Experimental study of the effects of a vertical channel on the natural convection of a horizontal cylinder

Abstract

In this study, the natural convective flow and heat transfer from a hot horizontal cylinder surrounded by two vertical plates with a negligible thickness was experimentally investigated. These plates act as a channel so that the natural convective flow of the hot cylinder passes through this channel. The flow field was visualized using PIV technique to investigate the effect of changing the width of the channel and the height of the water free surface on the flow behavior. In each case, by changing the mentioned geometric parameters, flow velocity at the top of the cylinder, temperature of the cylinder surface, volume flow rate of the channel, the structure and location of vortices, and flow pattern inside the channel were studied. The results show that the flow is appropriately formed around the cylinder and inside the channel at a ratio of water free surface height above the channel to the cylinder diameter equal to 2, and a ratio of the channel width to the cylinder diameter equal to 2. Also, the cylinder Nusselt number was increased for the channel with a width ratio of 2, relative to the case without channel around the cylinder.