Thermal Slip Conditions Research Articles

Entropy generation and Joule heating of two layered electroosmotic flow in the peristaltically induced micro-channel

We analyze the flow characteristics, thermal behavior, and entropy generation for two layered flow driven by combined effects of electroosmosis and peristaltic pumping in an asymmetric microfluidic channel subjected to velocity and thermal slip conditions. Aqueous solutions having different viscosity and different zeta potentials at the walls of the micro-channel are considered in upper and lower layers to examine the two layered flow variation. This study is motivated towards investigating micro-vascular two layered biofluid flow in capillary, by taking into account of heat transfer effects. Analysis is carried out under suitable physical assumptions (low Reynolds number, long wavelength and low zeta potential). The effects of slip parameter, viscosity, zeta potential and electroosmotic parameter on velocity field and the effects of Joule heating parameter, Brinkman number, thermal slip parameter on temperature field are reported. The variations in Nusselt number based on the velocity and temperature fields, and the variations in Bejan number based on heat transfer irreversibility are also computed. Furthermore, the implications of Joule heating on system irreversibility through entropy generation analysis due to fluid friction and heat transfer are studied. The outcomes of the present study is applicable in designing the thermofluidic micropumps which can be utilized in chemical mixing/separation processes and biomicrofluidics devices for the purpose of diagnosis.

Effects of Velocity and Thermal Slip Conditions with Radiation on Heat Transfer Flow of Ferrofluids

To analyze the thermal convection of ferrofluid along a flat plate is the persistence of this study. The two-dimensional laminar, steady, incompressible flow past a flat plate subject to convective surface boundary condition, slip velocity in the presence of radiation has been studied where the magnetic field is applied in the transverse direction to the plate. Two different kinds of magnetic nanoparticles, magnetite Fe3O4 and cobalt ferrite CoFe2O4 are amalgamated within the base fluids water and kerosene. The effects of various physical aspects such as magnetic field, volume fraction, radiation and slip conditions on the flow and heat transfer characteristics are presented graphically and discussed. The effect of various dimensionless parameters on the skin friction coefficient and heat transfer rate are also tabulated. To investigate this particular problem, numerical computations are done using the implicit finite difference method based Keller-Box Method.

Corrigendum to “Optimization of SWCNTs and MWCNTs (single and multi-wall carbon nanotubes) in peristaltic transport with thermal radiation in a non-uniform channel” [J. Mol. Liq. 273(2019) 383–391

• Carbon nanotubes are considered. • Viscosity is taken as a function of temperature. • Effective heat transfer at lower and upper walls are discussed. • Velocity and thermal slip conditions comprises at peristaltic walls. • Thermal radiation effects are taken.

Peristaltic activity of blood–titanium nanofluid subject to endoscope and entropy generation

Entropy generation and endoscopic effects on peristalsis of nanofluid are addressed. Inner tube is taken rigid, while sinusoidal wave travels along the outer tube. Blood is used as the base fluid, whereas titanium is considered as nanoparticle. Maxwell model of effective thermal conductivity is utilized. Velocity and thermal slip conditions are imposed at outer tube. Moreover, the walls of tubes are complaint in nature. Viscous dissipation is also utilized. Long wavelength and small Reynolds number consideration is employed. Series solutions are obtained for small Grashof number. Analysis is carried out for physical parameters on velocity, temperature, entropy generation and Bejan number. Heat transfer rate at wall is also analyzed via bar charts for different pertinent parameters. Results reveal that an enhancement in nanomaterial volume fraction causes decay in temperature and velocity, whereas it leads to increase the heat transfer rate at the wall. Grashof number causes an enhancement in velocity and temperature. The study also declared that elastance coefficients of walls lead to enhancement, whereas damping coefficient results in decay of velocity, temperature and entropy generation.

Effects of velocity and thermal wall slip on magnetohydrodynamics (MHD) boundary layer viscous flow and heat transfer of a nanofluid over a non-linearly-stretching sheet: a numerical study

In this analysis, the boundary layer viscous flow of nanofluids and heat transfer over a non-linearly-stretching sheet in the presence of a magnetic field is presented. Velocity and thermal slip conditions are considered instead of no slip conditions at the boundary. A similarity transformation set is used to transform the governing partial differential equations into non-linear ordinary differential equations. The reduced equations are solved numerically using the Keller box method. The influence of the governing parameters on the dimensionless velocity, temperature, nanoparticle concentration as well as the skin friction coefficient, Nusselt number, and local Sherwood number are analyzed. It is found that as the velocity slip parameter increases, the velocity profile is decreased and the skin friction and heat transfer decreased while the mass transfer is increased. Increasing the thermal slip parameter causes decreases in the heat and mass transfer rates. The results are presented in both graphical and tabular forms.

Influence of thermal stratification and slip conditions on stagnation point flow towards variable thicked Riga plate

Abstract This article addresses thermally stratified stagnation point flow of viscous fluid induced by a non-linear variable thicked Riga plate. Velocity and thermal slip effects are incorporated to disclose the flow analysis. Solar thermal radiation phenomenon is implemented to address the characteristics of heat transfer. Variations of different physical parameters on the horizontal velocity and temperature distributions are described through graphs. Graphical interpretations of skin friction coefficient (drag force at the surface) and Nusselt number (rate of heat transfer) are also addressed. Modified Hartman number and thermal stratification parameter result in reduction of temperature distribution.

Heat and Mass Transfer in MHD Micropolar Fluid Flow over a Stretching Sheet with Velocity and Thermal Slip Conditions

This study presents the problem of a steady, two-dimensional, heat and mass transfer of an incompressible, electrically conducting micropolar fluid flow past a stretching surface with velocity and thermal slip conditions. Also, the influences of temperature dependent viscosity, thermal radiation and non-uniform heat generation/absorption and chemical reaction of a general order are examined on the fluid flow. The governing system of partial differential equations of the fluid flow are transformed into non-linear ordinary differential equations by an appropriate similarity variables and the resulting equations are solved by shooting method coupled with fourth order Runge-Kutta integration scheme. The effects of the controlling parameters on the velocity, temperature, microrotation and concentration profiles as well as on the skin friction, Nusselt number, Sherwood and wall couple stress are investigated through tables and graphs. Comparison of the present results with the existing results in the literature in some limiting cases shows an excellent agreement.

Analysis of Heat Transfer on Peristaltic Transport of Powell- Eyring Fluid in an Inclined Tapered Symmetric Channel with Hall and Ohm's Heating Influences

In this paper, we present an analysis of heat transfer on peristaltic flow for Powell- Eyring fluid in an inclined symmetric tapered channel is discussed. Hall effect, velocity, thermal slip conditions, and Ohm's heating are taken into consideration. The governing equations for the balance of mass, momentum and energy are modeled, and then simplified by holding the consideration of long wavelength and low Renolds number approximation. Graphical results are given to analyze the behavior of the parameters emerging in the problem. Effect of Hall parameter and Hartman number on velocity axial have opposite characteristics.

Influence of variable thermal conductivity and thermal radiation on slip flow and heat transfer of MHD power-law fluid over a porous sheet

In this paper, the problem of boundary layer flow and heat transfer of MHD power-law fluid over a porous sheet in the presence of partial slip is investigated numerically. We assume a temperature dependent thermal conductivity and slip conditions are employed in terms of shear stress. The suitable similarity transformations are used, to transform the governing partial dif- ferential equations (PDEs) into a system of nonlinear ordinary differential equations (ODEs). The resulting system of ODEs is solved numerically using Matlab bvp4c solver. The numerical values obtained for the velocity and temperature depend on power-law index, slip parameters, permeability, suction/injection parameter, Prandlt number and Nusselt number. The effects of various parameters on the flow and heat transfer characteristics are presented through graphs and tables and discussed from physical point of view.

HEAT TRANSFER IN VISCOPLASTIC BOUNDARY-LAYER FLOW FROM A VERTICAL PERMEABLE CONE WITH MOMENTUM AND THERMAL WALL SLIP: NUMERICAL STUDY

A mathematical model is presented for the laminar free convection boundary layer flow of Casson viscoplastic non-Newtonian fluid external to a vertical penetrable circular cone in the presence of thermal and hydrodynamic slip conditions. The cone surface is maintained at non-uniform surface temperature. The boundary layer conservation equations, which are parabolic in nature, are transformed into non-dimensional form via appropriate similarity variables, and the emerging boundary value problem is solved computationally with the second order accurate implicit Keller-box finite-difference scheme. The influence of velocity (momentum) slip, thermal slip and Casson non-Newtonian parameter on velocity, temperature, skin friction and Nusselt number are illustrated graphically. Validation of solutions with earlier published work is included. The computations show that the flow near the cone surface is strongly decelerated with increasing momentum slip whereas the temperature and thermal boundary layer thickness are increased. Increasing Casson parameter generally decelerates the flow and also decreases temperatures. Both velocity and thermal boundary layer thickness are reduced with greater Prandtl number. The study is relevant to petro-chemical engineering (polymer) processing systems.

Transportation of ionic liquids in a porous micro-channel induced by peristaltic wave with Joule heating and wall-slip conditions

This article presents a mathematical model for studying peristaltic mechanism of combine pressure and electro-osmotically driven flow of ionic liquids through a micro-channel having electrokinetic effects. The velocity slip and the thermal slip conditions at the channel wall are taken into account for investigating the thermomechanical interactions. The micro-channel is assumed to have porous structure. The governing equations for fluid flow and heat transfer in the electrical double layer (EDL) together with the Poisson-Boltzmann equation are considered. The analytical solutions have been obtained under low Reynolds number and long wave length assumptions. It is also assumed that the channel height is much greater than the thickness of the electrical double layer (EDL). The essential features of electro-osmotically driven flow and associated heat transfer characteristics in a micro-channel are clearly demonstrated by varying dimensionless parameters for velocity profile, temperature profile, pressure distribution, stream function, wall shear stress and the Nusselt number. The pressure drop exhibits a linear dependence on the flow rate. The study reveals that the electro-osmotic parameter has an enhancing effect on the size of the trapping bolus while the reducing effect on porous permeability of the channel. The temperature distribution is significantly influenced by Joule heating parameter and Brinkman number. The study bears the potential applications in biomedical engineering for the development of microfluidic devices in particular microfluidic pump to transport small volume of ionic liquids by maintaining temperature distribution.

MHD stagnation point flow accounting variable thickness and slip conditions

This communication addresses the second-order velocity and thermal slip features in magnetohydrodynamic (MHD) stagnation point flow past a stretching sheet with variable thickness. Energy expression in presence of dissipation and thermal radiation are examined. A comparative study with first-order velocity and thermal slip condition is analyzed. Analytical solutions of the resulting systems are obtained by homotopy analysis method. Plots for important variables in the flow quantities are made and discussed. It is observed that velocity of fluid increases for higher estimation of velocity power index while it decreases for wall thickness parameter. Surface drag force and heat transfer rate are decreased for larger wall thickness and Prandtl number. Present computations are consistent with those of existing studies in limiting sense.

Magnetohydrodynamic (MHD) flow of nanofluid with double stratification and slip conditions

ABSTRACTThis paper concerns with the analysis of double stratification in magnetohydrodynamic (MHD) flow of nanofluid by a stretching cylinder. Brownian motion and thermophoresis effects are present in the transport equations. The flow is subjected to velocity, thermal and solutal slip conditions. Non-linear ordinary differential equations are obtained from the governing non-linear partial differential equations after using appropriate transformations. The resulting non-linear ordinary differential equations are solved for the convergent series solutions. The velocity, temperature and concentration profiles are illustrated for different emerging parameters. Velocity distribution decays for higher estimation of velocity slip parameter. Furthermore, temperature decreases and concentration enhances for higher values of thermal stratification parameter and thermophoresis parameter, respectively. Numerical results for the skin friction, Nusselt number and Sherwood number are also presented and examined. Comparison between the published limiting solutions and present results is found in an excellent agreement.

Mixed convection peristaltic motion of copper-water nanomaterial with velocity slip effects in a curved channel

Background and objective: The primary objective of present analysis is to model the peristalsis of copper-water based nanoliquid in the presence of first order velocity and thermal slip conditions in a curved channel. Mixed convection, viscous dissipation and heat generation/absorption are also accounted.Method: Mathematical formulation is simplified under the assumption of small Reynolds number and large wavelength. Regular perturbation technique is employed to find the solution of the resulting equations in terms of series for small Brinkman number. The final expression for pressure gradient, pressure rise, stream function, velocity and temperature are obtained and discussed through graphs. Mathematica software is utilized to compute the solution of the system of equations and to plot the graphical results.Results: Results indicates that insertion of 30% copper nanoparticles in the basefluid (water) velocity and temperature reduces by almost 3% and 40% respecively. Moreover it is seen that size of the trapped bolus also reduces almost 20% with the insertion of 20% nanoparticles (copper) in the basefluid (water).Conclusion: It is noted that velocity and temperature are decreasing functions of nanoparticle volume fraction. Moreover the temperature rises when heat generation parameter and Brinkman number are enhanced.

MHD boundary layer thermal slip flow by nonlinearly stretching cylinder with suction/blowing and radiation

A mathematical model has been developed to study the magnetohydrodynamic (MHD) flow of viscous fluid due to a nonlinear stretching cylinder. The flow is discussed in the presence of velocity and thermal slip conditions. Effects of viscous dissipation and Joule heating are also examined. Suitable transformations are utilized to reduce the governing PDEs into a set of nonlinear ODEs. These equations are solved using Range-Kutta Fehlberg Scheme. Influence of pertinent variables on velocity, temperature, concentration, surface drag force and heat transfer rate are computed and analyzed. Graphical and tabulated results are given to deliberate the physical nature of problem. Finally comparison with previously available limiting results in the literature are made and an excellent agreement is noted. As expected the velocity is decreased by suction. Nusselt number enhances for larger thermal radiation.

Hall and Joule heating effects on peristaltic flow of Powell–Eyring liquid in an inclined symmetric channel

This article is intended to investigate the influence of Hall current on peristaltic transport of conducting Eyring–Powell fluid in an inclined symmetric channel. Energy equation is modeled by taking Joule heating effect into consideration. Velocity and thermal slip conditions are imposed. Lubrication approximation is considered for the analysis. Fundamental equations are non-linear due to fluid parameter A. Regular perturbation technique is employed to find the solution of systems of equations. The key roles of different embedded parameters on velocity, temperature and heat transfer coefficient in the problem are discussed graphically. Trapping phenomenon is analyzed carefully.

Radiative peristaltic flow of magneto nanofluid in a porous channel with thermal radiation

Peristaltic flow of MHD nano fluid in a porous channel with velocity and thermal slip conditions is examined. Nanomaterial is comprised with water and copper/silver. Thermal radiation is present. The relevant problems have been solved for the velocity, temperature, pressure rise, frictional force and heat transfer rate. Physical impact of parameters in this study is analyzed.

Steady MHD Heat and Mass Transfer Flow Over a Permeable Stretching Surface with Velocity, Thermal, and Mass Slip Conditions

Steady MHD Heat and Mass Transfer Flow Over a Permeable Stretching Surface with Velocity, Thermal, and Mass Slip Conditions

Entropy generation impact on peristaltic motion in a rotating frame

Outcome of entropy generation in peristalsis of Casson fluid in a rotating frame is intended. Formulation is based upon thermal radiation, viscous dissipation and slip conditions of velocity and temperature. Lubrication approach is followed. The velocity components, temperature and trapping are examined. Specifically the outcomes of Taylor number, fluid parameter, slip parameters, Brinkman, radiation and compliant wall effects are focused. In addition entropy generation and Bejan numbers are examined. It is observed that entropy is controlled through slip effects.

Energy conversion under conjugate conduction, magneto-convection, diffusion and nonlinear radiation over a non-linearly stretching sheet with slip and multiple convective boundary conditions

Energy conversion under conduction, convection, diffusion and radiation has been studied for MHD free convection heat transfer of a steady laminar boundary-layer flow past a moving permeable non-linearly extrusion stretching sheet. The nonlinear Rosseland thermal radiation flux model, velocity slip, thermal and mass convective boundary conditions are considered to obtain a model with fundamental applications to real world energy systems. The Navier slip, thermal and mass convective boundary conditions are taken into account. Similarity differential equations with corresponding boundary conditions for the flow problem, are derived, using a scaling group of transformation. The transformed model is shown to be controlled by magnetic field, conduction-convection, convection-diffusion, suction/injection, radiation-conduction, temperature ratio, Prandtl number, Lewis number, buoyancy ratio and velocity slip parameters. The transformed non-dimensional boundary value problem comprises a system of nonlinear ordinary differential equations and physically realistic boundary conditions, and is solved numerically using the efficient Runge-Kutta-Fehlberg fourth fifth order numerical method, available in Maple 17 symbolic software. Validation of results is achieved with previous simulations available in the published literature. The obtained results are displayed both in graphical and tabular form to exhibit the effect of the controlling parameters on the dimensionless velocity, temperature and concentration distributions. The current study has applications in high temperature materials processing utilizing magnetohydrodynamics, improved performance of MHD energy generator wall flows and also magnetic-microscale fluid devices.