基于非结构化VOSET方法的沸腾传热  

Boiling heat transfer by using the VOSET method based on unstructured grids

作　　者：曹志柱 孙东亮[2] 魏进家[1,3] 宇波[2] Zhizhu Cao;Dongliang Sun;Jinjia Wei;Bo Yu(School of Chemical Engineering and Technology,Xi’an Jiaotong University,Xi’an 710049,China;School of Mechanical Engineering,Beijing Institute of Petrochemical Technology,Beijing 102617,China;State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学化学工程与技术学院,西安710049 [2]北京石油化工学院机械工程学院,北京102617 [3]西安交通大学动力工程多相流国家重点实验室,西安710049

出　　处：《科学通报》2020年第17期1723-1733,共11页Chinese Science Bulletin

基　　金：国家自然科学基金(51636006,51776019);北京市自然科学基金委员会-北京市教育委员会联合项目(KZ201810017023);长城学者培养计划(CIT&TCD20180313);高水平创新团队建设计划(IDHT20170507)资助。

摘　　要：将非结构化VOSET方法推广至求解气液界面存在相变的流动传热问题.为准确计算界面两侧因相变导致的能量跳跃,给出了含界面非结构网格控制单元温度的计算方法,并对非界面网格温度场采用隐式求解以提高计算精度.为验证所构建相变模型的正确性,编写程序分别模拟了恒壁面过热度和恒热流密度两种边界条件下的水平表面膜态沸腾,计算结果与Klimenko经验关联式吻合良好.通过圆弧表面膜态沸腾问题,验证了本文基于带相变非结构VOSET方法对不规则区域沸腾相变问题的适用性.通过模拟近临界压力水的膜态沸腾问题,并与Berenson和Klimenko经验关联式对比,验证了本文方法对实际沸腾问题的适用性.It is well known that the fluid mass is not conserved by the level set methods while the accuracy of volume-of-fluid(VOF)methods is highly dependent on the calculation of interface normal and curvature from volume fractions. Advanced interfacial tracking methods appear by combining the two techniques to compensate each other. The coupled VOF and level set method named VOSET is one of such methods. This paper presents the extension work to include heat and mass transfer due to phase change for the VOSET method on an unstructured triangular grid. In this method, the liquid/gas interface is tracked by the VOSET method, which combines the advantages of both VOF and level set methods. The proposed method can not only preserve mass conservation but also facilitate the interface normal and curvature calculation with a high accuracy. The interfacial tracking methods are integrated to Navier-Stokes solvers accordingly. A critical issue for the mass transfer across the boiling interface is the treatment of energy jump. We propose a numerical algorithm to model energy jump based on VOSET for unstructured grids. The heat flux on each side of the interface within an interface cell needs to be computed separately. The interface is tackled as an internal boundary for temperature field. For cells with a pure phase, unlike previous studies, we solve the energy equation in an implicit way. For cells with a liquid/gas phase interface, an interpolation algorithm is developed to calculate the temperature. To validate the present numerical method,four classical boiling tests are implemented. To be specific, the first case is the constant heat flux film boiling on the horizontal plate. In this case, dimensionless wall heat flux 20.0 is set up for the bottom solid wall. The top boundary is open and the fluid is allowed to exit, no slip boundary is set to the bottom, periodic condition is set to the left boundary and symmetrical condition is imposed on the right boundary to save computational cost. The comparison of the Nusselt number wi

关 键 词：相变 VOSET 膜态沸腾 非结构化网格 

分 类 号：TK124[动力工程及工程热物理—工程热物理]