Rama Subba Reddy Gorla

Magnetohydrodynamic three-dimensional flow of nanofluids with slip and thermal radiation over a nonlinear stretching sheet: a numerical study

A numerical simulation for mixed convective three-dimensional slip flow of water-based nanofluids with temperature jump boundary condition is presented. The flow is caused by nonlinear stretching surface. Conservation of energy equation involves the radiation heat flux term. Applied transverse magnetic effect of variable kind is also incorporated. Suitable nonlinear similarity transformations are used to reduce the governing equations into a set of self-similar equations. The subsequent equations are solved numerically by using shooting method. The solutions for the velocity and temperature distributions are computed for several values of flow pertinent parameters. Further, the numerical values for skin-friction coefficients and Nusselt number in respect of different nanoparticles are tabulated. A comparison between our numerical and already existing results has also been made. It is found that the velocity and thermal slip boundary condition showed a significant effect on momentum and thermal boundary layer thickness at the wall. The presence of nanoparticles stabilizes the thermal boundary layer growth.

Second Law Analysis for Free Convection in Non-Newtonian Fluids Over a Horizontal Plate Embedded in a Porous Medium: Prescribed Surface Temperature

Second law characteristics of heat transfer and fluid flow due to free convection of non-Newtonian fluids over a horizontal plate with prescribed surface temperature in a porous medium are analyzed. Velocity and temperature fields are obtained numerically using an implicit finite difference method under the similarity assumption and these results are used to compute the entropy generation rate Ns, irreversibility ratio Φ, and the Bejan number Be for both Newtonian and non-Newtonian fluids. The effects of viscous frictional parameter G, Rayleigh number Ra, temperature variation λ, axial distance (x) on the dimensionless entropy generation rate Ns, and the Bejan number Be are investigated for Newtonian and non-Newtonian fluids and presented graphically.

Mixed convection from a discrete heater in lid-driven enclosures filled with non-Newtonian nanofluids

The transport mechanism of laminar combined convection flow of an incompressible viscous non-Newtonian nanofluid in a shear- and buoyancy-driven enclosure has been investigated in this article. The micropolar fluid model is used for the rheological behavior of the non-Newtonian fluid. A heat source with constant volumetric rate is attached in a part of the bottom wall and the remaining parts are thermally insulated. The vertical walls of the cavity are considered to be adiabatic, while the top wall is cooled and moves from left to right with uniform velocity. The thermal conductivity and the dynamic viscosity of the nanofluid are represented by different experimental correlations that are suitable to each nanoparticles. The finite volume method is applied to solve the dimensionless form of the governing equations. A discussion is provided for the effects of the governing parameters on the local Nusselt number and average Nusselt number along the heat source. It is found that an increase in the vortex-viscosity parameter causes a reduction in the local Nusselt number. As the vortex-viscosity parameter increases by 10 times from 0.5 to 5, the Nusselt number reduces by 15%. Additionally, as the nanoparticle volume fraction increases, the rate of heat transfer increases. As the volume fraction increases by 100% from 0.1 to 0.2, the Nusselt number increases by 86%.

Numerical exploration of the combined effects of non-linear thermal radiation and variable thermo-physical properties on the flow of Casson nanofluid over a wedge

Purpose n n n n nThe effect of non-linear thermal radiation and variable thermo-physical properties are investigated in the Falkner-Skan flow of a Casson nanofluid in the presence of magnetic field. The paper aims to discuss this issue. n n n n nDesign/methodology/approach n n n n nSelected bunch of similarity transformations are used to reduce the governing partial differential equations into a set of non-linear ordinary differential equations. The resultant equations are numerically solved using Runge-Kutta-Fehlberg fourth-fifth-order method along with shooting technique. n n n n nFindings n n n n nThe velocity, temperature and concentration profiles are evaluated for several emerging physical parameters and are analyzed through graphs and tables in detail. n n n n nResearch limitations/implications n n n n nThis study only begins to reveal the research potential and pitfalls of research and publishing on boundary-layer flow, heat and mass transfer of Casson nanofluid past and the moving and static wedge-shaped bodies. n n n n nOriginality/value n n n n nIt is found that the presence of non-linear thermal radiation and variable properties has more influence in heat transfer. Furthermore, temperature profile increases as the radiation parameter increases.

Numerical Solutions by EFGM of MHD Convective Fluid Flow Past a Vertical Plate Immersed in a Porous Medium in the Presence of Cross Diffusion Effects via Biot Number and Convective Boundary Condition

Abstract In this investigation, the numerical results of a mixed convective MHD chemically reacting flow past a vertical plate embedded in a porous medium are presented in the presence of cross diffusion effects and convective boundary condition. Instead of the commonly used conditions of constant surface temperature or constant heat flux, a convective boundary condition is employed which makes this study unique and the results more realistic and practically useful. The momentum, energy, and concentration equations derived as coupled second-order, ordinary differential equations are solved numerically using a highly accurate and thoroughly tested element free Galerkin method (EFGM). The effects of the Soret number, Dufour number, Grashof number for heat and mass transfer, the viscous dissipation parameter, Schmidt number, chemical reaction parameter, permeability parameter and Biot number on the dimensionless velocity, temperature and concentration profiles are presented graphically. In addition, numerical results for the local skin-friction coefficient, the local Nusselt number, and the local Sherwood number are discussed through tabular forms. The discussion focuses on the physical interpretation of the results as well as their comparison with the results of previous studies.

Nonlinear Thermal Convection in Jeffrey Liquid Flow with Cross Diffusion Effects Past a Stretched Surface

Nonlinear thermal convection in heat and mass transfer mechanism of dissipating Jeffrey liquid is investigated. The impact of cross diffusion and convective conditions are also accounted. Before integrating pertinent partial differential equations; a set similarity variables are employed to reduce them into multidegree ordinary differential equations. The validation process comprised a comparison with existing data, reaching an excellent agreement. Later, the influence of distinct physical parameters on diverse flow characteristics are comprehensively discussed and analyzed. It is established that the nonlinear convection is favourable for the escalation of the thickness of momentum boundary layer. Further, the convective conditions are used as controlling constraints.

Numerical solution of contaminated oil along a vertical wavy frustum of a cone

The effect of wavy surface on natural convection flow of two-phase dusty fluid over a vertical frustum of a cone is presented in this paper. The boundary layer regime having the large value of Grashof number Gr is considered and the wavy surface is assume to have wavelength and amplitude of O(1). A sinusoidal surface is used as a particular example to elucidate the heat transfer mechanism near such surfaces. The transformed boundary layer equations are solved numerically and detailed results for the skin friction and rate of heat transfer coefficients are presented for a selected parameters: wavy surface amplitude, half cone angle, mass concentration parameter and dust parameter. Comprehensive flow formations of the contaminated oil having Pr equal to 500.0, are given with the aim to predict the enhancement of heat transport across the heated wavy frustum of the cone.

Natural convection flow of two-phase dusty gas with variable thermophysical properties along a vertical wavy surface

The purpose of the present study is to establish the detailed parametric solutions for laminar natural convection flow of two-phase dusty fluid moving along a vertical wavy plate. Typical sinusoidal surface is used to elucidate the heat transport phenomena for the carrier gas having variable thermophysical properties. The governing equations are cast into a system of parabolic partial differential equations by using set of continuous transformations and then the resulting system is integrated through implicit finite difference method. In order to ensure the accuracy, the present numerical results are also compared with the available published results and good compatibility is found between the present and previous results. It is showed that mass concentration parameter, Dρ, and the variable thermophysical properties extensively promotes the rate of heat transfer near the uneven surface. It is also established that amplitude of the wavy surface enhances very drastically, which is also due to the variable properties of the fluid.

Oxygen Transport In and Around the Systemic Capillary in Hyperbaric Environment

Oxygen transport from a systemic capillary to its surrounding tissue region in the hyperbaric environment is analyzed. Longitudinal and transversal diffusion in the capillary and tissue regions, convective effect of the blood, and equilibrium chemical kinetics of oxygen with hemoglobin are studied in this model. The effect of capillary wall permeability and capillary wall pressure gradient constant on the oxygen transport is also investigated in this study. The nonlinear oxyhemoglobin dissociation curve is considered at hyperbaric environment; further, the zeroth- and first-order oxygen uptake kinetics are considered for the oxygen consumption by the tissue cells. The analytical solution for the oxygen transport in both capillary and tissue regions is obtained using the method of eigenfunction expansion. It is noticed that the amount of oxygen consumption in the tissue region is larger with the first-order metabolism than the zeroth-order metabolism. It is also seen that in the first two-fifth part of the tissue, oxygen is delivered by longitudinal and transversal diffusion, and in the rest of the tissue, it is transported by transversal diffusion only.

Thermal analysis of a fully wet porous radial fin with natural convection and radiation using the spectral collocation method

Abstract Heat transfer with natural convection and radiation effect on a fully wet porous radial fin is considered. The radial velocity of the buoyancy driven flow at any radial location is obtained by applying Darcy’s law. The obtained non-dimensionalized ordinary differential equation involving three highly nonlinear terms is solved numerically with the spectral collocation method. In this approach, the dimensionless temperature is approximated by Chebyshev polynomials and discretized by Chebyshev-Gausse-Lobatto collocation points. A particular algorithm is used to reduce the nonlinearity of the conservation of energy equation. The present analysis characterizes the effect of ambient temperature in different ways and it provides a better picture regarding the effect of ambient temperature on the thermal performance of the fin. The profiles for temperature distributions and dimensionless base heat flow are obtained for different parameters which influence the heat transfer rate.