Development of thixotropic nanomaterial in fluid flow with gyrotactic microorganisms, activation energy, mixed convection

Bioconvective flow of Maxwell nanoparticles with variable thermal conductivity and convective boundary conditions

Owing to recent development in the thermal sciences, scientists are focusing towards the wide applications of nanofluids in industrial systems, engineering processes, medical sciences, enhancing the transport sources, energy production etc. In various available studies on nanomaterials, the thermal significance of nanoparticles has been presented in view of constant thermal conductivity and fluid viscosity. However, exponents verify that in many industrial and engineering process, the fluid viscosity and thermal conductivity cannot be treated as a constant. The motivation of current research is to investigates the improved thermal aspects of magnetized Maxwell nanofluid attaining the variable viscosity and thermal conductivity. The nanofluid referred to the suspension of microorganisms to ensure the stability. The insight of heat transfer is predicted under the assumptions of radiated phenomenon. Additionally, the variable thermal conductivity assumptions are encountered to examine the transport phenomenon. Whole investigation is supported with key contribution of convective-Nield boundary conditions. In order to evaluating the numerical computations of problem, a famous shooting technique is utilized. After ensuring the validity of solution, physical assessment of problem is focused. It is claimed that velocity profile boosted due to variable viscosity parameter. A reduction in temperature profile is noted due to thermal relaxation constant.

Effects of Hall Current and Viscous Dissipation on Bioconvection Transport of Nanofluid over a Rotating Disk with Motile Microorganisms

The study of rotating-disk heat-flow problems is relevant to computer storage devices, rotating machineries, heat-storage devices, MHD rotators, lubrication, and food-processing devices. Therefore, this study investigated the effects of a Hall current and motile microorganisms on nanofluid flow generated by the spinning of a disk under multiple slip and thermal radiation conditions. The Buongiorno model of a nonhomogeneous nanofluid under Brownian diffusion and thermophoresis was applied. Using the Taylor series, the effect of Resseland radiation was linearized and included in the energy equation. By implementing the appropriate transformations, the governing partial differential equations (PDEs) were simplified into a two-point ordinary boundary value problem. The classical Runge-Kutta dependent shooting method was used to find the numerical solutions, which were validated using the data available in the literature. The velocity, motile microorganism distribution, temperature, and concentration of nanoparticles were plotted and comprehensively analyzed. Moreover, the density number, Sherwood number, shear stresses, and Nusselt number were calculated. The radial and tangential velocity declined with varying values of magnetic numbers, while the concentration of nanoparticles, motile microorganism distribution, and temperature increased. There was a significant reduction in heat transfer, velocities, and motile microorganism distribution under the multiple slip conditions. The Hall current magnified the velocities and reduced the heat transfer. Thermal radiation improved the Nusselt number, while the thermal slip conditions reduced the Nusselt number.

Two-Dimensional Electromagnetohydrodynamic (EMHD) Flows of Fractional Viscoelastic Fluids with Electrokinetic Effects

The present study provides analytical and numerical solutions for an electromagnetohydrodynamic (EMHD) flow using a Caputo time-fractional Maxwell model. The flow is a typical rectangular channel flow. When the scale of the cross-stream is much smaller than the streamwise and spanwise scales, the model is approximated as a two-dimensional slit parallel plate flow. Moreover, the influence of the electric double layer (EDL) at the solid-liquid interface is also considered. The electro-osmotic force generated by the interaction between the electric field and the EDL will induce a flow (i.e., electro-osmotic flow). Due to the application of the electric field at the streamwise and the vertical magnetic field, the flow is driven by Lorentz force along the spanwise direction. Simultaneously, under the action of the magnetic field, the electro-osmotic flow induces a reverse Lorentz force, which inhibits the electro-osmotic flow. The result shows that resonance behavior can be found in both directions in which the flow is generated. However, compared with the classical Maxwell fluid, the slip velocity and resonance behavior of fractional Maxwell fluid are suppressed. In the spanwise direction, increasing the strength of magnetic field first promotes the slip velocity and resonance behavior, and then suppresses them, while in the streamwise direction, both the electro-osmotic flow and resonance behavior are suppressed with the magnetic field.

Second-order slip effect on bio-convectional viscoelastic nanofluid flow through a stretching cylinder with swimming microorganisms and melting phenomenon

The uses of nanofluid in cooling technology is growing. The nanofluid is made up of metallic and nonmetallic particles that are distributed in a base fluid. This research provides a summary of fuel cell models, uses, and how they function. Researchers have made significant contributions in the following era due to the importance of bioconvection in nanotechnology and a variety of biological systems. The idea of the recent work is to evaluate the aspects of the Cattaneo-Christov (C-C) heat and mass flux model, the second-order boundary with melting phenomenon on the bioconvective flow of viscoelastic nanofluid across a cylinder. The nature of the activation energy, thermal conductivity is also taken into account. Appropriate similarity transformations are utilized to reframe the PDEs of the modeled system into a system of ODEs. The governing equations for the renovated system of ODEs are treated by a shooting function. Here bvp4c built-in function computational tool MATLAB is used. The two-dimensional flow has ceased application in several areas, such as polymer industry, material synthesis technology, nano-biopolymer computer graphics processing, industry, mechanical engineering, airplane structures, and scientific research, which is much more useful in nanotechnology. The results of emerging important flow-field parameters are investigated with the aid of graphs and numerical results.

Effects of Variable Transport Properties on Heat and Mass Transfer in MHD Bioconvective Nanofluid Rheology with Gyrotactic Microorganisms: Numerical Approach

Rheology of MHD bioconvective nanofluid containing motile microorganisms is inspected numerically in order to analyze heat and mass transfer characteristics. Bioconvection is implemented by combined effects of magnetic field and buoyancy force. Gyrotactic microorganisms enhance the heat and transfer as well as perk up the nanomaterials’ stability. Variable transport properties along with assisting and opposing flow situations are taken into account. The significant influences of thermophoresis and Brownian motion have also been taken by employing Buongiorno’s model of nanofluid. Lie group analysis approach is utilized in order to compute the absolute invariants for the system of differential equations, which are solved numerically using Adams-Bashforth technique. Validity of results is confirmed by performing error analysis. Graphical and numerical illustrations are prepared in order to get the physical insight of the considered analysis. It is observed that for controlling parameters corresponding to variable transport properties c2, c4, c6, and c8, the velocity, temperature, concentration, and bioconvection density distributions accelerates, respectively. While heat and mass transfer rates increases for convection parameter and bioconvection Rayleigh number, respectively.

Entropy Generation in Magnetized Bioconvective Nanofluid Flow Along a Vertical Cylinder with Gyrotactic Microorganisms

This paper presents the analysis of thermal optimization in magnetic materials based on the entropy generation in a mixed convective MHD flow of an electrically conductive nano liquid having motile microorganisms together with a vertical cylinder. By using the convection boundary condition, the process of heat transport is examined in detail. With coupled linear boundary conditions the related equations (continuity, momentuum and energy) are reduced to five ODE’s. The RKF-4,5 method by shooting algorithm was employed to examine variation of physical parameters under study. The resuts of vital physical parameters on the wall friction, Nusselt number, mass flux, wall of motile microorganism flux, along with velocity profiles, temperature, concentration of nanopar-ticles, and density of motile microbes, were studied in detail. It is detected that heat transport rate is 0.81% greater for cylindrical surface compared to flat plate surface.

Fully developed Darcy-Forchheimer mixed convective flow over a curved surface with activation energy and entropy generation

BACKGROUND

Mixed convection (forced+natural convection) is frequently observed in exceptionally high output devices where the forced convection isn't sufficient to dissipate all of the heat essential. At this point, consolidating natural convection with forced convection will frequently convey the ideal outcomes. Nuclear reactor technology and a few features of electronic cooling are the examples of these processes. Mixed convection problems are categorized by Richardson number (Ri), which is the ratio of Grashof number (for natural convection) and Reynolds number (for forced convection). For buoyancy or mixed convection the relative effect can be addressed by Richardson number. Typically, the natural convection is negligible when Richardson number is less than 0.1 (Ri < 0.1), forced convection is negligible when Richardson number is greater than 10 (Ri > 10) and neither is negligible when (0.1 < Ri < 10). It might be noticed that generally the forced convection is large comparative with natural convection except in case of remarkably low forced flow velocities. The current work gives significant insights regarding dissipative mixed convective Darcy-Forchheimer flow with entropy generation over a stretched curved surface. The energy equation is developed with respect to nonlinear radiation, dissipation and Ohmic heating (Joule heating). Binary reaction via activation energy is accounted.

METHOD

Curvilinear transformations are utilized to change the nonlinear PDE's into ordinary ones. Computational outcomes are obtained via NDSolve MATHEMATICA. The results are computed and discussed graphically.

RESULTS

Velocity decays for Forchheimer number. Entropy generation enhances for diffusion parameter and chemical reaction parameter. Concentration profile reduces chemical reaction parameter and enhances for activation parameter.