National Aeronautics and Space Administration

Commercial ModularAero-Propulsion System Simulation 40k

(C-MAPSS40k)

www.nasa.gov

3rd NASA GRC Propulsion Control and Diagnostics WorkshopFebruary 28, 2012

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James (Yuan) LiuN&R Engineering

National Aeronautics and Space Administration

C-MAPSS40k Overview

• Engine description• Engine simulation• Control system• User features• Recent updates & ongoing work

www.nasa.gov

• Recent updates & ongoing work

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Engine Description

www.nasa.gov

• 40,000-lbf thrust class• High-bypass, dual-spool turbofan

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Engine Simulation

• Component-level modeling• Physics-based

– Aerothermodynamics– Performance maps

• Operates over wide range of environmental conditions

www.nasa.gov

-50 0 50 100 150 200 250 3001

1.5

2

2.5

3

3.5

4

Flow rate

Pre

ssu

re r

atio

environmental conditions– Mach, altitude, DTamb

• Faster than real-time– Components coded in C– Assembled in Simulink– Run via MATLAB

• Detailed stall margin model• Engine health condition

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National Aeronautics and Space Administration

Engine Simulation

• Dynamics– Nonlinear dynamical system with

spool speeds as state variables

• Flow continuity– Iterate to ensure mass flow

balance at each time step– Realistic transient performance

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14 15 16 17 18 19 20 21 22 230

5

10

15

Itera

tions

14 15 16 17 18 19 20 21 22 23-0.015

-0.01

-0.005

0

0.005

0.01M

ax F

low

Err

or

14 15 16 17 18 19 20 21 22 231.2

1.4

1.6

1.8

2

2.2

2.4

2.6x 10

4

Time (s)

Net

Thr

ust (

lbf)

max iter = 1

max iter = 200

National Aeronautics and Space Administration

Control System

• Representative of industry standard

• Controls engine based on throttle input

• Calculate fuel flow, variable stator vane

www.nasa.gov

variable stator vane position (VSV), variable bleed valve position (VBV)

• Uses typically sensed engine outputs

• Simulates actuator/sensor dynamics

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National Aeronautics and Space Administration

Control System

• VSV, VBV are scheduled on sensed engine parameters

• Fuel: gain-scheduled PI feedback control on EPR/Nfwith protection logic

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User Features: Graphical Interface

• Environmental & throttle inputs

• Control settings• Simulation settings• Engine health settings• Plot & save data

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User Features: Script/Command Line

• MATLAB command line• MATLAB scripts• MS Excel input profile

generation

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• Steady-state engine model calculates the initial conditions for any point in flight envelope before simulation run

User Features: Steady-State Solver

FlightEnvelope

• Faster and more elegantthan “flying” to

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than “flying” to desired starting point from a known initial flight condition

X

Start at any point

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User Features: Linear Models

• Generate linear models about any equilibrium point (i.e., flight

www.nasa.gov

condition)• Specify flight/health

condition• Specify state/input

variable vectors• Verify and save linear

model

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National Aeronautics and Space Administration

Updates & Ongoing Work

• Heat soakage– Metal temperature state variables to enhance realism of

transient performance

• Simulink library structure– Main Simulink file links to libraries for engine, controller, and

actuators

www.nasa.gov

• Different fuel types– Easily swappable thermodynamic tables

• Off-nominal variable stator vane positions• High angle-of-attack

– Inlet distortion effects due to high angle-of-attack flight

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National Aeronautics and Space Administration

Summary

• Simulation of 40,000-lbf class, high-bypass, dual-spool turbofan engine

• Physics-based, component-level model• Faster than real-time• Realistic control system• Graphical/command-line user interfaces

www.nasa.gov

• Graphical/command-line user interfaces• Linear model generation

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National Aeronautics and Space Administration

Related NASA Publications

• Csank, Jeffrey, May, Ryan D., Litt, Jonathan S., and Guo, Ten-Huei, "Control Design for a Generic Commercial Aircraft Engine," AIAA-2010-6629, 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Nashville, TN, July 25-28, 2010, also NASA/TM—2010-216811, October 2010.

• May, Ryan D., Csank, Jeffrey, Lavelle, T. M., Litt, Jonathan S., and Guo, Ten-Huei, "A High-Fidelity Simulation of a Generic

www.nasa.gov

and Guo, Ten-Huei, "A High-Fidelity Simulation of a Generic Commercial Aircraft Engine and Controller," AIAA-2010-6630, 46th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit, Nashville, TN, July 25-28, 2010, also NASA/TM—2010-216810, October 2010.

Available for download from the NASA Software Repositoryhttps://sr.grc.nasa.gov/public/project/77/

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