Heat transfer in the rod bundle is augmented by the mixing vanes on the spacer grid. We conducted a computational fluid dynamics (CFD) simulation with three isotropic turbulence models – standard k–ε, realizable k–ε, and SST k–ω models – to investigate the relationship between heat transfer and turbulence behaviors downstream a simulant spacer (with four vanes) in a single tube under single-phase flow conditions. Quantitatively, the predicted heat transfer coefficient (HTC), secondary flow intensity, and turbulence intensity with the SST k–ω model displayed a better agreement (than the other isotropic models) with the experimental data in previous studies. Moreover, the turbulence production was localized in the near-spacer region (z/D < 10, where D is the inner diameter), which corresponds with the HTC augmentation region. These results indicate that examining the turbulence production when discussing the HTC augmentation downstream the spacer is essential.

杆束中的热传递通过隔离栅上的混合叶片而增加。我们使用三种各向同性的湍流模型（标准k–ε，可实现的k– ε和SST k–ω模型）进行了计算流体动力学（CFD）仿真，以研究模拟隔片下游的传热与湍流行为之间的关系（其中包括四个叶片）在单相流动条件下。从数量上讲，随着SST k–ω的预测传热系数（HTC），二次流动强度和湍流强度该模型显示出与以前研究中的实验数据更好的一致性（比其他各向同性模型更好）。此外，湍流产生局限在与HTC增大区域相对应的近间隔区域（z / D <10，其中D为内径）中。这些结果表明，在讨论垫片下游的HTC增强时，检查湍流产生至关重要。