BTZ-Feb. 16, 2000 MITE NASA Glenn/Army Visitors February 16, 2000 MITE PROGRAM OVERVIEW MURI...

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


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


Compressor Control Surge Stall Margins

Control Issues

Combustor Control Stability Ignition (relight, cold) Temperature (pattern factor) Combustor size Efficiency and emissions

Interactions


• 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


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


MITE Research Team


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


• Robustness, disturbance rejection, control saturation

Nonlinear Control TheoryUnified Robust Optimal Framework


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


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


Unsteady CFD of Centrifugal Compressor

DLR/AGARD: pr=4.7, 22360 RPM, 4 kg/s


Unsteady CFD of Compressor Flows

0.04RInlet

Casing

5°

Rotation Axis

ImpellerRInlet

3-6% injection by mass


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


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


Fuel-Air Mixing Results

Unforced 9 on, no modulation 9 on, pulse modulation

Air (f=0) Acetone (f=1)Ui/Uo=4


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


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


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

BTZ-Feb. 16, 2000 MITE NASA Glenn/Army Visitors February 16, 2000 MITE PROGRAM OVERVIEW MURI...

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