thermopile test bench detailed design review team thermopilers adrian aspinall, david eld, tyler...
Post on 22-Dec-2015
216 views
TRANSCRIPT
Thermopile Test BenchDetailed Design Review
Team Thermopilers
Adrian Aspinall, David Eld, Tyler Merritt, Paul Sowinski, Michael Sotolongo
1
Overview
• Updated Specifications• Drawing Package• System Design
o Thermal Subsystemo Structural Subsystemo Vacuum Subsystemo Electrical Subsystemo Software & Data
Acquisition Subsystem• Bill of Materials & Budget• Schedule• Questions
2
Experimental Test Stand
Updated Specs
• Measure Electrical Characteristics• Measure Heat Transfer and Efficiency• Adjust Axial Loading• Display and Record Data• Test in Vacuum
See Specification Table for Specifics
3
Drawings
See Drawing Package Handouts
4
System Design
• Thermal Subsystem • Structural Subsystem
• Vacuum Subsystem
• Electrical Subsystem
• Software & Data Acquisition Subsystem
5
Thermal Components
• Heat Flux Sensors • Thin Film Thermocouples
• Peltier Cooler
• Thermostone Heater
• Water Block
• Radiator
6
Heat Flux Sensors
Size: 10 mm x 10 mmThichness: 1 mmWire Length: 1 mSensitivity: 3 mV/(W/cm^2) Max Temperature: ~200 C
7
Thin Film Thermocouples
Size: 13 mm x 9 mmThickness: 0.13 mm Type KWire Length: 1 mMax Temperature: 260 C
8
Peltier Cooler
Size: 40 mm x 40 mmThickness: 3 mmResistance: 1.5 ohms @ 25CMax Temperature: 138 CQmax : 71 WDelta Tmax: 66 degreesPower in max: 130 W @ 15.4V , 8A
9
Thermostone Heater
Size: 1 in x 1 inThickness: 0.040 inResistance: 33 ohmsWire Length: 1 mMax Temperature: 250 C
*Image from www.thermostone.com
10
Structural Subsystem
• Internal Frame • Linear Actuator and Spring(s) • Load Isolation
11
Internal Frame12
Linear Actuator• Our current design would use a DC linear
actuator (mechanically in series with a spring)
• Controlling DC actuator would be very
similar to controlling the heater or cooler (won't have to learn/troubleshoot stepper motor controller)
• Voltage to actuator would be regulated
using feedback from load cell (voltage would ramp down as load cell reading approaches desired load)
13
www.surpluscenter.com
Springs for Actuator
• Spring would allow the load to be applied over a greater displacement, should result in fine resolution of load application.
• Two springs will be in parallel
with each other for a higher spring rate but is still able to deflect a good amount (more compact than one spring).
• The Linear actuator would
have a 4" stroke to account for different sizes of thermopiles.
14
Load Cell
http://www.omega.com/ppt/pptsc.asp?ref=LC302&Nav=pref03 Excitation: 5 - 15 Vdc Output: 1 mV/V Accuracy: 0.5% Operating Temperature Range: -54 to 125 C Safe Overload: 150%
15
Load Isolation Model16
Load Isolation- FEA17
Stresses and Deflections Shown on Handout
FOS - 3.01
Vacuum Chamber Subsystem
• Chamber• Chamber Door• Seals• Vacuum Pump • Feed Throughs
oElectrical Feed Through (Sensors)oElectrical Feed Through (Power) oThermocouple Feed ThroughoFluid Feed Through
18
Vacuum Chamber Preliminary Designs
Initial
Angle Iron Skeleton
I-Beam Skeleton
19
Current Vacuum Chamber Model20
Vacuum Chamber- FEAStresses and Deflections Shown on Handout
21
FOS - 4.79
Chamber Door
• 1 in thick clear Plexiglas • Overlaps door cutout by 1.5 in (so cumulative load on door
is distributed more evenly)
22
Vacuum Chamber Seals
• Rectangular seal for door• Square seal for base• Two materials considered for
vacuum sealsoVitonoNitrile
• Custom seals available through RSR
23
www.rubbersheetroll.com
Vacuum Pump (absolute pressures)
• The actual difference between convective losses associated with a medium vacuum pump and an ultra high vacuum pump should be very small. (Even a rough industrial pump capable of 29.8" Hg would remove about 99.6% of the air)
• Laboratory grade pumps capable of 20-75 microns have
been considered as well as larger industrial vacuum pumps. (see spreadsheet for various pump specs)
24
Vacuum Pump (evacuation time)
• Evacuation times have been estimated for a 3.0 ft^3 chamber assuming a final pressure of about 75 micron.
• The time in minutes is
plotted against a range of common pump flow rates.
25
Suggested Vacuum Pump
JB DV-6E Eliminator
Pressure: 25 Micron
CFM: 6.0 (~3.45 min evacuation time)
Cost: $275
• Good flow rate and very good vacuum pressure compared to similarly priced pumps.
• Designed for continual use on AC systems, durable.
26
www.jbind.com
Vacuum Feed Throughs
*Image from www.pavetechnologyco.com
*Image from www.ancorp.com
27
Electrical Subsystem Schematic28
Relay Wiring for Thermopile Impedance Measurment29
Relay Wiring for Linear Actuator Polarity30
Electrical SubsystemSensors
• Axial Loadingo Omega Load Cell LC302-500 1 mV/V
• Temperatureo Omega Thin Film Thermocouple CO 1K 41 uV/C
• Heat Fluxo Captec Thin Film Heat Flux 3 mV/W/cm^2
Other Measurements
• Thermopile Open Circuit Voltage• Load Impedance• Load Voltage• Load Current
31
Software & Data Acquisition Subsystem
• LabView• .NET
o Managed Assemblieso C API
• Pros & Cons• Current Hardware Issues
32
Data Acquisition Components• NI PXI 1031 4 Slot 3U PXI Chassis
o NI PXI 6251 PXI input card NI SCC 68 Voltage box
o NI PXI 6281 PXI input card NI SCXI 1000 4 Slot SCXI Chassis
NI SCXI 1125 8 channel isolation amplifier NI SCXI 1303 32 channel isothermal terminal block
33
Bill of Materials / Budget
See BOM / Detailed Budget Handout
34
Schedule
Detailed Design Review 9/30/2010
Drawing package for fabrication finalized 10/6/10
Finish Fabrication Late October
Submit Testing Data 11/19/2010
Submit Manual Draft 11/30/2010
Final Snapshot 12/3/2010
Final Report and Manual 12/15/2010
35
Questions
• Will we receive the power supply in time to incorporate into the design?
• Is there a preference for set up time for a test (chamber evacuation
time, load application, etc)? • Should we order duplicates of any parts? (Custom seals, specialty
heat flux sensors, heaters, etc?) • Do you know if the power supply can change polarity?
• Is an accuracy of 2.5 lbs acceptable for the load application?
www.home.agilent.com
36