Time-Transformation Simulation of a 1.5 Stage Transonic Compressor

Abstract

Time-accurate transient blade row (TBR) simulation approaches are required when there is a close flow coupling between the blade rows, and for fundamentally transient flow phenomena such as aeromechanical analysis. Transient blade row simulations can be computationally impractical when all of the blade passages must be modeled to account for the unequal pitch between the blade rows. In order to reduce the computational cost, time-accurate pitch-change methods are utilized so that only a sector of the turbomachine is modeled. The extension of the time-transformation (TT) pitch-change method to multistage machines has recently shown good promise in predicting both aerodynamic performance and resolving dominant blade passing frequencies for a subsonic compressor, while keeping the computational cost affordable. In this work, a modified 1.5 stage Purdue transonic compressor is examined. The goal is to assess the ability of the multistage time-transformation method to accurately predict the aerodynamic performance and transient flow details in the presence of transonic blade row interactions. The results from the multistage time-transformation simulation were compared with a transient full-wheel simulation. The aerodynamic performance and detailed flow features from the time-transformation solution closely matched the full-wheel simulation at fractional of the computation cost.