Turbulent Free Convection Heat Transfer to Air from Vertical Parallel Plates

Abstract

Turbulent free convection heat transfer to air from vertical parallel plates (height of 5000 mm and spacings B of 50, 100 and 200 mm) were studied experimentally. Turbulence quantities (intensities and correlations of fluctuating temperature and velocities, and turbulent shear stress) in the induced flow between the parallel plates were measured using LDV and fine thermocouples at height X (=820, 1690, 2630 and 3840 mm). The measured streamwise variations of the turbulence quantities, which were affected by the inlet disturbances in the upstream flow region, demonstrated that there were three types of flow regions corresponding to the laminar, transition and turbulent regions of the free convection boundary layer on a single vertical plate. The characteristics of the turbulence quantity profiles in each flow region were consistent with those of the local Nusselt number distributions on heated plates, calculated from the vertical distributions of temperature on it.