Steam Engine Specifications/Work Diagrams: Difference between revisions
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A more complete work diagram with an operating boiling pressure of 100 psi. | A more complete work diagram with an operating boiling pressure of 100 psi. | ||
One thing to note about this diagram is that it shows the full length of the piston travel and assumes that steam left in the bore is exhausted at the very end of the travel distance. In the current design, the exhaust vent is opened somewhat before the end of the travel distance. This would affect the work curve above somewhat (a bit of power is lost). Still, some time is needed to exhaust the bore down to atmospheric pressure level. The current design has four steam exit ports, which means (in theory), that pressure would drop fairly quickly (how much time?). | |||
[[Category:Steam Engine]] | [[Category:Steam Engine]] | ||
Revision as of 15:31, 17 May 2011
Main > Energy > Steam Engine
Design 5
50 PSI Boiler Pressure
Cutoff: 1/4
Bore: 4"
Stroke: 4"
Boiler Pressure: 50psi
Doing such diagrams is quite informative. Note that the expansion curve falls off below atmospheric pressure near the end of the stroke. Naturally, pressure in the cylinder cannot fall below atmospheric pressure, but it could fall to meet it. This is actually not desired. Some amount of back pressure in the cylinder softens the ends of the stroke cycle. This diagram also indicates how long the bump valve pins need to be in order to reach cutoff at 1/4 of the stroke length. Varying this will impact the amount of work produced in one cycle.
100 PSI Boiler Pressure
Cutoff: 1/4
Bore: 4"
Stroke: 4"
Boiler Pressure: 100psi
A more complete work diagram with an operating boiling pressure of 100 psi.
One thing to note about this diagram is that it shows the full length of the piston travel and assumes that steam left in the bore is exhausted at the very end of the travel distance. In the current design, the exhaust vent is opened somewhat before the end of the travel distance. This would affect the work curve above somewhat (a bit of power is lost). Still, some time is needed to exhaust the bore down to atmospheric pressure level. The current design has four steam exit ports, which means (in theory), that pressure would drop fairly quickly (how much time?).