Runner Blade Number Influencing the RPT Runner Upstream Flow Characteristics: A CFD Numerical Simulation

Reversible Pump turbines (RPT) are, for most of their service time, run under off-design conditions, making them frequent victims to flow instability and associated damages. However, these instabilities are known to take source from runner flow separations and grow to terribly affect the flow zones in the upstream. This study seeks to numerically investigate the influence of runner design on flow characteristics in the upstream zones. Three blade numbers namely 8, 9, and 10 were investigated, where flow instability in these zones was found to weaken with the runner blades number increase.