lecture 27 low speed psp large tunnel - wmich.edu

Innovative Scientific Solutions, Inc.

Development of Pressure-Sensitive Paint

Systems for Low-Speed Flows and Large

Wind Tunnels

Sergey Fonov, Alan Forlines,

Steve Palluconi, Jim Crafton

Innovative Scientific Solutions Inc., Dayton Ohio


Pressure kPaPressure kPa

Pressure-Sensitive Paint


PSP for Research and Aircraft Design • Full model coverage

– Sounds nice, but is rarely practical

– We are not replacing taps, PSP is complementary

• Difficult to tap regions

– trailing edge, winglets, flaps, rotorcraft

• Build models with fewer taps

– Resolve pressure distribution on leading edge

– Pressure distribution on fuselage

– Need 2-3 taps per camera view

• Unsteady pressure measurements

– A few fast taps and a fast PSP system

Use PSP to provide higher spatial resolution, taps anchor data

Model you can’t tap

Improve loads calc.

Fast camera 1Mpix at 12 kHz

You can’t build that


PSP for Production Wind Tunnel Testing

Mach 0.7

5˚ Angle of Attack

Innovative Scientific Solutions

Dayton Ohio

Aircraft Research Association

Bedford England

CP

Binary PSP

Lifetime PSP

Binary PSP

8 foot test section


Lifetime PSP in a Transonic Wind Tunnel

Mach 0.7

5˚ Angle of Attack

Innovative Scientific Solutions

Dayton Ohio

Aircraft Research Association

Bedford England

CP


Fast Response PSP Unsteady Pressure measurements in a supersonic cavity

AIAA-2013-0678

Fast response PSP systems are evolving quickly and will soon be deployed in larger tunnels such as AEDC 16T

Asai AIAA-2013-0485

Merienne AIAA-2013-1136

Flaherty AIAA-2013-0678


NASA SBIR Program

ISSI, OSU, NASA, US Army

Tunnel is lower speed, but blade tip is ~ 220-m/s

Not really low speed PSP

Rotorcraft Experimental Setup

PSP data from 2-meter Rotor in NASA 14X22

Single-Shot Concept

Unsteady PSP on Rotorcraft Model

Single-Shot Lifetime Detection of Fast PSP

Combine fast responding PSP with single-shot lifetime detection concept to

produce a system for measurements of unsteady pressure on rotorcraft blades.

Most recent measurements conducted on 2 blades using 5 cameras

Tip vortex

Klein AIAA-2013-0483

Gregory AIAA-2013-0484


Motivation

• PSP used regularly in transonic tunnels

– Academic, Research, and Production systems

– AEDC, ARA, DLR/DNW, NASA, TsAGI, JAXA, ONERA

• Fast PSP quickly developing

– Academic and Research tunnels

• PSP measurements demonstrated at low-speed

– NASA – Bell/Brown, Tohoku - Asai, ISSI - ADD

• Production PSP system for large low-speed tunnel

– Productivity? Accuracy? Low-Speed? Large?

– Definition differs for Academic, Research, Production,

Military, and Commercial


System Performance Requirements

• Academic (University)

– Accurate ~ flow visualization to quantitative

– Productive > student graduation rate? basic research

• Research and Development (NASA, AEDC, DLR, ...)

– Accurate ~ 3% of dynamic pressure

• need meaningful error bars

– Productive > tunnel run time

• Production (Boeing, Airbus)

– Accurate ~ 3% of dynamic pressure, used for loads design

– Productive > tunnel occupation time & data delivery

• Design cycle requires final data delivery in weeks

1-4 foot test section

Speed < Mach 0.3

Small blow-down tunnels

6+ foot test section

M 0.6 < Speed < M 2.5

return on investment


Very Low Speed (17-m/s) PSP AIAA 2004-878 (James Bell)

• ISSI Binary FIB

• Taps –vs- PSP ~ 35-Pa >> Q ~ 180-Pa

Flow

p (psi)

-0.06

0.01

-0.07

-0.06

-0.05

-0.04

-0.03

-0.02

-0.01

0

-0.07 -0.06 -0.05 -0.04 -0.03 -0.02 -0.01 0

Tap Data (psi)

PS

P D

ata

(p

si)

RMS Difference = 0.0046 psi


Binary PSP for Low-Speed

• Errors in PSP measurements (Liu & Sullivan)

– Temperature

– Illumination (model movement & lamp stability)

– Camera noise (photon statistics)

– Paint Calibration (accuracy & stability)

– Photo-degradation, Filter Leakage

– Sedimentation (dirt, oil deposits on model)

– Spectral content of excitation (Flash-lamp)

• Determine sensitivity coefficients

• Identify major sources of error

– Temperature, Illumination


Temperature Errors

• Model construction

– metal model to minimize temperature gradients

• isothermal boundary condition

– plastic model to maximize temperature gradients

• adiabatic boundary condition

• Temperature changes during the run

– Tunnel stagnation temperature increases at startup

– Mach number is changed

– Angle of attack is changed

– Stagnation temperature in a blow-down tunnel


Illumination Errors

• Model movement/deformation

– Sting mounted model shifts

– Structural bending, twisting

– Motion Wind-on to Wind-off

• Estimation of error

– Assume LED is 1-m from model

– Wind bends 1-mm under load

– Intensity change is 0.2%

– Pressure error is ~ 250-Pa

– Wing bends 5-mm, pressure error is ~ 1,300 Pa

– 30-m/s = 540-Pa 60-m/s = 2,100-Pa


Binary Pressure-Sensitive Paint Acquisition

• 1 camera + filter wheel

– Sequential images (time)

– Stable experiment

• 2 cameras

– Image alignment

– Perspective distortion


Binary FIB Calibration with Filter Switch

• Temperature sensitivity

– ~ 25 times less than FIB

• Uncertainty

– 50 Pa/K


PSP at lower speeds in Research Tunnels

• UCAV in SARL – 2004

– Mach 0.2, 0.4

– Taps –vs- PSP ~ RMS 1,100-Pa

• Slow-Scan CCD

• 4 LED lights

– 1.2-W each

– LM4-400 (4 inch unit)

• Binary FIB

• Filter Switch

• Acquisition time

– ~ 10-s/image

• Average 32 images

Background lighting is a

major issue in the SARL

Open circuit, runs in

daytime. Hope for a dry,

cloudy, summer day.


PSP at 50-m/s in 3X4 AFIT Tunnel

• LM2X LED

– 2.2-W

– 2 inch unit

• Binary FIB

• Filter Switch

• PCO.1600 camera

– Electronic shutter


– ~ 1-s/image

• Average 64

images

Open circuit tunnel


PSP at 60-m/s in 3X4 AFIT Tunnel

• LM2X LED

– 2.2-W

– 2 inch unit

• Binary FIB

• Filter Switch

• PCO.1600 camera

– Electronic shutter


– ~ 1-s/image


PSP deviation ~ 200 Pa

Starting to get useful


NACA 0012 with 2D Ice

Mike Bragg

Greg Elliott

University of Illinois Taps –vs- PSP ~ 130 Pa


PSP on MicroX in SARL

Side Top

Mach = 0.3

ISSI & AFRL

2007

• PCO.1600

• 8 LED lights

– 2.5-W each

• Binary FIB

• Filter Switch


– ~ 2-s/image


• Dynamic background

35°


15°

5° 10°

35°

85 90 95 100

Pressure kPa

• Mach = 0.3

• Thin, removable tail section

– Difficult to tap

• Multi-vortex structure?

• Taps –vs- PSP

– ~ 270-Pa (model body)

– 5% dynamic pressure

• Substantial improvement

– 2004 ~ 1100 Pa

– 2007 ~ 270 Pa

• Better lights > S/N

• Dynamic background


-3

1 Cp Frees stream U∞ = 50 [m/s] （Re = 3×105），Yaw angle y = 0 [deg]

Hatchback’s

transverse and

trailing vortices

Taps –vs- PSP ~ 50 Pa

Oil Flow Visualization

・Yamashita, T., et al, Journal of Visualization, Vol. 10, No. 3, 2007, pp. 1343-8875.

・Yorita, D. et al., Paper No. P04-005 Flow Visualization Symposium, 2008


High Power LED

• Output power ~ 8-12 W

• Stability ~0.1 % per hour

• Maximum duty cycle 100%

• Rise time (10% - 90%) < 1-ms

• Fall time (90% - 10%) < 1-ms


ADD System – Tunnel Integration

• Master PC

– Tunnel PC control

– Collect & transmit

• Run conditions

• Pressure taps

– Pulse generator

• Fire cameras & lamps

• Slave system

– Camera

– Filter wheel

– Data storage


Taps –vs- PSP

• ADD 2009

• Tunnel

– 3m X 2.25m

– Closed circuit

• Max 90 m/s


– 2 second exposure

• Data mapped to mesh


Mach Number Sweep, a=5° Top

Bottom 46-m/s 60-m/s 80-m/s


a = -4° 0° 5° 8°

a Sweep, V = 46-m/s


Binary PSP Acquisition

Seem to be reaching limit for

filter switch. Explore color

camera. Need paint to match

color mask on camera. Need

high quality color camera.


• Temperature sensitivity

– not quite as good as filter switch

• Pressure sensitivity

– Slightly lower


Test section 3-m x 2.25-m

Speed 80, 60, 46–m/s

rms deviation ~ 130-Pa

Single Color Camera


Bridge Model at 30 m/s

• LM2XX LED

– 4-W

– 2 inch unit

• Binary FIB

• Color Camera

– RFZ lens


– ~ 300 ms

• Average 64

images


Color Camera System for Production Test

• Production system

– Acquire accurate data

– At reasonable rates

• Remotely control FOV

– Add Pan/Tilt and Motorized Focus-Zoom-Aperture

– Integrate these into data acquisition software

• Get more cameras on model

– Resolve leading edge, focus on flap, etc.

– Cost of camera and data transfer rate

– GigE color camera

Pan/Tilt

RFZ Lens

Current systems have

fixed position and

manual lens


Conclusions

• Production Systems for Transonic Tunnel

– Systems becoming more common

• Lifetime and Binary systems are effective

– Multi-camera systems to cover model

– System integration essential for productivity

• Low Speed Measurements < 80-m/s

– Becoming common in Academic tunnels

– Better hardware, cost is coming down

– Systems developing in larger Research Tunnels

– Taps-vs-PSP ~ 50-Pa small tunnels, 100-Pa large tunnels

• Future systems based on color camera


PSP on a Low-Speed Propeller

Single-shot PSP on

rotating machinery

at low speed

Tip speed ~ 55-m/s

Dynamic pressure ~ 1,800-Pa

Pressure variation ~ 2,500-Pa gate ratio

ISSI & OSU

2009


Evolution of Instrumentation

• Academic

– 1) Make it work

– TC & taps, balance, MDM, PSP/TSP, PIV, oil , S3F, etc.

– PSP works here at all speeds

• Research and Development

– & 2) Acquire accurate data, 3) at reasonable rates

– TC & taps, balance, MDM, TSP, oil, PIV?

• Production

– & 4) In a cost effective manner

– TC & taps, balance, MDM

Lots of cleaver instrumentation ideas are developed and demonstrated.

Very few are used in production testing.

Practical implementation (i.e. seed a transonic tunnel without compromising operation, optical access, etc.) is the major limit to wide spread deployment in many cases.

lecture 27 low speed psp large tunnel - wmich.edu

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