Gas turbine engines operating in areas where the atmosphere is polluted by small solid particles are examples of machines operating under particulate two-phase flow conditions. The presence of solid particles in the working media leads to erosion and loss of engine power. In the present paper, particle trajectories are calculated by direct integration of the particle equations of motion through a compressor impeller with two different size splitters. Particle collisions with the blade, hub, and casing surfaces are determined. Erosion caused by the particle collisions with the compressor surfaces is calculated.