过冷流动沸腾相变过程汽泡特性的VOF方法模拟  

VOF Simulation of Bubble Characteristics of Subcooled Flow Boiling

作　　者：魏敬华[1] 潘良明[1] 袁德文[2] 闫晓[2] 黄彦平[2] 

机构地区：[1]重庆大学低品位能源利用技术及系统教育部重点实验室,重庆400044 [2]中国核动力研究设计院中核集团核反应堆热工水力技术重点实验室,成都610041

出　　处：《核动力工程》2012年第6期65-71,共7页Nuclear Power Engineering

基　　金：国家自然科学基金(50406012);中国核动力研究设计院空泡物理和自然循环重点实验室资助项目(9140C7101020802)

摘　　要：基于计算流体动力学(CFD)软件对不同压力和热流密度下矩形流道内过冷流动沸腾进行模拟。相变模型通过用户自定义函数(UDF)描述质量和能量传递实现,汽-液界面捕捉通过流体体积法(VOF)获得。研究结果表明,蒸发和冷凝的交互作用会在垂直于流动方向的截面内形成二次流以增强壁面附近的微对流。汽泡在滑移过程中逐渐长大,并与邻近汽泡聚合形成更大的汽泡,且变形逐渐加大。汽泡滑移会增强下游区域的换热,从而抑制下游核化点的产生。随着压力升高和热流密度降低,汽泡尺寸、生长速度以及出口处平均空泡份额都会减小。汽泡生长曲线和沸腾起始点(ONB)附近加热壁面温度模拟结果与文献中关联式吻合良好。Subcooled flow boiling in vertical rectangular channel under different pressure and heat flux was numerically investigated based on CFD. The phase change process was accomplished through the User Defined Function （UDF） to describe the mass and energy transportation, and the interface of liquid and vapor was captured by the Volume of Fluid （VOF） method. The results reveal that the interaction of evaporation and condensation in the cross section perpendicular to the flow direction forms the secondary flow, and enhances the natural convection near the wall. The bubble grows up in the sliding process, and merges with the adjacent ones to form bigger one, which has greater deformation. The bubble sliding enhances the heat transfer in the down stream and restrains the nucleation. With the higher pressure and lower heat flux, the bubble size, growth rate and the average void fraction at the outlet will be reduced. The simulation results of bubble growth and the wall temperature near the Onset of Boiling （ONB） agree well with the correlations in the literature.

关 键 词：相变 二次流动 汽泡滑移 VOF模型 Lee模型 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TL331[动力工程及工程热物理—热能工程]