叶顶压力侧小翼对跨声速涡轮级气动性能影响的数值研究

Numerical Study of Effects of Blade Tip Pressure-Side Winglet Cavity on Aerodynamic Performance of a Transonic Turbine Stage

关键词:  涡轮级  叶顶间隙  肋条小翼  涡轮效率  间隙泄漏流

Key words:  Gas turbine stage  Tip gap  Rim winglet  Turbine efficiency  Tip Leakage flow

摘要:

为了研究涡轮叶顶间隙泄漏流动有效控制的方式，本文将肋条小翼结构这种被动流动控制技术应用于涡轮级动叶叶顶中，以控制跨声速涡轮级叶顶间隙泄漏流动并改善其气动性能。通过数值模拟方法，分析了采用平顶方案、肋条方案和小翼肋条方案的涡轮级气动性能和叶顶间隙流动特性，研究了变间隙条件下小翼肋条方案对间隙泄漏流的控制效果，深入探讨小翼最大偏置距离和外倾角对小翼控制效果的影响。结果表明：所采用的肋条小翼结构能够有效地控制叶顶间隙泄漏流动并提高涡轮级的效率；在间隙高度为1mm时，涡轮级效率的提升达到0.51%，叶顶间隙泄漏流率下降48.6%；此外，随着小翼外倾角的增加，涡轮级效率逐渐增加并存在一个最佳的向外偏置距离为1.2mm。

Abstract:

In order to study the effective control method of turbine tip clearance leakage flow， the present study applies the passive flow control technology of the rim winglet structure to the turbine stage rotor blade tip to control the transonic turbine stage tip clearance leakage flow and improve its aerodynamic performance. The aerodynamic performance and flow field around the blade tip were evaluated by numerical simulations under a flat-tip case， a groove tip case and a rim winglet case. The effects of different tip clearance heights of rim winglet cases on the tip leakage flow were investigated in this study. In addition， the influence of both the maximum off-set position and the inclination angle of the winglet were discussed in detail. The results supported that the tip leakage flow was well regulated and consequently the efficiency was enhanced with the application of the rim winglet. More concretely， the efficiency of the turbine stage was improved by 0.51% and the mass flow rate of the tip leakage flow was decreased by 48.6% under 1mm tip clearance. Moreover， the efficiency of the turbine stage increased with an enlarged winglet inclination angle. The optimal winglet off-set position turned out to be 1.2mm.