Modelling of deposit mechanisms around the stator of a gas turbine

The analysis of particle laden flow in turbines stages is a very actual topic as deposit can alter the blade cooling due to a partial or total blockage of film cooling holes and the modification of heat transfer coefficient between the internal cooling fluid and the blade surface. A computational tool for predicting particle deposition on a solid surface, developed by the authors, is here applied and validated against literature data. The computational model is based on an Euler-Lagrangian approach with a one-way coupling for the description of the fluid-particles interaction. The deposit model used is based on the paper of Walsh et al., 1990. The prediction of the fluid phase is carried out by using a URANS (Unsteady Reynolds Averaged Navier Stokes) approach on the well-validate open-source code OpenFOAM widely tested and validated by the authors and many other researchers worldwide in a number of turbomachinery relevant cases. The numerical campaign was firstly focused on the analysis of the details of the flow field in order to identify the eventual presence and position of shocks as well as to put in evidence the shock/boundary layer interaction. Then, the trajectories of two class of particles are analyzed in order to determine the influence of drag, pressure and velocity gradient on the particle pattern. Finally, the adhesion on the blade surface and the influence of flow temperature is discussed. Copyright © 2013 by ASME.