AP1000设计基准事故试验热冲击过程数值模拟

Numerical Simulation on Thermal Shock Process in AP1000 DBA Testing

针对AP1000核电厂安全级设备鉴定设计基准事故(DBA)模拟试验第1s热冲击过程,构建了过热蒸汽由储汽罐充入试验仓的模型.利用Fluent流体计算软件对瞬态热冲击过程进行了数值模拟,得到试验系统内气体温度、压力、流速、组分质量分数瞬态变化过程及其空间分布状态.结果表明:超音速蒸汽射流进入试验仓,经挡板减速并改变方向,与仓内空气混合,同时压缩空气,使仓内介质温度和压力快速上升并达到要求值;试验仓内瞬态压力分布均匀,但温度分布取决于蒸汽的流动,随着蒸汽不断充满试验仓,1s后仓内温度分布趋于均匀;储汽罐释放高温高压过热蒸汽充入试验仓的工艺可以满足DBA试验第1s热冲击试验要求.

A model was set up to simulate the thermal shock process in first second of design basis accident （DBA） testing for AP1000 nuclear power plant safety related equipment, in which superheated steam was injected into the test chamber from a steam accumulator. Using Fluent software, numerical simulation was carried out to the transient thermal shock, so as to obtain transient evolution and space distribution of vari- ous factors in the system, such as the temperature, pressure, velocity and species concentration etc. Re- sults show that after entering into test chamber, the supersonic steam jet is to be blocked by a baffle plate, which then mixes with and compresses the air inside the chamber, and finally makes the temperature and pressure of the medium rapidly get up to required values; the pressure distribution transiently gets uniform in the chamber, but the temperature distribution depends on the steam flow, which, with the continuous filling of steam, tends to get uniform after one second; by injecting high temperature high-pressure super- heated steam into test chamber from accumulator, the process can satisfy the requirements of DBA thermal shock testing within one second.