Thermal Analysis Of Dual-Evaporator Loop Heat Pipe In Steady-state Operation And Start-up Process

Multiple Evaporator Loop Heat Pipe（ME-LHP）has high heat transfer efficiency and high heat transfer limit.It has unique advantages in heat dissipation occasions with multiple heat sources and high heat flux,making it widely used in spacecraft and satellites and other electronic equipment thermal control.In order to promote the application of ME-LHP in the aerospace and electronic thermal control fields,precise mathematical models are needed to predict its thermal performance.In this thesis,the steady-state and transient heat transfer models of the asymmetric dual evaporator loop heat pipe（DE-LHP）are established,the flow distribution at the junction of the liquid pipes is corrected,and the DE-LHP is analyzed.The conversion law of LHP’s steady-state operating temperature control rights between the two compensators,heat sharing characteristics,the law of the influence of heat sink temperature and ambient temperature on the steady-state operating temperature,and the evaporator first and The influence of starting the evaporator first during the start-up process on starting the evaporator later.The main research conclusions are as follows:The results show that:（1）The conversion of DE-LHP steady-state operating temperature control between two compensators is influenced by the position of compensation chamber and the distribution of heat load on two evaporators.When the heat load applied on the evaporator at the far end of the condenser is less than that on the evaporator at the near end,two control regions can be observed:the position control region and the heat load distribution control region,and the calculation formula of the influence range of the position control region is given.（2）When the same heat load is applied to the two evaporators,the steady-state operating temperature of DE-LHP system reaches the lowest.When the heat load applied to the system is small,the ambient temperature has a greater impact on the working temperature,and when the heat load applied to the system is large,the heat sink temperature has a greater impact.The amount of heat sharing is related to the heat load of the system and the pressure drop of the pipeline,and is proportional to the flow distribution at the intersection of the gas pipeline.（3）When unequal heat loads are applied to the double evaporators,the startup time difference increases first and then decreases,indicating that the evaporator started first promotes the start-up of the later one.This promotion effect increases first and then weakens,and there is a maximum value.Compared with the effect of starting first of the evaporator（E₁）at the far end of the condenser on E₂,the effect of starting first of the evaporator（E₂）at the near end of the condenser on E₁ is greater.