高压涡轮气冷叶片冷却掺混损失数值研究

Numerical Investigation into Coolant Mixing Loss ofHigh Pressure Turbine Air-Cooled Blade

关键词:  气冷叶片  冷却掺混损失  数值模拟

Key words:  Air-cooled blade  Coolant mixing loss  Numerical simulation

摘要:

为探索高压涡轮气冷叶片多排冷却孔出流对各排孔冷却掺混损失的影响，采用三维粘性流场数值模拟技术，对典型气冷叶片多排孔冷却射流流场和叶栅性能进行了研究，并将冷却掺混损失数值计算结果与Hartsel模型预测值进行了对比。研究结果表明:气冷叶片表面多排冷却孔射流相互作用对各排冷却射流与主流掺混引入的流动损失影响较小，各排射流冷却掺混损失相互独立具有简单的可叠加性质；叶片表面各区域冷却射流出流对叶栅性能影响程度有所不同，尾缘劈缝与吸力面冷却射流对叶栅性能影响较大，前缘区域次之，压力面冷却射流对叶栅性能影响较小；和数值计算结果相比，总压损失系数Hartsel冷却掺混损失模型预测值偏高，尤其对于尾缘和吸力面主流马赫数较大的区域，损失模型预测值为计算结果的2～4倍，而前缘和压力面预测值和计算结果符合性较好。

Abstract:

In order to investigate the effects of air-cooled blade in high pressure turbine multi-row injection on the mixing loss of each cooling row， the flow fields and performance for a typical multi-row injection air-cooled blade planar cascade by using 3D viscous CFD simulation were presented， and the coolant mixing loss coefficient from numerical simulation results were contrasted to the Hartsel mixing loss prediction value. The investigation results illustrate that the multi-row injection interaction in air-cooled blade has little effect on coolant mixing loss from each row， the total loss could be obtained simply by adding each mixing loss. The coolant injections from different blade surface location have different extent of influence to blade performance. The trailing edge slot and suction side coolant injection affect more important than leading edge injection， and the pressure side cooling almost has no effect to blade performance. Comparing to the simulation results， the mixing loss model predicted larger total pressure loss coefficient， especially for trailing edge and suction side coolant injections where the main flow Mach number higher than other regions， the loss model predicted values are 2 to 4 times simulation results. For the leading edge and pressure side coolant injections the prediction value shows acceptable agreement.