不同粒径颗粒在涡轮流道内沿程温度及其与叶片的撞击特性研究

Temperature of Particles with Different Diameters along Turbine Flow Path and Impingement Characteristics on Turbine Vanes and Blades

关键词:  涡轮  颗粒粒径  运动轨迹  沿程温度  撞击特性

Key words:  Turbine  Particle diameter  Trajectory  Temperature along the path  Impingement characteristic

摘要:

涡轮叶片表面的颗粒沉积会影响其气动性能和冷却效率，因此很有必要开展颗粒在流道内的运动、温度及其在涡轮叶片表面的撞击特性研究。基于离散相模型，采用CFD数值模拟了涡轮流道内的燃气流动以及不同粒径颗粒在涡轮流道内的运动轨迹与沿程温度变化，并获得了颗粒与涡轮叶片的撞击特性。模拟结果表明，随着颗粒粒径由1μm增加至200μm，颗粒在涡轮流道内的随流性变差，颗粒在流道内的撞击、反弹现象加剧，这促使颗粒在流道内的运动路程整体呈上升趋势；颗粒粒径的增大还会导致颗粒散热能力下降，促使颗粒的沿程温降逐渐降低；同时，颗粒粒径的增大会导致颗粒在导叶片表面的撞击系数上升，而动叶则与之相反。

Abstract:

Particle deposition on a turbine blade influences its aerodynamic performance and cooling efficiency, the particle’s trajectory, temperature along turbine flow path and impingement characteristic on the turbine blades should be researched. The CFD combined with discrete phase model is applied to simulate the gas flow along the turbine flow path, the trajectories and temperatures of particles with different diameters, and finally to obtain the impingement characteristic of particles on the turbine blades. The simulation results indicate that, with the increase of particle diameter from 1μm to 200μm, the flow-following of the particle becomes worse, and the impingement and rebound become more frequent, so that the overall moving distance of the particle in the turbine flow path increases roughly. The increase of particle diameter can also weaken the heat dissipation ability of the particle and suppress the decrease of particle temperature along the process. In addition, the increase of particle diameter can also lead to the rise of impingement coefficient of particles on the vanes, and the decrease of impingement coefficient on the blades.