CFD-Aided Design of a Transonic Aeroelastic Compressor Rig

This paper presents the results of computational fluid dynamics (CFD)-aided design calculations of a transonic linear cascade wind tunnel. The purpose of the wind tunnel is to generate data for the validation of numerical methods employed to calculate aerodynamic damping for forced response cases in transonic compressors. It is common for transonic wind tunnels to use transonic walls (perforated walls with controlled suction) to adjust the transonic flow in the experiment. Unfortunately, perforated walls are difficult to model in CFD simulations, and they complicate the validation process. One of the goals of the new tunnel is not to use perforated walls. The main difficulty in the design of a transonic linear cascade is achieving periodic flow for the central blades due to shock reflections from the side walls and the sensitivity of transonic flow to small changes in geometry. Other design constraints are the maximum available mass flow of 4.5 kg/s and the minimum required blade thickness of 2 mm for instrumentation. The purpose of the current CFD simulations is to determine the optimum geometry (sidewalls, tailboards, and throttle) of the tunnel with the goal of achieving near periodic flow conditions for the central blade channels at the similar condition in a typical transonic compressor.