Abstract
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.
Highlights
By raising turbine-entry temperatures, some axial turbomachines may reach an efficiency of approximately 80% with well-designed impellers
This paper investigates the effect of turbine blade fracture on the rotor-stator cavity, employing numerical simulation in terms of swirl ratio, mass flow rate
From preliminary can thatdirection the ratefor of different change of the 5 shows the calculations, distribution of it the β inbe theconcluded circumferential radii.toFrom calculations, it can be concluded that the rate of change the β blad relative thatpreliminary of an unfractured blade hardly varies with the radius afterofturbine relative to that of an unfractured blade hardly varies with the radius after turbine blade fractures
Summary
By raising turbine-entry temperatures, some axial turbomachines may reach an efficiency of approximately 80% with well-designed impellers. This paper focuses on the influence of the non-axisymmetric boundary caused by turbine blade fracture on a simple rotor-stator cavity. On the be rotor-stator cavity, employing simulation in termsbecause of swirl ratio the radial velocity difference between different radii in the cavity is so small, the orifice flow rate distribution, thrust, and moment coefficients. This paper investigates the effect of turbine blade fracture on the rotor-stator cavity, employing numerical simulation in terms of swirl ratio, mass flow rate. The backpressure of the outlet in the rotor-stator cavity is no longer axisymmetric, assuming that the backpressure profile of the outlet is a stepped distribution, as shown, P(θ ).
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