Particles deposition on film cooling plates with different types of trenches

Particles deposition could reduce the aerodynamic and cooling performance of turbines and how to mitigate the harmful effect of particles deposition is an issue of concern. To find potential film cooling configurations to mitigate the harmful effects of particles deposition, an experiment of particles deposition at ambient temperature is designed to simulate the deposition due to film cooling and different types of transverse trenches. The new test models are basically plates with film cooling configuration, or in addition configured with transverse rectangular trench (TRT), transverse backward trench (TBT) and transverse corrugated trench (TCT). The experimental results show that all trenches could make the particles deposition and cooling effectiveness more uniform in the vicinity of film cooling holes in the spanwise direction and TRT has the most visible effect. As the trench depth increases or the trench backward angle decreases, this effect is more visible. All trenches could reduce the deposition amount and this reduction increases with the trench depth increasing and the trench backward angle decreasing. TRT could generate the maximum deposition reduction among the three types of trenches, e.g. maximum relative reduction of 75 %. TCT could generates the comparable deposition reduction to TRT. This paper gives deeper understanding of the deposition on film cooled turbines and provides some potential film cooling configurations of reducing the deposition and its harmful effects on turbines.