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 Re_ϕ, 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 Re_ϕ is large. As for the distribution of the mass flow rate, there may be a critical θ_c at which the other blades are least affected. The θ_c would increase as the Re_ϕ or the E increase, and the (Formula presented) whenCw = 10, 137, Re_ϕ = 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 Re_ϕ will reduce the effect of turbine blade fracture on the thrust and moment coefficients, when the Re_ϕ is small.