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Throttling Characteristics of the RL10 Derivative Common Extensible Cryogenic Engine -- Demo 1.6 and 1.7 Test ResultsThe Common Extensible Cryogenic Engine (CECE) is a deep throttling cryogenic Lunar Module Descent Engine (LMDE) technology development demonstrator based on the Pratt & Whitney Rocketdyne (PWR) RL10 engine. Previous testing on this engine occurred during 2006 as Demo 1.0, then Demo 1.5 in 2007, Demo 1.6 in 2008 and finally Demo 1.7 in 2010. A review of Demo 1.0, 1.5, and preliminary results of 1.6 were reported in previous JANNAF papers. Demo 1.6 was tested at the PWR E-6 test facility in November 2008. The primary goal of this series was to mitigate low frequency combustion instability observed at low power levels. To mitigate the chug, the Demo 1.6 injector was modified from the previous configurations to include an approximately 0.050 inch thick teflon-type spray-on insulation to reduce heat transfer to the LOX manifold, which was believed to be a significant contributor to the low power instability. In addition, gaseous helium injection into the LOX manifold was used as a means to stabilize the system. Also explored in this test series was mitigation for a low power 1 Hz fuel system oscillation caused by sub-critical hydrogen boiling in the chamber cooling jacket. Reduced area gas venturis were utilized to avoid the 1 Hz fuel-size oscillation by keeping the cooling jacket supercritical down to lower engine power levels. Demo 1.7 began testing in March 2010. Its primary objectives were to demonstrate closed loop control capability on mixture ratio and chamber pressure, start to lower power levels and increased throttling ramp rates. Secondary test objectives that are discussed include multiple engine starts, higher mixture ratio excursions and additional time at low power level. While the complete test series and data reduction is not yet complete for Demo 1.7, an overview and up-to-date status is provided.
Document ID
20100022021
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Devine, Matthew K.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Hulka, James
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Adamski, Walt
(Pratt and Whitney Rocketdyne West Palm Beach, FL, United States)
Brown, Corey
(Pratt and Whitney Rocketdyne West Palm Beach, FL, United States)
Date Acquired
August 24, 2013
Publication Date
May 3, 2010
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
M10-0118
Meeting Information
Meeting: 57th JANNAF Joint Propulsion Meeting
Location: Colorado Springs, CO
Country: United States
Start Date: May 3, 2010
End Date: May 7, 2010
Sponsors: Department of the Army, NASA Headquarters, Department of the Navy, Department of the Air Force
Funding Number(s)
CONTRACT_GRANT: NNM05AB08C
Distribution Limits
Public
Copyright
Other

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