气热耦合条件下涡轮静叶三维优化

Conjugate Heat Transfer 3-D Optimization for Turbine Stator

关键词:  涡轮  弯叶片  气热耦合  多目标优化 

Key words:  Turbines  Bowed blade  Conjugate heat transfer  Multi-objective optimization

摘要:

为解决涡轮静叶尾缘烧蚀问题并提升气动效率,采用气热耦合优化的方法对该叶片进行优化,优化分为对叶型优化以及对弯叶片优化两部分。优化结果显示,对叶型进行优化时由于叶型变化以及冷气流量增加2.68%导致叶片平均温度降低4.15%,最高温度下降61.7K,气动效率提升0.17%；对弯叶片进行优化时,顶部正弯效果明显,冷气流量增加0.11%,叶片平均温度下降2.4%,最高温度下降10.6K,气动效率提升0.16%。通过分析,对于该径高比较小的叶片,无论是叶型变化还是弯叶片变化,低能流体由端区进入主流导致的端区损失降低和激波损失的降低是导致气动效率提升的主要原因；冷气流量加大以及端区二次流减弱是造成叶片温度场降低的主要原因。 

Abstract:

To avoid the turbine blade tail edge ablation and improve the aerodynamic performance, conjugate heat transfer optimization was used to change the parameters of blade profiles and bowed blade. The blade profiles optimization and bowed blade optimization were carried out independently. The results show that during the blade profile optimization as the blade profiles are changed and the mass flow of the coolant increases by 2.68%, the average temperature of the blade decreases by 4.15% and the maximum temperature decreases by 61.7K, also the aerodynamic efficiency increases by 0.17%. During the process of bowed blade optimization, the effect of blade positive curving near the tip is obvious, the mass flow of the coolant increases by 0.11%, the average temperature decreases by 2.4%, the maximum temperature decreases by 10.6K and the aerodynamic efficiency increases by 0.16%. For the blade with small diameter-blade height ratios, there are two major factors influencing the efficiency, the first one is the decrease of the shock loss and the second one is the decrease of the end wall loss as the low energy fluids near the end wall moves into the mainstream.The increase of the coolant mass flow and the reduction of secondary flow are the major factors lowering the blade temperature.