Enhanced heat transfer in Poiseuille–Rayleigh–Bénard flows based on dielectric-barrier-discharge plasma actuation

Abstract

Poiseuille–Rayleigh–Bénard (PRB) flow has been observed in nature as well as many industrial applications. Enhancing the rate of heat transfer of PRB flow has long been a subject of interest in the relevant research. This study proposed a novelty non-intrusive method to control PRB flow through numerical simulations by using jets generated by nine groups of alternating-current dielectric-barrier-discharge (AC-DBD) plasma actuators arranged in the spanwise direction. We considered PRB flows (Pr = 2/3) in air in channels with an aspect ratio equal to length/height = 20, with Reynolds numbers in the range of 10 ≤ Re ≤ 100 and a Rayleigh number of Ra = 10 000. The effect of plasma control on PRB flow was qualitatively and quantitatively analyzed. The results showed that at a low Reynolds number (Re = 10, 20, 30), the jet generated by the plasma actuators promoted the plume on the wall to form stable transversal rolls and enhance mixed convection. At a high Reynolds number (Re = 50, 100), the jet suppressed Poiseuille flow, promoted the rise in the flow of heat at the bottom wall, and enhanced the vertical temperature gradient. Moreover, steady DBD plasma actuation-based control significantly improved the coefficient of heat transfer of the flow, at times providing up to a tripling of transport compared to the unactuated case. The results here are useful for technological and industrial applications.