Ejector tip injection system for active aerodynamic compressor stabilization part I: design and experiment

The subject of compressor tip air injection in full jet engine test setups has been under in-vestigation at the Institute of Jet Propulsion for many years. Latest experiments revealed that the utilization of the ejector effect can help to raise both effectiveness and efficiency of air injection systems. Based on the gathered experiences, an advanced Ejector Injection System (EIS) was designed from scratch and built most recently. The presented design process is focused especially on the optimal application of the ejector effect in order to achieve maximum performance. As the EIS features complicated 3D flow paths and uti-lizes not only the ejector but also the Coanda effect, its internal aerodynamics include complex interactions of multiple phenomena. Therefore, extensive stand-alone tests are performed before the ejector injection system is attached to the jet engine. The described test setup features high precision mass flow measurement devices and has created valuable results for a more detailed understanding of the ejector effect and the flow inside the EIS. The experimental work is accompanied by extensive CFD simulations with detailed focus on the internal flow phenomena in the second part of the paper.