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Performance of an Axisymmetric Rocket Based Combined Cycle Engine During Rocket Only Operation Using Linear Regression AnalysisThe all rocket mode of operation is shown to be a critical factor in the overall performance of a rocket based combined cycle (RBCC) vehicle. An axisymmetric RBCC engine was used to determine specific impulse efficiency values based upon both full flow and gas generator configurations. Design of experiments methodology was used to construct a test matrix and multiple linear regression analysis was used to build parametric models. The main parameters investigated in this study were: rocket chamber pressure, rocket exit area ratio, injected secondary flow, mixer-ejector inlet area, mixer-ejector area ratio, and mixer-ejector length-to-inlet diameter ratio. A perfect gas computational fluid dynamics analysis, using both the Spalart-Allmaras and k-omega turbulence models, was performed with the NPARC code to obtain values of vacuum specific impulse. Results from the multiple linear regression analysis showed that for both the full flow and gas generator configurations increasing mixer-ejector area ratio and rocket area ratio increase performance, while increasing mixer-ejector inlet area ratio and mixer-ejector length-to-diameter ratio decrease performance. Increasing injected secondary flow increased performance for the gas generator analysis, but was not statistically significant for the full flow analysis. Chamber pressure was found to be not statistically significant.
Document ID
19980233245
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Smith, Timothy D.
(NASA Lewis Research Center Cleveland, OH United States)
Steffen, Christopher J., Jr.
(NASA Lewis Research Center Cleveland, OH United States)
Yungster, Shaye
(NASA Lewis Research Center Cleveland, OH United States)
Keller, Dennis J.
(RealWorld Quality Systems, Inc. Rocky River, OH United States)
Date Acquired
September 6, 2013
Publication Date
March 1, 1998
Subject Category
Spacecraft Propulsion And Power
Report/Patent Number
NAS 1.15:206632
NASA/TM-1998-206632
E-11090
Funding Number(s)
PROJECT: RTOP 242-72-01
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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