NASA/TM—2010-216907 U.S. ARMY RESEARCH LABORATORY Effects of Gas Turbine Component Performance on Engine and Rotary Wing Vehicle Size and Performance Christopher A. Snyder Glenn Research Center, Cleveland, Ohio Douglas R. Thurman U.S. Army Research Laboratory, Glenn Research Center, Cleveland, Ohio November 2010 NASA STI Program . in Profi le Since its founding, NASA has been dedicated to the • CONFERENCE PUBLICATION. Collected advancement of aeronautics and space science. The papers from scientifi c and technical NASA Scientifi c and Technical Information (STI) conferences, symposia, seminars, or other program plays a key part in helping NASA maintain meetings sponsored or cosponsored by NASA. this important role. • SPECIAL PUBLICATION. Scientifi c, The NASA STI Program operates under the auspices technical, or historical information from of the Agency Chief Information Offi cer. 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Does not contain • Write to: extensive analysis. NASA Center for AeroSpace Information (CASI) 7115 Standard Drive • CONTRACTOR REPORT. Scientifi c and Hanover, MD 21076–1320 technical fi ndings by NASA-sponsored contractors and grantees. NASA/TM—2010-216907 U.S. ARMY RESEARCH LABORATORY Effects of Gas Turbine Component Performance on Engine and Rotary Wing Vehicle Size and Performance Christopher A. Snyder Glenn Research Center, Cleveland, Ohio Douglas R. Thurman U.S. Army Research Laboratory, Glenn Research Center, Cleveland, Ohio Prepared for the 66th Annual Forum and Technology Display (AHS Forum 66) sponsored by the American Helicopter Society Phoenix, Arizona, May 11–13, 2010 National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio 44135 November 2010 Acknowledgments We would like to thank the management of the Subsonic Rotary Wing vehicle project within the NASA Fundamental Aeronautics Program for supporting this research, and Mr. Michael Tong for his assistance using the Weight Analysis of Turbine Engines (WATE) code for engine weight analyses. This report is a formal draft or working paper, intended to solicit comments and ideas from a technical peer group. This report contains preliminary fi ndings, subject to revision as analysis proceeds. Trade names and trademarks are used in this report for identifi cation only. Their usage does not constitute an offi cial endorsement, either expressed or implied, by the National Aeronautics and Space Administration. Level of Review: This material has been technically reviewed by technical management. Available from NASA Center for Aerospace Information National Technical Information Service 7115 Standard Drive 5301 Shawnee Road Hanover, MD 21076–1320 Alexandria, VA 22312 Available electronically at http://gltrs.grc.nasa.gov Effects of Gas Turbine Component Performance on Engine and Rotary Wing Vehicle Size and Performance Christopher A. Snyder National Aeronautics and Space Administration Glenn Research Center Cleveland, Ohio 44135 Douglas R. Thurman U.S. Army Research Laboratory Glenn Research Center Cleveland, Ohio Abstract In support of the Fundamental Aeronautics Program, Subsonic Rotary Wing Project, further gas turbine engine studies have been performed to quantify the effects of advanced gas turbine technologies on engine weight and fuel efficiency and the subsequent effects on a civilian rotary wing vehicle size and mission fuel. The Large Civil Tiltrotor (LCTR) vehicle and mission and a previous gas turbine engine study will be discussed as a starting point for this effort. Methodology used to assess effects of different compressor and turbine component performance on engine size, weight and fuel efficiency will be presented. A process to relate engine performance to overall LCTR vehicle size and fuel use will also be given. Technology assumptions and levels of performance used in this analysis for the compressor and turbine components performances will be discussed. Optimum cycles (in terms of power specific fuel consumption) will be determined with subsequent engine weight analysis. The combination of engine weight and specific fuel consumption will be used to estimate their effect on the overall LCTR vehicle size and mission fuel usage. All results will be summarized to help suggest which component performance areas have the most effect on the overall mission. Nomenclature ft feet GW gross weight HP horsepower HPC high-pressure compressor HPT high-pressure turbine lbm pounds mass LCTR Large Civil Tiltrotor LCTR2 Large Civil Tiltrotor—iteration 2 LPC low-pressure compressor LPT low-pressure turbine MRP maximum rated power NPSS Numerical Propulsion System Simulation OPR overall pressure ratio PR pressure ratio PSFC power specific fuel consumption, lbm/hour/HP sec second SOA State Of the Art T3 compression system exit temperature, °F T4 combustor exit temperature, °F °F degrees Fahrenheit NASA/TM—2010-216907 1 Figure 1.—Conceptual view of LCTR2. Introduction The NASA Heavy Lift Rotorcraft System Investigation (Ref. 1) identified a large tiltrotor as the best concept to meet the various airspace and other requirements for the future, short-haul regional market. This evolved into a conceptual vehicle designated as LCTR2 (Large Civil Tiltrotor—iteration 2) (Ref. 2) as seen in Figure 1. This vehicle iteration was designed to carry 90 passengers, at minimum cruising speed of 300 knots, 1,000 nautical mile range. It is powered by four turboshaft engines designed for 7,500 HP each (MRP, sea level static conditions, standard day). Other design features included a rotor tip speed of 650 ft/sec in hover and 350 ft/sec during cruise, enabled by a two-speed gearbox. This range of rotor tip speeds was needed to achieve the high level of performance and efficiency at two very different flight conditions. Another contributor to efficient LCTR2 vehicle operations was an efficient and high power-to-weight gas turbine power plant. The previous study (Ref. 3) identified notional gas turbine characteristics and an engine layout that could meet fuel and weight requirements, while also identifying potential levels of component performance to meet overall vehicle objectives. However the inclusion of advanced technologies and better understanding component performance and designs for this particular engine size class might suggest different configurations that could better meet or exceed overall vehicle and mission requirements. This effort will therefore review the previous notional engine design, its component performance assumptions and revised baseline values for this effort. Then the analysis tools and methodology will be discussed, including some discussion on updated component performance assumptions and the inclusion of advanced compressor and turbine technologies. This will result in new engine configurations in terms of their specific size, weight and fuel consumption, which will then be used to estimate their effect on the overall vehicle for the baseline mission. Gas Turbine Engine Study, Previous and Updated Assumptions Previous engine efforts included several assumptions that helped define an optimum cycle (from a thermodynamic and power specific fuel consumption perspective). An example block representation of the turboshaft engine model is shown in Figure 2. Table 1 includes the sets of assumptions used in the previous parametric analyses and the updated baseline values. The previous assumptions came from a variety of sources (preliminary estimates from component technical experts and previous engine studies— although not necessarily from the same engine class). Each particular component performance assumption will be discussed further in the next section. The engine as defined met all performance requirements, although several areas needing refinement were also noted. Overall parameters from the previous optimum