Numerical Simulation of Erosion in Pelton Spear Valve at Different Openings

Abstract

The spear valve is one of the most eroded hydro-mechanical components of the Pelton turbine operating in sediment-laden conditions. The spear valve is used to regulate or control the flow. In a multi-nozzle system, though having the same design, the spear valves show varying erosion patterns and intensities. The only difference was found to be the openings of the nozzle/spear valve. This demonstrates that there is some sort of connection between the nozzle opening and the erosion of the spear valve. The difference in erosion intensity in different spear valves can be seen on the site but the underlying phenomenon behind the erosion needed to be studied numerically. In this research, erosion patterns were numerically investigated using an open-source CFD tool, OpenFOAM. For this simulation, the sediment particles and their properties were incorporated into the flow using the built-in Lagrangian library of the OpenFOAM. To investigate the erosion in real time, a transient simulation was undertaken for various nozzle openings. This study only focuses on the erosion at the tip of the spear valve neglecting other parts of the nozzle. This study demonstrates that the erosion in the tip of the spear valve increases with the restriction in flow.