| Popis: |
Atmospheric particulate pollutants are prone to deposit in aero-engine turbines due to high-temperature and high-velocity gas flows. The resulting deposition changes the blade profile, leading to a degradation of aerodynamic performance, increase in surface roughness, and blockage of film cooling holes and internal cooling channels, which further reduces cooling performance of the blade. Therefore, the blades are easily ablated, especially for the rotating parts as they have high rotating speed. In present study, unsteady simulations on the effects of particle deposition were carried out by demonstrating the migration trajectories and deposition distributions of particles in turbine rotor passages of an aero-engine that operates at real engine conditions. The effects of rotating speed, blade tip clearance and its cavity depth on the deposition and migration of contaminant particulates were examined. Results reveal that the deposition on the blade surfaces varies with the rotating speeds and the rotor tip clearances. The deposits are mainly concentrated on the pressure side of the blade where multiple rebounds of the particles are observed under a cruise operating condition. At a larger tip clearance, more particles flow into the tip clearance due to stronger leakage flow, and the squealer tip increases the capture efficiency of the particles on the blade tip. |
