Cooling of hot cylinder placed in a flexible backward-facing step channel

Abstract

This paper copes with the mixed convection heat transfer and fluid–structure interaction (FSI) of a hot cylinder placed in a backward-step channel. The step is set to be flexible and deforms according to the force imparted by fluid. To attain the best cooling, different configurations of the flexible step were assessed. Equations governing the problem are solved using the finite element technique with the Arbitrary Lagrangian–Eulerian (ALE) approach to go along the moving domain. The influential parameters of such a problem are the Reynolds number Re, Richardson number Ri and the configuration of the flexible back step. Results demonstrated an improvement in the Nusselt number where at Ri = 100, a step of horizontal flexible wall augments the Nusselt number by 7.3% and 1.4% when Re = 100 and 500, respectively. Including the pressure drop in a performance criterion, it is shown that making the vertical wall of the step flexible (VFW) improves the aspects of heat transfer and the hydrodynamic of low Reynolds number, while at high Reynolds number, all suggested configurations of flexible step do not improve the performance criterion. It is found also that Reynolds number greatly improves the performance criterion while Richardson number does not.