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Title: Experimental Investigation of a High-Frequency Pulsed Supersonic Co-Axial Injector using Optical Diagnostics
With an increased national emphasis on the development of high-speed systems, especially those utilizing air-breathing propulsion, there is a strong demand for efficient means of enhancing the mixing of fuel injection and an air stream that may be moving at supersonic speeds. In recent years, small scale fluidic-based actuators have shown promise in their ability promote efficient mixing in these scenarios due to their small size and having no moving parts. High-frequency pulsed co-axial actuators developed at Tuskegee University are one such device that only rely on a compressed gas source and particular geometric designs to enable rapid pulsed injection. These actuators are able to efficiently atomize injected fluids, such as fuels or oxidizers, and they can be designed to pulse at frequencies in excess of 15 kHz. This paper presents the results of an experimental investigation of one such device using advanced optical and laser diagnostics to measure both the spectral content and the unsteady velocity fields of the pulsed jet output. The flowfield is visualized with high-speed schlieren imaging, and the near-field acoustic emission is measured by a microphone. Focused laser differential interferometry (FLDI) and planar particle image velocimetry (PIV) are conducted within the actuator’s pulsed jet output. The spectral content measured from FLDI closely matches the acoustic spectra. While the phase-locked velocity fields demonstrate the pulsing behavior of the actuator’s core flow jet, the calculated velocities appear to be lower than what was anticipated based on inspection of the high-speed schlieren images. Velocity fields are presented for the actuator operating in both steady and pulsed modes of operation, and the results indicate that the pulsed actuation jet has the potential to significantly enhance mixing of the annular stream when it is introduced.  more » « less
Award ID(s):
1900177
PAR ID:
10433927
Author(s) / Creator(s):
Date Published:
Journal Name:
AIAA Aviation 2023
Issue:
4240
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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