Study of Sand Particle Trajectories and Erosion Into the First Fan Stage of a Turbofan

Abstract

Ingestion of dust particles by aero-engines or stationary gas turbines is inevitable when operating in extremely polluted environments. The impingements of particles on the surfaces of blades cause erosion damage and permanent losses in engine performance. This paper presents a study of the particle dynamics and erosion in the first stage of a turbofan. The steady flow field through the turbomachinery components was solved separately from the solid phase. The particle trajectories computations used a stochastic Lagrangian tracking code that implements probabilistic modeling for particle size rebound and fragmentation, and considers the eddy-lifetime concept for turbulence and the complex flow features near walls. The equations of a particle motion were solved in a stepwise manner using the seventh order RK-Fehlberg technique, whereas particle tracking in different cells of the computational domain used the finite element method. Computations of particle trajectories were carried out for sand particles MIL-E5007E (0–1000 microns) at low, mid and high concentrations. As the locations of impacts were predicted, erosion contours were estimated and the subsequent blade deteriorations were assessed. The rotor blade shows a noticeable erosion of the blade leading and trailing edges almost from root to tip and a rounding of blade tip. Erosion patterns in the diffuser depict high erosion at blade leading and trailing edges and the erosion of pressure side is spreading almost from root to tip, in addition to erosion over the suction side. The actual findings may serve in improving erosion resistance of the blades in this fan stage.