竖直窄缝过冷沸腾实验模型及数值模拟

Numerical Investigation of Subcooled Flow Boiling Based on Experimental Data in Vertical Rectangular Narrow Channel

基于常压下竖直窄缝通道的过冷沸腾实验结果,提出了2 mm窄缝通道的壁面核化数值新模型,模型包括:汽化核心密度、气泡脱离直径、气泡脱离频率和核化起始点(ONB)关联式。分别采用新模型和CFX模型对典型实验工况进行数值模拟分析,模拟结果与实验的壁面温度和平均壁面温度结果吻合较好。详细讨论了2个模型中的3个主要关联式的差异,最后讨论了ONB模型对过冷沸腾数值模拟结果的影响。结果表明,考虑ONB模型的新核化模型能更准确地预测窄缝通道过冷流动沸腾传热特性。

This paper proposes and discusses a new wall boiling model developed based on our previous experimental work for the 2mm narrow rectangular channel. The new model includes the active nucleation site density, bubble departure diameter, bubble departure frequency and the onset of nucleate boiling （ONB） sub-models. The thermal-hydraulics of the narrow channel was separately simulated by the new model and CFX model under specific experimental conditions. The simulation results of wall temperature and average temperature were compared with experiment data in good agreement. The difference of three main correlations of two models and the ONB sub-model influence on the result were discussed. The results show that the NEW model with ONB sub-model provides better predictions of the thermai-hvdraulics in the narrow channel.