低温脉动热管冷却超导磁体实验研究

Experimental study on cooling superconducting magnet using cryogenic pulsating heat pipe

为了研究低温脉动热管(PHP)冷却超导磁体的可行性,搭建了以液氦脉动热管为传热部件的GM制冷机传导型冷却超导磁体模型的实验装置,采用该装置实验研究了48通道液氦PHP的冷却性能和传热性能。该液氦PHP由内径为0.5 mm的不锈钢毛细管制成,其蒸发段、绝热段、冷凝段的长度分别为50 mm、100 mm、50 mm。实验结果表明,液氦PHP可将超导磁体模型从常温冷却至6 K,用时约95个小时,冷却过程中观察到液氦PHP超临界脉动和近临界强化换热现象。在充液率为38%时,液氦PHP最大可传递1.5 W热量,有效导热系数在2000—9200 W/(m·K)之间。而该液氦PHP在充液率为70%时未能正常启动。

In order to study the feasibility of cooling superconducting magnets with cryogenic pulsating heat pipe(PHP),an experimental device for conducting cooling superconducting magnet model using the GM cryocooler with liquid helium pulsating heat pipe as heat transfer component was established.The cooling performance and heat transfer performance of liquid helium PHP with 48 channels was experimentally studied by this device.The liquid helium PHP is made of stainless steel capillary tubes with an internal diameter of 0.5 mm.The length of the evaporator,adiabatic,and condenser sections are 50 mm,100 mm,and 50 mm,respectively.The experimental results show that liquid helium PHP can cool the superconducting magnet model from room temperature to 6 K,which takes about 95 hours.During the cooling process,the phenomenon of supercritical pulsation and near-critical enhanced heat transfer were observed.When the filling ratio of liquid helium PHP is 38%,the maximum heat transfer capacity is 1.5 W,and the effective thermal conductivity is between 2000 and 9200 W/(m·K).However,the liquid helium PHP failed to start normally when the filling ratio is 70%.