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Subscale Injector Testing to Support J-2X Engine DevelopmentThe J-2X engine being pursued for the Ares I will be a derivative of the J-2 engine developed by Pratt & Whitney Rocketdyne (PWR). As part of the engine development, a subscale injector was fabricated by PWR and hot-fire tested at NASA s Marshall Space Flight Center (MSFC) to evaluate performance data. This subscale injector had a reduced injector diameter and fewer elements than the full scale design, but the element density (#elements / injector area), and element geometries nearly identical to the full scale design. Three different materials were used for the LOX posts in order to test for durability. The subscale injector included 46 standard elements and 6 baffle elements, corresponding to the ratio of baffled elements to core elements in the full scale design. The baffle elements were included to demonstrate thermal compatibility of the baffles and to more closely represent the full scale performance. Fifteen hot-fire tests were conducted totaling over 200 seconds of mainstage time on the injector. Chamber pressures with oxygen/hydrogen propellants ranged from 870-1380 psig with mixture ratios ranging from 4.8-6.1. Fuel manifold inlet temperatures were varied from 190 to 300 R. Modular, water cooled, calorimeter chamber assemblies were used to provide heating rate data and evaluate the effects of characteristic length (L*). Performance was evaluated relative to the resulting characteristic velocity (C*) efficiency. Performance met the value required in order to proceed with this design for the full scale hardware. Hardware inspections show no evidence of cracking at the tip of the LOX post for any of the materials tested. Minor erosion of the baffle element tips was observed in the early testing. A design change was quickly implemented and tested, and this change resolved the issue. Development of the J-2X is continuing with this element density and design.
Document ID
20090014737
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Protz, Christopher
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Elam, Sandy
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Weber, Jim
(Pratt and Whitney Rocketdyne Canoga Park, CA, United States)
Miller, Ken
(Pratt and Whitney Rocketdyne Canoga Park, CA, United States)
Date Acquired
August 24, 2013
Publication Date
December 8, 2008
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
MSFC-2185
Meeting Information
Meeting: JANNAF''s 6th Modeling and Simulation Joint Subcommittee Meeting
Location: Orlando, FL
Country: United States
Start Date: December 8, 2008
End Date: December 12, 2008
Sponsors: Department of the Navy, Department of the Army, Department of the Air Force, NASA Headquarters
Distribution Limits
Public
Copyright
Other

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