Investigation of the Interaction between Blade Tip Flow and Blade Vibrations in highly loaded axial compressors

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In turbomachinery, gap flow effects at the blade tips lead to large losses and stability impairments, especially for highly loaded compressor stages. The scientific investigation of these phenomena is very difficult because both the numerical and experimental methods for studying the flow reach their limits due to the complex processes in the gap. In addition, interactions occur between aerodynamic and structural-mechanical effects that could be studied and modelled only rudimentary up to now.Within this proposed project, simultaneous high-precision measurements of both the blade tip flow profile and the compressor blade vibration amplitudes and mode shapes will be enabled employing novel laser-based measurement methods. Therewith, the mechanisms of interaction between gap flow and blade vibrations will be investigated experimentally at a transonic compressor test rig alongside with numerical simulations in order to gain a better, fundamental understanding of the aeroelastic processes in turbomachinery, especially in highly loaded compressor stages.The results would be very valuable for turbo machine design, e.g. for being able to reduce the blade row spacing in future. Accordingly, higher power density and improved rotor dynamics can be achieved. This would directly allow for an increase in both operating reliability and flexibility of load changes. Furthermore the energy efficiency of future turbo machines, such as aircraft engines, could be improved.