Study of Erosion Effects on an Axial Fan Global Range of Operation

Abstract

Operating in sandy environments can cause significant erosion damage to gas turbine installations, particularly in the compressor system. This effect is a result of the ingestion of sand particles and their consequent abrasive impacts on blades. In order to better understand the mechanism of sand ingestion in an axial fan stage and the subsequent effects of erosion over its global range of operation, a methodology was developed and presented in this paper. This includes the computations of particle trajectories through an axial fan stage, erosion and blade profile deterioration, in addition to the aerodynamic performance degradation. The flow field at different operating conditions was solved with the CFD code TASCflow. The particle trajectories were computed using an in-house developed trajectory code, which was based on the lagrangian method. The effects of flow turbulence on particles were simulated using the eddy lifetime concept. The estimation of the aerodynamic performance degradation was based on a mean-line method involving Lieblein and Koch correlations, and an erosion fault model derived from blade profile deterioration. This global procedure was applied successfully to a contra-whirl axial fan, and can be generalized easily to other configurations of axial compressors.