安注过程蒸汽直接接触冷凝的数值模拟

压水反应堆发生失水事故（LOCA）时，应急堆芯冷却系统（ECCS）将过冷的安注水注入到冷管段中，安注水与管道中的蒸汽发生直接接触冷凝，导致温度波动及压力振荡。选用流体体积分数模型、大涡湍流模型和双阻力冷凝模型，在FLUENT平台上对饱和蒸汽与安注水直接接触冷凝过程进行数值模拟，获得直接接触冷凝过程中温度场和压力场的变化情况。结果表明，冷凝主要发生在汽液界面附近，主管内蒸汽流量的增加能够阻止安注水回流现象发生。

Numerical simulation of steam direct contact condensation during safe injection

During a loss of coolant accident in a pressurized water reactor (PWR), direct contact condensation occurs when the water undergoing safe injection from the emergency core cooling system pipe is poured into the cold leg, resulting in temperature fluctuations and pressure oscillations. The volume of fluid model, large eddy simulation and two resistance condensation model of FLUENT have been used to simulate the direct contact condensation process. By analyzing the mechanism of steam direct contact condensation, the variation characteristics of the temperature field and pressure field have been obtained. The numerical results indicate that the direct contact condensation mainly occurs at the two-phase interface, and increasing the steam mass flow in the main pipe can prevent the backflow of cooling water.