核供热堆条件下自然循环两相漂移流模型参数的确定

Determination of Parameters for Two-Phase Drift-Flow Model for Natural Circulation System of Nuclear Heat Reactor

以5MW核供热低温堆全模拟试验回路(HRTL-5)为物理原型,在一个考虑了加热段欠热沸腾、上升段入口冷凝、上升段闪蒸以及气空间压力平衡等物理过程的两相流动数学模型基础上,编制了两相流计算程序。通过计算,与已有实验结果比较后,确定了两相漂移流模型中参数的取值;这些参数可用于计算低压低干度自然循环系统的流动问题。计算结果表明:①在核供热堆条件下,漂移流模型在C0取1.1、uvj取0.48时,计算结果与实验数据符合较好;②模型参数C0、uvj的取值对计算结果的影响比较复杂,不是单独改变一个参数时的简单叠加,在模型内部存在耦合或增强的效应;③均匀流模型和漂移流模型在计算HRTL-5自然循环流动问题时结果相差较大。

Taking HRTL-5 for the 5MW nuclear heat reactor as a physical model and based on two-phase flow mathematical model , in which the physical processes such as sub-cooled boiling in theheated section, condensation at the inlet of the riser, flashing in the riser and pressure balance have beenconsidered, a calculation program for the two-phase flow has been developed. In this paper, calculated and experimental results have been compared and parameters for the two-phase drift-flow model have beendetermined, which can be used in the simulation of the flow characteristics in the natural circulation system at low pressure and low dryness fraction. Calculated result shows that: ①for a nuclear heat reactor, if thevoid distribution parameter C0 equals 1.1 and uvj equals 0.48, calculated results are very closed to theexperimental results; ②C0 and uvj have rather complicated effects on the calculated results, which is not the simple accumulation as a parameter varies, but there is the effect of coupling or enhancement in the model; ③as for the calculation of natural circulation flow characteristics for HRTL-5, there are great differencebetween the uniform flow model and drift-flow model.