Fluid Wall Interaction Parameter Research Articles

Magnetohydrodynamic Free Convective Flow in a Vertical Microchannel with Heat Sink

Electrically conducting fluid flowing past a micro-channel is investigated in the presence of heat sink. The governing equations of the system are non-dimensionalzed by using suitable dimensionless quantities. Exact solutions are computed for the momentum, energy, volume flow rate, skin friction and the rate of heat transfer. The impact of flow controlling factors like the fluid-wall interaction parameter, the rarefaction parameter, Hartmann number, suction/injection, and heat sink are presented pictorially. Results show that the velocity is augmented with rarefaction parameter whereas it is decelerated with fluid-wall interaction, Hartmann number, and heat sink for all values of temperature difference ratio. Injection retards the flow whereas suction accelerates the flow. The volumetric flow rate decreases for asymmetric heating and increases for symmetric heating. The heat sink parameter increases the rate of heat transfer at the right plate whereas it decreases at the left plate. The results which are analyzed have applications in modelling the combustion heat exchangers and nuclear energy.

Insights into an analytical simulation of a natural convection flow controlled by Arrhenius kinetics in a micro-channel

The focus of this paper is the investigation of an Arrhenius-driven chemical reaction in an upstanding micro-channel over an imposed transverse magnetic field with fully developed constant free convection flow. Subject to suitable boundary conditions, the temperature and velocity equations are resolved in non-dimensional form employing the homotopy perturbation method (HPM). the fundamental flow behaviors of temperature, velocity, and volumetric flow are explored as a consequence of regulating characteristics such as fluid-wall interaction parameter, rarefaction parameter, chemical reaction parameters, wall-ambient temperature difference ratio, and Hartman number. The findings are carefully investigated and graphically represented in several mesh grid graphs. It was established that increasing the values of the rarefaction parameters and chemical reaction results in an upsurge in the fluid velocity and volume flow rate, respectively, whereas increasing the Hartman number results in observable flow retardation. Additionally, when the chemical reactant parameter is ignored, the numerical comparison is in excellent agreement with the previously published results.

Mixed Convection Flow in a Micro-channel in the Presence of Magnetic Field and Thermal Property

The fully developed MHD mixed convection flow in a micro channel having variable thermal conductivity is considered. The velocity slip and temperature jump at both plates were taken into consideration. The effects of various flow parameters entering into the problem such as Hartmann number, variable thermal conductivity, mixed convection parameter, rarefaction parameter, fluid-wall interaction parameter and wall-ambient temperature difference ratio were discussed with the aid of line graphs. It is revealed that greater values of variable thermal conductivity tend to significantly improve the temperature and velocity gradients respectively. Furthermore, mixed convection parameter, significantly influence the flow pattern.

Heat transfer analysis of arrhenius-controlled free convective hydromagnetic flow with heat generation/absorption effect in a micro-channel

The study of a chemically reacting fluid in a vertical micro-channel limited to an applied transverse magnetic field that has fully developed steady natural convection flow under the impact of internal heat generation or absorption effects is the focus of this research. The governing equations are solved in dimensionless form using the homotopy perturbation method, HPM. Temperature, velocity, volume flow rate, and frictional drag force fundamental flow attributes are investigated as a function of controlling parameters such as heat generating or absorbing parameters, chemical reaction parameter, rarefaction parameter, fluid-wall interaction parameter and wall-ambient temperature difference ratio. The results are thoroughly analyzed and graphically depicted in a variety of plots. It is worth noting that raising the chemical reaction and rarefaction parameters increases fluid flow and volume flow rate, respectively. Furthermore, the action of heat absorption is observed to suppress fluid flow whereas heat generation establishes the opposite condition. Additionally, numerical data was generated and tabulated to compare the findings of this study to those of Jha et al. (2014) when the chemical reactant and heat generating/absorbing parameters were neglected, and an excellent agreement was discovered.

Influence of Heat Generation and Thermal Radiation on MHD Flow in a Vertical Micro-Porous-Channel in the Presence of Viscous Dissipation

This article analyses the influence of heat generation and thermal radiation on steady hydromagnetic fully developed natural convection flow in a vertical micro-porous–channel in the presence of viscous dissipation. The governing ordinary differential equations, exhibiting the physics of the flow formation are displayed. Using the relevant non–dimensional variables, the governing equations are transformed into their corresponding non–dimensional form and then solved exactly by employing the perturbation technique. The influence of different admissible parameters such as fluid wall interaction parameter, Knudsen number, heat generation parameter, thermal radiation parameter, magnetic parameter, Eckert number, and permeability parameter on the fluid velocity, temperature, skin friction coefficient, and heat transfer coefficient at the micro-porous–channel surfaces is discussed with the aid of line graphs and tables.

Hall effects on MHD couple stress fluid flow through a vertical microchannel subjected to heat generation: A numerical study

AbstractThe present study analyzes the irreversibility in an electrically conducting couple stress fluid between two vertical channel plates with the aspects of exponential space and temperature‐dependent, radiative heat flux, heat generation, and Joule heating. A reduced system of the governing equations is obtained via applying suitable nondimensional variables. To determine the solutions of velocity, thermal field, irreversibility, and irreversibility ratio, the Runge‐Kutta‐Fehlberg method along with the shooting technique has been employed. The various pertinent parameters that are involved in the problem have been discussed in detail through graphs. The results show that the entropy production can improve with the viscous dissipation, Joule heating, exponential space and temperature‐dependent, and radiative heat flux. Furthermore, it is clear that the entropy enhances with wall ambient temperature difference, radiation parameter, and the effect is reversed with higher estimations of the fluid wall interaction parameter, couple stress parameter, and rarefaction. The present numerical results are compared with the existing results that are in good agreement.

MHD natural convection flow of Casson fluid in an annular microchannel containing porous medium with heat generation/absorption

AbstractThis study has been conducted to focus on natural convection flow of Casson fluid through an annular microchannel formed by two cylinders in the presence of magnetic field. The process of heat generation/absorption is taken into consideration. Combined effects of various parameters such as porous medium, velocity slip and temperature jump are considered. Solution of the present mathematical model is obtained numerically using fourth-fifth order Runge-Kutta-Fehlberg method. The flow velocity, thermal field, skin friction and Nusselt number are scrutinized with respect to the involved parameters of interest such as fluid wall interaction parameter, rarefaction parameter, Casson parameter and Darcy number with the aid of graphs. It is established that higher values of Casson parameter increases the skin friction coefficient. Further it is obtained that rate of heat transfer diminishes as fluid wall interaction parameter increases.

Second law analysis on Hall effect of natural convection flow through vertical channel in the presence of uniform heat source/sink

Purpose Microfluidics is one of the extensive elaborated technologies in thermal and engineering fields due to its wide range of applications, such as micro heat exchangers, micro mixture and microchannel heat sinks, which is used to develop a large number of microscopic devices and systems. Enhancement of thermal energy using verity of nanoliquids is one of the challenges in these applications of microfluidics. Therefore, using single wall carbon nanotubes for enhancement of thermal energy in microchannel is the main purpose of this study. Hall effect of natural convection flow in a vertical channel with slip and temperature jump condition is considered. The impacts of radiative heat flux, uniform heat source/sink, viscous dissipation and joule heating are also taken into account. Design/methodology/approach Suitable non-dimension variables are applied to the governing equations to reduce the system into ordinary differential equations. The reduced nonlinear system is then solved numerically using Runge–Kutta–Fehlberg fourth–fifth-order method along with shooting technique. The impact of different pertinent parameters on numerical solutions of primary velocity, secondary velocity, temperature, entropy generation and Bejan number is comprehensively discussed in detail. Also, the obtained numerical results are compared with existing one which perfectly found to be in good agreement. Findings It is established that, with the aspects of Joule heating, viscous dissipation, radiative heat flux and uniform heat source/sink, the production in the entropy can be improved. Further, it is found that the increasing ratio of wall ambient temperature difference and nanoparticle volume fraction leads to enhance the entropy generation. The same effect reverses with increasing values of fluid wall interaction parameter (FWIP) and rare faction. The irreversibility ratio enhances with larger values of nanoparticle volume fraction and decelerates with increment values of FWIP. Originality/value The impact of single wall carbon nanoliquid in a vertical channel flow by using radiative heat flux, heat source/sink, joule heating and viscous dissipation is first time investigated. Further, the influence of Hall current is explored in detail.

Mixed Convection Flow Behaviour in Existence of Lorentz Forces in a Vertical Micro Circular Duct having Time Periodic Boundary Conditions: Steady Periodic Regime

The purpose of this research is to study mixed convection flow behaviour in existence of Lorentz forces in a vertical micro circular subjected to a periodic sinusoidal temperature change at the surface. Effects of velocity slip and temperature jump are also taken into consideration. The research analysis is carried out by considering fully developed parallel flow and steady periodic regime. The governing equations, together with the constraint equations with arise from the definition of mean velocity and temperature, are written in a dimensionless form and mapped into equations in the complex domain. One obtains two independent boundary value problems, which provide the mean value and the oscillating term of the velocity and temperature distributions. These boundary value problems are solved analytically. Numerical procedures are examined for various active parameters namely; fluid wall interaction, rarefaction, Hartmann number, Prandtl number, the dimensionless frequency. The results of the research revealed that, magnetic field plays a damping impact in flow and results in decreases in fluid velocity for both air and water. Further, increases the rarefaction parameter and fluid-wall interaction parameter reduces the oscillation amplitude of the dimensionless velocity.

Entropy generation analysis of Casson fluid flow through a vertical microchannel under combined effect of viscous dissipation, joule heating, hall effect and thermal radiation

PurposeFully developed Casson fluid flow through vertical microchannel is deliberated in the presence of thermal radiation. The two predominant features of micro scale phenomenon such as velocity slip and temperature jump are considered. The paper aims to discuss this issue.Design/methodology/approachThe governing equations of the physical phenomenon are solved using Runge–Kutta–Fehlberg fourth fifth order method.FindingsThe outcome of the present work is discussed through graphs. This computation shows that entropy generation rate decreases with enhancing wall ambient temperature difference ratio and fluid wall interaction parameter. Also, it is found that Bejan number is fully retarded with rise in fluid wall interaction parameter. Enhancement in heat transfer or Nusselt number is achieved by increasing the wall ambient temperature ratio and fluid wall interaction parameter.Originality/valueCasson liquid flow through microchannel is analyzed by considering temperature jump and velocity slip. This computation shows that entropy generation rate decreases with enhancing wall ambient temperature difference ratio.

Role of Induced Magnetic Field on Hydromagnetic Mixed Convection Flow in Vertical Microannulus in Existence of Radial Magnetic Field

The present study presents the convective flow of an electrically conducting fluid in vertical microannulus formed by two concentric cylinders in the presence of imposed radial magnetic field and induced magnetic field. The governing equations of the motion are a set of simultaneous ordinary differential equations, and their exact solutions in dimensionless form have been obtained for the velocity field, the induced magnetic field and the temperature field. The expressions for the induced current density and skin friction have also been obtained. Results for various flows characteristic are presented through graphs and tables delineating the effect of various parameters characterizing the flow. Furthermore, it is observed that the reverse flow near the inner surface of outer cylinder is controlled by selecting suitable values of Knudsen number, fluid–wall interaction parameter and radius ratio.

Natural convection flow in a vertical micro-annulus with time-periodic thermal boundary conditions

Purpose The purpose of this paper is to investigate the impact of time-periodic thermal boundary conditions on natural convection flow in a vertical micro-annulus. Design/methodology/approach Analytical solution in terms of Bessel’s function and modified Bessel’s function of order 0 and 1 is obtained for velocity, temperature, Nusselt number, skin friction and mass flow rate. Findings It is established that the role of Knudsen number and fluid–wall interaction parameter is to decrease fluid temperature, velocity, Nusselt number and skin friction. Research limitations/implications No laboratory practical or experiment was conducted. Practical implications Cooling device in electronic panels, card and micro-chips is frequently cooled by natural convection. Originality/value In view of the amount of works done on natural convection in microchannel, it becomes interesting to investigate the effect that time-periodic heating has on natural convection flow in a vertical micro-annulus. The purpose of this paper is to examine the impact of time-periodic thermal boundary conditions on natural convection flow in a vertical micro-annulus.

Fully developed mixed convection flow in a vertical microtube with time periodic heating boundary condition

Purpose The purpose of this paper is to investigate fully developed mixed convection flow in the steady-periodic regime for a Newtonian fluid in a vertical microtube in the presence of velocity slip and temperature jump, which has not been accounted for in the literature. Design/methodology/approach To achieve this objective, the governing equations for the problem are separated into steady and oscillatory components using separation of variable method; this gives a pair of independent boundary value problems. This is then solved along with its boundary conditions and constraint equations using the method of undetermined coefficient. The exact solutions of momentum and energy equations are obtained under the velocity slip and temperature jump conditions. Findings The significant result from the study is that increase in rarefaction parameter as well as fluid–wall interaction parameter decreases the oscillation amplitude of the dimensionless velocity. Furthermore, it was found that the product of dimensionless frequency and Prandtl number initiate a strong convection current inside the microtube. Practical implications Such type of study may be used on the determination of the thermal and tangential momentum accommodation coefficients and be applicable to the designs and fabrications of microheat exchanger. Moreover, it provides the possibility to get a bench mark for numerical solvers with reference to basic flow configuration. Originality/value These solutions generally deserve great attention, since the application of a magnetic field has been found to be effective tool in controlling the convection current. The current work is aimed as an extension of the previous analytical studies to prove some insight into a number of industrial applications, which use similar configurations.

Impact of Viscous Dissipation on Fully Developed Natural Convection Flow in a Vertical Microchannel

In this research paper, fully developed natural convection flow in a vertical parallel plate's micro-channel in the presence of viscous dissipation is theoretically examined by using a perturbation series method. The effects of velocity slip and temperature jump are taken to consideration. Due to the presence of viscous dissipation, the momentum and energy equations are coupled system of ordinary differential equations. The influences of Knudsen number, fluid wall interaction parameter, and viscous dissipation on the flow formation and heat transfer aspects are demonstrated through graphs and tables. This result indicates that increasing the value of rarefaction parameter decreases the effect of viscous dissipation on the Nusselt number. Furthermore, it is found that the effects of rarefaction parameter as well as buoyancy parameter on temperature and velocity are significantly pronounced in the case of symmetric heating

Hall effects on MHD natural convection flow in a vertical microchannel

In this work, the steady fully developed magnetohydrodynamic natural convection flow in a vertical microchannel formed by two infinite vertical parallel plates due to asymmetric heating of parallel plates in the presence of Hall current is studied. Effects of velocity slip and temperature jump have been considered on the microchannel surfaces and exact solutions have been obtained for momentum and energy equations under relevant boundary conditions. The influence of each governing parameter such as Hall current parameter, Hartmann number, rarefaction parameter, fluid wall interaction parameter and wall-ambient temperature ratio on flow formation is discussed with the aid of graphs. The significant result from the study is that, increase in the value of rarefaction parameter leads to enhancement in volume flow rate. Furthermore, it is evident that volume flow rate is found to be increasing function of Hall current parameter.

Transient magnetohydrodynamic free convective flow in vertical micro-concentric annuli

This article analyses the transient magnetohydrodynamic free convective flow in vertical micro-concentric annuli in the presence of velocity slip and temperature jump at the outer surface of the inner cylinder and the inner surface of the outer cylinder. The Laplace transform technique has been used to find the solutions for the velocity and temperature fields by solving the governing partial differential equations in Laplace domain. However, the Riemann-sum approximation method is used to invert the Laplace domain to the time domain. The solution derived is validated by assenting comparison with exact solutions derived for the steady state which has been derived separately. An excellent agreement was found for transient and steady state at large value of time. The solution obtained for the velocity has been used to compute the skin friction, while the temperature has been used to compute the Nusselt number. The effect of various flow parameters entering into the problem such as time, Prandtl number, curvature radius ratio, Hartmann number, rarefaction parameter, and fluid–wall interaction parameter are discussed with the aid of line graphs.

Role of suction/injection on steady fully developed mixed convection flow in a vertical parallel plate microchannel

Abstract This paper examined the hydrodynamic and thermal behaviour of steady fully developed mixed convection flow in a vertical parallel-plate micro-porous-channel (MPC) in the presence of suction/injection with velocity slip and temperature jump at the boundaries. The exact solutions of the energy and momentum equations are obtained. The influence of each governing parameter on dimensionless velocity, temperature, volume flow rate, rate of heat transfer and skin friction at the micro-porous-channel surfaces is discussed. During the course of numerical computation, it is observed that as suction/injection at the micro-porous-channel surfaces increases, the volume flow rate increases while rate of heat transfer decreases. Furthermore, it is found that the probability of reverse flow formation decreases at cold wall of the micro-porous-channel as Knudsen number or fluid–wall interaction parameter increases.

MHD natural convection flow in a vertical micro-concentric-annuli in the presence of radial magnetic field: An exact solution

Abstract This paper deals with a theoretical investigation of steady fully developed MHD natural convection flow of viscous, incompressible, electrically conducting fluid in micro-concntric-annuli in the presence of radial magnetic field. The velocity slip and temperature jump at the micro-concentric annuli surface are taken into account. Exact solutions are derived for energy and momentum equations under relevant boundary conditions. The solution obtained is graphically represented and the effects of various controlling parameters such as the radius ratio (η), Hartmann number (M), rarefaction parameter (βvKn), and fluid-wall interaction parameter (F) on the flow formation are discussed. The significant result from the study is that as rarefaction parameter (βvKn) increases the velocity slip on the surface of cylinders increases while fluid wall interaction parameter (F) decreases the velocity inside the micro-concntric-annuli. Furthermore, it is found that increase in radius ratio leads to increase in the volume flow rate.

Fully developed MHD natural convection flow in a vertical annular microchannel: An exact solution

An exact solution of steady fully developed natural convection flow of viscous, incompressible, electrically conducting fluid in a vertical annular micro-channel with the effect of transverse magnetic field in the presence of velocity slip and temperature jump at the annular micro-channel surfaces is obtained. Exact solution is expressed in terms of modified Bessel function of the first and second kind. The solution obtained is graphically represented and the effects of radius ratio (η), Hartmann number (M), rarefaction parameter (βvKn), and fluid–wall interaction parameter (F) on the flow are investigated. During the course of numerical computations, it is found that an increase in Hartmann number leads to a decrease in the fluid velocity, volume flow rate and skin friction. Furthermore, it is found that an increase in curvature radius ratio leads to an increase in the volume flow rate.

MHD natural convection flow in a vertical parallel plate microchannel

The fully developed steady natural convection flow of conducting fluid in a vertical parallel plate micro-channel in the presence of transverse magnetic field is considered. The velocity slip and temperature jump at the plates are taken in to consideration. The effect of various flow parameters entering into the problem such as Hartmann number, rarefaction parameter, fluid-wall interaction parameter and wall-ambient temperature difference ratio are discussed with the aid of line graphs. During the course of computation, it is found that increase in the effects of rarefaction and fluid wall interaction leads to increase in volume flow rate while the volume flow rate decreases with increase in Hartmann number.