双面加热环形通道内干涸点的确定

根据环形管通道内流体流动和换热的特点,以Kirillov和Smogalev提出的干涸点理论模型假设为基础,从最基本的质量守恒方程出发,并引入临界液膜厚度等相应的辅助模型,得到了双面加热环形通道内流动沸腾干涸点的理论模型。同时针对间隙为1.0mm和1.5mm的环形窄缝进行了低压低质量流速工况下干涸点的实验研究。比较发现理论模型预测值与实验结果基本相符。说明本文提出的理论模型适用于低压低流量条件下的窄环形通道。实验同时发现:环状流临界热流密度在系统压力为2.2MPa达到最大值,临界含汽量随质量流速的增大呈缓慢下降趋势。

THEORETICAL PREDICTION OF DRYOUT POINT IN BILATERALLY HEATED ANNULI

Based on the fundamental mass conservation equation and considering the special characteristics of fluid flow and heat transfer in bilaterally heated annuli, a physical model used to predict dryout in bilaterally heated annuli is proposed. Physical models on annular flow in circular tubes are cited for the derivation. Corresponding experimental study is also carried out under low flow condition and the experimental result showed a good agreement with the prediction result. It was also found in out experiment that the Critical Heat Flux arrived the maximal value under pressure of 2.2 MPa, the critical quality decreased with mass flow increasing.