2023 BFY4 Abstract Detail Page
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| Abstract Title: |
W04: Real-time quantitative measurement of a Stirling engine P-V diagram |
| Abstract: |
This workshop will demonstrate a real-time measurement of a Stirling engine P-V diagram. The experiment uses an inexpensive gamma-type Stirling engine. The only modifications required to the as-purchased engine are a single hole drilled in the top plate to accommodate a pressure sensor and attaching circular choppers to the flywheel. The outer chopper is completely transparent except for a single narrow black line which is positioned such that it is at the top of the flywheel when the internal volume of the Stirling engine is a minimum. The inner chopper, on the other hand, has 100 equally-spaced divisions and is used to track the orientation of the flywheel. The P-V diagram is constructed using electronics and a dual photogate that were designed inhouse. The outer chopper is used to reset a counter and the inner chopper increments the count. A digital-to-analog converter converts the binary output of the counter to a voltage between -3.14 V to +3.14 V (i.e., a voltage that spans 2π) which can then be used to calculate the gas volume. Our system allows a calibrated P-V diagram to be displayed on oscilloscope while the Stirling engine is running. We are also able to observe the phase shift between the pressure and volume oscillations as well as how the P-V diagram changes when friction is applied to the flywheel. Finally, we can run the Stirling cycle in reverse to demonstrate refrigeration. A rotary tool with a felt attachment is used to rotate the flywheel while the temperature difference that develops across the top and bottom plates of the engine is monitored using a differential thermocouple. |
| Abstract Type: |
Workshop
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Author/Organizer Information |
| Primary Contact: |
Jake Bobowski
University of British Columbia
Kelowna, British Columbia, Canada, Non U.S. V1V 1V7
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Co-Author(s)
and Co-Presenter(s) |
Nikolai Lesack, University of British Columbia, 2329 West Mall, Vancouver, British Columbia, Canada, V6T 1Z4
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Workshop Documents |
| Workshop Doc 1: |
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| Workshop Doc 3: |
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| Workshop Doc 5: |
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