CFD analysis of particulate flow in a radial inflow turbine

Abstract

In the present thesis a study of the erosion rates that blades from a typical radial inflow turbine suffer because of the ingested flow containing solid particles is presented. The mentioned study has been conducted by carrying out a series of CFD simulations using the software package ANSYS CFX. The obtained results indicate that there are three main surface areas where significant erosion loss occurs. The first of them and by far the most affected part of the turbine is located at the trailing edge of the stator blade, where a relatively great number of impacts with low angles strike the surface. This surface area is found to be affected by a concentration effect, that is, many particles impinging a small surface area. The second but lesser affected part is the leading edge of the suction side of the rotor blade, on which many particles strike many times due to particles being trapped in a vortex area. The third and last surface area which is eroded significantly, but in comparison to the other parts facing much less erosion, is the central part of the pressure side of the rotor blade. Additionally, several influencing factors have been studied to determine their influence on the erosion rate density, such as angular velocity, particle concentration, particle shape and size and blade material. The relation between these factors and the erosion rate density has been determined. Besides, a final study about the compressibility effects that may have been affected the study has been conducted in order to ensure the validity of the simulations of the thesis.