单回路紫铜—水脉动热管传热性能的实验研究

Experimental Study of the Heat Transfer Performance of a Single-loop Copper-water Pulsation Heat Pipe

实验研究了单回路紫铜—水脉动热管在水冷方式和定传热功率时,冷却水流量、倾角、管径和充液率4种因素对热管传热性能,包括管壁测点温度、冷热段均温、传热温差、传热热阻和温度振幅的影响规律,得到提高传热性能的一些措施。结果显示:水平放置的单回路脉动热管无法启动;30°以上倾角管内可产生振荡,增加倾角可降低传热热阻;定加热功率下,冷却水流量存在最佳值,过大和过小都会增加传热热阻;在脉动热管允许管径范围内,增加管径可大大降低传热热阻;相同传热功率时,30%充液率热管的传热热阻明显低于70%充液率管;小而均匀的壁温振荡比大幅锯齿状振荡时的传热性能好。

Experimentally studied was the law governing the influence of four factors,namely,cooling water flow rate,inclination angle,tube diameter and liquid filling rate,on the heat transfer performance of a single-loop copper-water pulsation heat pipe,including its tube wall temperature at measuring points,mean temperature in the cold and hot section,heat transfer temperature difference,heat transfer resistance and temperature fluctuation.As a result,some measures for enhancing the heat transfer performance were obtained.The research results show that the single-loop pulsation heat pipe arranged horizontally can not be started up with any possible methods and at an inclination angle of over 30 degrees,oscillation may be produced inside the pipe and to increase the inclination angle can lower the heat transfer resistance.At a given thermal power,there exists an optimum value of the cooling water flow rate and if excessively higher or lower than it,the heat transfer resistance will always increase.Within the limits of the tube diameter permited by the pulsation heat pipe,to increase the tube diameter can greatly reduce the heat transfer resistance.At a same heat-transfer power,the heat transfer resistance of a heat pipe having a liquid filling rate of 30% will be obviously lower than that having a liquid filling rate of 70%.The heat transfer performance resulted from a small and uniform wall temperature fluctuation is superior to that from a big and serration wall temperature fluctuation.