两相热虹吸循环动量模型评价  

An Assessment of Momentum Models for Two-phase Thermosyphon Loop

作　　者：张朋磊[1] 石文星[1] 韩林俊[1] 王宝龙[1] 李先庭[1] 

机构地区：[1]清华大学建筑学院建筑技术科学系,北京100084

出　　处：《制冷学报》2013年第2期1-8,共8页Journal of Refrigeration

基　　金：国家自然科学基金(51176084);国家杰出青年基金(51125030)资助项目~~

摘　　要：两相热虹吸管在工业领域应用广泛,其内部工质的流动模拟是热虹吸管设计的主要因素。然而在模拟过程中,存在着两相流模型适用范围有限而自然循环模拟精度要求高的矛盾,因此有必要根据热虹吸特性对现有两相流动量模型进行适用性评价。建立了稳态两相热虹吸循环模型,结合不同工质(水、R113和R600a)的两相热虹吸循环实验数据,分别对4种均相流动量模型和24种分相流动量模型组合(4种分相流摩阻压降模型和6种截面含气率模型组合)进行了计算比较,发现Lorkhart-Martinelli摩阻压降模型结合Tom截面含气率模型的模拟精度最高。利用此模型分析两相热虹吸循环内工质的流动特征,证实了质量流速随着热流密度的增大先增大后减小的规律,并从内部分布参数变化角度给出了新的解释。Two-phase thermosyphon heat exchangers are widely used in different industry fields. The fluid flow characteristic is very im- portant for the design of thermosyphon. However, the existing two-phase models are not accurate enough for the simulation of two-phase thermosyphon loop. Therefore it is important to make an assessment of existing two-phase momentum models corresponding to thermosyphon loop features. The mathematical model of two-phase thermosyphon loop, which include 4 homogenous pressure drop models, 24 separated- phase momentum combination models （4 separated-phase frictional pressure drop models multiply 6 representative void fraction correla- tions）, has been developed in the paper. The predicted results from different models are compared with the experimental ressuhs of two- phase thermosyphon with refrigerants H2 O, R113 and R60Oa. The comparison results show that the combination of Lorkhart-Martinelli frictional pressure drop model and Tom void fraction model is better than other models. Finally, the flow features of two-phase thermosy- phon loop have been simulated. It is shown that for a specific loop, the mass flux increases and then decreases slowly with the increase of heat flux. A reasonable explanation is given to the phenomenon.

关 键 词：热虹吸 两相流 模拟 评价 流动特性 

分 类 号：TK124[动力工程及工程热物理—工程热物理]