Soret effect on mixed convection flow in a nanofluid under convective boundary condition

Although many studies have been conducted on the nanofluid flow in microtubes, this paper, for the first time, aims to investigate the effects of nanoparticle diameter and concentration on the velocity and temperature fields of turbulent non-Newtonian Carboxymethylcellulose (CMC)/copper oxide (CuO) nanofluid in a three-dimensional microtube. Modeling has been done using low- and high-Reynolds turbulent models. CMC/CuO was modeled using power law non-Newtonian model. The authors obtained interesting results, which can be helpful for engineers and researchers that work on cooling of electronic devices such as LED, VLSI circuits and MEMS, as well as similar devices.,Present numerical simulation was performed with finite volume method. For obtaining higher accuracy in the numerical solving procedure, second-order upwind discretization and SIMPLEC algorithm were used. For all Reynolds numbers and volume fractions, a maximum residual of 10−6 is considered for saving computer memory usage and the time for the numerical solving procedure.,In constant Reynolds number and by decreasing the diameter of nanoparticles, the convection heat transfer coefficient increases. In Reynolds numbers of 2,500, 4,500 and 6,000, using nanoparticles with the diameter of 25 nm compared with 50 nm causes 0.34 per cent enhancement of convection heat transfer coefficient and Nusselt number. Also, in Reynolds number of 2,500, by increasing the concentration of nanoparticles with the diameter of 25 nm from 0.5 to 1 per cent, the average Nusselt number increases by almost 0.1 per cent. Similarly, In Reynolds numbers of 4,500 and 6,000, the average Nusselt number increases by 1.8 per cent.,The numerical simulation was carried out for three nanoparticle diameters of 25, 50 and 100 nm with three Reynolds numbers of 2,500, 4,500 and 6,000. Constant heat flux is on the channel, and the inlet fluid becomes heated and exists from it.,The authors obtained interesting results, which can be helpful for engineers and researchers that work on cooling of electronic devices such as LED, VLSI circuits and MEMS, as well as similar devices.,This manuscript is an original work, has not been published and is not under consideration for publication elsewhere. About the competing interests, the authors declare that they have no competing interests.

Investigating the effect of nanoparticles diameter on turbulent flow and heat transfer properties of non-Newtonian carboxymethyl cellulose/CuO fluid in a microtube

The present study is intended to study heat and mass transfer in a vertical annular cylinder embedded with saturated porous medium. The inner surface of cylinder is maintained at uniform wall temperature and uniform wall concentration. The governing partial differential equations are non-dimensionalised and solved by using finite element method (FEM). The porous medium is discritised using triangular elements with uneven element size. Large number of smaller-sized elements are placed near the walls of the annulus to capture the smallest variation in solution parameters. The results are reported for both aiding and opposing flows. The effects of various non-dimensional numbers such as buoyancy ratio, Lewis number, Rayleigh number, aspect ratio, etc on heat and mass transfer are discussed. The temperature and concentration profiles are presented.

Analysis of Heat and Mass Transfer in a Vertical Annular Porous Cylinder Using FEM

Magnetic effect on thermally stratified nanofluid saturated non-Darcy porous medium under convective boundary condition

The two-dimensional steady laminar boundary-layer free convective flows along an isothermal solid horizontal flat plate located in a porous quiescent medium filled with non-Newtonian power law nanofluids that contain both nanoparticles and gyrotactic microorganisms are investigated numerically. The horizontal plate has uniform surface temperature, solute, nanoparticle concentrations and density of the motile microorganism. The governing partial differential equations are nondimensionalized, and then similarity transformations are developed using a linear group of transformations. Using similarity transformation, the governing equations are reduced to a system of nonlinear ordinary differential equations, which are solved numerically. The influence of controlling parameters on the dimensionless velocity, temperature, nanoparticle concentration, and density of motile microorganisms, as well as the local Nusselt, Sherwood, and motile microorganism numbers, are studied. It is found that the bioconvection para...

https://arc.aiaa.org/doi/pdf/10.2514/1.T4746

Free Convective Flow of Non-Newtonian Nanofluids in Porous Media with Gyrotactic Microorganism

Effect of viscous dissipation on natural convection heat and mass transfer from vertical cone in a non-Newtonian fluid saturated non-Darcy porous medium

\n Microorganism cells movement in the fluid is universal and affects many ecological and biological processes, including infection, reproduction, and marine life ecosystem. There are many biological and medical applications that require an understanding of the transport process in nanofluids containing a suspension of microorganism. The present problem deals with the bioconvection of Casson nanofluid containing a suspension of motile gyrotactic microorganisms over an inclined stretching sheet in the presence of thermal radiation, viscous dissipation, and chemical reaction and magnetic field. At the surface, the influence of the thermosolutal Marangoni convection and suction/injection impact are considered. The governing equations are solved numerically by using fourth-order Runge–Kutta–Fehlberg method with shooting technique. The impact of the major pertinent parameters on the velocity, temperature, nanoparticles concentration, and density of the motile microorganism is illustrated graphically. Finally, the correlations of various crucial parameters on skin friction, local Nusselt number, Sherwood number, and local motile microorganism density number are displayed through the graphs and tables.

Thermosolutal Marangoni Impact on Bioconvection in Suspension of Gyrotactic Microorganisms Over an Inclined Stretching Sheet

Double dispersed bioconvective Casson nanoﬂuid fluid ﬂow over a nonlinear convective stretching sheet in suspension of gyrotactic microorganism

This paper investigates the influence of melting and thermo-diffusion effect on natural convection heat and mass transfer from vertical flat plate in a non-Newtonian fluid saturated non-Darcy porous medium. The wall and the ambient medium are maintained at constant but different levels of temperature and concentration such that the heat and mass transfer occurs from the wall to the medium. The Ostwald-de Waele power law model is used to characterize the non-Newtonian fluid behavior. A similarity solution for the transformed governing equations is obtained, computation is carried out for various values of the non-dimensional physical parameters. The variation in velocity, temperature, concentration, heat and mass transfer coefficients with the power law index, inertia parameter, melting parameter, thermo- diffusion parameter, buoyancy ratio and Lewis number is discussed for a wide range of values of these parameters.

Rishi Raj Kairi

Papers

Effect of viscous dissipation on natural convection heat and mass transfer from vertical cone in a non-Newtonian fluid saturated non-Darcy porous medium

Thermosolutal Marangoni Impact on Bioconvection in Suspension of Gyrotactic Microorganisms Over an Inclined Stretching Sheet

Double dispersed bioconvective Casson nanoﬂuid fluid ﬂow over a nonlinear convective stretching sheet in suspension of gyrotactic microorganism

Effect of Melting and Thermo-Diffusion on Natural Convection Heat Mass Transfer in a Non-Newtonian Fluid Saturated Non-Darcy Porous Medium

Effect of double dispersion on mixed convection heat and mass transfer in a non-newtonian fluid-saturated non-darcy porous medium