Session: 33-01 Deposition, erosion and fouling in gas turbine engines

Paper Number: 151423

CFD Assessment of the Magnus Effect and Collision Induced Rotation of Solid Particulate on Compressors 

Erosion due to particle impacts on surfaces is a widely studied topic in engineering. Erosion occurs commonly in pneumatic conveying systems where the transport of particles is the goal of the system. Erosion is also important in gas turbine engines. The ingestion of small particles such as sand, ash, and ice cause harm to the engine, which can eventually lead to engine failure. The trajectory and size of the particles play an important role in predicting the damage occurring in the engine and pneumatic systems. This work is a first step in reducing damage due to erosion in pipe flows and gas turbine engines by understanding the motion of particles within the engine. One important, but often neglected aspect of particle trajectory is accurate prediction of particle rotation. Previous studies indicate that the particle angular velocity plays a significant role on their trajectories even in simple geometries such as curved pipes. The rotation leads to a higher velocity on one side of the particle and lower velocity on another side, and hence causes a pressure difference across the particle. This pressure difference influences the trajectory of the particle by modifying the drag force and introducing an additional lift force (Magnus force). The primary source of the angular velocity of the particles is through particle collisions with walls. However, few models of particle-wall impact introduce rotation. The most widely used rotational model (Tsuji et al. 1985) is incomplete in that it does not consider surface tangential elasticity in its approach. Miranda et al. (2024) introduces an improvement to this model that improves the prediction of particle trajectories after rebound and is implemented in this study. This work uses computational fluid dynamics to investigate the impact of particle trajectory modelling on prediction of damage in a gas turbine engine. Particles of various diameters relevant for sand ingestion, ranging from 10 microns to 200 microns are introduced into a High Pressure 3 stage compressor section of a gas turbine engine to analyze and quantify the importance of particle rotation on their trajectories, and obtain statistical data of their impact properties. The flow physics and particle motion are analyzed using Reynolds Averaged Navier Stokes (RANS) CFD techniques coupled with Lagrangian particle tracking (LPT). The SST k-omega turbulence model is chosen to model the turbulence physics, and the gas phase is two way coupled to the Lagrangian particle phase. The Lagrangian phase uses the particle equations of motion to solve for the particle trajectories. When considering the effects of rotation, the particle angular momentum equation is coupled to the particle equations of motion. The improved particle-surface collision model by Miranda et al. (2024) is used to accurately capture rotational motion induced due to particle-blade collisions. Standard closure models from literature are used for the lift and drag of the rotating particles. A quantitative analysis on the impact locations, impact kinetic energies, as well as erosion occurring based on particle size and the implementation of the rotation model is demonstrated in this study.

Presenting Author: Cairen Miranda Virginia Tech

Presenting Author Biography: Cairen Miranda is a PhD candidate and a Rolls-Royce Graduate Fellow in the Mechanical Engineering Department at Virginia Tech. His work in Computational Fluid Dynamics focuses on modeling particle-laden turbulent flows and understanding the interactions between the particles and the gaseous phase as well as particle-surface collisions.

Authors:

Cairen Miranda Virginia Tech
John Palmore University of Washington
Changmin Son Virginia Tech