Convection Flow Of Fluid Research Articles

Parametric study and application of a data-mining model in 2D and 3D micro-fin tubes

• The application of least squares-support vector regression method in micro-fin study. • The best 2D and 3D micro-fins had similar design parameters. • The best 2D micro-fin tube enhanced the efficiency index up to %18. • Importance of micro-fin’s axial pitch over height ratio on the efficiency index. Micro-fins (<0.5 mm tall) are an engineered roughness with the advantage of reducing thermal resistance and the disadvantage of increased pressure drop when applied inside a tube in heat-exchange applications. The competing effects highlight the need for careful optimization that identifies micro-fin surfaces with the potential to match heat exchanger design needs. Hence, the objectives of this study are chosen to enable efficient optimization in future studies. The main goals are: (1) study the effects of micro-fin design variables on heat transfer and friction factors; and (2) evaluate the potential of a data-mining model as a surrogate of computational fluid dynamic ( CFD ) models in 2 dimensional ( D ) and 3 D micro-fin tubes. This study applied conductive and convective heat transfer and turbulent fluid flow simulation to evaluate the performance of different 2 D and 3 D micro-fin tubes. Different configurations were generated by varying micro-fin height ( e ), helix angle ( α ), number of starts ( N f ), and discontinuity features. Coupled solid and periodic fluid domains were applied in ANSYS Fluent 19.1 . Performance was mapped for 210 different simulations (including a smooth tube) using a realizable k - ε turbulence model at Reynolds number ( Re ) of 48,928. Two different least squares-support vector regression ( LS - SVR ) models were employed to estimate the Colburn j factor as a function of geometric variables and the Fanning friction factor ( f ) as a function of geometric variable and j factor. Results of the parametric study showed that the best 2 D micro-fin tube can enhance efficiency index ( η ) up to 1.18. Results of the LS - SVR model showed that the percentage of average absolute error ( AAE ) between simulated and estimated j and f factors are 2.05% and 2.93% for 3 D micro-fin tubes, respectively.

Transient MHD convective flow of a micropolar fluid past a moving vertical plate in the presence of thermal diffusion

AbstractIn this article, we investigate a transient magnetohydrodynamic convective micropolar fluid flow over a semi‐infinite vertical plate embedded in a porous medium in the presence of chemical reaction and thermal diffusion. The dimensionless governing equations are solved by adopting the regular perturbation technique. The impact of various parameters on the velocity, microrotation, temperature, concentration profiles, skin friction, Sherwood number, and Nusselt number over the boundary layer is analyzed using graphs. The fluid velocity and microrotation reduce under the effect of thermal diffusion and chemical reaction. Furthermore, concentration rises due to thermal diffusion (Soret) effect, but concentration falls under the effect of chemical reaction. It is found that the velocity and skin friction fall with enhancing value of magnetic parameter. But Sherwood number increases as the magnetic parameter increase.

Effect of the Spacing Design of Two Alternate Baffles on the Performance of Heat Exchangers

The present study investigates numerically the heat transfer process based forced convective flow of an incompressible fluid in a two-dimensional rectangular channel. Two baffles are imposed periodically on the lower and upper walls. The study mainly focused on the influence of the arrangement and spacing separating the baffles on the heat transfer's intensification. The values of the Reynolds number for the present turbulent flow regime were chosen in the range of 104 to 8.73 × 104. The equations resulting from the three conservation laws, namely continuity, Navier-Stokes, and energy equations, are solved numerically based on the finite volume method. SIMPLE algorithm is used to overcome the pressure-velocity coupling, and k-ε model is used for the computation of turbulent patterns. Numerical simulations are carried out to study the dynamic and thermal behavior influenced by the control parameters. The physical quantities calculated are the axial velocity, the local, mean Nusselt numbers and the friction coefficient. The obtained results show that the friction coefficient decreases proportionally with the increase of Re number, and the local Nusselt number increases with the Reynolds number. As the spacing between the baffles decreases, the NR ratio increases, and as the Reynolds number increases, NR decreases NR = 6.13, 5.31, 4.62, and 4.30 for case P1, NR = 5.1, 4.5, 3.89, and 3.64, for case P2, NR = 5.00, 4.45, 8.83, and 3.51, for case P3, for equal Reynolds number, 104, 2×104, 4×104, 8.73×104, respectively.

Slip Effects on Unsteady MHD Free Convective Flow of Rivlin-Ericksen Fluid in the Presence of Heat Source/Sink

In the present work, an investigation on MHD flow of viscoelastic fluid of Rivlin-Ericksen type across a semi-infinite plate in the presence of heat source/sink under free convection is conducted. The plate is moving with constant velocity subjected to periodic suction along with slip conditions. Further, the free stream velocity is taken of oscillatory in nature. The transport equations governing the flow are solved using perturbation analysis. The solutions obtained for the required fields viz. velocity, temperature, and concentration which characterizes the flow are discussed graphically for varying situational parameters appeared in the flow. The presence of heat source/sink in the vicinity of considered fluid has significant effect on the velocity near the plate. Further, the drag at the plate, Nusselt and Sherwood number, are evaluated for varying situational parameters which are compiled in the tabular format.

Lorentz force and Darcy-Forchheimer effects on the convective flow of non-Newtonian fluid with chemical aspects

The purpose of this study is to inspect the flow of magneto-hydrodynamic third-grade liquid through Darcy-Forchheimer’s porous space with variable features. Energy expression is explored by the convective condition and Joule heating effect. Features of homogeneous-heterogeneous reactions are accounted. Both auto-catalysts and reactants are considered equal diffusion coefficients. The incompressible liquid is conducted electrically. Proper variables convert the nonlinear flow systems to ordinary ones. Then the HAM technique is implemented for the series solution. The upshots of various variables such as the Magnetic variable, diffusion coefficient ratio parameter, Baiot number, and Prandtl number are displayed graphically. Numerical data of drag force is executed and elaborated. Our outcomes declared that temperature gradient enhances with increment in magnetic parameter and Biot number. Moreover, concentration shows a contrary trend against higher strength of homogeneous and heterogeneous reactions.

Features of energy transfer in buoyancy-driven unsteady flow of Maxwell fluid via Cattaneo–Christov theory

The characteristics of mixed convective unsteady two-dimensional laminar Maxwell fluid flow engendered by the stretchable cylinder in the presence of a Lorentz force are the subject of this article. The partial differential equations (PDEs) that govern the physical problem are formulated by utilizing convective phenomena for heat and mass transportation under specific suppositions for controlling energy transport. Ordinary differential equations (ODEs) are derived from partial differential equations (PDEs) using appropriate similarity transformations. The numerical outcomes for the velocity field, thermal, and solutal energy transport are calculated using the MATLAB approach bvp4c and presented in graphical abstracts. These outcomes prove that the transportation of thermal and solutal energy is controlled by the phenomenon of relaxation for thermal waves. Moreover, increase in the buoyant fluid motion, the convective heat energy transport declines. The fluid motion is also decreased due to increment in relaxation time while fluid solidity of material improves heat conduction.

Numerical Investigation of Forced Convective Heat Transfer and Fluid Flow Analysis in a Double Lid Driven Staggered Cavity With Various Blocks

Numerical Investigation of Forced Convective Heat Transfer and Fluid Flow Analysis in a Double Lid Driven Staggered Cavity With Various Blocks

Effect of multiple forces on convective micropolar fluid flow in a permeable channel with stretching walls considering second order slip conditions

This paper is intended to study the impact of velocity and thermal slip boundary conditions of order two on MHD buoyancy driven radiative micro-polar fluid in a channel with permeable stretching walls. The governing equations are transformed and solved numerically. Convergence of the numerical results are tested with grid independence test and obtained results are validated by comparing with existing results. The influence of velocity and thermal slip of order two, suction or injection, vortex viscosity, micro-rotation, magnetic and thermal radiation parameters on fluid velocity, microrotation profiles and temperature distributions are discussed over the graphs and tables. It is worth mentioning that second- order velocity and thermal slips dominate the stretchable walls and influence the flow characteristics (axial velocity, micro-rotation and temperature) more prominently. The micro-rotation profile decreases at and increases at of the channel for the first slip. This study is useful in blood rheology and fibre spinning etc. and these findings are highly useful to enhance the effectiveness of catalytic reactors.

Heat and mass transfer analysis of chemically reactive non-Newtonian fluid with the implementation of generalized Fourier’s and Fick’s laws over a vertical sheet

This article focuses on the 2D nonlinear mixed convective MHD Casson fluid flow influenced by the gyrotactic microorganism boundary layer and nonlinear thermal radiation across the vertical stretching sheet. The solutal and thermal energy analysis is established applying the Cattaneo–Christov theory and thermophoretic impact. The stratification boundary condition and injection/suction effects are imposed on the surface of the boundary. The developed flow model PDEs are assimilated into nonlinear ODEs using appropriative conversion. The built-in Bvp4c Matlab approach is used on the converted nonlinear equations. It is analyzed from the graph that the stronger estimation of magnetic and Casson fluid parameters declines the fluid velocity by the occurrence of resistive forces. More heat transfer in the fluid was due to a larger estimation of radiation parameter. Additionally, it is found from the numerical values of tables that the improvement occurs in the skin friction with the augmentation of buoyancy ratio and mixed convection parameter.

An impact on non-Newtonian free convective MHD Casson fluid flow past a vertical porous plate in the existence of Soret, Dufour, and chemical reaction

The objective of this research is to explore the heat and mass transfer properties of an unsteady MHD natural convective Non-Newtonian, Casson fluid flow through a permeable vertical plate in the existence of Soret, Dufour, and chemical reaction. The aspects of heat and radiation absorptions are also factored in. Applications of the present study would be useful in magnetic material processing and chemical engineering systems. Mathematically, the flow field situation is expressed in terms of partial differential equations. The transformed flow-narrating partial differential equations of momentum as well as energy and species concentration were numerically solved using the finite element technique. Non-dimensional flow parameters were used to extract the numerical outcomes of velocity, temperature, and concentration, and the outcomes are envisioned graphically. The significance of the factors determining, Nusselt number, Sherwood number, and skin friction is also considered. The outcomes reveal that raising the permeability parameter causes the velocity to improve while enhancing the Casson parameter causes the velocity distribution to reduce.

Mixed convective flow of a magnetohydrodynamic Casson fluid through a permeable stretching sheet with first-order chemical reaction.

This research article presents the magnetohydrodynamic Casson fluid flow through an extending surface embedded in a porous medium. Furthermore, the Casson fluid flow is investigated under the effects of thermal radiation, Joule heating, viscous dissipation, and chemical reaction. The analytical solution of the modeled problem is utilized with the help of homotopy analysis method (HAM). The convergence region of the applied technique is portrayed graphically. The impacts of the embedded factors on the flow profiles are exhibited with the help of figures. Furthermore, numerical values of the surface drag force, heat, and mass transfer rates are highlighted via table. The results show that the augmented Darcy number, Casson and magnetic parameters have declined the velocity profile of the Casson fluid flow. Growth in Brownian motion augments the chaotic motion amongst the particles due to which the kinetic energy of the particles transforms to heat energy which consequently augmented the thermal profile, while reduced the concentration profile. The mass and energy profiles are positively effects with the increment of thermophoresis term. And the growing values of chemical reaction and Lewis number cause a reduction in the diffusivity of mass of fluid due to which less transfer of mass takes place that weakens the concentration layer thickness and declines the concentration profiles.

Magnetoconvection around an elliptic cylinder placed in a lid‐driven square enclosure subjected to internal heat generation or absorption

AbstractThe impacts of MHD and heat generation/absorption on lid‐driven convective fluid flow occasioned by a lid‐driven square enclosure housing an elliptic cylinder have been investigated numerically. The elliptic cylinder and the horizontal enclosure boundaries were insulated and the left vertical lid‐driven wall was experienced at a fixed hot temperature, and the right wall was exposed to a fixed cold temperature. COMSOL Multiphysics 5.6 software was used to resolve the nondimensional equations governing flow physics. A set of parameters, such as Hartmann number (), Reynolds number (), Grashof number (), heat generation‐absorption parameter (), and elliptical cylinder aspect ratio (AR) () have been investigated. The current study discovered that for low Reynolds number, the adiabatic cylinder AR of 2.0 provided the optimum heat transfer enhancement for the model investigated, also the impact of cylinder size diminishes beyond Gr = 104. But for high Reynolds (Re = 1000), the size of the cylinder with AR = 3.0 offered the highest heat transfer augmentation. The clockwise flow circulation reduces because of an increase in AR, which hinders the flow circulation. In addition, heat absorption supports heat transfer augmentation while heat generation can suppress heat transfer improvement.

Effects of the Rotation on the Mixed Convection Heat Transfer Analysis for the Peristaltic Transport of Viscoplastic Fluid in Asymmetric Channel

In this paper, we study the impact of the variable rotation and different variable on mixed convection peristaltic flow of incompressible viscoplastic fluid. This is investigated in two dimensional asymmetric channel, such as the density, viscosity, rate flow, Grashof number, Bingham number, Brinkman number and tapered, on the mixed convection heat transfer analysis for the peristaltic transport of viscoplastic fluid with consideration small Reynolds number and long wavelength, peristaltic transport in asymmetric channel tapered horizontal channel and non-uniform boundary walls to possess different amplitude wave and phases. Perturbation technique is used to get series solutions. The effects of different values of these parameters for the axial velocity, stream function, stress, temperature and pressure gradient have been obtained. The impact of these parameters is discussed and illustrated graphically through the set of figures. Numerical results have been computed by using MATHEMATICA software.

Thermo-solutal dual stratified convective magnetized fluid flow from an exponentially stretching Riga plate sensor surface with thermophoresis

A theoretical study is presented for the coupled thermo-solutal free convection two-dimensional boundary layer flow of a of a magnetized fluid from an exponentially stretched magnetic sensor (Riga plate) surface. Heat generation/absorption, nonlinear thermal radiation and thermophoretic body force effects are included. Furthermore, thermal and solutal stratification are also featured in the boundary layer model. The derived nonlinear partial differential equation system with associated wall (sensor surface) and free stream boundary conditions is transformed to system of ordinary differential equations (ODE) via applicable similarity variables. A numerical solution is developed with the efficient Runge–Kutta–Fehlberg (RKF) technique with a shooting numerical method, in MATLAB software using the RKF-45 method. The graphical profiles were represented to examine the impacts of physically parameterics on the important physical stream features. Streamline and isotherm plots are also included for thermal buoyancy effect (Grashof number).Validation of solutions with earlier simpler models is included. A relatively well agreement is achived between model prediction and the benchmark value. Values for skin friction factor, Nusselt number and Sherwood numbers are also tabulated to quantify momentum, heat and mass (species) transfer characteristics at the sensor surface. The results indicate that the significant depletion in temperature accompanies accumulation in magnetization and thermal stratification parameters. Significant accumulation in mixed convection and Riga plate electrode width parameter enhance the concatenation profiles. Nusselt number grows substantially as thermal stratification and radiative parameter increases. Sherwood number grows substantially as solutal stratification, thermophoresis and Schmidt parameter increases. The present study generalizes previous models to include simultaneously exponential stretching, thermophoresis, thermal and solutal (mass) stratification and heat source/sink effects.

Convective flow of Carreau fluid over a curved surface in presence of thermophoresis and Brownian motion

The aim of this article is to develop the numerical study of the convective flow of a Carreau fluid due to curved stretchable surface in the presence of viscous dissipation effect. onvective condition is considered at the boundary. The effects of thermophoresis and Brownian motion are also taken into consideration. The modeled equations of the problem are converted from nonlinear partial differential equations (PDEs) to nonlinear ordinary differential equations (ODEs) by using similarity variables. The resulting non linear ordinary differential equations are solved numerically by using the shooting technique. It is observed that the temperature of the fluid decreases with growing values of thermophoresis and brownian parameters. Brownian parameter declines the concentration of fluid while thermophoresis parameter enhances the concentration of fluid. Thermophoresis and Brownian parameter reduces the local Nusselt number but reverse behavior is noted in the case of the Sherwood number. The impactsof various flow parameters on velocity, temperature, and concentration distributions are explored graphically and deliberated in detail. The results of skin friction, Nusselt number, and Sherwood number are discussed in tabular form for various parameters.

Mixed Convection in a Lid-Driven Horizontal Rectangular Cavity Filled with Hybrid Nanofluid by Finite Volume Method

In the present work, a new type of nanofluid called the hybrid nanofluid (Al2O3-Cu-water) is used to enhance the heat transfer. The Finite-Volume-Method (FVM) along with the SIMPLE-algorithm has been utilized to study the heat-transfer and, mixed convection fluid-flow of the hybrid nanofluid (Al2O3-Cu-water), placed within the lid-driven rectangular cavity. The bottom and top walls are subjected to constant high temperature (Th) and low temperature (Tc) respectively. The side walls are treated as adiabatic. The top wall moves in the positive x-direction. The effects of Reynolds number and hybrid nanoparticle volume fraction on the flow field have been investigated. It is found that the mean Nusselt number increases with respect to Reynolds numbers and hybrid nanoparticle volume fraction.

Heat and mass transfer in mixed convection MHD micropolar fluid flow due to non-linear stretched sheet in porous medium with non-uniform heat generation and absorption

In this paper, mixed convection flow is considered with micropolar fluid in the presence of the magnetic field. In addition, the flow is defied with a non-linear stretching sheet through a porous medium. Non-uniform heat generation/absorption as well as chemical reaction are studied. The similarity transformation is used to change the governing equations. The Homotopy Analysis Method is used to solve the system of ODE. The impacts of several important parameters on velocity profiles, angular velocity profiles, temperature profiles and concentration profiles are represented graphically. With the help of tables, the coefficients of Skin friction, Nusselt number, and local Sherwood number are also anticipated and shown. When the new finding results were compared to earlier findings, they revealed a high-level agreement. The findings show that the velocity profile and angular velocity profiles are enhanced by thermal radiation parameter and material parameter. When Biot number and Eckert number are raised, the temperature profiles increase noticeably. Furthermore, when the chemical reaction parameter is raised, the concentration profile is reduced and it is improved as Soret number is increased. Heat transfer rate increased as thermal radiation parameter increased and decreased as Biot number decreased for both linear and non-linear stretching.

Gravity Orientation Effects on Convection in the Gap Between Partially Heated Cylinders

This paper reports the results of numerical simulation of a steady-state convective flow of incompressible fluid in the gap between two coaxial cylinders. It is assumed that only half of the inner cylinder is heated, and the external cylinder is kept at constant temperature. It has been established that the rotation of the heater through a certain angle causes the convective plume axis to deviate. This strongly affects the flow pattern and the related heat transfer process. The maximum integral heat flux is observed when the heater is in its uppermost position, and the minimum heat flux is observed when the heater is located sidewise. Approximating the obtained results, the dependence of the Nusselt number on the Rayleigh parameter and the rotation angle is obtained.

MHD Mixed Convective Slip Flow along an Inclined Porous Plate in Presence of Viscous Dissipation and Thermal Radiation

The present study investigates the mixed convective MHD flow of Newtonian fluid along an inclined permeable plate which is saturated in porous medium. A non-uniform magnetic field along with viscous dissipation and thermal radiation is also considered in the model. Velocity and thermal slip conditions are applied at the plate. Expressions for skin friction and Nusselt number are obtained with the help of suitable similarity transformation. Governing equations are solved numerically by Runge-Kutta fourth order method with shooting technique. Graphs of the fluid velocity and temperature are plotted and their behaviours are discussed. Numerical values of skin friction and Nusselt number are tabulated and analysed.&#x0D; HIGHLIGHTS&#x0D; &#x0D; Rate of heat transfer can be enhanced by decreasing Eckert number or radiation parameter&#x0D; Higher fluid velocity with lesser skin friction can be obtained by using larger values of velocity slip parameter&#x0D; Mixed convection plays a significant role in enhancing fluid velocity&#x0D; &#x0D; GRAPHICAL ABSTRACT

The convective flow of Carreau fluid over a curved stretching surface with homogeneous-heterogeneous reactions and viscous dissipation

This article aims to develop the modeling and simulation of Carreau fluid over a curved stretching surface along with convective boundary conditions in homogeneous-heterogeneous reactions and viscous dissipation. The modeled boundary layer equations are reduced from nonlinear partial differential equations to a structure of ordinary differential equations via relevant transformations. The developed equations are solved numerically by the shooting method. The decrease in the velocity and temperature of the fluid for the growing values of curvature parameter is because the larger values of curvature decline the drag friction. The concentration profile decreases for increasing values of homogeneous reaction, but the effect of heterogeneous reaction on concentration profile away from the boundary is conserved. The Weissenberg number raises the velocity and temperature of the fluid. The impact of various flow parameters on velocity, temperature, and concentration distribution for shear thickening cases is explored graphically and deliberated in detail. Skin-friction and local Nusselt numbers are computed numerically for various parameters through tables.