两相自然循环系统的静态漂移特性及输热能力限分析

Investigation on the Static Flow Excursion and Maximum Capability of Heating Load in Two Phase Natural Circulation System

基于分岔理论及其DERPAR数值方法 ,运用最简单的均相模型计算出典型两相自然循环系统的静态分岔解图 ,详细讨论了由浮力和阻力随加热功率(含汽率)的非线性变化特性引起的静态分岔机理 ;导出对应于强迫循环系统的Ledinegg 不稳定性现象及其判断准则 ;定义稳定性裕度、自然循环系统输热能力限、静态分岔迟滞现象 ;讨论了系统压力、欠热度、阻力、几何构型等参数对运行稳定性及输热能力限的影响 ;强调指出了简单理论预测启示两相自然循环系统的启动、变工况、瞬变、事故工况及安全停闭等过程的思路 。

Applying theory of bifurcation and its DERPAR algorithm,the static bifurcation solution diagram of a typical two phase natural circulation system based on homogenous model is calculated With the solution diagram,the static bifurcation mechanism due to the nonlinear variation characteristics of buoyancy and loss with the changing of heating power (quality) is discussed and revealed Moreover,the static instability phenomenon in two phase natural circulation,corresponding to the Ledinegg instability in forced one,and its criterion is hereby delivered And the instability margin,heat transport capability and thermal siphon hysteresis phenomenon is accordingly defined Furthermore,effect of such parameters as system pressure,subcooling,loss and geometric boundary condition on running stability and transport capability of heat load is also presented Finally,it is emphatically pointedout that the strategy of this analysis using simple model may lead to anoutline understanding of the process in startup,varying regime,transient,accident and trip conditions,which deserves to be studied intensively through experiment and finer two phase flow model