Development of a compact heat exchanger consisting of tubes and interconnecting struts forming parallel place arrays: Part II prototype assessment

Abstract

Part I of this study centred on a flow visualisation of an alternative heat exchanger design. The heat exchanger consists of a conventional tube bundle having flat tubes as used in typical radiator cores. However instead of fins, there are interconnecting rows of heat conducting struts which collectively form a parallel plate array. The purpose of the struts is twofold. They provide a much larger number of leading edges, and since they are arranged in a parallel plate array, they facilitate the generation of streamwise vortices at certain Reynolds Numbers. The visualisation indicated that at certain strut spacings and inlet flow velocities, stream wise vortices were present. These stream wise vortices could be expected to improve heat transfer. In this paper we report on the measured heat transfer and pressure drop performance of prototypes based on the three visualisation models tested. It was found that the measured performances agreed well with the suppositions put forward from the flow visualisation results.