Hartmann number

About: Hartmann number is a research topic. Over the lifetime, 2593 publications have been published within this topic receiving 61342 citations.

Unsteady magneto-hydrodynamics flow between two orthogonal moving porous plates

Abstract: An investigation has been performed to describe the unsteady MHD, laminar, incompressible and two-dimensional motion of viscous fluid between two orthogonal moving porous plates. The similarity transformation is adopted to amend the governing model into a non-linear problem of the ordinary differential equation. The homotopy analysis method (HAM) is then invoked to get the approximate solution. The influence of different substantial parameters such as wall permeable ratio, Reynold's number and Hartmann number are explained in detail. A further HAM's comparison is shown with an efficient numerical technique.

Effects of partial slip on entropy generation and MHD combined convection in a lid-driven porous enclosure saturated with a Cu–water nanofluid

Abstract: In this work, the influences of heat generation/absorption and nanofluid volume fraction on the entropy generation and MHD combined convection heat transfer in a porous enclosure filled with a Cu–water nanofluid are studied numerically with of partial slip effect. The finite volume technique is utilized to solve the dimensionless equations governing the problem. A comparison with already published studies is conducted, and the data are found to be in an excellent agreement. The minimization of entropy generation and the local heat transfer according to various values of the controlling parameters are reported in detail. The outcome indicates that an augmentation in the heat generation/absorption parameter decreases the Nusselt number. Also, when the volume fraction is raised, the Nusselt number and entropy generation are reduced. The impact of Hartmann number on heat transfer and the Richardson number on the entropy generation and the thermal rendering criteria are also presented and discussed.

Effect of magnetic field on mixed convection and entropy generation of hybrid nanofluid in an inclined enclosure: Sensitivity analysis and optimization

Abstract: In this paper, a numerical study has been examined on the effect of the presence of a magnetic field on the rate of convective heat transfer and entropy generation of a hybrid nanofluid (water/Al2O3-CuO (50/50)) in a square diagonal cavity. The horizontal walls of the insulating cavity and fixed temperature source are set on the left and right vertical wall with cold temperature. The governing equations are solved by finite volume method using the SIMPLE algorithm. In this paper, the effect of the Richardson number, Hartman number, thermal source length on hybrid entropy generation and convective heat transfer rate has been examined. Using the Response Surface Methodology (RSM) method, a polynomial equation is obtained between the three parameters given for the Nusselt number, total entropy generation and Bejan number. Then the sensitivity of responses to factors is checked. Finally, depending on the importance of each of the responses, we use the optimal points where simultaneously the highest Nu number, the lowest entropy generation, and Bejan number occur. The results show that with increasing Richardson number, heat transfer rate is reduced, and this reduction is more pronounced in smaller Hartmann number. Also, total entropy generation increased with increasing Richardson number, but Bejan number reduced. With increasing the intensity of the magnetic field and reducing the length of the thermal source, the heat transfer rate also reduces. However, with increasing the intensity of the magnetic field, the total entropy generation and Bejan number increase. Also, with increasing the length of the thermal source, the total entropy generation and Bejan number increase.