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基于微液层蒸干的临界触发机理,构建了偏离泡核沸腾(DNB)型的临界预测模型。通过对临界点处的汽块进行受力平衡分析,基于优化后的侧面提升力系数CL,确定了汽块滑移速度、微液层液膜厚度等参数,实现对均匀加热下DNB型临界热流密度的理论预测。采用2种加热长度下矩形窄缝通道内的临界热流密度实验数据对该模型进行了验证。结果表明:模型所预测矩形窄缝通道内的临界热流密度值与实验结果的偏差均在±15%之内,该模型的预测精度高于Bowring公式和Bettis公式的预测精度。
Based on the critical trigger mechanism of micro-liquid layer evaporation and drying, a critical prediction model deviating from nucleate boiling nuclei (DNB) type was constructed. Through the force balance analysis of the steam block at the critical point, parameters such as the slipping velocity of the steam block and the thickness of the liquid film in the micro-liquid layer are determined based on the optimized lateral lifting force coefficient CL, and the DNB-type critical heat flow Theoretical prediction of density. The model was verified by the experimental data of the critical heat flux density in two narrow rectangular channels with heating length. The results show that the predicted critical heat flux density in the rectangular narrow channel is within ± 15% of the experimental results. The prediction accuracy of this model is higher than that of the Bowring and Bettis formulas.