p.v. panel wind load effects m arch 2011 arman hemmati, brady zaiser, chaneel park, jeff symons,...
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P.V. PANEL WIND LOAD EFFECTS
MARCH 2011
Arman Hemmati , Brady Zaiser, Chaneel Park, Jeff Symons, Katie Olver
Interim Review II
TEAM 12
MARCH- 2011Design Review #4: DeLoPREC
2
Overview
• Refresh
• Wind Tunnel Experiment Progress
• CFD Progress
MARCH- 2011Design Review #4: DeLoPREC
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Refresh
• Ideal angle of inclination is 51°
• Too much weight for the roof?
• Wind Tunnel testing – Experimental
• Computational Fluid Dynamics (CFD) - Computational
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Where We Were
•Designed model in SolidWorks•Talked to Mike Johnson
▫Increase the thickness of adjustable support rods
▫Panel to be made from MDF•Machining to be done at faculty shop
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Building the Model
• Work order submitted February 4• Started work on February 22
▫ ½” MDF was unavailable substituted ¾”
• Picked up on Friday February 25• Some problems with design
▫ Filler on welded parts means that parts don’t fit together
▫ MDF panel is heavier than expected Need to do force analysis
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Budget
•Estimated cost of model▫Materials: ~$10
▫Labour: ~$25
▫Total: ~$35
•This is the only planned cost for our project•Extra costs may occur if something breaks
or we do further tests
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Force Measurement
•2 load cells measure lift force & pitching moment
•Drag plate measures drag▫Old springs & strain gauge were not stiff
enough▫Rebuilt with load cell
•Using LabView program to capture data▫3 data streams
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Wind Speed Measurement• Wind speed affects drag/lift force by:
FD or L = CD or L ∙ ½ ρv2A
• Cannot control speed in wind tunnel• Need to measure wind speed• Unable to capture digitally
▫Pressure too small for department’s pressure transducers
▫Hot wire anemometer fragile and expensive• Manually read dynamic pressure
▫Source of error▫Average not instant
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Testing Parameters
•Testing 3 parameters:▫Wind direction▫Panel angle▫Panel height
•Wind direction▫How does the force on the panel change
depending on the wind direction? Front, back
▫2 levels
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Testing Parameters•Panel angle
▫How does the force on the panel change as the angle increases?
▫In Calgary the ideal angle is 51°▫Testing at: 35°, 50°, 65° and 80°
▫4 levels
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Testing Parameters
•Panel height▫How does the force on the panel change as
the distance between the ground and the bottom of the panel increases?
▫Unable to use CFD for this▫ Testing at: 0, 1”, 2”, …, 6”
▫7 levels
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel – Testing Procedure
•How many runs?▫2∙4∙7 = 56 runs per replication▫2 replications = 112 runs
•Randomize run order▫Lots of set-up between runs
•How long will it take?▫5 min/run + daily set-up ▫Estimate 15 hours 1 week
MARCH- 2011Design Review #4: DeLoPREC
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Wind Tunnel - Schedule
•Behind schedule▫Hoped to test during reading week▫Machining took longer than anticipated
•Next 5 weeks:▫1 week testing▫1 week analysing results▫2 weeks further testing if necessary▫1 week preparing report
MARCH- 2011Design Review #4: DeLoPREC
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CFD - Update
• Pressure Coefficient
• Initially, CP > 1.5
• Now, CP < 1.1▫ Biggest contributing factor: length of CV in front of
panel
MARCH- 2011Design Review #4: DeLoPREC
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CFD - Verification
• Vertical Flat Plate
• Reference: “On the Flow of Air Behind an Inclined Flat Plate of Infinite Span” -Fage and Johansen, 1927.
MARCH- 2011Design Review #4: DeLoPREC
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13 13.5 14 14.5 15 15.5
-1.6
-1.1
-0.6
-0.1
0.4
0.9
FrontBack
Distance Along Y-Axis (m)
Pre
ssure
(P
a)
MARCH- 2011Design Review #4: DeLoPREC
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CFD – Initial Results
20 30 40 50 60 70 80 90 1000%
25%
50%
75%
100%
f(x) = − 0.000430477231319 x + 0.266165919788991
Coefficient of Drag Error (Exp. v.s. Comp.)
[ ]a degreesCD
-ER
RO
R [
%]
20 30 40 50 60 70 80 90 1000%
25%
50%
75%
100%
f(x) = 1.65071261752211E-05 x + 0.251118597093687
Lift Coefficient Error (Exp. v.s. Comp.)
[ ]a degreesCL-E
RR
OR
[%
]
MARCH- 2011Design Review #4: DeLoPREC
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MARCH- 2011Design Review #4: DeLoPREC
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CFD – Initial Results
MARCH- 2011Design Review #4: DeLoPREC
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CFD – Next Step
• Determine why pressure increases with finer mesh• Overcome convergence problems• Try different solution models
MARCH- 2011Design Review #4: DeLoPREC
www.ucalgary.ca/deloprec