革新涡轮航空发动机验证机综述

AIAA/CIRA 13th International Space Planes and Hypersonics Systems and Technologies
AIAA 2005-3250
Revolutionary Turbine Accelerator (RTA) Demonstrator
Ms. Nancy McNelis * and Dr. Paul Bartolotta† NASA Glenn Research Center, Cleveland OH, 44135
RTA-1 is a demonstrator engine which is seeking to demonstrate and validate advanced turbine technologies. Its primary objective is to push turbine technologies above existing SOA such that an advanced turbine engine system can be developed / evaluated for Mach 4+ applications through use of an advanced system level ground demonstrator. This demonstrator would allow promising technologies to be validated in an actual engine and provide an in-depth evaluation of the issues associated with operability of a turbine-based propulsion system over a wide Mach range. As such, this project was the USA’s first high Mach turbine engine development program within the past 40 years (last program was the J58 for the SR71).
Nomenclature
BPR CB CDFS CFD Exp ATR GTOW HiMaTE HiSPA HP Isp LEO LP NGLT RASER RBCC RLV RTA SFC SLS TAD TFRJ TRF TTRJ T/W TBCC TSTO VPS VSV WTRJ Bypass ratio Center Body Core-drive fan stage Computational Fluid Dynamics Expander air turboramjet Gross Take-Off Weight High Mach Turbine Engine High-Speed Propulsion Assessment High Pressure Specific impulse Low Earth Orbit Low Pressure Next Generation Launch Technologies Revolutionary Aero-Space Engine Research Rocket-based combined cycle Reusable launch vehicle Revolutionary Turbine Accelerator Specific fuel consumption Sea level, static Technology Availability Date Turbofan ramjet Turbine Rear Frame Tandem turboramjet Thrust-to-weight ratio Turbine-based combined cycle Two stage to orbit Vision Propulsion System Variable Stator Vane Wraparound turboramjet
I.
Introduction
T
* †
he use of a turbine-based propulsion system for access to space is a promising concept which could provide the potential for aircraft-like, space flight operations with a two-stage-to-orbit vehicle which could enable
Aerospace Engineer, Code PRV, 21000 Brookpark Road Cleveland OH 44135, Mail Stop 60-5 Aerospace Engineer, Code PRV, 21000 Brookpark Road Cleveland OH 44135,Mail Stop 60-5 1 American Institute of Aeronautics and Astronautics
This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.

significantly reduce launch costs and improve safety. To meet the rigors of space launch application versatility is the key to the engine cycle. The RTA’s variable cycle approach allows the engine cycle to be tailored for a wide range of applications to provide system efficiencies and high performance. The development of the RTA engine cycle represents a deviation from the conventional design for optimal performance at a point to a design for optimal performance over the range of operation. This unconventional approach to cycle development means that lessons learned in developing and demonstrating these advanced turbine engine technologies can be applied across all high Mach turbine applications. In this endeavor NASA GRC is partnered with scientists and engineers of academia, industry, DoD, and NASA to ensure the RTA technologies will benefit multiple aerospace platforms, both civilian and military. This versatility could aid in significant reductions in development and production costs. Through the partnerships the RTA project was able to base the demonstrator’s design around an existing YF120 advanced turbine engine core. This engine, which was previously developed by the Air Force, provided the variability required in the core and incorporates many advanced turbine engine technologies in the core of the engine. To expand the operability and performance of this baseline, the RTA project has been developing advanced fan and augmentor technologies which will allow the RTA demonstrator to achieve a demonstration of Mach 4 at a system level
II.
Vision Vehicle Definition
To address and define turbine-based propulsion requirements for space access a series of vision vehicle studies were conducted by several vehicle contractors. In these studies, the contractors were responsible for defining the space access architecture, staging Mach speed, payload size, and fuel types. Design boundary space was limited to horizontal take-off and landing, the use of turbine-based propulsion, and gross take-off weight (GTOW) of less than 1.3 million pounds. Different from typical vehicle studies, the RTA vision vehicle study utilized separate contracts with propulsion and vehicle contractors. Each propulsion contractor supplied each vehicle contractor with the appropriate turbine and high speed flow path engine performance values. As engine requirements changed through the iterative vehicle design process of the vehicle contractors, each engine company was required to scale their engine performances and identify technology challenges and technology availability dates (TAD). This ensured unbiased assessment of engine concepts from each of the engine manufacturers as it pertained to the complete vehicle system. Results from the vision vehicle studies produced two concepts for a turbine-based TSTO vehicle. Figure 1 illustrates the launch architecture for one of the concepts. In this concept the TSTO vehicle takes-off from a conventional runway using large (>100,000 pound) thrust RTA engines on the first stage. These RTA engines propel the vehicle up to Mach 4 where the second stage is separated from the first. The first stage then returns to the launch site at subsonic speeds like a conventional aircraft. The second stage is propelled using scramjets from Mach 4 up to Mach 15 to higher altitudes when small tail rockets tip the second stage out of the atmosphere into orbit. This concept can deliver a medium sized payload of 20,000 pounds into LEO.
Figure 1: TSTO concept utilizing RTA engines on first stage. Second stage separation at Mach 4
2 American Institute of Aeronautics and Astronautics