Pressure and Temperature Effects on Particle Deposition in an Impinging Flow

Particle deposition is a significant problem in gas turbine engines. Internal cooling passages are of particular interest because deposition build up is observed at far lower temperatures than it is for external flows. Computational fluid dynamics were employed to investigate how changes in the particle Reynolds number affected deposition in an impinging flow. Three-dimensional, steady Reynolds-Averaged Navier-Stokes equations were solved for a single impinging jet that had a jet to wall spacing of H/D = 2. Pressure ratios of 1.015 and 1.03 were considered at three different discharge pressures, 0.1, 1 , and 3 MPa. Three different flow temperatures were also considered, 300, 700, and 1000 K. Five different particle diameters ranging from 0.5 – 10 μm were tracked in each solution. The aerodynamic lensing focal point of the particle tracks, particle impact velocities, particle impact angles, and particle impact locations were all characterized well by the effective Stokes number. The effective Stokes number adjusts the Stokes number by the non-Stokes drag correction factor, which is a function of the particle Reynolds number.