承压热冲击下压水堆压力容器壁面换热特性的数值模拟研究

为了研究压水堆因安注冷水直接注入反应堆压力容器下降环腔而导致的承压热冲击（PTS）热工水力问题，基于1∶10比例模型，应用计算流体力学商用软件FLUENT5．4进行了紊流流动换热的数值模拟分析，同时进行了常压传热实验研究。针对下降环腔折算流速0．5m/s，安注流速10m/s的典型工况，研究了压力容器下降环腔的壁面换热特性。通过分析下降环腔内的流动及混合特性，从流动机理上解释了压力容器内壁上准重接触点附近换热强烈的现象，并指出壁面换热强弱与近壁流体紊流脉动动能密切相关，为热冲击分析提供参考。

Numerical Simulation of Heat Transfer Characteristics of RPV Downcomer in PWR under PTS

Numerical simulation by using the commercial computational fluid dynamics software FLUENT5.4,combined with the heat transfer experiments with the1:10setup at ambient pressure,were performed to investigate the thermal-hydraulicphenomena of the pressurized thermal shock(PTS),which is caused by the cold safety injection fluid direct into the reactor pressure vessel(RPV)down-comer in the pressurized water reactor(PWR).Heat transfer characteristics in the RPV downcomer were studied at the typical case with the superficial velocity in the downcomer0.5m/s and the safety injection velocity10m/s.The calculations well matches the experimental data.Via analysis of the flow characteristics and fluid mixing behavior,it was explained from the flow mechanism that intensive heat transfer takes place near the quasi-reattachmentpoint of the RPV downcomer.The results may be used for further thermal shock analysis.