Unveiling particle deposition characteristics on flat plate with a shaped film cooling hole

Abstract

Particle deposition on turbine blades poses a significant challenge to the safe operation of gas turbines. The blockage of film-cooling holes and alteration in the aerodynamic shape of blades affect the turbine's efficiency, highlighting the importance of reducing particle deposition on turbine blades. To investigate the characteristics and potential mechanisms of deposition, experimental and numerical studies were conducted on two typical film-cooling holes: cylindrical and 777-shaped. A multi-perspective scanning method was used to measure the three-dimensional deposition topography on flat plates under a particle-laden environment. The wax deposition experiments showed that the deposition thickness of both holes increased with the blowing ratio. However, the 777-shaped hole exhibited a 10–40% reduction in deposition compared with the cylindrical hole. The computational predictions of deposition patterns agreed well with the experimental results. The numerical simulations revealed that the presence of film cooling reduced deposition in some areas but increased deposition in the vicinity of the film coverage region owing to the entrainment of vortices. Overall, this study further elucidates particle deposition characteristics and the influencing factors, which can guide the design of blade cooling systems with reduced deposition.