April 4 - 5, 2000

1. Aero-Space Propulsion Simulation and Modeling Dr. John K. Lytle Chief, Computing and Interdisciplinary Systems Office April 4 - 5, 2000 GLENN RESEARCH CENTER at Lewis Field

2. NASA Goals Directly Supported by Simulation and Modeling • Provide next generation design tools and experimental aircraft to increase design confidence, and cut the development cycle time for aircraft in half.

3. High Fidelity, Physics-based Simulations • Combustion • Turbomachinery • Aeroelasticity • Probabilistic Methods • Full System • Virtual Design Environment, Life Cycle Simulation Outline Intelligent Synthesis Environment Program (LaRC) Advanced Space Transportation Program (MSFC) Aero-Space Propulsion and Power R&T Base (GRC) Intelligent Systems Program (ARC) Information Technology R&T Base Program (ARC) High Performance Computing and Communications Program (ARC)

4. The National Combustion Code is an integrated system of computer codes that takes advantage of solid modeling and automated meshing of complex geometries. The National Combustion Code uses unstructured meshes and parallel computing. Physical models include: a turbulence module containing the nonlinear k-epsilon models; conventional reduced chemical kinetics or the Intrinsic Low Dimensional Manifold (ILDM) approach; a spray module; and a joint probability density function for species and enthalpy. The National Combustion Code Fuel Nozzle Flow Midplane Temperature Contour Midplane Total Pressure Contour Cold and Hot Isotherm Interactions

5. APNASA 21 Blade Row Compressor Simulation Turnaround Time Reduced by a Factor of 400:1 BASELINE ANALYSIS 1992 PARALLEL PROCESSING ALGORITHMIC CHANGES COMPUTER HARDWARE IMPROVEMENTS Estimated Turnaround Time Factors Influencing Turnaround Time ~ ÷ 40 ~ ÷ 6 ~ 2.4 X Hours INCREASED RESOLUTION ~ ÷ 4

6. Flutter Mode 1 Mode 2 Aero-Damping No Flutter Flutter Forced Response Unsteady Aerodynamic Loading Dynamic Stress Prediction Aeroelastic Analysis using TURBO • TURBO version for fluid-structure interaction analysis being developed • three-dimensional, viscous, unsteady aerodynamics • Purge flow, real gas effects, K-e & Baldwin-Lomax turbulence models • phase-lagged boundary conditions reduce computational domain to one blade passage per blade row • dynamic grid deformation to simulate blade vibration • Code validated for flutter analysis • Pratt & Whitney, Honeywell and Rolls-Royce Allison used code on in-house data to predict flutter • Validation in progress for forced response • GE validating the code using in-house data Mass Flow

7. Probabilistic Loads Probability of Occurrence P m m Structural Response Mechanical Response (stress) Resistance (strength) Information for Reliability & Risk Assessment P P Probabilistic Materials Behavior m Geometry and Material Probability of Failure Thermal Probabilistic Simulation of Component Reliability using NESTEM Multidisciplinary Probabilistic Heat Transfer/Structural analysis code

8. Validated Models • Fluids • Heat Transfer • Combustion • Structures • Materials • Controls • Manufacturing • Economics • Rapid Affordable • Computation of: • Performance • Stability • Cost • Life • Certification Requirements Integrated Interdisciplinary Analysis and Design of Propulsion Systems High Performance Computing • Parallel Processing • Object-oriented Architecture • Expert Systems • Interactive 3-D Graphics • High Speed Networks • Database Management Systems A Numerical Test Cell for Aerospace Propulsion Systems

9. Aero-Space Propulsion Simulation and Modeling A Government/Industry/ University Partnership • Industry • General Electric • Pratt&Whitney • Honeywell • Rolls-Royce Allison • Williams Intl. • Teledyne Continental • Boeing • Lockheed-Martin • University • Stanford • Cleveland State • Winston-Salem • IUPUI • Mississippi State • Government • NASA • ARC • LaRC • MSFC • Air Force Research Laboratory • Naval Air Research Center • Arnold Engineering and Development Center • Department of Energy

10. Simulation Environment • Computationally efficient (cross-platform operation, parallel processing) • Modular design (object-oriented:“Plug-n-Play” system model assembly, easily modified and expanded) • Provide a common modeling tool for U.S. Government, aerospace industry, and academia • Numerical Zooming and Geometry Access Standards through NPSS for physics based modeling • NPSS Common System Model expected to save Aircraft Industry $50M/year

12. The Road to Full 3D Overnight Engine Simulation Full 3-D Primary Flow Path Scheduled for Completion 2Q FY2001 NPSS for Space Transportation High Pressure Core Scheduled for Completion 3Q FY2000 Fan/Booster Scheduled for Completion 3Q FY2000 Compressor Simulation Completed 1998 Combustion Subsystem Completed 4Q FY1999 Turbine Subsystem Completed FY1998 Single Blade Row Completed 1985 Single Stage Completed 1990 CD-00-79981

13. Engine-Airframe Structural Simulations Provide High Fidelity Analysis and Assessment of Blade-Out Event NASA Glenn, General Electric Aircraft Engines, Pratt & Whitney, and Boeing have teamed to develop new simulation tools for engine-airframe structural systems. Development of these tools will enable high-fidelity analyses of blade-out events, more credible design of engine containment systems and improvements in blade-out margin-of-safety predictions. Industry/Government Standard Simulation Procedures Physics Based Blade Loss Modeling Mathematical Modeling of Turbomachine Rotors

14. ISE Vision and Long-Term Goal Vision To effect a cultural change that integrates into practice widely-distributed science, technology and engineering teams to rapidly create innovative, affordable products Long-Term Goal To develop the capability for personnel at dispersed geographic locations to work together in a virtual environment, using computer simulations to model the complete life-cycle of a product/mission with near real-time response time before commitments are made to produce physical products

15. ISE Will Enable Tomorrow What Cannot Be Easily Done Today • • • • • • • • • • • • A • Comprehensive life-cycle trade-studies to: • reduce design cycle time and testing • reduce redesign and rework, • reduce maintenance costs • increase performance and safety • Bound uncertainties arising from assumptions, scarcity of knowledge and unknowns • Comprehensive and rapid mission life-cycle simulations will minimize the risks and maximize the benefits • Provide a means for productive teaming of • the best and brightest people and capabilities • Create and assess new innovative design options and new technologies from anywhere and at anytime

16. Summary • Revolutionary advances in simulation and modeling will lead to increased design confidence that translates into significant reductions in aerospace propulsion: • Development, manufacturing and certification time and cost • Maintenance and operations costs • Greater opportunities to introduce advanced technologies that “buy their way” into new products • Government/Industry/University partnerships are required to accomplish these goals and to ensure technology transfer • Useful products must be delivered throughout the Program on a frequent basis to sustain interest

17. Major Elements of NPSS • Code Parallelization • 3–D Subsystems/System Engineering Applications Computing Testbeds Simulation Environment • Gov’t/Industry Collaborative Effort • Object - Oriented Programming • CAD Geometry Interface • High-Speed Networks • PC Cluster • Metacenter Computing Seamless Integration of Data, Analysis Tools and Computing Resources • 0–D Engine/1–D Compressor • 0–D Core/3–D LP Subsystem • Coupled Aero-Thermal-Structural Analysis • Multi-physics Methods Low-Cost, Distributed Parallel Computing High Fidelity, Large Scale Simulations

18. APNASA Coupled Flow Simulation of High Pressure-Low Pressure Turbines Results in Significant Fuel Savings Objective: Create a high-fidelity computer simulation of the flow through a full modern high bypass ratio turbofan engine. Approach: Using a modular approach to the full engine simulation goal, a flow simulation of the tightly coupled high pressure and low pressure turbines has been completed. The computer simulation was performed using NASA’s 3-D average passage approach (APNASA). The simulation was done using 121 processors of a Silicon Graphics Origin cluster with a parallel efficiency of 87% in 15 hours. Low Pressure Turbine Transition Duct High Pressure Turbine Significance: The accurate and rapid simulation of a large turbine subsystem enabled designers to reduce turbine interaction losses in dual-spool engines by 50%. This will result in a $3 million/year savings in fuel costs for a typical fleet of commercial aircraft. Point of Contact: Joseph P. Veres (216)433-2436