气膜孔附近粒子沉积特性的数值研究

Numerical investigation on particle deposition characteristics in vicinity of film cooling holes

研究了气膜孔附近的粒子运动与沉积特性,重点研究了粒子直径和气膜出流吹风比对粒子运动与沉积特性的影响.基于EI-Batsh粒子沉积模型,考虑了粒子的黏附/反弹和离去机制,编制了相应的粒子沉积计算模块集成在Fluent软件中,并利用相关实验数据对该计算方法进行了验证.结果表明:1,2μm直径粒子沉积率随吹风比增大而增大;3,4μm直径粒子沉积率则随吹风比增大而减小.1μm直径粒子易受气膜出流卵形涡对的卷吸作用而沉积于相邻气膜孔之间区域,当吹风比为2时粒子沉积率比吹风比为0时高约5倍;5μm直径粒子运动轨迹受气膜出流影响较小.总体沉积率随吹风比升高而不断降低,吹风比为2时总体沉积率比吹风比为0时减小1.7%.

Numerical study on the particles movement and deposition in the vicinity of film cooling holes was performed, focusing on the effects of particle diameter and film out- flow blowing ratio on the particle movement and deposition characteristics. Based on the EI- Batsh deposition model including particle sticking/rebounding and particle detachment, user definition functions were linked with FLUENT to predict the particle deposition, and verify the calculation data with relevant experimental data. The research results show that the dep- osition rates of 1, 2 μm diameter particles increase with the growing blowing ratio, but the deposition rates of 3, 4μm diameter particles decrease with the growing blowing ratio. 1 μm diameter particles are prone to deposit in the local region between adjacent film cooling holes under the suction of kidney vortices, and the particle deposition rate of the blowing ratio of 2 is about 5 times higher than that of the blowing ratio of 0. The trajectories of 5μm diameter particles are less affected by the film outflow. The total deposition rate decreases with the increase of blowing ratio, and the total deposition rate at blowing ratio of 2 decreases by 1.7% compared with that at blowing ratio of 0.