Two dimensional analysis of low pressure flows in the annulus region between two concentric cylinders

Linear and Quadratic Radiation of Dynamical Non-Fourier Flux in a Disk Flow with the Suspension of Hybrid Nanoparticles

Considering putting in diverse nanoparticles to the base fluid is the latest technique to increase the thermal accomplishment of ordinary fluids. for the present investigation, the flow and heat transfer of nanofluids over a spinning disk with an invariable stretching pace is observed. The non-Fourier flux, magnetic field, and radian heat have all been paid regard to. The nanoparticle used here is Graphene with water as a base fluid. The governing equations are reshaped by utilizing Von Karman transformation and worked it out numerically via boundary value problem solver (bvp5c). We also provided some of the results with magnetic field and beside magnetic field cases and found disparity in both circumstances. Results pointed out that with little proliferation in stretching force constant, the skin friction and the local Nusselt number, the velocity in radial and axial paths improved, when the velocity in the tangential trend and the thermal boundary layer thickness reduce, significantly.

An Effect of a Porous Structure, Slip Velocity and Rosensweig’s Viscosity on the Ferrofluid Based Squeeze Film in Porous Curved Annular Plates

An endeavor has been made to analyze porous squeeze film performance in curved annular plates considering slip velocity, Kozeny-Carman’s porous structure and Rosensweig’s viscosity in Shliomis model-based magnetic fluid lubrication. The globular sphere model of Kozeny-Carman for porous facing is adopted here. An extension of the Einstein’s viscosity for ferrofluid proposed by Rosensweig is considered here to improve the viscosity of ferrofluid for the Shliomis model, while Beavers and Joseph’s slip model is used for evaluating the slip effect. The pressure and load lifting capacity in dimensionless form is obtained by modifying the Reynolds equation incorporating the Rosensweig’s viscosity, Kozeny-Carman’s model-based porosity, slip and Shliomis model-based ferofluid lubrication. The graphical representation reveals that load carrying capacity (LCC) can be increased by increasing the curvature of upper plates, volume concentration and magnetization parameter but decrease with the slip velocity, porous structure parameter and porosity parameter. This study indicates that the load-bearing capacity remains higher as compared to the case of Einstein’s viscosity model. However, this investigation conclusively establishes that the Shliomis model goes ahead of the other two magnetic fluid flow models in overall improvement of bearing performance characteristics. Interestingly, even considerable amount of slip may not pose a serious problem when Kozeny-Carman’s model is resorted to. This investigation reveals that this type of bearing system sustains good amount of load even in the absence of flow which does not happen in the case of conventional bearing system.

Numerical Analysis of Natural Convection Driven Flow of a Non-Newtonian Power-Law Fluid in a Trapezoidal Enclosure with a U-Shaped Constructal

Placement of fins in enclosures has promising utilization in advanced technological processes due to their role as heat reducing/generating elements such as in conventional furnaces, economizers, gas turbines, heat exchangers, superconductive heaters and so forth. The advancement in technologies in power engineering and microelectronics requires the development of effective cooling systems. This evolution involves the utilization of fins of significantly variable geometries enclosed in cavities to increase the heat elimination from heat-generating mechanisms. Since fins are considered to play an effective role in the escalation of heat transmission, the current study is conducted to examine the transfer of heat in cavities embedding fins, as well as the effect of a range of several parameters upon the transmission of energy. The following research is supplemented with the interpretation of the thermo-physical aspects of a power-law liquid enclosed in a trapezoidal cavity embedding a U-shaped fin. The Boussinesq approximation is utilized to generate the mathematical attributes of factors describing natural convection, which are then used in the momentum equation. Furthermore, the Fourier law is applied to formulate the streaming heat inside the fluid flow region. The formulated system describing the problem is non-dimensionalized using similarity transformations. The geometry of the problem comprises a trapezoidal cavity with a non-uniformly heated U-shaped fin introduced at the center of the base of the enclosure. The boundaries of the cavity are at no-slip conditions. Non-uniform heating is provided at the walls (l1 and l2), curves (c1,c2 and c3) and surfaces (s1 and s2) of the fin; the upper wall is insulated whereas the base and sidewalls of the enclosure are kept cold. The solution of the non-dimensionalized equations is procured by the Galerkin finite element procedure. To acquire information regarding the change in displacement w.r.t time and temperature, supplementary quadratic interpolating functions are also observed. An amalgam meshing is constructed to elaborate the triangular and quadrilateral elements of the trapezoidal domain. Observation of significant variation in the flow configurations for a specified range of parameters is taken into consideration i.e., 0.5≤n≤1.5 and 104≤Ra≤106. Furthermore, flow structures in the form of velocity profiles, streamlines, and temperature contours are interpreted for the parameters taken into account. It is deduced from the study that ascending magnitude of (Ra) elevates level of kinetic energy and magnitude of heat flux; however, a contrary configuration is encapsulated for the power-law index. Navier–Stokes equations constituting the phenomenon are written with the help of non-dimensionalized stream function, temperature profiles, and vortices, and the solutions are acquired using the finite element method. Furthermore, the attained outcomes are accessible through velocity and temperature profiles. It is worth highlighting the fact that the following analysis enumerates the pseudo-plastic, viscous and dilatant behavior of the fluid for different values of (n). This study highlights that the momentum profile and the heat transportation increase by increasing (Ra) and decline as the viscosity of the fluid increases. Overall, it can be seen from the current study that heat transportation increases with the insertion of a fin in the cavity. The current communication signifies the phenomenon of a power-law fluid flow filling a trapezoidal cavity enclosing a U-shaped fin. Previously, researchers have studied such phenomena mostly in Newtonian fluids, hence the present effort presents novelty regarding consideration of a power-law liquid in a trapezoidal enclosure by the placement of a U-shaped fin.

Galerkin finite element analysis of magneto two-phase nanofluid flowing in double wavy enclosure comprehending an adiabatic rotating cylinder

In this work, the finite element method is employed to simulate heat transfer and irreversibilities in a mixed convection two-phase flow through a wavy enclosure filled with water-alumina nanoliquid and contains a rotating solid cylinder in the presence of a uniform magnetic field. Impact of the variations of undulations number (0 ≤ N ≤ 5), Ra (10³ ≤ Ra ≤ 10⁶), Ha (0 ≤ Ha ≤ 100), and angular rotational velocity (- 500 ≤ Ω ≤ 500) were presented. Isotherms distribution, streamlines and isentropic lines are displayed. The governing equations are verified by using the Galerkin Finite Element Method (GFEM). The Nusselt numbers are calculated and displayed graphically for several parametric studies. The computational calculations were carried out using Buongiorno's non-homogeneous model. To illustrate the studied problem, a thorough discussion of the findings was conducted. The results show the enhacement of the maximum value of the flow function and the heat transfer process by increasing the value of Rayleigh number. Furthermore the irreversibility is primarily governed by the heat transfer component and the increment of the waviness of the active surfaces or the cylinder rotational velocity or hartmann number will suppress the fluid motion and hinders the heat transfer process.

Entropy Generation and MHD Convection within an Inclined Trapezoidal Heated by Triangular Fin and Filled by a Variable Porous Media

Analyses of the entropy of a thermal system that consists of an inclined trapezoidal geometry heated by a triangular fin are performed. The domain is filled by variable porosity and permeability porous materials and the working mixture is Al2O3-Cu hybrid nanofluids. The porosity is varied exponentially with the smallest distance to the nearest wall and the permeability is depending on the particle diameter. Because of using the two energy equations model (LTNEM), sources of the entropy are entropy due to the transfer of heat of the fluid phase, entropy due to the fluid friction and entropy due to the porous phase transfer of heat. A computational domain with new coordinates (ξ,η) is created and Finite Volume Method (FVM) in case of the non-orthogonal grids is used to solve the resulting system. Various simulations for different values of the inclination angle, Hartmann number and alumina-copper concentration are carried out and the outcomes are presented in terms of streamlines, temperature, fluid friction entropy and Bejan number. It is remarkable that the increase in the inclination angle causes a diminishing of the heat transfer rate. Additionally, the irreversibility due to the temperature gradients is dominant near the heated fins, regardless of the values of the Hartmann number.