient to grow, while adding the Reynolds number causes it to decrease. As the Lorentz forces increase, the velocity decreases; nevertheless, as the Reynolds number rises, the velocity decreases. With the reduction of the fluid's dynamic viscosity, the temperature will decrease, which will decrease the thermal trend along the vertical length of the pipes.

Performance study on a solar concentrator system for water distillation using different water nanofluids

The rapid growth in the world-population urges the need for potable water in various regions, especially in hot and dry regions. The main challenge in the productivity of potable water is the cost and availability of water sources. Thus, it is crucial to develop effective methods to overcome this global need. Utilizing solar power is proven to be a promising path to implementing thermal solar radiation in solar distillation applications. This work investigates the effectiveness of using concentrated solar power to irradiate heat exchange to evaporate water in a receiver, which will be collected as pure water in a condenser later. The thermal performance of the proposed model and its productivity are tested experimentally by using tap water only, and the test was repeated twice using two nanofluids namely, (aluminium oxide (Al2O3) and zinc oxide (ZnO)). The results showed that using (Al2O3) has a superior influence on the productivity of the solar unit, where the productivity is increased by 43.53% and 21.89% when compared to tap water and zinc oxide (ZnO) nanofluid respectively. The thermal efficiency of the solar unit was also increased by 9.91% (maximum) when using (aluminium oxide (Al2O3) as a working fluid compared to tap water. The model has simple components and is easy to install with a compact size, which can be developed be utilized in urban and desert areas.

A review of different twisted tape configurations used in heat exchanger and their impact on thermal performance of the system

Heat transfer in water with the help of solar energy is an effective way to harness renewable energy and reduce reliance on non-renewable sources of energy. The utilization of turbulent promoters is an efficient solution to ameliorate the performance of heat exchangers (HE). The current work summarizes the experimental and numerical behaviour of HE reported in the literature, including the thermal examinations of HT and fluid flow characteristics with various turbulent promoters and tube arrangements. This article reviews multiple studies in which different twisted tape (TT) geometry enhances the HT rate in various HE tubes. The current work also compares the thermal performance (η) of TT configurations in HE tubes using correlations developed by different investigators. Maximum heat transfer and minimum friction factor concerning fluid utilized in the system may also produce the optimal form for twisted tapes.

Examination of bio convection with nanoparticles containing microorganisms under the influence of magnetism fields on vertical sheets by five-order Runge-Kutta method

In this paper, we analyzed vertical bio convection in nanofluids containing microorganisms. The novelty of this article is the numerical and analytical investigation of magnetic flow, radiation heat transfer, and viscous dissipation on bio convective fluid flow using the Five-order Runge-Kutta technique. Utilizing similitude parameters, determined ODE (ordinary differential equation) equations from partial differential equations for continuity, momentum, energy, and nanofluid concentration. Five-order Runge-Kutta was then used to solve the equations. The results show that it has a more significant influence on and then and. In addition, it exerts a force on neighboring particles, which causes them to shift from a hot zone to a great region. The density of microorganisms inside a part rises as it grows; when Le rises and Ha remains the same, x(ξ) falls, and When Ha rises, and Le remains the same, x(ξ) fall.

A design of neuro-computational approach for double-diffusive natural convection nanofluid flow

The artificial intelligence based neural networking with Back Propagated Levenberg-Marquardt method (NN-BPLMM) is developed to explore the modeling of double-diffusive free convection nanofluid flow considering suction/injection, Brownian motion and thermophoresis effects past an inclined permeable sheet implanted in a porous medium. By applying suitable transformations, the PDEs presenting the proposed problem are transformed into ordinary ones. A reference dataset of NN-BPLMM is fabricated for multiple influential variants of the model representing scenarios by applying Lobatto III-A numerical technique. The reference data is trained through testing, training and validation operations to optimize and compare the approximated solution with desired (standard) results. The reliability, steadiness, capability and robustness of NN-BPLMM is authenticated through MSE based fitness curves, error through histograms, regression illustrations and absolute errors. The investigations suggest that the temperature enhances with the upsurge in thermophoresis impact during suction and decays for injection, whereas increasing Brownian effect decreases the temperature in the presence of wall suction and reverse behavior is seen for injection. The best measures of performance in form of mean square errors are attained as 7.1058 × 10 - 10 , 2.9262 × 10 - 10 , 1.1652 × 10 - 08 , 1.5657 × 10 - 10 and 5.5652 × 10 - 10 against 969, 824, 467, 277 and 650 iterations. The comparative study signifies the authenticity of proposed solver with the absolute errors about 10^-7 to 10^-3 for all influential parameters results.

Thermohydraulic performance investigation of a heat exchanger with combined effect of ribbed insert and Therminol55/MXene+ Al2O3 nanofluid: A numerical two-phase approach

MXene-based nanofluids are novel trends with improved dispersion stability and thermophysical characteristics over previously established nanofluids. In the present work, the thermohydraulic characteristics of a double pipe heat exchanger (DPHEX) with a Therminol55(TH55)/MXene + Al₂O₃ nanofluid and various geometrically shaped (triangular, rectangular) ribbed twisted tape (TT) inserts are numerically investigated using the ANSYS Fluent interface. A counter flow arrangement with three different types of inserts (RRTT, TRTT, TT) and TH55/MXene + Al₂O₃ nanofluid at 0.20 wt% are studied inside the heat exchanger. Adding ribbed inserts to the conventional TT insert enhances the turbulence intensity by creating extra vortices. The thermal boundary layer grows thinner due to increased axial and radial velocity. Due to the substantial flow obstruction, adding ribs increases the overall pressure drop between the inlet and outlet. The maximum increase in Nu is 11.04 % using nanofluid instead of water, whereas the combination of insert and nanofluid exhibited up to 105 % enhancement for rectangular-ribbed TT compared to the plain tube. Nevertheless, the pressure decrease is found to be maximum in rectangular-ribbed TT because of significant flow disruption. This was likewise true with triangular-ribbed TT and TT insert. According to the PEC assessment, the RRTT insert had a maximum PEC value of 1.67 greater than TRTT and traditional TT for both TH55 and nanofluid flowing inside the tube. To summarize, the combination of TH55/MXene + Al₂O₃ RRTT insert may be a promising choice for improving heat exchanger performance in a new generation efficient thermal system.

Experimental study of thermal characteristics of ZrO2/EG nanofluid for application of heat transfer

In thermal management system, nanofluids will act as robust elements in future for coolants. Nanofluids have remarkable potential during the heat transfer increase reported by researchers from all over the world. Nanofluids have attracted many researchers, and there have been tremendous advances because of the high thermal characteristics and possible applications in certain areas such as the transport sector, aerospace, medical regions, and microelectronics. This current study reports on the thermal characteristics of nanofluid based on ZrO₂/EG. The nanoparticles are characterized by XRD and SEM techniques. Nanofluid was prepared by a two-step method in ethylene glycol (EG) using ultra sonication. The thermal conductivity of ZrO₂/EG nanofluid was investigated experimentally at various volume concentrations (0.02-0.1vol. %) and temperature range between 35 and 55 °C. The enhancement in thermal conductivity was observed to be 26.2% at 0.1 vol. % which exhibits superior performance as compared to base fluid (EG). The results of the experiment were compared with the three most often utilized model in the literature. The behavior of ZrO₂/water-based nanofluid thermal conductivity, viscosity, and stability in various concentrations was studied.

The use of a hybrid photovoltaic/thermal (PV/T) collector system as a sustainable energy-harvest instrument in urban technology

A solar cell is a converter that uses semiconductor material to convert photon energy packets. The electrons located in the material's crystalline structure can escape from the bonds between their atoms and generate electricity. Photovoltaic (PV) solar cells can work via diffuse radiation and have the highest efficiency among other types of solar cell generation. Photovoltaic Thermal Collector (PVT)-based active cooling technology makes it possible to increase the efficiency of PV solar cells and to generate thermal energy at the same time through the direct conversion of solar radiation. Therefore, this study modeled various riser configurations on PVT collectors to cool PV solar cells using water heat transfer fluids and nanofluids: TiO₂, SiO₂, and Al₂O₃. The mass flow rates were varied. An ANSYS models a simulation of the heat transfer phenomenon between the PV cell layer and the fluid. Only the heat transfer phenomenon generated from the natural convection of the PV cell layer is studied using steady-state thermal ANSYS with simulated controlled conditions. The radiation intensity of 1000 W/m² has the photovoltaic solar cells with the most negligible efficiency. The semicircular collector configuration with water at a mass flow rate of 0.5 kg/s demonstrated the highest electrical efficiency, achieving 11.98%.

Intensification of CO2 absorption and desorption by metal/non-metal oxide nanoparticles in bubble columns

In this study, four different metal/non-metal oxide nanoparticles including CuO, Fe₃O₄, ZnO, and SiO₂ were employed to improve CO₂ absorption and desorption in methyl diethanolamine (MDEA)-based nanofluid. CO₂ absorption experiment with various nanofluids was done in a bubble column reactor at ambient temperature. Also, CO₂ stripping experiments for all nanofluids were done at 60 and 70 °C. The influence of nanoparticles type, nanoparticle concentration, and the stability of nanoparticles were studied on both CO₂ absorption and stripping. The obtained results revealed that Fe₃O₄ nanoparticles at 0.01 wt.% concentration had the best influence on CO₂ absorption and it improved the CO₂ loading up to 36%. Also, CO₂ stripping experiments for all nanofluids were done at 60 and 70 °C. The desorption experiments illustrated that metal oxide nanoparticles can be more efficient in improving CO₂ desorption. In CO₂ desorption, the CuO nanoparticles at 0.05 wt.% had higher efficiency, and enhanced CO₂ concentration at outlet gas phase up to 44.2 vol.% at 70 °C. Finally, as an indication, the chemical stability of Fe₃O₄ NPs under optimum operational conditions was studied using XRD analysis and the result showed that the proposed operational condition did not have any negative effect on the chemical nature of Fe₃O₄ NPs.

Simultaneous effects of MWCNT and SiO2 on the rheological behavior of cooling oil and sensitivity analysis

Many scholars are attracted to nano-lubricants due to their unique properties. In the present study, the rheological behavior of a new generation of lubricants has been investigated. SiO₂ nanoparticles with an average diameter of 20-30 nm along with MWCNT with an internal diameter of 3-5 nm and the external diameter of 5-15 nm has been dispersed in 10W40 engine oil as base-lubricant and MWCNTs-SiO2 (20%-80%)/10W40 hybrid nano-lubricant has been produced. Nano-lubricant behavior agrees with the Herschel-Bulkley model and is of Bingham pseudo-plastic type below 55 ° C . Also, in the temperature of 55 ° C , nano-lubricant behavior has changed to Bingham dilatant. The viscosity is increased by 32% in the proposed nano-lubricant compared to base lubricant (Dynamics Viscosity Enhancement). Finally, a new correlation with a precision index of R-squared >0.9800, Adj. R-squared >0.9800, and the maximum margin of deviation of 2.72% has been presented, increasing the applicability of this nano-lubricant. Eventually, the sensitivity analysis of nano-lubricant has been conducted, studying the comparative effect of volume fraction and temperature on viscosity.

Double-diffusive stagnation point flow over a vertical surface with thermal radiation: Assisting and opposing flows

In numerous industrial procedures, the main concern of design engineers is ensuring adequate heat and mass transfer, such as in the heating and cooling practices of solar water heaters, geothermal systems, extrusion of metal, insulation of buildings, electronics, turbines, aerodynamics, electronics, paper manufacturing, and glass fiber production. The unsteady double-diffusive mixed convection flow of boundary layer nanofluids above a vertical region near stagnation point flow is developed and examined here. The Brownian motion and thermophoresis effects are incorporated by using Buongiorno's model. In the thermal energy equations, diffusion of regular and cross types is also used. By the use of the local similarity method along with suitable similarity transformations, nonlinear unsteady partial differential equations are converted to nonlinear ordinary differential equations and are numerically solved by the Keller-Box method. The investigation expresses that these profiles of solute concentration and nanoparticle concentration, temperature, and velocity in their boundary layers, respectively, depending on several parameters. A graphic analysis of all these parameters' possessions on nature's boundary layers is depicted. The highest rate of heat transfer is obtained with negligible thermophoresis effect. Furthermore, it is perceived that an increase in Nc and Nt results in a reduction in the reduced Sherwood number of nanoparticles, whereas addition results in an increase in the Nb number. There is a reverse effect on the temperature field and layer thickness for heat generation. In the wake of the above-mentioned potential applications, the current study of fluid flow has been found to be very interesting and innovative in the analysis of the influence of Brownian motion and thermophoresis effects near stagnation point flow, which will further make revolutions in industrial fields. Moreover, Buongiorno's model predicts the characteristics of double-diffusive fluids in enhancing heat transfers. This investigation has been established as a result of the numerous industrial applications mentioned above.

A novel design for solar collector used for water heating application having nanofluid as working medium: CFD modeling and simulation

A solar collector is a simple and cheap device that converts solar radiation into valuable heat energy. The thermal performance of the solar collectors can be enhanced significantly with the suspension of nanoparticles in the base fluid. A novel design for a solar-assisted water heater (SWH) is proposed in the current study, and the effect of nanofluid has been investigated on the thermal efficiency of the SWH. The use of nanofluid is one of the prominent methods in comparison to other techniques for improving the performance of solar collectors. Therefore, the base working fluid, i.e., water is mixed with the alumina nanoparticles of average particle size of 30 nm, and they are assumed to be spherical. The flow and thermal characteristics of nanofluid through the solar water heater are simulated numerically with the help of the Eulerian-Eulerian two-phase model using the finite volume method (FVM). The commercial package ANSYS Fluent, is used for modeling the problem under transient conditions with a pressure-based solver. In comparison to a conventional flat plate collector, the proposed solar water heater consists of a corrugated absorber-plate and the effect of the radius of curvature has been investigated on the heat transfer and collector efficiency. With the proposed design, the heat transfer area available with the riser tubes increases remarkably and it leads to a 43% and 14% increase in heat transfer augmentation and collector efficiency, in comparison to the conventional solar water heater.

Data on the cooling rate using nano carbon-fluid quenching medium and its effect on the hardness of S45C steel

This dataset provides the effect of cooling rate using nano-fluid quenchant. The nanofluid consists of 0.1, 0.3, and 0.5 gram of nano-sized carbon particles in 100 ml of distilled water. Pure distilled water was also used as a comparison control. The particle was produced by using planetary ball-mill at 500 rpm for 15 hours. Field-Emission Scanning Microscope (FE-SEM) and Energy Dispersive X-Ray (EDX) were also used to confirm the size, shape, and purity of the nanoparticles. These nanofluids were then applied to quench annealed S45C carbon steel samples. The samples were connected to a thermocouple with a temperature data logger to observe the cooling rate of the nano-fluid quenchant. The quenched samples were tested to get the information on the hardness of S45C carbon steel.

Entropy generation and characteristics of mixed convection in lid-driven trapezoidal tilted enclosure filled with nanofluid

The investigation of steady, incompressible, laminar mixed convective fluid flow within two different types of tilted lid-driven trapezoidal enclosures filled with nanofluid composed of water and Al₂O₃ nanoparticles has been carried out in this paper. The upper wall of the enclosure is an isothermal cold surface that travels at a constant speed, while the bottom surface of the cavity maintains a constant high temperature. Non-dimensional governing equations along with the appropriate boundary conditions are solved using Galerkin finite element technique. Parametric simulation has been conducted by varying tilt angle of the base wall from 0° to 45°, Reynolds number from 0.1 to 10³, Grashof number from 10^-2 to 10⁶, and Richardson number between 0.1 and 10 for three different cases. The streamlines and the isotherms are used to describe the fluid flow and heat transfer characteristics within the enclosure. Besides, the quantitative evaluations of thermal enhancement in terms of the average Nusselt number, average fluid temperature, and Bejan number of the enclosure are presented. Effects of base wall tilt angle and the presence of nanofluid on convection heat transmission characteristics as well as Bejan number are also explored.

Study of the performance of thermoelectric generator for waste heat recovery from chimney: impact of nanofluid-microchannel cooling system

A huge number of chimneys all over the world utilized in many industrial applications and applications like restaurants, homes, etc. contribute badly on the global warming and climate change due to their waste heat. So, in this paper, the performance of thermoelectric generator (TEG) cooled by microchannel heat spreader having nanofluid and used for waste heat recovery from vertical chimney is investigated. Using heat spreader with microchannel cooling system increases the output TEG power compared to natural convection cooling system. In this paper, the impact of microchannel sizes, using nanofluid and heat spreader with different sizes on the TEG performance and cooling, is considered. Three-dimensional mathematical models including TEG, microchannel, nanofluid, and heat spreader are presented and solved by Ansys Fluent software utilizing user-defined memory, user-defined function, and user-defined scalar. All TEG effects (Joule, Seebeck, and Thomson) are considered in TEG model. Results indicate that TEG power rises with increasing the heat spreader and microchannel sizes together. Increasing microchannel and heat spreader sizes four times of TEG size raises the TEG output power by 10%. This also achieves the maximum cooling system efficiency of 88.9% and the maximum net output power. Microchannel heat spreader cooling system raises the system (TEG power-pumping power) net power by 125.2% compared to the normal channel and decreases the required cooling fluid flow rate. Utilizing copper-water and Al₂O₃-water nanofluids rises maximally the TEG output power by 14% and 4%, respectively; however, it increases the pumping power. Moreover, using nanofluids increases the net output power at low Reynolds number and decreases it at higher Reynolds number.

Thermal analysis of different shape nanoparticles on hyperthermia therapy on breast cancer in a porous medium: A fractional model

Cancer is clearly a major cause of disease and fatality around the world, yet little is known about how it starts and spreads. In this study, a model in mathematical form of breast cancer guided by a system of (ODE'S) ordinary differential equations is studied in depth to examine the thermal effects of various shape nanoparticles on breast cancer hyperthermia therapy in the existence of a porous media with fractional derivative connection, when utilizing microwave radiative heating. The unsteady state is determined precisely using the Laplace transform approach to crop a more decisive examination of temperature dissemination of blood temperature inside the breast tissues. Durbin's and Zakian's techniques are used to find Laplace inversion. Mild temperature hyperthermia is used in the treatment, which promotes cell death by increasing cell nervousness to radiation therapy and flow of blood in tumor. In the graphical findings, we can witness the distinct behavior of hyperthermia therapy on tumor cells by applying various metabolic heat generation rates across various time intervals to attain the optimal therapeutic temperature point. Particularly, we used graphs to visualize the behavior of different Nanoparticles with different shaped during hypothermia therapy. In comparison to other nanoparticles and shapes, it demonstrates that gold nanoparticles with a platelet shape are the best option for improving heat transmission. Which assess of heat transfer up to 16.412%.