Effects of Slot Injection on Blade Erosion in Direct Coal-fueled Gas Turbines

Effects of injection on the erosion of gas turbine blades (due to particle laden combustion gas) are examined. The problem is simplified through simulation of the flow field as a slot injection into a two-dimensional boundary layer with a given initial angle of incidence (30-maximum damage angle) of the particles at the edge of the boundary layer in the injection region. Particle sizes from 5 μm to 20 μm are considered. Equations of motion of a particle are derived by considering only the effect of the drag forces. Resulting equations are solved for the angle of impact of the particles on the surface as a function of particle diameter for several injection ratios. Results show that angle of impact of the particles, thereby erosion can be reduced with injection especially for particles whose diameters are less than 10 μm.