热工水力分析程序中的液位追踪模型对比与研究

Comparison and Investigation of Level Tracking Models in Thermal Hydraulic Analysis Codes

混合液位(Mixture Level),又称两相液位(Two phase level)或液位膨胀(Level swell),是气体存在导致两相流体液面抬升的现象。反应堆堆芯中的混合液位是决定堆芯是否裸露的重要因素,其他如蒸汽发生器或抑压水池等部件的混合液位也对安全性有重要影响。物理过程中,混合液位主要由空泡份额及两相流型所决定,相对于坍塌液位(Collapsed level),混合液位的实验测量及数值模拟更为复杂。混合液位的计算对反应堆热工水力瞬态模拟有比较重要的影响,因此在多数系统分析程序中设有混合液位追踪模型。本文对主流热工水力程序中的混合液位追踪模型及其验证评估进行了总结,并结合实验数据使用部分热工水力程序进行了模拟和验证,该研究可对自主化分析程序中相关模型的开发提供一定的借鉴和参考。

The mixture level,also known as two-phase level or level swell,refers to a phenomenon of rise of two phrase level due to the existed gas.The mixture level in the reactor core determines whether it is exposed or not.Components like steam generator and the mixture level of the suppression pool also have a significant impact on the safety of nuclear power plant(NPP).The mixture level depends mostly on void fraction and its related two-phase flow patterns.Compared with the collapsed level,the experimental measurement and numerical simulation of the mixture level are more complicated.Since the calculation of mixture level has a relatively important influence on the simulation of the thermal hydraulic transients of the reactor,a mixture level tracking model is set for the analyzer of relevant system.In this paper,the mixture level tracking model and its verification and evaluation in main thermal-hydraulic procedures are summarized,and the relevant thermal-hydraulic procedures are used for simulation calculation and verification based on the existed experimental data,which is expected to have insights on the model R&D in related analyzer in the future.