空泡份额模型在矩形通道沸腾压降计算中的适用性评价

Applicability Evaluation of Void Fraction Model in Boiling Pressure Drop Calculation of Rectangular Channel

分析了各空泡份额模型随质量流量、系统压力及质量含气率的变化关系,并对各空泡份额计算模型在窄矩形通道内的应用进行了评价。研究结果表明:尽管空泡份额模型选取对重位压降及加速压降计算影响极大,但由于窄矩形通道内的饱和沸腾流动以环状流为主,重位压降及加速压降在两相总压降中的份额极小,因此在两相摩擦压降计算过程中,空泡份额模型的影响非常轻微。采用Zivi模型计算得到的沸腾摩擦压降与其他关系式计算值相对偏差在±5%范围内,因此建议采用Zivi模型计算窄矩形通道内空泡份额。

The relationship between void fraction models and mass flux,pressure and mass quality was analyzed,and the applicability of these void fraction models in boiling pressure drop calculation of rectangular channel was evaluated.The results show that different void fraction models lead to the large discrepancy of gravitation pressure drop and acceleration pressure,however,the proportions of gravitation pressure drop and acceleration pressure in the total pressure drop are very small because the predominant two-phase flow pattern in narrow rectangular channel is annular flow,thus the effect of void fraction model on frictional pressure drop can be neglected.The results also indicate that the relative deviation of frictional pressure drops calculated by Zivi model andother void fraction models is within ±5% and Zivi model is proposed to calculate the void fraction in narrow rectangular channel.