气膜冷却射流对叶片微细颗粒沉积影响

Effect of film cooling jet on deposition of micro particles on blades

针对微细颗粒在涡轮叶片表面的沉积问题,采用EI⁃Batsh沉积模型对涡轮叶片表面微细颗粒沉积情况进行数值仿真,探究压力面冷却射流对颗粒沉积特性的影响。研究表明:沉积主要发生于叶片前缘与压力面,且沉积率随着粒径的增大不断增大,但粒径增大到17μm后沉积率增加幅度开始变小。存在冷却射流时,射流可以通过吹离和卷吸作用影响小粒径颗粒的碰撞率,从而影响到沉积率,但对大粒径颗粒碰撞率基本不存在影响。射流还可以通过冷却壁面降低颗粒黏附率,进而影响沉积率,且大粒径颗粒所受影响更明显;改变吹风比后,颗粒沉积率随吹风比增加总体上呈现出先减小后增大的趋势。

In view of the deposition of micro particles on the surface of turbine blades,the EI⁃Batsh deposition model was used to simulate the deposition of micro particles on the surface of turbine blades to explore the effect of pressure surface cooling jets on particle deposition character⁃istics.Results showed that,particles were mainly deposited on the leading edge and pressure sur⁃face of the blade,and the deposition rate increased with the particle diameter.However,when the particle diameter increased to 17μm,the increase of deposition rate began to decrease.When there was a cooling jet,the collision rate of small particles can be affected by off and entrainment,thereby affecting the deposition rate.But there was basically no impact on the collision rate of large particles.The jet can also reduce the particle adhesion rate by cooling the wall surface,and affect the deposition rate in this way.The large⁃size particles were affected more obviously.After changing the blowing ratio,the particle deposition rate decreased first and then increased as the blowing ratio increased.