The aviation industry contributes a significant 2.6% of the global emissions. This scenario pushes policy makers and designers to work towards developing disruptive aircraft engine architectures that will meet
the demands of reduced emissions, higher thrust-to-weight ratio, and higher propulsive efficiency. From a broader perspective, novel engine configurations are likely to also operate under highly distorted inflows. In the first part of this talk, the design and experimental analysis of a contra-rotating fan, which is one such disruptive technology with several aerodynamic benefits, is discussed. A detailed experimental study on a low-speed test case shows how the contra-rotating fan responds to clean and distorted inflows. Certain flow features identified can be generalized to all fans and compressors while certain features are typical to low hub-tip ratio designs. The stall of the machine is found to trigger from the blade passing frequency of the front rotor and the stall cells subsequently propagate at frequencies much lower than the blade passing frequency. Techniques that could potentially increase the stability margin of the stage are proposed.

The limitations with most typical turbomachinery measurements are that they are based on discrete
probe measurements and detailed flow visualizations are often difficult. This gives limited information
on the flowfield, especially when non-uniform flows are present. Therefore, in the second part of the
talk, the design of a high-speed facility to fully characterize engine-realistic distorted inflows will be
discussed. The design of the test facility is carried out using a systematic reduced order model approach
and measurements of the distorted flow are carried out using PIV. An extensive set of probe measurements are recorded to validate the PIV results. The talk will address the advantages of the test facility and the challenges faced during its design, commissioning, and testing.