Abstract
Large eddy simulation of supercritical CO2 flow carrying solid oxide particles through a radial turbine nozzle has been conducted at a Reynolds number of 0.5 × 106. The three-dimensional geometry corresponds to the nozzle where erosion damage was observed by Fleming and Kruizenga [1]. The turbulent flow through the passage was approximated as incompressible, and the spatially filtered Navier-Stokes equations were solved on an unstructured grid. One way coupled, porous, oxide particles (30μm diameter, 2500 kg ṁ m−3) were continuously injected upstream of the passage and tracked in a Lagrangian manner as they were carried through the domain by the turbulent flow. Statistics of mean particle concentration and particle-nozzle impacts were collected to identify regions along the passage prone to erosion damage. For this condition, the particles became highly concentrated as they passed along the pressure side of the nozzle. High impact velocities and oblique collision angles near the trailing edge led to relatively high predicted rates of erosion, near the location where damage was observed in the laboratory. Extrapolation of simulation results to proposed operational Reynolds numbers suggests that very small particles, with diameter < 10μm, could cause high velocity impacts and eventual degradation.
Large-Eddy Simulation of Three-Dimensional Turbulent Flow Around a Circular Pier
