Reynolds应力模型在热分层流场中的应用及优化

Reynolds stress model of 11 equations in the thermally stratified turbulent flows

对Reynolds应力模型(RSM)在数值模拟热分层流场方面进行了优化,即在Reynolds应力方程和湍动能耗散方程的基础上加入标量通量方程和温度扰动方程,使原来的7方程成为了11方程。优化后的模型可以通过精确计算湍流通量输运方程来求解加热湍流中重要的热浮力项。采用7方程RSM、11方程RSM,并用k-ε湍流模型作为参考,对平板间非稳定热分层流动和模拟池式快堆堆心上方的腔室内受迫对流和热分层之间的混合流动进行数值模拟和比较分析,并将计算结果与现有实验数据相比较。结论是:优化后的11方程RSM比其他的湍流模型更适合于计算各向异性的热分层流动。

The Reynolds Stress Model (RSM) for turbulence is described together with the kε model with and without the buoyancy term. This article describes the RSM of 11 Equation which was developed from RSM of 7 Equation for heated flows by solving additional transport equations for the turbulent heat fluxes and for the variance of the temperature fluctuations. These two models are verified by comparison to unheated turbulent pipe flow data and then applied to two problems having thermal stratification and mixing. The first application had unstable thermally stratified flow between two horizontal plates. The second had thermal mixing between a forced convection flow and a thermal cavity which simulates the plenum above the core of a pool type fast reactor. The computational results were compared with various experimental data and show that RSM of 11 Equation is the most suitable model for simulating anisotropic turbulence in thermally stratified flows.