压水堆稳压器波动管热分层现象的流固耦合传热数值模拟

Fluid-solid Conjugate Heat Transfer Numerical Simulation of Pressurized Water Reactor Pressurizer Surge Line Subjected to Thermal Stratification

采用三维全尺寸非稳态流固耦合传热的计算流体动力学(computational fluid dynamics,CFD)方法对压水堆稳压器波动管发生热分层现象时的流动与传热进行数值研究。与以往的模型相比,将计算控制区域扩展到波动管管壁所在的固体区域,采用更适合于求解具有二次回流和流动分离情况的剪切应力输运(shear stress transport,SST)K-ω湍流模型。在评价浮升力对管内流动与换热影响时,利用较Boussinesq近似更有效的计算方法。从而,得到更加精确的管道瞬态壁温分布及变化规律并对所得结论进行了详尽分析,为准确评价热分层现象对波动管使用寿命损耗的影响提供可靠依据。

3-D full-scale transient computational fluid dynamics （CFD） technique involving fluid-solid conjugate heat transfer （CHT） was employed for investigating flow and heat transfer in pressurized water reactor （PWR） pressurizer surge line subjected to thermal stratification. Compared to past models, computing control domain was extended to solid wall region of surge line and shear stress transport （SST） K-co turbulent model was adopted for more suiting to secondary flow and fluid separation. More efficient method of calculation was utilized for evaluating effects of buoyancy on pipe flow and heat transfer than Boussinesq approximation. Consequently, more accurate transient temperature distribution and changing patterns in the pipe wall were obtained and detailed analysis was performed, which provide reliable basis for assessing effects of thermal stratification on life loss of pressurizer surge line.