De-swirled nozzles were fitted in a rotating cavity to reduce the inlet flow tangential velocity thus to reduce the pressure loss associated with radial inflow in the cavity. In this work

experiments were conducted to measure the pressure difference through the test rig and k-ω SST model was applied to simulate the flow structures. Experimental results revealed that the proportion of pressure loss through nozzles to the overall pressure loss through test rig exists maximum and non-maximum conditions. While the proportion of pressure loss through nozzles to the overall pressure loss reaches the top there are no large scale vortex. In the other conditions there are always two large scale vortexes in the cavity

which lead to the largest pressure loss in the rotating cavity.