Abstract: Loop heat pipe (LHP) is a kind of high efficient heat transfer device driven by the capillary force，and flat loop heat pipe (FLHP) is LHP with flat evaporator，which can reduce the thermal resistance between the flat heat source and the evaporator.To make the loop heat pipe a better performance，an FLHP with bi-transport loops (BTL) is designed to reduce the pressure drop and enlarge the condenser cooling area.The evaporator and pipe is made from copper and ultrapure water is filled as the working fluid.Two valves are fixed in the two liquid lines.Experimental results show that，the FLHP can be changed successfully to be an FLHP with BTL or an FLHP with single-transport loop (STL) by controlling the valves，and no big temperature oscillation is observed in the experimental range.The FLHP with BTL has a better performance than that with STL.The evaporator temperature of FLHP with BTL can be 10℃ lower than that of FLHP with STL at 30W.Compared to that of the FLHP with STL，the total thermal resistance of the FLHP with BTL can have a decline rate more than 20% at different power.The reason why the decline rate is much less than 50% is discussed.Compared with the FLHP with STL，the FLHP with BTL can only reduce the thermal resistance caused by the pressure drop in the loop and in the condenser，but it cannot reduce the thermal resistance in the evaporator.If the evaporator is optimized，the decline rate of the total thermal resistance from FLHP with STL to FLHP with BTL would be even larger.

Key words: loop heat pipe, flat evaporator, bi-transport loops, electronic cooling

摘要： 以铜为主要材料、超纯水为工质研发了双通道平板型环路热管。分别在双通道环路热管的两根液管上安装阀门，通过阀门的开关，实现双通道平板型环路热管和单双道平板型环路热管的互相转换。通过实验，发现双通道平板型环路热管的传热性能比单通道平板型环路热管要好。在热源的加热量为30W时，蒸发器温度的降幅可达10℃。在不同的功率下，双通道环路热管比单通道环路热管总热阻的下降幅度在20%以上。但双通道平板型环路热管的总热阻与单通道平板型环路热管相比，降幅并没有达到50%，这是由于采用双通道的形式，只能减小通道压降造成的热阻以及冷凝热阻，但不能减小蒸发器热阻。

关键词: 环路热管, 平板型蒸发器, 双通道, 电子冷却