带脉冲式涡流发生器的低压透平叶片流动控制数值模拟

 基于Langtry-Menter转捩模型的SST两方程模型,通过数值求解三维非定常雷诺时均Navier-Stokes方程,详细研究了脉冲式射流涡流发生器(pulsed VGJs)对Pak-B低压透平叶片吸力面流动分离的影响,揭示了pulsed VGJs流动控制机理以及脉冲频率和占空系数在流动分离控制过程中的内在关联。数值计算结果表明,pulsed VGJs的引入能够有效抑制甚至消除低雷诺数条件下叶片吸力面上的流动分离,减小总压损失和尾迹宽度。在pulsed VGJs流动控制中,存在最佳射流参数(脉冲频率f和占空系数DC)以获得最大程度的流动控制效果。当f=10 Hz,DC=0.5时,pulsed VGJs流动控制效果最佳,相对于无pulsed VGJs控制时总压损失减少了58%。

Numerical Simulation of Low-pressure Turbine Blade Flow Control with Pulsed Vortex Generator Jets

Based on an SST turbulence model coupled with a Langtry-Menter transition model, three-dimensional viscous unsteady Reynolds-averaged Navier-Stokes equations are solved, and the effect of pulsed vortex generator jets (pulsed VGJs) on the flow separation on the suction side of a Pak-B low-pressure turbine (LPT) blade is investigated numerically. The flow control mechanism of pulsed VGJs is revealed. The inherent relevance between the pulse frequency and duty cycle is demonstrated from the flow simulations of a low-pressure turbine blade with pulsed VGJs. The numerical results indicate that pulsed VGJs can effectively suppress or even eliminate flow separation on the blade suction side under low Re conditions. The total pressure loss coefficient and wake width are also reduced evidently. For pulsed VGJs, there is a reasonable pulse frequency (f) and duty cycle (DC) to achieve the optimal flow control effectiveness. Compared to the case without pulsed VGJs, the total pressure loss coefficient is reduced by 58% when pulsed VGJs with f=10 Hz and DC=0.5 is used.