Investigation of erosion and corrosion on the surface, temperature, pressure profiles and efficiency losses of gas turbine engine components

This paper presents the results of the experimental and computational research programs to investigate the effects of erosion and corrosion on turbine stators and rotors. In the areas of experimental research, 3-dimensional surface profiling and airfoil contour measurement were conducted on a set of blades to determine the least degraded and most degraded blades as well as degradation along the radial direction. Numerical simulations for 2-dimensional and 3-dimensional flow fields through first stage rotor blades were employed to indicate differences in pressure, temperature profiles, drag and lift between the most degraded blade and the design blade. Stage efficiency losses were calculated based airfoil contour measurement results. Relevant side studies of effect of solidity on flow separation as well as design optimization of blade shape were carried out. The suction side of turbine blades had higher surface roughness compared to the pressure side. Blade 3 was found to be the most degraded blade amongst the five HPT Stage 1 rotors, with the greatest degree of degradation found around one third chord from the tip. Using STAR-CCM+, a Computational Fluid Dynamics (CFD) simulation software, degraded blade was computed to have higher drag coefficient due to shock and wake produced by flow across erosion pits. Pressure, temperature, Mach profiles were similar for both blades except for regions affected by erosion and deposition. 3-D numerical simulation investigated secondary flows in form of vortex leakage, passage vortex and wakes for both blades. The degraded blade suffered from greater wake losses and lower stage efficiency as a result of higher profile and secondary losses. This model has found to be of practical use to Pratt & Whitney plant managers where a cost-benefit analysis can be used to determine if clients should procure a design blade or adopt the less aerodynamically efficient reinstated blade for operations.Bachelor of Engineering (Aerospace Engineering