Forced Response Analysis of Gas Turbine Rotor Blades Using CFD-Based Aeroelastic Tools

Integration of computational fluid dynamics (CFD) and structural dynamics codes is critical to the advancement of turbomachinery designs. This paper describes the successful integration of the CFD code UNSFLO with the structural dynamics code ANSYS® for a case study rotor. To evaluate the software combination, AlliedSignal Engines (AE) intiated a program to compare experimental observations from a set of high-pressure turbine tests to analytical predictions from UNSFLO and ANSYS®. The rotor under investigation exhibited significant blade vibratory response due to pressure wakes from upstream stator vanes. Experimental data, collected on two stator-rotor configurations, indicates dramatic strain reductions when the axial space between the stator and rotor blades is increased. Forced response analyses, which compare favorably to the experimental data, indicate a 90 percent reduction in vibratory strain levels.