涡轮叶片蜂巢式冷却结构减阻能力数值研究

Numerical study on flow resistance reduction of honeycomb-like cooling schemes of turbine blade

先进航空发动机中高耐温能力涡轮叶片通常要以增加冷却系统的流动阻力来提高冷却效果,但由此导致的二次流系统损失增大可能会引起整机性能的下降。研究了先进涡轮叶片中典型层板冷却结构的内部流动损失产生机理,并针对性地提出两种(进/出气孔平行式和交叉式)低流动阻力的蜂巢式冷却结构。基于三维数值仿真方法研究了其流动特点和损失特性,并揭示了该结构可以显著减小通道内气流转折角度、抑制旋涡产生和避免多股气流对撞的减阻强化机理。通过与典型层板结构的对比分析,初步验证了在相同的结构无量纲参数和流量下,两蜂巢式冷却结构的总压损失分别可降低65%~66%和67%~69%,在高推重比航空发动机涡轮叶片冷却设计上具有较好的应用前景。

In modern advanced aero-engines, coolant flow resistance was commonly increased to improve the cooling efficiency and the temperature capacity of turbine blades. Thus, the engine performance might be decreased, for the losses increasing of secondary flow system. In order to reduce the flow losses of typical Lamilloy cooling configurations in advanced turbine blades, two honeycomb-like cooling schemes(inlet/outlet parallel or cross) were proposed and studied. The flow loss reducing mechanisms were revealed by 3D numerical simulation that, these creative schemes could decrease the coolant flow turning angle, suppress the vortex, and prevent the impingement between flows. For the same conditions of dimensionless structure parameters and mass flow, the total pressure loss of two honeycomb-like cooling designs could be reduced by 65%-66% and 67%-69% respectively comparing with that of typical Lamilloy. These advantages indicated the application prospect of these honeycomb-like cooling innovations on future high thrust-to-weight ratio aero-engines.