关键词: 两相换热器, 航空热管理, 有限界面热流, 相变模型, 流动沸腾

Abstract: Two-phase water-cooled heat exchangers have promising application prospects in aviation thermal management systems due to their high heat transfer efficiency and compact structure. With the assistance of the advanced interface-resolved technique, the incorporation of a reasonable phase change model becomes crucial for accurately simulating the flow boiling characteristics in two-phase water-cooled heat exchangers. However, the uncertainty of empirical factors and the complexity of phase change theories pose great challenges to the development of phase change models. The present paper proposes a finite-interface-heat-flux phase change model, which converts the interfacial heat flux into phase change source terms for the cells within the finite interface by considering the interface position in the interfacial cell. The proposed model is validated by one-dimensional Stefan and two-dimensional pool boiling benchmark problems first. The deviation of the instantaneous interface position and the time averaged Nusselt number is 3.33% and 1.2%, respectively. Then it is validated by a three-dimensional microchannel boiling benchmark problem and presents the deviation of 4.48% in terms of the instantaneous bubble diameter. Finally, the present model is validated by a flow boiling experiment and presents the lowest deviation of 14.4% in terms of the wall superheat. Besides, the simulation result of the flow regime falls into the prediction range of the flow regime criteria. The proposed model outperforms the existing phase change models, showing great potential in providing a reliable numerical tool for the design and optimization of two-phase water-cooled heat exchangers in aerospace.

Key words: two-phase heat exchanger, aviation thermal management, finite-interface-heat-flux, phase change model, flow boiling