强制冷却下闭式回路脉动热管启动性能的试验研究

Study on the Start-up Characteristics of Closed Loop Pulsating Heat PipesUnder Forced Cooling

针对闭式脉动热管搭建试验平台,用紫铜管做试件,管内径2.7mm,全长1384mm,6弯头,丙酮为工质,采用底部电加热、上部分别采用强制对流冷却和自然对流冷却,分析了强制对流下脉动热管的启动特征及性能,对比了不同冷却方式对脉动热管启动性能的影响。结果表明,脉动热管在强制冷却下存在两种启动方式:低功率下呈现间歇性温度突变型启动特征;高功率下呈现光滑缓慢连续启动特征并可以稳定运行。强制对流冷却方式不仅能够改善脉动热管传热,更有助于脉动热管的稳定运行。

The experiments were conducted on a close loop pulsating heat pipes （PHPs） which consist of a six-bended copper tube.The inside diameter of the capillary tube is 2.7mm and the working fluid is selected as acetone.PHPs are 1384mm.Vertical bottom adopted electrical heating,top natural cooling and forced cooling was adopted respectively.Analyze the start-up operational characteristics of the PHPs under forced cooling and compare the start-up characteristics of closed loop pulsating heat pipes under difference types of cooling.Results show that the PHPs have two kinds of start-up modes：An intermittent and apparent temperature overshoot process at lower heating power,a smooth continual start-up process incorporating with a steady operation at higher heat-ing power;Forced cooling can improve PHPs heat transfer and contribute to the steady operation.