CFD analysis of heat transfer enhancement by wall mounted flexible flow modulators in a channel with pulsatile flow

The aim of the present study is to explore heat transfer and pressure drop characteristics in a pulsating channel flow due to wall-mounted flexible flow modulators (FFM). Cold air in pulsating fashion is forced to enter through the channel having isothermally heated top and bottom walls with one/multiple FFMs mounted on them. The dynamic conditions of pulsating inflow are characterized by Reynolds number, non-dimensional pulsation frequency and amplitude. Applying the Galerkin finite element method in an Arbitrary Lagrangian-Eulerian (ALE) framework, the present unsteady problem has been solved. Flexibility (10-4 & LE; Ca & LE; 10-7), orientation angle (60 degrees & LE; & theta; & LE; 120 degrees), and location of FFM(s) have been considered in this study to find out the best-case scenario for heat transfer enhancement. The system characteristics have been analyzed by vorticity contours and isotherms. Heat transfer performance has been evaluated in terms of Nusselt number variations and pressure drop across the channel. Besides, power spectrum analysis of thermal field oscillation along with that of the FFM's motion induced by pulsating inflow has been performed. The present study reveals that single FFM having flexibility of Ca =10-5 and an orientation angle of & theta; = 90 degrees offers the best-case scenario for heat transfer enhancement.