Abstract
In a steam turbine partial admission stage, particular losses and lift fluctuations occur even under a full load condition because the working steam isn't supplied to the rotor raw around flanges. Unsteady three-dimensional flows in a partial admission stage are numerically investigated and compared with the result of two-dimensional analysis. A numerical method developed by authers' group is used in this study. Then, the lift fluctuations in the three-dimentional analysis is in good agreement with that of two-dimentional analysis, but the local flactuations are lower than that of two-dimentional analysis. The pressure distributions of three-dimensional analysis show lower flactuation too. The cause of this difference may be due to radial flows which equalize the flow field. Finally, the radial flow affects the rotor performance.
