Transcript Slide 1

Renovating An Ancient Low Speed Wind
Tunnel
Narayanan Komerath and the
Experimental Aerodynamics and Concepts Group
Daniel Guggenheim School of Aerospace Engineering
Georgia Institute of Technology, Atlanta
Experimental Aerodynamics and Concepts Group
Acknowledgements
This paper, and the EXTROVERT system that enabled it,
were developed using resources provided under the NASA
Innovations in Aerospace Instruction initiative, under NASA
Grant NNX09AF67G, monitored by Mr. Tony Springer. The
assistance of the students in the Experimental
Aerodynamics and Concepts Group is gratefully
acknowledged.
Experimental Aerodynamics and Concepts Group
John J. Harper Wind Tunnel
10 - 165mph; Closed return; Ambient pressure
test section, Floor turntable, 7’ x 9’; <0.3%
turbulence
•Pressure scanning; Hot film anemometry; 30Hz.
Dual Nd-YAG PIV, Stereo & Tomographic PIV.
•6-DOF load cells; LabView signal analysis; 16channel A/D; DSP/DIP.
Experimental Aerodynamics and Concepts Group
The paper describes how a team of aerospace engineering
students planned, organized, implemented and recorded a
fast-paced project in support of the repair and renovation of
a very old, major university low speed wind tunnel.
1960-vintage water-cooled clutch failed on Nov 1, 2011.
Project ~ April 2012 to replace the clutch and the 600 hp
motor with a modern variable frequency drive and motor.
Experimental Aerodynamics and Concepts Group
Problem Statement
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Use shutdown period to reorganize inventory.
Experiments & analysis to specify new motor and braking.
Pressure washing, turning-vane repair, diffuser painting.
Tunnel feedback control system & control panel.
Honeycomb repair and tunnel calibration.
1 summer to do it all.
Experimental Aerodynamics and Concepts Group
Technical Problem Statement
Safety, safety, safety!
• Unknowns in dealing with 80-year-old components.
• Needed skills had to be learned.
• Cell-phone compatible Inventory Organization.
• Finding the inertia of an inoperable fan/shaft system.
• Tunnel control system and control panel development.
• Predicting performance to specify emergency braking.
• Calibrating open tunnel motor performance.
• Repairing honeycomb in the settling chamber.
• Calibrating the turbulence in the test section.
• Planning a new fan system.
Experimental Aerodynamics and Concepts Group
Educational Problem Statement
• Needed skills had to be learned on the job.
• AE students from freshman to PhD.
• Technical content outside AE curriculum.
• Where and how do we find the required knowledge?
• How do we ensure correctness of use of the knowledge?
• How do students communicate within and across task teams?
• How are project timelines met, with a diverse team of
students?
Experimental Aerodynamics and Concepts Group
Team organization
Communications & Archiving:
•Project Document
•Whiteboard Walls
•Countdown List
•Facebook
•LaTEX
•Email
•Meetings
Experimental Aerodynamics and Concepts Group
Issues, Knowledge Needs, and Sources
Issue
Knowledge area
Sources
Fan inertia
Dynamics
Courses, innovation.
Tunnel power
Fluid & thermodynamics; fan
Books, papers on closed circuit tunnel loss;
requirement; Braking
aerodynamics, electric machines.
calculations, EE textbooks.
Sizing equipment and procedures,
Retail outlets, equipment specs
profile
Pressure washing
drainage rigging.
Inventory
Smartphone apps, QR code system
Friends in ECE/ computing, cellphone ads, web
Painting options;
Chemical safety, application difficulties,
RTK certification & Research ethics courses,
Safety issues; Vane
surface nature, cost, color selection.
MSDS, discussion experts, paint manufacturer
repair options
protection, sealing and removal. Metal
sites; equipment specs, discussions with experts
vs. wood vs. Bondo /fiberglass. Safety,
& team, textbooks, safety manuals, practice.
equipment, training.
Composite blade making experience
Sensors & data
Pressure, temperature, velocity, torque,
Our group, vertical transfer.
acquisition
strain. signal processing.
Feedback control
System dynamics, control systems,
system
dynamics.
organization
AE courses, textbooks, discussions
Experimental Aerodynamics and Concepts Group
Images from Summer 2012
Old motor gone, new
arrival
Installed!
How will
the diffuser
look with a
paint job?
After
Vanes Before
Experimental Aerodynamics and Concepts Group
Methods Used
Extensive
use of
paste-on
whiteboards
Video-based MI
measurement
Safety eqpt.
Smartphone
Inventory
Controls
Development
Experimental Aerodynamics and Concepts Group
Level of detail needed in the Project Document
Movie frame from experiment to
measure fan/gear/shaft inertia
Experimental Aerodynamics and Concepts Group
First Run After Repairs!
Experimental Aerodynamics and Concepts Group
Lessons
• Case study of a project done to an exacting timeline and success metric.
Students with diverse experience.
• Countdown list with deadline and contingencies.
• Students learned LaTEX quickly - team-authored project document.
• Skills with cellphone apps - a smart-phone/ QR-code inventory system.
• Engage least experienced team members, ask them to delegate tasks and
track timelines.
• Paste-on whiteboards for communication and technical thinking.
• Huge, proven improvement in the effectiveness and depth with which our
students are able to pose and solve problems that cut across disciplines.
Experimental Aerodynamics and Concepts Group
Constant-Torque Braking Power Required
450
Power Required (hp)
400
350
300
250
200
150
100
50
0
0.00
5.00
10.00
15.00
20.00
Time (s)
Experimental Aerodynamics and Concepts Group
25.00
30.00
35.00
500
Torque-limited braking
Flow speed (MPH)
Fan speed (rad/s)
Peak Power (HP)
Flow Brake Power (HP)
Excess Needed For Braking (HP)
Torque % rated
Flow speed (MPH)
Fan speed (rad/s)
Peak Power (HP)
Flow Brake Power (HP)
450
400
350
300
250
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150
100
50
0
1
3
5
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11
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15
Experimental Aerodynamics and Concepts Group
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