The Effect of Particle Shape on their Trajectories in Particle Laden Flows

Solid particle erosion and fouling are major deterioration processes within modern aeroengines, which reduce the overall engine efficiency and stability. The numerical simulation of particle deterioration requires the accurate computation of particle trajectories through the individual components and their specific impact locations on the components. The dominant force for the particle motion is the drag force, which strongly depends on the shape of the particles. The drag force of angular particles is higher than for spherical particles. Therefore, the particle shape has a significant influence on the individual particle trajectories. In current numerical simulations, the shape of the solid particles is assumed constant for all particle sizes as either a sphere or an angular particle. In this study, the shape of sand particles is evaluated based on images that are generated with a scanning electron microscope. The developed algorithm analyses the particle contours and shows a dependency of the particle shape with the particle size. The determined particle shapes are used within a numerical simulation of an erosion test facility and compared to measured particle velocities. The numerical simulation reveals that the particle shape directly influences the particle velocity and trajectory. It is also shown that an individual shape for each particle in the simulation improves the numerical predictions of particle trajectories. This individual particle shape enables the accurate prediction of particle laden flows in modern turbomachinery applications.