带肋变截面回转通道内换热特性的实验研究

An Experimental Study of Flow Performance in a 180° Turn-Over Channel with Ribs

与等截面回转通道相比较,变截面通道更接近叶片内冷通道原型。本文采用实验的方法研究带90°直肋的变截面180°回转通道壁面的换热特性,以单个直肋为基本特征将通道分成若干单元,在满足通道面积连续的条件下,考察了各特征无因次几何参数和气流雷诺数对带肋面换热的影响。在实验验证的进口雷诺数的范围内,与Dittus-Boelter公式比较,实验模型带肋面的平均努赛尔特数Nuav提高了74%～128%不等,并且在较小的Rein时,Nuav提高的幅度更大。

Compared to the channel with uniform section area,those with various section areas are much similar to the internal cooling structure of the turbine blade.In this thesis,a 180°turnover channel with various sectional areas and 90° parallel ribs is studied of its characteristic of heat transfer.The channel is divided into some heattransfer elements each with one,single rib as the basic character.The influences of every characteristic nondimensional geometric parameter and Reynolds number on the heat transfer of the ribbed walls are studied on the premise that the channel area changes continually.At the same channel inlet Reynolds number,the average Nusselt number of the test model's rib walls is 74%～128% larger compared with DittusBoelter formula and much larger at smaller Reynolds number.