低展弦比微型轴流涡轮弯叶片设计

Micro Axial Turbine Bowed Blade Design at Low Aspect Radio

针对微型轴流涡轮机面临的低展弦比、低雷诺数导致效率降低的问题,以某型200kW微型燃气轴流涡轮发电机高压涡轮为研究对象,采用数值模拟方法开展了低展弦比下微型弯曲轴流涡轮叶片设计技术研究。对展弦比为0.88的涡轮静叶,分析对比了正弯和J型弯静叶对微型涡轮流场的影响,结果显示:正弯静叶顶部出口气流角较大,造成下游动叶叶尖泄漏损失增大,整体效率下降;而J型弯方案抑制了下游动叶叶背中径的流动分离,整体性能较原型有所提升。然后,研究了J型静叶弯高和弯角对涡轮性能的影响规律,结果表明:采用大弯高小弯角设计的J型静叶提高了静叶根部通流能力,同时合理分配了静叶通道内的负荷以及出口气流方向,对涡轮级流场的改善效果更佳。J型静叶弯高为1、弯角为+5°时,级效率达到0.852,流量为1.205kg/s,较原型分别提高了0.77%和0.96%。

Based on the problem of the micro axial turbine efficiency being reduced at low aspect radio and low Reynolds number, regarding a high-pressure turbine of a 200 kW micro turbine generator as the ob- ject of study, the micro bow axial turbine stator design technology is researched using the numerical simulation method at low aspect radio. When the turbine stator aspect radio is 0.88, the effect of posi tive bow stator and J bow stator on the turbine flow field is analyzed and compared, and the results show that： The positive bow stator enlarges the stator exit flow angel on the tip and the rotor tip clearance loss, so drops the efficiency. The J bow stator restrains the flow separation of rotor in the mid and im- proves the overall efficiency. Then, the effect of bow height and bow angel on the J bow stator is stud- ied, and the result indicates the J bow stator with big bow height and little bow angel can improve the mass flow of hub. At the same time, the passage aerodynamic load and the exit flow angel are reasona- bly distributed, which can improve the turbine internal flow. When J bow stator＇s bow height is 1 and bow angel is ＋5°, the stage efficiency and the mass flow achieve 0. 852 and 1. 205 kg/s, and increase by 0.77% and 0.96% compared witch original ones, respectively.