Steam Engine Specifications/Work Diagram Construction: Difference between revisions
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(Created page with "{{Category=Steam Engine}} =Construction of a Work Diagram= Refer to fig. 7 in "Steam Engines' '''Procedure''' # Determine the initial pressure, ratio of expansion, and percent...") |
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=Construction of a Work Diagram= | =Construction of a Work Diagram= | ||
[[Image:Steam_Engines-fig-7.png]] | |||
Refer to fig. 7 in "Steam Engines' | Refer to fig. 7 in "Steam Engines' | ||
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# Make OR the clearance displacement percent. | # Make OR the clearance displacement percent. | ||
# Make RX the length of the stroke | # Make RX the length of the stroke | ||
# Draw RA perp. at the clearance | # Draw RA perp. at the clearance displacement length to represent 3-8% (med. speed engine) of the total displacement. | ||
to represent | |||
# Draw AK at 0.98 of the boiler pressure | # Draw AK at 0.98 of the boiler pressure | ||
# Draw KX at the stroke length. | # Draw KX at the stroke length. | ||
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Area of actual diagram is slightly smaller than the theoretical: | Area of actual diagram is slightly smaller than the theoretical: | ||
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|Large, med. speed | |Large, med. speed | ||
Latest revision as of 23:54, 25 May 2011
Main > Energy > Steam Engine
Construction of a Work Diagram
Refer to fig. 7 in "Steam Engines'
Procedure
- Determine the initial pressure, ratio of expansion, and percent of clearance.
- Draw lines OX and OY at right angles.
- Make OR the clearance displacement percent.
- Make RX the length of the stroke
- Draw RA perp. at the clearance displacement length to represent 3-8% (med. speed engine) of the total displacement.
- Draw AK at 0.98 of the boiler pressure
- Draw KX at the stroke length.
- Draw LH at 14.7 psi for atmospheric pressure.
- Locate cutoff point B for expansion ratio (1/8, 1/4, etc. of stroke len)
- Divide BK into equal distances (a,b,c, etc)..
- Connect them to point O
- Extend horizontals from the points where diagonals meet with line BP.
- Extend verticals down from (a,b,c, etc)
- Connect these points to form the expansion curve.
- Back pressue curve at FD about 2psi above atmospheric
- Compression curve at DE, rounded up to start of cycle.
Area of actual diagram is slightly smaller than the theoretical:
| Large, med. speed | 0.90 |
| Small, med. speed | 0.85 |
| High speed | 0.75 |