低温脉动热管传热特性的数值模拟研究

NUMERICAL SIMULATION STUDY ON HEAT TRANSFER CHARACTERISTICS OF CRYOGENIC PULSATING HEAT PIPE

近年来,脉动热管作为一种具有较高传热效率的传热元件被广泛研究,应用领域十分广泛。为了研究在低温区内各因素对脉动热管传热性能的影响,以液氮为工质,采用多相流VOF方法建立了弯头数为6的闭环脉动热管的三维数值求解模型,并对其进行数值模拟。结果表明,脉动热管进入稳定运行阶段后,管之间会形成相间分布的上升管和下降管,且在上升管中以塞状流居多,下降管中以泡状流居多;在较低加热功率时,脉动热管的热阻随充液率的增加而减少;对不同充液率,热阻随加热功率都是先减小而后增大,充液率的增加可以一定程度上降低倾角减小对传热热阻的影响。

In recent years,pulsating heat pipe has been widely studied as a kind of element with high heat transfer efficiency,and its application field is very extensive.In order to study the influence of various factors on the heat transfer performance of pulsating heat pipe in low temperature region,a three-dimensional numerical solution model of the closedloop pulsating heat pipe with 6 turns is established by using the multiphase flow VOF method.The results show that when pulsating heat pipe worked stably,the tubes formed a staggered distribution between the riser and the descending tube,in the riser tubes the majority of flow patterns were plug flow and in the drop tube the majority of flow patterns were bubble flow.When heating power was lower,the thermal resistance of pulsating heat pipe decreased as the filling rate increased.For different filling ratio,the thermal resistance increased with the heating power and then increased,the increase of the filling ratio can reduce the influence of the inclination angle on the heat transfer resistance to a certain extent.