基于两相CFD的非均匀加热圆管CHF预测方法研究

为建立非均匀加热工况临界热流密度(CHF)预测方法,以对换热系统的安全分析提供新的辅助手段,本研究采用欧拉两流体模型和壁面沸腾模型,对非均匀加热圆管的CHF进行预测。通过数值计算得到不同热流密度下近壁面空泡份额和壁面温度的分布,将壁面温度出现二次峰值和此时近壁面空泡份额的峰值位置分别作为CHF发生的依据和CHF发生的点,并用此方法对2种不同功率分布圆管的CHF进行研究。研究结果表明,预测得到临界时的平均热流密度及临界发生的位置都与实验结果符合较好。因此,本研究建立的数值预测方法能够用于非均匀加热圆管CHF的预测。

Prediction of Critical Heat Flux in Non-Uniformly Heated Tubes Based on Two-Phase CFD

In order to establish the critical heat flux (CHF) prediction method with non-uniform heat flux, as an additional approach for the safety analysis in the heat transfer systems, Eulerian two-fluid model coupled with wall boiling model are used to predict the critical heat flux in non-uniformly heated tubes. The calculated wall temperature and near-wall void fraction distributions under different heat fluxes are obtained and compared. The second peak of wall temperature and near wall void fraction are used as the criteria for CHF and the location of the highest near wall void fraction is regarded as the location of CHF. Two different power distributions are researched. The prediction has good agreement with the experiment, including both the CHF and their locations. Thus, the prediction method used in this paper can be used in the CHF prediction in non-uniformly heated tubes.