Slip Flow Heat Transfer Research Articles

Viscous dissipation effects on slip flow heat transfer in rhombic microchannels

This study aimed to numerically investigate the viscous dissipation effect on forced convection in rhombic microchannels for gases in a slip flow regime. The numerical analysis was carried out by assuming a 2D steady-state flow. The solution of governing equations was obtained by adopting the finite element method and assuming that the fluid is Newtonian, with constant thermophysical properties, and in a fully developed laminar flow regime. The solution of the momentum equation is obtained by considering a first-order boundary condition, while the solution of the energy balance equation is obtained by assuming a constant wall heat flux (H2 boundary condition) and taking into account the wall temperature jump. The validation of the numerical model was carried out using the data available in the scientific literature. The numerical outcomes obtained for several values of the acute angle of the rhombus, the Knudsen number (i.e., rarefaction effects), and the Brinkman number (i.e., viscous dissipation effects) reveal that viscous forces play an opposite role with respect to rarefaction and significantly affect the convective heat transfer coefficient, especially for low Knudsen numbers and for high values of the acute angle. In particular, it was observed that Nu is significantly affected by the Brinkman number for acute angles higher than 50°.

Nanoparticle aggregation dynamics on convective heat transfer in third-grade slip flow: A heat transfer application

Solar energy is a natural renewable energy source. The sunlight that spreads the earth’s atmosphere is sufficient to power all of our essentials. The real-world usage of solar energy is critical to fulfilling current and future needs. This article focuses on the vital use of solar energy by utilizing the nanoaggregation concept. A suitable mathematical model is established by considering the flow slip, hydrodynamics, Ohmic, and radiative heats. The modeled problem was resolved using R-K-based shooting process. Simultaneous outcomes are obtained for the aggregation and nonaggregation cases. This study is a practical application of enhanced heat transport in Parabolic Trough Solar Collector (PTSC). It is found that nanoparticle aggregation aids in enlarging the thermal conduction rate of PTSC. This helps with the practical usage of solar energy.

Numerical simulation of melting heat transfer in cylindrical slip flow of complex nanofluid

The heat diffusion in the cylindrical film stream of the second-grade cross nanofluid is examined numerically. In this study, solid nanoparticles of the aluminum alloys AA7072 and AA7075 are submerged in water as the base liquid. A consistent magnetic field is effective to the stream along with the nonlinear radiation, Ohmic heating, and Catteneo–Christov heat flux to inspect base fluid and composite nanofluids’ stream and thermal transport properties. The flow model is created and solved mathematically utilizing the bvp5c MATLAB scheme. Comparable outcomes for water and composite nanofluids have been delivered and explored. The present research focuses on using solar energy with parabolic trough solar collectors (PTSC). It is discovered that the thermal diffusion rate of the AA7072-AA7075-water combination is more remarkable than the base liquid. The external magnetic field's drag force can be used to moderate the flow and thermal areas. Also, radiative heat contributes to boosting the thermal transport rate of composite nanofluid without impacting the wall resistance. Therefore, AA7072-AA7075-water pumping through PTSC will help to improve heat diffusion to a higher level. The findings are original and aid in understanding how well hybrid nanomaterials function in a second-grade non-Newtonian liquid. The information from this study about the elements that contribute to the working fluid's thermal improvement is also helpful to researchers in this field and a broad audience from industries.

Two-dimensional computational fluid dynamics modeling of slip-flow heat transfer in the hot filament chemical vapor deposition process

The computational fluid dynamics (CFD) modeling on the hot filament chemical vapor deposition (HFCVD) process used to produce a diamond film has been conducted to anticipate the heat transfer and calculate the generation of H. The effect in the slip-flow regime owing to the low-pressure process should be considered to simulate the heat transfer accurately. In addition, a heterogeneous reaction occurring on the filament should be included to calculate the generation of H. The parameters to simulate such microscopic phenomena were applied in the present work and validated by comparing the results with the previous work. The thermal accommodation coefficient (TAC) for H2 was determined as 0.3, at which the calculated mass fraction and H concentration showed good agreement. In addition, It was confirmed that the value could be applied over various filament temperatures and operating pressure. Further, the behavior of H is analyzed above the substrate; the analysis results indicate that there is a correlation between the gas temperature and the gradient of H concentration on the substrate. The high gas temperature caused a severe gradient; thus, a non-uniform film may be deposited. The developed modeling method suggested that microscopic phenomena could be simulated without experimental materials. This fact implied that it is possible to anticipate the temperature and H concentration regardless of the structural design.

Analytical solutions of slip flow and H1 heat transfer in elliptical microchannels

The slip flow and heat transfer problems inside a micro- or nano-channel are active research topics. Understanding the velocity and temperature distributions in these channels is essential in both theory and applications. In this paper, the analytical solutions of the fully developed slip flow and heat transfer under the H1 boundary condition in elliptical microchannels are obtained with the velocity slip and temperature jump. The separation of variables method is employed to solve the momentum and energy equations, and the coefficient of the velocity profile is calculated using the binomial series twice. Based on the result of the velocity profile, the analytical solution of the temperature profile is also derived. A new model is deduced to predict the Poiseuille number in elliptical microchannels. The close-form solution of the Nusselt number is first obtained and can serve as a benchmark for other approaches.

Numerical study of chemical reaction and heat transfer of MHD slip flow with Joule heating and Soret–Dufour effect over an exponentially stretching sheet

AbstractA study of Soret–Dufour effects along with chemical reaction, viscous dissipation combining on MHD Joule heating for viscous incompressible flow is presented. It is assumed that fluid is flowing past an angled stretching sheet saturated in porous means. The slip conditions of velocity, concentration, and temperature are accounted for at the boundary. The mathematical expression of the problem contains highly nonlinear interconnected partial differential equations. To convert governing equations into ordinary differential equations, appropriate similarity transformations were utilized. These differential equations with boundary constraints are resolved by homotopy analysis method. Expression for velocity, concentration, and temperature are derived in the form of series. Effects of numerous physical parameters, for example, Schmidt number, Soret number, buoyancy ratio parameter, slip parameter, and so forth, on various flow characteristics are presented through graphs. Numerous values of velocity, concentration, and temperature gradient are tabulated against different parameters. Results show that the fluid velocity increases by enhancing the Soret number, Dufour number, or permeability parameter. The fluid's concentration rises as the Soret number increases, while it falls as the Dufour number, chemical reaction parameter, or permeability parameter increases.

Heat transfer in steady slip flow of tangent hyperbolic fluid over the lubricated surface of a stretchable rotatory disk

The heat transfer phenomenon is beneficial and applicable in engineering, industries, and technological processes. The production of energy with the help of some cheap resources plays a pivotal and renewable role in the industrial development of the countries. Owing to such a significant performance of heat transfer, the steady slip flow and heat transfer of tangent hyperbolic fluid over a lubricating surface of the stretchable rotatory disk is investigated. The effects of MHD, nonlinear radiation, and non-uniform heat source/sink subject to nonlinear boundary conditions are included in motion and energy equations. Because of the lubrication, a thin layer of the power-law fluid is produced at the surface of the disk. Since the lubricating layer is thin, the interfacial conditions are applied at the surface between the fluid and lubricant. The governing nonlinear partial differential equations (PDEs) have been converted into ordinary differential equations (ODEs), which are solved numerically using the Keller-box method. The upshots of pertinent parameters upon the dimensionless distributions of velocity and temperature are deliberated. The surface drag forces and heat transfer rates are computed, and the effects of governing parameters on them are examined. With the enhancement in the slip at the interface and Weissenberg number, the radial and azimuthal velocities enhances close to the disk, whereas they observe two diverse trends for the power-law index. Also, temperature escalates for radiation parameter, and this escalation is prominent for nonlinear radiation.

MHD slip flow and convective heat transfer due to a moving plate with effects of variable viscosity and thermal conductivity

PurposeThe steady two-dimensional laminar boundary layer flow, heat and mass transfer over a flat plate with convective surface heat flux was considered. The governing nonlinear partial differential equations were transformed into a system of nonlinear ordinary differential equations and then solved numerically by Runge–Kutta method with the most efficient shooting technique. Then, the effect of variable viscosity and variable thermal conductivity on the fluid flow with thermal radiation effects and viscous dissipation was studied. Velocity, temperature and concentration profiles respectively were plotted for various values of pertinent parameters. It was found that the momentum slip acts as a boost for enhancement of the velocity profile in the boundary layer region, whereas temperature and concentration profiles decelerate with the momentum slip.Design/methodology/approachNumerical Solution is applied to find the solution of the boundary value problem.FindingsVelocity, heat transfer analysis is done with comparing earlier results for some standard cases.Originality/value100

Slip flow and radiative heat transfer behavior of Titanium alloy and ferromagnetic nanoparticles along with suspension of dusty fluid

The main concern of current investigation is to develop a steady mathematical model for flow and heat transfer of dusty hybrid nanofluid over a stretching sheet. The amended in the energy equations has been executed by indorsing the viscous dissipation expressions. Moreover, the radiation effects are also permitted with help of Rosseland's approximation. In addition, Titanium alloy, ferromagnetic nanoparticles and slip effect are taken in to the account. The consideration of appropriate variables leads to self-similarity expressions. These non-dimensional expressions are treated numerical scheme known as RKF 45th-order technique. To see clear insight of engineering parameters, a detailed graphical workout has been performed. Various substantial quantities like effective Skin friction coefficient and Nusselt number are adequately altered with physical parameters and delineated through various tables. It is recognized that, the reduction in heat transfer in observed in rising values of Pr for both phases. Further, Hybrid nanomaterial flow plays more effective role in heat transportation process as compared to regular nanofluid flow.

Natural convection effects on heat and mass transfer of slip flow of time-dependent Prandtl fluid

Abstract We proposed a mathematical model for an incompressible, viscous, natural convection, and stagnation point slip flow of MHD Prandtl fluid over an infinite plate. The governing flow equations are constructed using the Prandtl rheological model. In account of physical relevance, we investigated the Soret and Dufour effects on the flow field. The complex natured flow equations are transformed to a set of PDEs using a suitable similarity variables. The non-dimensionalized ruling problem together with physical boundary conditions is numerically analyzed via Crank-Nicolson scheme. The velocity, temperature and concentration of the diffusing species distributions are enhanced for higher values of unsteadiness parameter. It is noted that velocity is slightly decreasing for higher values of Reynolds number while smaller values of Re providing more dominant effects on the velocity, temperature and concentration of the diffusing species profiles and enhanced heat and mass transfer rates is noticed. The physical behavior of reduced Nusselt and Sherwood numbers, friction factor, for distinct values of emerging parameters is examined and representative set of graphs are presented. Highlights Flow model is presented for MHD Prandtl fluid flow over an infinite plate. Mathematical model is performed for unsteady flow with Soret and Dufour effects. The proposed model is solved via crank Nicolson finite difference scheme. Simulations are performed for skin friction, Nusselt and Sherwood numbers.

Comment on the paper: “Thermal radiation and chemical reaction effects on boundary layer slip flow and melting heat transfer of nanofluid induced by a nonlinear stretching sheet, M.R. Krishnamurthy, B.J. Gireesha, B.C. Prasannakumara, and Rama Subba Reddy Gorla, Nonlinear Engineering 2016, 5(3), 147-159”

Abstract The present comment concerns some doubtful results included in the above paper.

Spectral Relaxation Method for Powell-Eyring Fluid Flow Past a Radially Stretching Heated Disk Surface in a Porous Medium

In this study we use a spectral relaxation method to investigate heat transfer in axisymmetric slip flow of a MHD Powell-Eyring fluid over a radially stretching surface embedded in porous medium with viscous dissipation. The transformed governing system of nonlinear differential equations was solved numerically using the spectral relaxation method that has been proposed for the solution of nonlinear boundary layer equations. Results were obtained for the skin friction coefficient, the local Nusselt number as well as the velocity and temperature profiles for the same values of the governing physical and fluid parameters. Validation of the results was reached by the comparison with limiting cases from previous studies in the literature. We show that the proposed technique is an efficient numerical algorithm with assured convergence that serves as an alternative to common numerical methods for solving nonlinear boundary value problems. We show that the convergence rate of the spectral relaxation method is significant improved by using the method in conjunction with the successive over - relaxation method.

Comment on the paper “Heat and mass transfer in unsteady MHD slip flow of Casson fluid over a moving wedge embedded in a porous medium in the presence of chemical reaction: Numerical solutions using Keller‐Box method, Imran Ullah, Ilyas Khan, Sharidan Shafie, Numerical Methods for Partial Differential Equations, November 2017, https://doi.org/10.1002/num.22221”

The present comment concerns some doubtful results included in the above paper.

Exploration of Heat and Mass Transfer in the Convective Slip Flow of Non-Newtonian Casson Fluid

The present aim is concerned with heat and mass transfer of an unsteady convective slip flow of Casson fluid flow through a permeable vertical plate with heat source. The influence of radiation absorption and chemical reaction is also taken into consideration. Time depending governing equations are solved by implicit finite difference method using MATLAB. Results for various fluid flow parameter characteristics such as Casson fluid parameter, velocity slip parameter, Biot number, convection diffusion parameter, porosity parameter, Grashof number, heat source and radiative absorption parameter are presented through graphs and tables delineating the effect of various parameters characterizing the flow.

English

English

Convective heat transfer and entropy generation analysis of non-Newtonian power-law fluid flows in parallel-plate and circular microchannels under slip boundary conditions

This study deals with convective heat transfer and entropy generation analysis of slip flow of non-Newtonian power-law fluids through parallel-plate and circular microchannels. The microchannels were subjected to uniform heat flux boundary condition at the wall. The governing equations relevant to both hydrodynamically and thermally fully developed laminar flows were analytically solved using non-linear slip boundary condition while also including viscous dissipation. Analytical closed form solution of the velocity profiles, temperature distributions, Nusselt number, entropy generation rate and Bejan number in terms of different parameters such as slip coefficient, power-law index and Brinkman number were obtained. The results indicate that increase of the slip coefficient leads to an increase in Nusselt number and a decrease in average entropy generation rate. The effect of slip coefficient on Bejan number is strongly affected by Brinkman number. Low values of either power-law index or Brinkman number result in better working performance of microfluidic systems. Under same conditions, parallel-plate microchannel produce more entropy than circular microchannel. Viscous dissipation significantly affects heat transfer and entropy generation characteristics and cannot be neglected. The results of current study are helpful in deep understanding of flow and heat transfer rates and also designing more thermally efficient microfluidic devices which utilize non-Newtonian fluids.

Heat and mass transfer in unsteady MHD slip flow of Casson fluid over a moving wedge embedded in a porous medium in the presence of chemical reaction: Numerical Solutions using Keller‐Box Method

The hydromagnetic mixed convection flow of Casson fluid due to moving wedge embedded in a porous medium in the presence of chemical reaction and viscous dissipation is investigated. The Joule heating due to a magnetic field and porous medium heating is also considered. Similarity transformations are utilized to convert nonlinear partial differential equations into nonlinear ordinary differential equations. The resulting equations are solved numerically via Keller‐box method. The numerical results are achieved for limiting cases and are revealed in close agreement with those of the results available in the literature. It is noticed that unsteadiness parameter thinning the velocity boundary layer while opposite to this was found in the thermal and concentration boundary layers. The dimensionless temperature is observed to be enhanced with increment in Eckert number.

Thermal dispersion effects on heat transfer of laminar gas flow in a microtube filled with porous medium

In this paper, dispersion effects on forced convection heat transfer in a gaseous slip flow through a microtube filled with anisotropic porous medium are investigated semi-numerically. Microtube is subjected to constant heat flux and a local thermal non-equilibrium condition is assumed. Rarefaction effects are taken into account by applying first-order velocity slip and temperature jump boundary conditions. Dispersion is proven to have a significant impact on heat transfer in rarefied gases. Temperature distributions for both solid and fluid phases are obtained. Nusselt number variation with respect to porous shape factor and Biot number is illustrated, indicating enhancement up to 10% in predicted heat transfer due to dispersion. The influence of Reynolds number on thermal dispersion is proven to be insignificant. Dispersion plays a significant role as gas becomes more rarefied. It is seen that an increase in shape factor of a porous media can improve Nu for a non-rarefied gas, but as rarefaction effects grow, this can affect heat transfer negatively. Also, effects of dispersion on heat transfer diminishes for higher values of Biot Number due to the overcoming of interstitial heat transfer to thermal dispersion effect.

Intelligent computing strategy to analyze the dynamics of convective heat transfer in MHD slip flow over stretching surface involving carbon nanotubes

Abstract The research work presents the dynamics of system based on the model of convective heat transfer in Magnetodydrodynamics (MHD) slip flow over stretching surface with single-wall carbon nanotubes (CNTs) by exploiting the strengths of intelligent computing procedures including artificial neural networks (ANNs), genetic algorithms (GAs) and sequential quadratic technique (SQP). Using similarity transformation, the boundary layer mechanism for the baseline nanofluidics system modeled by partial differential equations (PDEs) is reduced to coupled ordinary differential equations (ODEs). The transformed system is modeled in an unsupervised manner with feed-forward ANNs and efficient adaptation of these networks is performed with global search optimization using GA, aided with SQP for local search. The proposed scheme is evaluated to analyze the dynamics of nanofluidics by taking different concentrations of single-wall CNTs based nano-materials mixed with base fluids such as water, kerosene oil or engine oil. Reliability and correctness of the proposed scheme is established through simulation experiments with results which consistently match with Adams numerical procedure. Moreover, Monte Carlo simulations based statistical analysis has been performed to validate the accuracy of the results in terms of performance metrics of variance account for (VAF), mean absolute error (MAE) and root mean square error (RMSE).

Slip Flow and Radiative Heat Transfer on a Convectively Heated Vertical Cylinder

Slip Flow and Radiative Heat Transfer on a Convectively Heated Vertical Cylinder