The flow structure and flow loss characteristic in a rotating cavity with tubed vortex reducer were studied numerically. The study focused on the mechanism of the tubed vortex reducer

especially the local loss characteristic at the tube entrance under different geometric parameters of the tube. Based on these studies

a mathematical model for predicting the pressure drop in a tubed cavity was established. It was found that the local loss characteristics at the tube entrance were related to the flow state before the entrance

and the incident angle can describe this flow state well. The static pressure loss at the tube entrance cannot be ignored

accounting for about 11% of the total static pressure drop in the rotating cavity. Furthermore

the tube with a moderate-length can restrict the rotation of the air and reduce the pressure drop in the rotating cavity more effectively. Under the research conditions

the tubed vortex reducer with the optimal tube length can reduce the local pressure drop at the tube entrance by about 25% and the overall static pressure drop in the cavity by about 10%. This also showed that

the mathematical model can provide accurate results of the static pressure distribution in the tubed vortex reducer. The average error was about 53% between the CFD results and the mathematical model results.