The presence of solid particles in turbomachinery flow affects the component performance as well as its life. The subject of particulated flows can be broadly divided into three parts, namely, particle trajectories, the effect of particles on the aerodynamics of flow and material erosion. The first two aspects are investigated in this paper taking into account the viscosity of the carrier fluid.

The Lagrangian formulation is adopted for the particles, whereas the Eulerian approach is used for the continuous phase. The effect of particles is incorporated as interphase force terms in the fully incompressible stream function-vorticity form of the Navier-Stokes equations. The field analysis is based on the numerical integration of this equation over the rotor blade to blade stream channels. The numerical code used to solve the governing equations employs a nonorthogonal boundary fitted coordinate system that suits the most complicated blade geometries. The trajectories of the solid particles are determined including particle impacts with the blades. The particle rebounding velocity and direction after each impact is determined using semi-empirical correlations for the restitution ratios obtained experimentally. The method of analysis is applied to a radial inflow turbine. The effect of particles on the aerodynamics of the flow is studied by analyzing the fluid streamline pattern in the rotor blades with and without solid particles. The analysis is carried out for various particle concentrations.

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