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MITEBTZ-Feb. 16, 2000
NASA Glenn/Army VisitorsFebruary 16, 2000
MITE PROGRAM OVERVIEW
MURI (Multidisciplinary University Research Initiative)on Intelligent Turbine Engines
Ben T. ZinnSchool of Aerospace Engineering
Sponsored by DoD-Army Research Office
MITEBTZ-Feb. 16, 2000
MITE Program Objectives• Develop general
• control approaches
• sensors/actuators
• computational tools
that will permit turbine engine manufacturers to improve the design process, performance, operability and safety of future gas turbines.
• Demonstrate developed technologies on small-scale experiments
• Transfer developed technologies to industry and government
MITEBTZ-Feb. 16, 2000
Compressor Control Surge Stall Margins
Control Issues
Combustor Control Stability Ignition (relight, cold) Temperature (pattern factor) Combustor size Efficiency and emissions
Interactions
MITEBTZ-Feb. 16, 2000
• Control theory for nonlinear systems• Improved system models for control applications• CFD/LES modeling of compressors/combustors• Neural network hardware (chip design)• High speed observers for system identification• Sensors: MEMS high temperature applications, optical• Synthetics jets for flow/combustion control• Smart fuel injectors
Enabling Technologies Being Developed
MITEBTZ-Feb. 16, 2000
Program Overview
• Start Date: November 1, 1995
• Research Team: Eleven faculty members from 3Schools (AE, ECE, ME) with expertise in controls, compressors, combustion, propulsion, fluid mechanics, diagnostics, sensors MEMS and neural nets.
• Facilities: Combustion, compressor,microelectronics and fluid mechanics laboratories
MITEBTZ-Feb. 16, 2000
MITE Research Team
MITEBTZ-Feb. 16, 2000
Compressor Control
Goal: reduce stall margin through active/passive control
Fundamental understanding of stall and surge dynamics through extensions to Moore-Greitzer model
lead to improved control models and approaches
Stall and surge control through bleed valve and fuel modulations using observations of precursor waves
Adaptive neural net/fuzzy logic control method being applied to several aerospace applications such as helicopter flight control, X-36, guided munitions
MITEBTZ-Feb. 16, 2000
• Robustness, disturbance rejection, control saturation
Nonlinear Control TheoryUnified Robust Optimal Framework
MITEBTZ-Feb. 16, 2000
Hierarchical switching control Provides theoretical foundation for designing gain scheduled controllers
Guarantees stability over a wide range of system operating conditions
Nonlinear Control Theory Hierarchical Control Architecture
MITEBTZ-Feb. 16, 2000
Computational Modeling
Develop computational (engineering) models for:
Investigation of control approaches
Development of control (system) models
Design aids
Approaches
Unsteady Navier-Stokes for compressor flows:
validated for axial and centrifugal compressors
Large Eddy Simulations (LES) for combustor:
reacting, two-phase (liquid fuel) systems
MITEBTZ-Feb. 16, 2000
Unsteady CFD of Centrifugal Compressor
DLR/AGARD: pr=4.7, 22360 RPM, 4 kg/s
MITEBTZ-Feb. 16, 2000
Unsteady CFD of Compressor Flows
0.04RInlet
Casing
5°
Rotation Axis
ImpellerRInlet
3-6% injection by mass
MITEBTZ-Feb. 16, 2000
Controlled Mixing ObjectivesFuel-Air Mixing
Reduce size Improved off-design performance (low
fuel/air rates): high altitude relight Improve stability - lean blowout Correct degraded performance
Turbine Inlet Temperature ProfileRemove hot/cold spots
(turbine lifetime)Minimize cooling air needs
MITEBTZ-Feb. 16, 2000
Control of (Fuel) Jet Mixing
Axial Forcing
D = 1”
U = 40 ft/s
ReD = 19,000
U
Main Jet with Actuators
Most approaches involve manipulation of large scale, vortical structures directly affect “stirring,” weakly coupled to small-scale mixing
Synthetic jets allow direct control of both scales
Synthetic Jet
h = 0.02”
f = 1200 Hz
MITEBTZ-Feb. 16, 2000
Fuel-Air Mixing Results
Unforced 9 on, no modulation 9 on, pulse modulation
Air (f=0) Acetone (f=1)Ui/Uo=4
MITEBTZ-Feb. 16, 2000
Pattern Factor Control Using Synthetic Jets
-25 -20 -15 -10 -5 0 5 10 15 20 25
Y (mm)
0
10
20
30
40
50
60
70
Z (
mm
)
750+683.636 to 750617.273 to 683.636550.909 to 617.273484.545 to 550.909418.182 to 484.545351.818 to 418.182285.455 to 351.818219.091 to 285.455152.727 to 219.09186.3636 to 152.72720 to 86.3636No actuation With synthetic jets
C
-25 -20 -15 -10 -5 0 5 10 15 20 25
Y (mm)
0
10
20
30
40
50
60
70
Z (
mm
)
750+683.636 to 750617.273 to 683.636550.909 to 617.273484.545 to 550.909418.182 to 484.545351.818 to 418.182285.455 to 351.818219.091 to 285.455152.727 to 219.09186.3636 to 152.72720 to 86.3636
MITEBTZ-Feb. 16, 2000
FineDroplets
Wetted area reduced Liquid accelerated High shear produced
m
liquid
DropletsProduced
m
air
• Air injected into liquid stream
Good atomization across wide flow range (turndown ratio)
Effective with low
• Insensitive to body acceleration (vs. effervescent methods)
liquidair m/m
MITEBTZ-Feb. 16, 2000
Wireless MEMS Sensors
Current system: <0.03” thick, 0-100 atm, >1000 F
side view bottom view
capacitor electrodes
ceramic tape
evacuatedcavity
inductor coils
viaconnections
flexiblediaphragm
C(p,T) L
Develop fast (unsteady) sensors for high temperature enviroments
Wireless pressure (and temperature) sensors based on ceramic packaging technology passive circuit element, no power supply: antenna readout