Highly Aggressive Inter Compressor Duct With Active Flow Control Part 1: Experimental Validation of Optimized Pulsed Jet Actuators

Abstract A highly aggressive Inter Compressor Duct (ICD) is well suited to reduce the total length and weight of the jet engine. However, the main disadvantage is to deal with challenges concerning flow separations within the flow path, characterized by an intense flow turning to lower radii. To counteract these separations, an Active Flow Control system (AFC) equipped with Pulsed Jet Actuators (PJA) is implemented in the ICD domain. In particular, PJAs are highly advantageous because the pulsation enhances mixing processes. However, the PJAs require fluid extracted from the already existing secondary flow system, which is an expensive approach to suppress flow separations. To maximize the positive impact of the PJA, their outlet position is determined by numerical optimization. The unsteady flow within the PJA induces an unsteady flow in the ICD, therefore an experimental validation of the AFC is necessary. This allows for the comparison of experimental and numerical data. A highly modular test rig was set up at the Technische Universität Berlin, which allows a quick implementation of additively manufactured PJAs with different outlet positions. The modular test rig features a variety of measurement planes for five-hole probe, static wall pressure measurements and oil flow visualizations. For the validation, five-hole probe measurements downstream of the ICD domain have been conducted. The experimental results clearly demonstrate the advantageous effect of the AFC on the ICD’s secondary flow structures and are in accordance with the numerical results.