Influence of Blade Fracture on the Flow of Rotor-Stator Systems with Centrifugal Superposed Flow

Rotor-stator cavities are often found in turbomachinery; they supply cold air that is bled from the compressor to the turbine blades. The pressure of the outlet of a rotor-stator cavity is axisymmetric under normal circumstances. However, its pressure would be non-axisymmetric in the event of blade fracture. The impact of blade fracture on a rotor-stator cavity with centrifugal superposed flow is studied in this paper. The Euler number E, the rotational Reynolds number Reφ , and the low-pressure zone range θ are investigated and, for the first time, with the non-axisymmetrical boundary conditions employing numerical simulation. The results of the numerical calculations show that after turbine blade fracture, the velocity is more affected in the downstream region at a high radius, especially when the Reφ is large. As for the distribution of the mass flow rate, there may be a critical θc at which the other blades are least affected. The θc would increase as the Reφ or the E increase, and the θc≅0.2 when Cw=10,137 , Reφ=5.12×105 , and 0.2≤E≤0.4 . In addition, the thrust coefficient increases as the E or the θ increases, and the increase in the thrust coefficient does not exceed 4% when the E=0.2 and the θ=0.1 in this paper. However, the moment coefficient on the rotating shaft is almost independent of the E and the θ. An increase in the Reφ will reduce the effect of turbine blade fracture on the thrust and moment coefficients, when the Reφ is small.