Cross-flow transport and heat transfer enhancement in laminar pulsed flow

Abstract

Abstract An experimental investigation to examine the influence of flow pulsation in a rectangular finned channel on cross-flow transport and convective heat transfer intensification was carried out. The fins were arranged in equal spacing and on the insulated wall opposite to the smooth flat heat transfer surface to avoid heat transfer enhancement by conduction. Pulsation amplitude A ranging from 0.28 to 0.53 mm and pulsation frequencies f in the range of 16 ≤ f ≤ 54 Hz were investigated. A steady flow Reynolds number in the laminar range of 50–1140 was studied. Recirculation eddies and complex flow structures formed within the modules were characterized by a mean cross-flow velocity using PIV. The intensification of the heat transfer coefficient due to the flow pulsation becomes more significant with increasing pulsation amplitude. The heat transfer enhancement was found to match with the cross-flow velocity. Maximum heat transfer enhancement, E = 2.5, was achieved at relative fin height, i.e. ratio of fin height to hydrodynamic boundary layer thickness of 29. No significant heat transfer was obtained at very low and very high flow rates.