Experimental Research On Boiling Heat Transfer Of Pipe Water Flow Under Hi-G Condition

With the rapid development of the onboard energy transport and heat control systems in aerospace technology, the research on two-phase flow in flight condition is in great request. An experimental investigation was carried out to obtain the heat transfer characteristics of single-phase water flow and two-phase pipe boiling flow under high gravity (Hi-G) in present work.For creating a Hi-G condition, a rotating platform was designed in this study, and boiling two-phase flow state was obtained by means of electric heating. The data were collected specifically in the test section, which was a plexiglass pipe with inner diameter of 200mm and length of 400mm. By changing the factors, such as rotating speed, inlet temperature, flow rate, and etc, the effects of acceleration on the flow and heat transfer characteristics of single phase water and boiling two-phase flow were investigated. The two-phase flow patterns under Hi-G condition were obtained with a video camera.In the paper, the data have been analyzed for its fluid resistance, thermal balance, heat transfer magnitude and ways. The results show that the acceleration significantly influences the flow characteristic and boiling heat transfer of the two-phase pipe flow. As the direction of the acceleration and the flow direction are opposite, the greater the acceleration, the higher the pressure and the flow resistance, and the lower the flow rate, the void, the inside-wall temperature and the heat transfer capability. Therefore, the dynamic load will block the fluid flow, enhance heat emission and reduce the heat transfer capability of the two-phase boiling flow.