Pressure sensitive paint demonstrates relationship between ejector wall pressure and aerodynamic performance

This paper provides an example of the application of Pressure Sensitive Pai nt (PSP) to complex internal suspersonic flows and demonstrates the relatio nship between ejector wall pressure and aerodynamic performance. Details of such jet mixer-ejector nozzles are relevant to jet noise reduction program s. Several ejector configurations with straight, convergent, and divergent side walls were used in our experiments. The side-wall that was painted wit h PSP was also instrumented with an array of 156 pressure taps connected to Electronically Scanned Pressure (ESP) modules, enabling simultaneous measu rement of "true" reference pressures. The PSP results agreed very well with the "true" reference pressures and also provided a detailed map of the com plicated pressure patterns that could not be detected using the pressure ta ps. Finally, we also demonstrated the direct relationship between ejector s ide-wall pressure distribution and ejector performance characteristics such as exit mean flow uniformity, pumping, and thrust augmentation.