带交错叉排肋的矩形通道流场和壁面换热特性的数值模拟

Prediction of Flow and Heat Transfer in Rectangular Passages with 60 Degree Rib Turbulators Arranged Crossly on the Opposite Walls

为了获得高的换热系数和流动损失小的涡轮叶片内冷通道，提出了在上下壁面交错叉排布置肋的通道结构，利用数值计算的方法研究了通道各个壁面的换热特性、流动特性和流体的温度分布规律。人口雷诺数变化范围为30000-120000。采用结构化网格进行网格划分，利用realizablek-8湍流模型和增强壁面函数封闭方程。计算结果表明，所提出的通道结构不仅在带肋的上下壁面具有较高的换热系数，大约为2．2～2．4，光滑的左右壁面的换热也增强了1．4-1．6倍，通道内的温度分布呈现出同心圆的分布，在靠近壁面的位置，二次流动较强。

Numerical prediction of three dimensional flow and heat transfer are presented for a rectangular passage with 60 degree rib turbulators arranged cross on opposite walls and channel aspect of 2 ： 1. The rib height-to hydraulic diameter ratio is 0.113 and the rib-pitch- height ratio is 10. Reynolds number varies from 30 000 to 120 000. A finite volume method is used to solve Navier-Stokes equations. The realizable k-8 model is used and the enhanced wall function is utilized for near wall treatment. A grid-refinement study is performed using different grid distributions. The focus of this study is heat trans- fer on the surfaces, temperature distribution and flow field. The numerical result shows that the uniform fluid temperature distribution is obtained on section of straight free-stream. The secondary flow is stronger than the center of the passage. En- hanced heat transfer and low flow loss are obtained through this rib structure. Heat transfer ratio is about 2.2 to 2.4 on the surface with ribs and is about 1.4 - 1,6 on the smooth surface.