Numerical Sensitivity Study on the Design of a Transonic Aeroelastic Compressor Rig

In modern transonic compressors, the forced response can occur thigh-order modes and at high-reduced frequencies. To understand this phenomenon, a new cascade test rig is being built to provide configurations and validations for the forced response simulations of transonic compressors. With the aid of Computation Fluid Dynamics (CFD) optimizations, the test section shape was roughly determined before. The purpose ofthis paper is to provide the finalization process of the cascade test-rig design including a transonic nozzle and blade tip gaps. Hence, the steady and unsteady simulations are employed based on three different geometries: test section, a test rig with nozzle, and test rig with 1% tip gap. The simulation results show that the unsteadiness in the test rig is related mainly to the oscillation performance of the shock waves in the passage. The comparison in the test rig with and without tip gap confirms that tip gap can reduce the unsteady pressure. The unsteady pressure reflection due to the tailboards, especially on the bottom tailboards, indicates this problem needs to be thoroughly considered in the installation and testing.