Abstract: This study simulates the details of the flow in a diversion open channel at a pumped storage power station to study its circulation characteristics under asymmetric terrain. It has been found that a large-size circulation is generated in the channel due to unfavorable terrain conditions, such as the asymmetric terrain boundaries in front and on both sides of the channel. This not only affects the flow pattern in the open channel, but reduces flow uniformity in the trash rack section at the inlet/outlet, thereby producing unfavorable effects. To improve the flow, we suggest two measures ? increasing the length of connection to the channel and expanding the excavation at one side of the channel. Numerical simulations show that these measures can shift the circulation to locations far away from the inlet/outlet, thus improving the flow pattern to a certain extent and reducing flow non-uniformity and other adverse effects. This study provides engineering measures to adjust the intake/outlet location and avoid large-scale excavation for the design of diversion channels of pumped storage power stations.

Key words: pumped storage power station, side inlet/outlet, open channel arrangement, circulation, numerical simulation