Simulated Syngas Ash Deposition on the Leading Edge of a Turbine Vane with Film Cooling

In using coal derived syngas in a gas turbine, solid particulates coming out of the gasifier can prove to be detrimental to the engine hardware. Not much is known about particle deposition, erosion, and corrosion on turbine blades as a result of these contaminants. Performing deposition studies at engine like conditions can be difficult. This study presents a method for substituting the particles with polymer materials so studies can be done under more workable conditions. PVC and Teflon particles were used and deposited against a flat plate to mimic a published experiment that used real coal ash. Temperatures were near the melting point of the material and oncoming momentum Stokes numbers were matched. It was found that using polymer materials is not a perfect substitute, but has the same trends and behaves in a similar fashion.

PVC particles were then used in an experiment to impact a leading edge with film cooling. The same particle substitution method was used. It was found that increasing the free stream temperature increased the amount of deposition while increasing the blowing ratio slightly decreased deposition. Particle deposition on the leading edge tended to cause an increase in the film cooling effectiveness. It was also found that deposition on the surface slightly increased the convective heat transfer.