低雷诺数涡轮叶栅损失的实验与数值模拟

Experimental and numerical investigation of loss in turbine cascade with low-reynolds number

关键词:  涡轮叶栅  流动  损失  流动分布  数值仿真

Key words:  Turbine cascade  Flow  Loss  Flow distribution  Numerical simulation

摘要:

发动机涡轮部件在高空低速飞行条件下工作雷诺数降低,其损失显著增大、效率显著降低。应用实验分析与数值模拟相结合的方法,深入认识高空低雷诺数条件下涡轮流动损失的特征和规律,数值计算是基于Jame son中心差分和Runge Kutta时间推进的N S方程计算的有限体积方法。研究表明,随着雷诺数降低,涡轮叶栅流动损失增大,当雷诺数小于42000之后,涡轮叶栅流动损失呈明显增大的趋势。数值计算结果表明在低雷诺数条件下,涡轮叶栅吸力面后部流动产生了分离,这是流动损失增大的主要原因。数值预测的结果与实验测量结果的趋势吻合得相当好。

Abstract:

Low Reynolds number of turbine at high-altitude results in the notable drop of efficiency of turbine.The objectives of the present work was to reveal the aerodynamic performance of low-pressure turbine blades at low Reynolds number.The airfoil being studied here is the mid-span section of the low-pressure turbine rotor blade of a turbofan.The Reynolds number, based on the cascade outlet velocity and blade chord, was varied from 10000 to 180000.A finite volume scheme for solving Reynolds averaged Navier-Stokes equations is used.The experiment was conducted on the low-speed linear cascade tunnel.Both the predicted and experimental results indicate increased cascade losses as the Reynolds number is reduced to the values associated with aircraft cruise conditions.Overall, the predicted aerodynamic and performance results exhibit fair agreement with experimental data.