Mixed convection characteristics in rectangular enclosure containing heated elliptical block: Effect of direction of moving wall

Abstract

The present research numerically explores the hydrodynamic and thermal characteristics due to mixed convection in the rectangular enclosure with one of the vertical wall moving and containing centrally placed heated elliptical block for steady state condition. In particular, the influence of different flow pertaining parameters, such as, the direction of moving vertical wall (either in positive –y or negative –y coordinate directions), aspect ratio of an elliptical cylinder (Er = 0.5, 1 and 2) are studied for the broad range of dimensionless parameters (Reynolds number: 1 ≤ Re ≤ 5000; Prandtl number: 1 ≤ Pr ≤ 100 and Grashof number: 0 ≤ Gr ≤ 105) by using finite volume method (FVM) and SIMPLE numerical approach. The analysis of physical insights of an enclosure is accomplished by systematic evaluation of the streamlines as well as isotherms profiles. In order to compare mean heat transfer from an elliptical cylinder with that of circular shape, normalized Nusselt number (NuN) is estimated. Heat transfer characteristics are more predominantly affected due to the direction of moving lid than the aspect ratio of the elliptical cylinder. Also, the enclosure with moving wall along positive –y direction tends to enhance heat transfer rate. Rather than a pure circular shape, the enclosure with heated elliptical block (Er≠1) shows a higher rate of convective heat transfer.