航天“Ω”形铝氨槽道热管传热特性分析

The Heat Transfer Characteristics Analysis of AeronauticalΩ-shaped Aluminum-ammonia Grooved Heat Pipe

热管的充液率、底板加热功率及重力场等都显著影响其传热性能.文中建立了"Ω"形铝氨槽道热管的三维模型并进行网格划分,采用流体体积法VOF(Volume of Fluid)模型,研究了热管中的气液两相分布、流动及传热过程,并与地面实验数据对比,来验证此模型计算结果的准确性.计算结果表明:底热管稳定运行后,在有重力条件下,气液两相处于上下分层状态,大部分液相聚集在热管蒸汽腔底部,形成液池,部分槽道内也充满液相;在无重力作用时,气相充满整个蒸汽腔,液相分布在各个槽道内;热管充液率为30%充液率时传热性能最好;当加热功率为15 W~45 W范围时,传热性能随底板加热功率提高而增加,当底板加热功率为45 W时,热管传热性能最好;无重力条件热管内液相热管的整体传热性能比有重力条件提升5%~20%,对航天领域中的工程实际问题具有指导和借鉴意义.

The heat transfer performance of heat pipe is significantly affected by its liquid filling rate,the heating power of the bottom plate and the presence or absence of gravity field.A three-dimensional model ofΩ-shaped aluminum-ammonia grooved heat pipe was constructed and meshed in this paper.Then the model of the volume of fluid(VOF)method were employed to study the gas-liquid two-phase distribution,flow and heat transfer process of the heat pipe.Finally,the ground experimental data was used to verify the accuracy of the calculation results of this model.The results showed that the gas-liquid phase is in a state of upper and lower stratification under the condition of gravity after the heat pipe runs stably.Most of the liquid phase gathers at the bottom of the steam chamber of the heat pipe which forming a liquid pool,and some grooves are also filled with liquid phase.In the absence of gravity,the gas phase fills the entire vapor chamber,the liquid phase is distributed in each groove.The heat transfer performance is best when the liquid filling rate of heat pipe is 30%,and it increases observably with the heating power of the bottom plate.When the heating power of the bottom plate is greater than 45 W,convective surface heat transfer the increases flattens out.The overall heat transfer performance of liquid phase heat pipe under zero gravity condition is improved by 5%~20%compared with that under gravity.The research results of this paper can provide guidance and reference for practical engineering problems in aerospace field.