Planar Doppler Velocimetry for Aircraft Exhausts

Award Information
Agency: Department of Defense
Branch: Navy
Contract: N68335-13-C-0232
Agency Tracking Number: N11A-004-0265
Amount: $749,934.00
Phase: Phase II
Program: STTR
Awards Year: 2013
Solitcitation Year: 2011
Solitcitation Topic Code: N11A-T004
Solitcitation Number: 2011.1
Small Business Information
MetroLaser, Inc.
8 Chrysler, Irvine, CA, 92618
Duns: 000000000
Hubzone Owned: N
Woman Owned: N
Socially and Economically Disadvantaged: Y
Principal Investigator
 Thomas Jenkins
 Senior Scientist
 (949) 553-0688
 tjenkins@metrolaserinc.com
Business Contact
 Cecil Hess
Title: President
Phone: (949) 553-0688
Email: cecilh@metrolaserinc.com
Research Institution
 Georgia Tech Research Corporation
 Joel Kennedy
 Georgia Institute of Technolog
505 Tenth Street
Atlanta, GA, 30332-0420
 (404) 385-6697
 Nonprofit college or university
Abstract
A diagnostic is being developed for aircraft engine exhausts that measures three velocity components in a slice through the plume. The method measures the Doppler shift of laser light scattered from particles naturally present in the flow, such as soot or dust. Two key areas of uncertainty were investigated in the Phase I study: 1) scattered light intensity from soot particles of sizes and concentrations that are representative of jet exhaust flows, and 2) image registration limitations that determine how accurately Doppler images can be normalized by reference images. Predictions were performed using a mathematical model that showed signal levels would be high enough in a typical aircraft engine exhaust to enable single shot measurements with uncertainties as low as 2 m/s. Experiments were conducted using a soot generator that showed uncertainties in Doppler shifts corresponding to about 6 m/s. Planned improvements in image registration should lead to even lower uncertainties. Photon fluxes were measured in a small turbojet engine, and were found to be on the same order of those measured in the soot generator. Scattering from dust was observed in regions outside the plume that may provide an opportunity for velocity measurements in these regions as well.

* information listed above is at the time of submission.

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