For better design and optimization of the heat exchanger (HX), forced convective heat transfer and flow characteristics of supercritical carbon dioxide (SCO2) in a water-cooled experimental counter-flow tube-in-tube HX were studied numerically with three-dimensional Reynolds-averaged Navier-Stokes equations and shear stress transport (SST) turbulence model by using computational fluid dynamics method in ANSYS CFX. With a sole tube model of the HX, effects of SCO2 inlet pressure, mass flux, tube diameter and wall heat flux on SCO2 mean heat transfer coefficient (MHTC) were investigated. Influences of turbulence models and discretisation schemes of the advection terms in the SST model, wall temperature of conservative and hybrid values in CFX-Post on MHTC were clarified, and buoyancy effect in the horizontal HX was explored. The SST model can achieve better agreement with the experimental MHTCs of SCO2 than the other models. The buoyancy effect can improve MHTC by the secondary flows in the tube.

为了更好地设计和优化换热器 (HX)，使用三维雷诺数值研究了水冷实验逆流管中管 HX 中超临界二氧化碳 (SCO2) 的强制对流传热和流动特性- 使用 ANSYS CFX 中的计算流体动力学方法平均 Navier-Stokes 方程和剪切应力传输 (SST) 湍流模型。使用 HX 的单管模型，研究了 SCO2 入口压力、质量通量、管径和壁热通量对 SCO2 平均传热系数 (MHTC) 的影响。阐明了湍流模型和 SST 模型中平流项的离散化方案、CFX-Post 中保守和混合值的壁温对 MHTC 的影响，并探索了水平 HX 中的浮力效应。与其他模型相比，SST 模型与 SCO2 的实验 MHTC 的一致性更好。浮力效应可以通过管内的二次流动提高 MHTC。