小高径比扰流柱冷却通道的换热和流动特性

采用数值模拟的方法,对涡轮叶片尾缘处圆形小高径比扰流柱冷却通道的换热和流动特性进行了研究,分析进口雷诺数和扰流柱间距对冷却通道换热和流动特性的作用过程.结果表明:进口雷诺数的提高能够有效改善冷却通道端壁的换热性能,但这种改善能力随着进口雷诺数的提高而逐渐减弱,同时降低冷却通道的压力损失系数.在两种扰流柱间距中,流向间距是影响端壁换热性能的主要因素,随着流向间距的减小,冷却通道换热性能逐渐变好,压力损失系数降低;横向间距是影响冷却通道流动损失的主要因素,两者大小成反比关系.在通道计算中,扰流柱平均换热性能约是端壁平均换热性能的1.8倍,端壁换热权重约是换热面积比0.824倍,同时该权重几乎不受进口雷诺数的影响.

Heat transfer and flow characteristics of low aspect ratio pin-fins in cooling channel

Numerical simulation was conducted to investigate the heat transfer and flow characteristics of low aspect ratio cylinder pin-fins arrays in turbine blade trailing edge cooling channel, and analyze the action process of inlet Reynolds numbers and pin-fins spacing on cooling channel heat transfer and flow characteristics. The result shows that, with the increase of inlet Reynolds numbers, the channel wall heat transfer performance is improved effectively while the augmentation ability is gradually weakened, and the array pressure loss coefficient is reduced. For the two kinds of spacing, streamwise spacing is the main factor affecting the wall heat transfer performance, and with the decrease of streamwise spacing, the cooling channel heat transfer performance becomes better while reducing pressure loss coefficient; spanwise spacing is the dominant factor affecting cooling channel flow loss, which has an inverse relation between each other. In calculation of the cooling channel, average heat transfer performance of pin-fins is about 1.8 times of the endwall, and endwall heat transfer weight is approximately 0.824 times of the heat transfer area ratio, while this weight is nothing to do with inlet Reynolds numbers.