液膜蒸干模型在液态金属CHF预测中的应用

Application of Film Dryout Model in Prediction of CHF in Liquid Metal

  • 摘要: 为对圆管中环状流烧干型沸腾临界进行预测,建立了考虑液滴沉积夹带作用的液膜蒸干模型。沉积率、夹带率等相关关系式采用水等常规流体的已有关系式。在一定参数范围内,将模型预测结果与实验数据和经验关系式进行了比较。结果表明:基于常规流体的液膜蒸干模型大体可应用于液态金属,但在临界热流密度(CHF)较大时可能造成较大偏差;钠、钾两种液态金属在CHF较低时预测准确度区别不大,但在CHF较高时区别较为明显。为更加准确预测液态金属CHF,应开发专门的沉积率、夹带率等相关关系式。

     

    Abstract: A film dryout model considering the deposition and entrainment of droplets was established to obtain the critical heat flux (CHF) of liquid metal in the flow of annular two-phase flow in tubes. The correlations of deposition rate, entrainment rate and so on for conventional fluids (e.g. water) were used, and the initial entrainment fraction was determined according to experimental data. The results show that the correlations for conventional fluids could be used for predicting CHF of liquid metal approximately, but relatively large error might occur for large heat flux. The accuracy of this model for sodium and potassium is similar for small heat flux, but has some differences for large heat flux. Special correlations of deposition rate, entrainment rate and so on should be developed in order to predict the CHF of liquid metal more accurately.

     

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