Journal of Thermal Analysis and Calorimetry - The paper presents the mixed convection heat transfer and entropy generation of a nanofluid containing carbon nanotubes, flowing in a 3D rectangular... 相似文献
This work is focused on the numerical modeling of steady, laminar, heat and mass transfer by MHD mixed convection from a semi-infinite,
isothermal, vertical and permeable surface immersed in a uniform porous medium in the presence of thermal radiation and Dufour
and Soret effects. A mixed convection parameter for the entire range of free-forced-mixed convection is employed and the governing
equations are transformed into non-similar equations. These equations are solved numerically by an efficient, implicit, iterative,
finite-difference scheme. The obtained results are checked against previously published work on special cases of the problem
and are found to be in excellent agreement. A parametric study illustrating the influence of the thermal radiation coefficient,
magnetic field, porous medium inertia parameter, concentration to thermal buoyancy ratio, and the Dufour and Soret numbers
on the fluid velocity, temperature and concentration as well as the local Nusselt and the Sherwood numbers is conducted. The
obtained results are shown graphically and the physical aspects of the problem are discussed. 相似文献
Journal of Thermal Analysis and Calorimetry - Bioconvection in magneto-nanoliquid embedded with gyrotactic microorganisms across an elongated sheet with velocity slip of second order is addressed.... 相似文献
An analysis has been carried out to determine the development of momentum and heat transfer occurring in the laminar boundary
layer of an incompressible viscous electrically conducting fluid in the stagnation region of a rotating sphere caused by the
impulsive motion of the free stream velocity and the angular velocity of the sphere. At the same time the wall temperature
is also suddenly increased. This analysis includes both short and long-time solutions. The partial differential equations
governing the flow are solved numerically using an implicit finite-difference scheme. There is a smooth transition from the
short-time solution to the long-time solution. The surface shear stresses in the longitudinal and rotating directions and
the heat transfer are found to increase with time, magnetic field, buoyancy parameter and the rotation parameter.
Received on 27 January 2000 相似文献
In this paper, the melting process of a PCM inside an inclined compound enclosure partially filled with a porous medium is theoretically addressed using a novel deformed mesh method. The sub-domain area of the compound enclosure is made of a porous layer and clear region. The right wall of the enclosure is adjacent to the clear region and is subject to a constant temperature of Tc. The left wall, which is connected to the porous layer, is thick and thermally conductive. The thick wall is partially subject to the hot temperature of Th. The remaining borders of the enclosure are well insulated. The governing equations for flow and heat transfer, including the phase change effects and conjugate heat transfer at the thick wall, are introduced and transformed into a non-dimensional form. A deformed grid method is utilized to track the phase change front in the solid and liquid regions. The melting front movement is controlled by the Stefan condition. The finite element method, along with Arbitrary Eulerian–Lagrangian (ALE) moving grid technique, is employed to solve the non-dimensional governing equations. The modeling approach and the accuracy of the utilized numerical approach are verified by comparison of the results with several experimental and numerical studies, available in the literature. The effect of conjugate wall thickness, inclination angle, and the porous layer thickness on the phase change heat transfer of PCM is investigated. The outcomes show that the rates of melting and heat transfer are enhanced as the thickness of the porous layer increases. The melting rate is the highest when the inclination angle of the enclosure is 45°. An increase in the wall thickness improves the melting rate.
Journal of Thermal Analysis and Calorimetry - The current problem is performed to analyze the heatline visualization of the mixed convection mechanism and heat transfer in a double lid-driven... 相似文献
The problem of steady, laminar, mixed convection boundary-layer flow over an isothermal vertical wedge embedded in a porous
medium saturated with a nanofluid is studied, in the presence of thermal radiation. The model used for the nanofluid incorporates
the effects of Brownian motion and thermophoresis with Rosseland diffusion approximation. The wedge surface is maintained
at a constant temperature and a constant nanoparticle volume fraction. The resulting governing equations are non-dimensionalized
and transformed into a non-similar form and then solved by Keller box method. A comparison is made with the available results
in the literature, and our results are in very good agreement with the known results. A parametric study of the physical parameters
is made, and a representative set of numerical results for the velocity, temperature, and volume fraction, the local Nusselt
and Sherwood numbers are presented graphically. The salient features of the results are analyzed and discussed. 相似文献
An analysis is performed to study unsteady free convective boundary layer flow of a nanofluid over a vertical cylinder. The model used for the nanofluid incorporates the effects of Brownian motion and thermophoresis. The governing equations are formulated and a numerical solution is obtained by using an explicit finite-difference scheme of the Crank-Nicolson type. The solutions at each time step have been found to reach the steady state solution properly. Numerical results for the steady-state velocity, temperature and nanoparticles volume fraction profiles as well as the axial distributions and the time histories of the skin-friction coefficient, Nusselt number and the Sherwood number are presented graphically and discussed. 相似文献
The problem of double-diffusive convection in inclined finned triangular porous enclosures for various thermal and concentration
boundary conditions and in the presence of heat source or sink was studied. The finite difference method was employed to solve
the dimensionless governing equations of the problem. The effects of the governing parameters, namely the dimensionless time
parameter, the inclination angle, Darcy number, heat generation/absorption parameter, the buoyancy parameter and the Rayleigh
number on the streamlines, temperature and concentration contours as well as selected velocity component in the x-direction, local and average Nusselt numbers and local and average Sherwood number at the heated and concentrated wall for
various values of the aspect ratio and the position of the fin were considered. The present results are validated by favorable
comparisons with previously published results. All the results of the problem were presented in graphical and tabular forms
and discussed. 相似文献