基于Non-Boussinesq模型的多流体域高温差乏燃料容器的自然对流传热特性研究

基于Boussinesq模型和全浮力模型原理，建立了高温差环境下Non-Boussinesq多流体域自然对流模型，通过对比高温差封闭空腔自然对流实验结果和预测结果，研究了Boussinesq模型、全浮力模型和Non-Boussinesq模型在单流体域和多流体域高温差环境下对流速和温度的预测能力。结果表明，单流体域下Non-Boussinesq模型和全浮力模型预测的流速和温度符合实验结果，平均预测误差小于9%；Boussinesq模型在高温差环境下对流速的预测精度较低；全浮力模型不能同时保证多流体域获得合理的流场分布；Non-Boussinesq模型能有效克服Boussinesq、全浮力模型的缺点；自然对流模型选取主要会影响内外部气体流速的预测，对容器内外部温度的预测影响较小。本研究建立的数值预测方法能够用于高温差环境下其他多流体域的自然对流的预测。 

Prediction of Natural Convection Characteristics of Spent Fuel Vessel with Multi-Fluid Domains and High Temperature Difference Based on Non-Boussinesq Model

Non-Boussinesq model is established based on Boussinesq model and full buoyancy model, to simulate the natural convection flow in multi-fluid domains with high temperature difference. The comparison between predicted profiles and experimental data in a single-fluid domain and in multi-fluid domains with high temperature difference is conducted by implementing respectively Boussinesq model, full buoyancy model and Non-Boussinesq model. The results show that for single-fluid domain, the predicted velocity and temperature using Non-Boussinesq model and full buoyancy model coincide with the experimental data with average derivation less than 9%. Boussinesq model is less accurate in simulating the velocity in high temperature different region. For multi-fluid domains, accurate velocity profiles in all fluid domains are not guaranteed for the full buoyancy mode. However, developed Non-Boussinesq model can not only simulate precisely the buoyancy force caused by density variation, but also guarantee an acceptable velocity results for multi-fluid domains. The momentum source term analysis and CFD analysis in multi-fluid domains coincide well with each other. The buoyancy force model is with significant effect on the velocity profile in multi-fluid domain problem, but with little effect on temperature profile prediction. Hence, the prediction method used in this paper can be used in the natural convection prediction in multi-fluid domains with high temperature difference.