Design and Characterization of Nozzle-Injection Assemblies Integrated with High-Frequency Microactuators

Two active nozzle-injection assemblies integrated with high-frequency, resonance-enhanced microactuators have been developed and characterized in this paper. In design 1, four injection nozzles each 400  μm diameter were integrated circumferentially to another 1 mm nozzle that provided pulsed flow. This actuation jet had a frequency of 13–21 kHz. Compressed CO2 injected through steady nozzles served as the mixing stream, and compressed N2 generated the actuation jet. The second design flipped roles of injection nozzles mentioned in design 1. In this case, the actuation jets pulsed out through the four nozzles, and the steady jet flowed through the 1 mm nozzle. In both cases, the resonance-enhanced microactuators nozzle flow generated a strong compressible vortex in the shear layer of steadily injected fluid that entrained and grew downstream, enhancing microscale mixing of the injected fluid and nitrogen at very high speed and at a designated frequency. This paper discusses the design and characteristics ...