Abstract
Improving the understanding of the interaction between multistage fan and an inlet total pressure distortion is benefical to design an advanced compression system and stabilizing measures with strong anti-distortion ability. Full-annulus unsteady simulation is applied in a two stage fan to supplement the physic of distorted flow transfer that is difficult to measure in the experiment. The tip flow fields of Rotor 1 with distorted inflow obtained by unsteady computations agree well with experiment. Total temperature distortion generates as flow passes through the first stage. The results obtained by orbit-method show that the position of the second stage of maximum flow separation locates in where the rotor turns out the lowest total pressure region and turns into the highest total temperature region. The application of inlet distortion distinctly alters the blade loading of Rotor 1, while has negligible effect on Rotor 2 loading, resulting in the blade loading of R1 is greater than that of R2 above 75% span. The process of disturbance generation-development-suppression is captured by unsteady simulations, which is consistent with measurement data. The stall inception finally generates at the tip of Rotor 1, and its circumferential position locates in where rotor turns out of distortion. Distinct from previous studies, the total pressure distortion level, with a large enhancement by the first stage, progresses through the fan with a significantly attenuation by the second stage, and so is the total temperature distortion level.
