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Proceedings Paper

Microscale ethanol vapor ejector and injector
Author(s): William G. Gardner; Ivan Wang; Natalya A. Brikner; Justin W. Jaworski; Jonathan M. Protz
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Paper Abstract

Two non-rotating pumping components, a jet ejector and injector, were designed and tested. Two jet ejectors were designed and tested to induce a suction draft using a supersonic micronozzle. Three-dimensional axisymmetric nozzles were microfabricated to produce throat diameters of 187 μm and 733 μm with design expansion ratios near 2.5:1. The motive nozzles achieved design mass flow efficiencies above 95% compared to isentropic calculations. Ethanol vapor was used to motivate and entrain ambient air. Experimental data indicate that the ejector can produce a sufficient suction draft to satisfy both microengine mass flow and power off-take requirements to enable its substitution for high speed microscale pumping turbomachinery. An ethanol vapor driven injector component was designed and tested to pressurize feed liquid ethanol. The injector was supplied with 2.70 atmosphere ethanol vapor and pumped liquid ethanol up to a total pressure of 3.02 atmospheres. Dynamic pressure at the exit of the injector was computed by measuring the displacement of a cantilevered beam placed over the outlet stream. The injector employed a three-dimensional axisymmetric nozzle with a throat diameter of 733 μm and a three-dimensional converging axisymmetric nozzle. The experimental data indicate that the injector can pump feed liquid into a pressurized boiler, enabling small scale liquid pumping without any moving parts. Microscale injectors could enable microscale engines and rockets to satisfy pumping and feedheating requirements without high speed microscale turbomachinery.

Paper Details

Date Published: 5 May 2010
PDF: 10 pages
Proc. SPIE 7679, Micro- and Nanotechnology Sensors, Systems, and Applications II, 76792P (5 May 2010); doi: 10.1117/12.858797
Show Author Affiliations
William G. Gardner, Duke Univ. (United States)
Ivan Wang, Duke Univ. (United States)
Natalya A. Brikner, Duke Univ. (United States)
Justin W. Jaworski, Duke Univ. (United States)
Jonathan M. Protz, Duke Univ. (United States)

Published in SPIE Proceedings Vol. 7679:
Micro- and Nanotechnology Sensors, Systems, and Applications II
Thomas George; M. Saif Islam; Achyut Kumar Dutta, Editor(s)

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