Free Convection Heat Transfer of Air-Water Layers in a Horizontal Cooled Circular Tube

Abstract

An experimental study has been performed to investigate the influence of density inversion of water on the free convection heat transfer of air-water layers within a cooled circular tube. The experiments were carried out under the condition that the tube-wall temperature was successfully decreased at a uniform rate. A holographic interferometry technique was adopted to determine the time-dependent distributions of thee temperature in the tube. It was observed that the temperature distribution characteristics were to a great extent changed based on the cooling rate of tube wall, along with the time-dependent sequential flow patterns. The heat-transfer characteristics along the tube wall were also extensively determined. Furthermore, it was found that there were three kinds from the water-air interface of the dendritic ice growths and also a pure ice growth along the tube wall.