Effects of Syngas Ash Particle Size on Deposition and Erosion of a Film Cooled Leading Edge

Abstract

The paper investigates the deposition and erosion caused by Syngas ash particles in a film cooled leading edge region of a representative turbine vane. The carrier phase is predicted using large eddy simulation for three blowing ratios of 0.4, 0.8, and 1.2. Ash particle sizes of 1 μm, 3 μm, 5 μm, 7 μm, and 10 μm are investigated using Lagrangian dynamics. The 1 μm particles with momentum Stokes number, Stp=0.03 (based on approach velocity and leading edge diameter), follow the flow streamlines around the leading edge and few particles reach the blade surface. The 10 μm particles, on the other hand with a high momentum Stokes number, Stp=0.03, directly impinge on the surface, with blowing ratio having a minimal effect. The 3 μm, 5 μm, and 7 μm particles with Stp=0.03, 0.8 and 1.4, respectively, show some receptivity to coolant flow and blowing ratio. On a number basis, 85–90% of the 10 μm particles, 70–65% of 7 μm particles, 40–50% of 5 μm particles, 15% of 3 μm particles, and less than 1% of 1 μm particles deposit on the surface. Overall there is a slight decrease in percentage of particles deposited with increase in blowing ratio. On the other hand, the potential for erosive wear is highest in the coolant hole and is mostly attributed to 5 μm and 7 μm particles. It is only at BR=1.2 that 10 μm particles contribute to erosive wear in the coolant hole.