环状流起始点初始携带份额的分析计算

目前大多数研究采用液膜干涸模型预测气液两相环状流的临界热通量，其中确定环状流起始点、起始点和平衡状态的携带份额、携带现象的发生条件、液滴沉积率以及携带率对模型的计算精度都起着决定性的作用。通过大量研究目前已经得到了适用于不同条件下的经验关联式来预测此模型中的大多数参数，然而环状流起始点的初始携带份额至今仍需通过假设来确定。本文对蒸气-水为工质，压力为0.18～0.27 MPa条件下得到的实验数据进行了分析，通过计算值与实验值的对比提出了初始携带份额的经验关联式。比较结果表明，计算值与实验值的偏差在20%以内。

New correlation for entrainment fraction at onset of annular flow

At present，the liquid film model is widely used for predicting critical heat flux in gas-liquid annular flow.The model consists of the following parameters：onset of annular flow，entrainment fraction at the onset point and the equilibrium state，inception criteria for droplet entrainment，droplets deposition and entrainment rates，which all have predominant effects on the prediction accuracy.Most parameters in this model can be determined by some empirical correlations，which are valid in specific conditions.However，up to now，the entrainment fraction at the onset of annular flow has been always assumed.In this paper，based on the experimental data with steam-water as working fluid and obtained from the pressure range of 0.18—0.27 MPa，a new correlation was proposed for the entrainment fraction at the onset of annular flow，which could make the errors between calculations and experiments within 20%.