GLTRS--Glenn
TITLE AND SUBTITLE:
Unsteady Ejector Performance: An Experimental Investigation Using a Pulsejet Driver

AUTHOR(S):
Daniel E. Paxson, Jack Wilson, and Kevin T. Dougherty

REPORT DATE:
June 2002

FUNDING NUMBERS:
WU-708-48-13-00

PERFORMING ORGANIZATION NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
John H. Glenn Research Center at Lewis Field
Cleveland, Ohio 44135-3191

PERFORMING ORGANIZATION REPORT NUMBER:
E-13462

SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS(ES):
National Aeronautics and Space Administration
Washington, DC 20546-0001

REPORT TYPE AND DATES COVERED:
Technical Memorandum

SPONSORING/MONITORING AGENCY REPORT NUMBER:
NASA TM-2002-211711
AIAA-2002-3915

SUPPLEMENTARY NOTES:
Prepared for the 38th Joint Propulsion Meeting and Exhibit cosponsored by AIAA, ASME, SAE, and ASEE, Indianapolis, Indiana, July 7-10, 2002. Daniel E. Paxson, NASA Glenn Research Center; Jack Wilson and Kevin T. Dougherty, QSS Group, Inc., Cleveland, Ohio 44135. Responsible person, Daniel E. Paxson, organization code 5530, 216-433-8334.

ABSTRACT:
An experimental investigation is described in which thrust augmentation and mass entrainment were measured for a variety of simple cylindrical ejectors driven by a gasoline-fueled pulsejet. The ejectors were of varying length, diameter, and inlet radius. Measurements were also taken to determine the effect on performance of the distance between pulsejet exit and ejector inlet. Limited tests were also conducted to determine the effect of driver cross-sectional shape. Optimal values were found for all three ejector parameters with respect to thrust augmentation. This was not the case with mass entrainment, which increased monotonically with ejector diameter. Thus, it was found that thrust augmentation is not necessarily directly related to mass entrainment, as is often supposed for ejectors. Peak thrust augmentation values of 1.8 were obtained. Peak mass entrainment values of 30 times the driver mass flow were also observed. Details of the experimental setup and results are presented. Preliminary analysis of the results indicates that the enhanced performance obtained with an unsteady jet (primary source) over comparably sized ejectors driven with steady jets is due primarily to the structure of the starting vortex-type flow associated with the former.

SUBJECT TERMS:
Pulsejet engines; Thrust augmentation; Ejectors

NUMBER OF PAGES:
19

PDF AVAILABLE FROM URL:
2002/TM-2002-211711.pdf
( 365 KB )
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