The paper, “Inlet Mode Transition Screening Test for a Turbine-Based Combined-Cycle Propulsion System,” submitted by the Aeropropulsion Division, has been selected for the NASA Glenn Research Center Distinguished Paper of the Year Award. This paper was presented at the Joint Army Navy NASA Air Force (JANNAF) Propulsion Meeting held May 13, 2008 in Newton, MA.
View the paper: Inlet Mode Transition Screening Test for a Turbine-Based Combined-Cycle Propulsion System (PDF)
Authors
- J. D. Saunders; J. W. Slater; V. Dippold; and J. Lee, NASA Glenn Research Center, Cleveland, Ohio
- B. W. Sanders and L. J. Weir, TechLand Research, Inc., North Olmsted, Ohio
Abstract
A combined computational and experimental study of inlet mode transition needed for Turbine-Based Combined-Cycle (TBCC) propulsion has been conducted. The Inlet Mode Transition Experiment (IMX) model used in this study is based on a careful design of an inlet system that supplies both a turbine engine and a ram/scramjet flowpath in an “over/under” configuration.
Traditional aerodynamic design techniques were used to develop an TBCC inlet design that balances aerodynamic and mechanical constraints to provide a practical approach to inlet mode transition. The current IMX inlet was designed for Mach 7 scramjet operation with an over/under turbine that becomes cocooned beyond its design point at Mach 4.
Conceptually, this propulsion system was designed for the needs of the first stage of a two-stage to orbit vehicle. The IMX dual or split-flow inlet matches engine requirements while maintaining both high performance and stability. To verify the design, the small-scale screening experiment was conducted in the NASA GRC 1×1 Supersonic Wind Tunnel to characterize the performance and operability of this TBCC inlet.
In addition, a series of increasing fidelity CFD-based tools were used to analyze the inlet configuration. Both the experiment and CFD analyses indicated that high performance (near MIL-E-5008B recovery) and smooth mode transitions are achievable for this design.
The efforts have validated the IMX design and contributed to a large-scale inlet/propulsion test being planned. This large-scale effort will provide the basis for a “Combined Cycle Engine Testbed,” which will be able to address integrated propulsion system and controls technology objectives.
