开式脉动热管传热极限的试验研究

Experimental Study on Heat Transfer Limit of Open Loop Pulsating Heat Pipes

在由内径分别为1 mm和2 mm的细铜管弯曲而成的2组40弯头开式回路脉动热管试验装置上,采用R123为工作介质,定性分析了充液率及加热方式对传热极限的影响,并将试验值与Katpradit传热极限关联式的计算值进行了比较,结果表明:随着充液率的提高,传热极限先增大而后减小,存在一个最佳充液率(约50%);在3种加热方式中,垂直底部加热有助于脉动热管取得较大的传热极限值,而垂直顶部加热则对应较小的传热极限值.通过对Katpradit传热极限关联式进行适当修正,得到了新的试验关联式.

Adopting R123 as the working medium,the effects of liquid filling ratio and heating mode on heat transfer limit were qualitatively analyzed on the open loop pulsating heat pipes test fig consisted of 40 elbows bent by fine copper tubes with inner diameter of 1 mm and 2 mm,and the experimental values were compared with calculated values by the Katpradit＇s correlations for heat transfer limit.Results show that with the increase of liquid filling ratio,the heat transfer limit increases at first,and then decreases.There is an optimum liquid filling ratio,which is about 50 %.Among the three heating modes,the vertical bottom heating mode helps the pulsating heat pipes obtain large heat transfer limit,while the vertical top heating mode corresponds to a small heat transfer limit.Through proper modification on Katpradit＇s correlations for heat transfer limit,a new experimental correlation was obtained.