临界热流密度后传热区二维计算模型

A TWO-DIMENSION ANALYTICAL MODEL DURING POST-CHF REGION

一、前言 反环状流和弥散流是临界热流密度后膜态沸腾传热区的二种主要形式。它们分别发生在低含汽率和高含汽率的条件下。反环状流由过冷的液芯和高温壁面处的过热汽膜所组成。主要换热是壁面与蒸汽、蒸汽与液芯表面的换热和壁面与液芯的热辐射。蒸发发生在液芯表面。可视化试验表明,界面有较大的波动,交界面的换热系数很难确定。气膜膜厚变化有两个阶段,初始阶段液芯表面温度尚未达到饱和,无蒸发,因此膜厚不变。

Based on recent experimental and theoretical works the authors reviewed the published literature on this subject and derived two dimention analytical models for dispersed flow and inverted annular flow separately. Further reseach has been made which take into account the similarities between the basic balance equations for above two flow patters. A generized two-dimension analytical model -POSTCHF has been developed. The basic idea and mathematical model are presented in this paper. The calculated results are agreed well with the exper-mental data.