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Old 04-22-2012, 05:25 AM   #70 (permalink)
IamIan
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Quote:
Originally Posted by ProDarwin View Post
Well, a piston steam engine is a different animal. Steam is not created in the cylinder, it is let into the cylinder. Water is heated in a pressurized vessel to well above 100C. When a valve is opened to release/inject/whatever the water it instantly converts to steam and will drive the piston down.
agreed ... sorry for my less than accurate simplification.

Quote:
Originally Posted by ProDarwin View Post
On any inline 4, the power stroke of 1 cylinder will always be opposite the exhaust of another. The effect you are describing is similar to what a tuned header does... only without the need for any complex water injection system.
agreed.

The difference is that the tuned header doesn't lower the pressures of the other side.

Past a certain point of converting engine heat to steam ... it would be increasing the pressure ... which gets back to the 6 stroke version.

Quote:
Originally Posted by ProDarwin View Post
And this is what BMW's gas turbine concept is.


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Quote:
Originally Posted by drmiller100 View Post
>>
Where did the exhaust gasses go? Do they now occupy .06 cc's????

are you saying the exhaust gasses and the water are all occupying the same space at the same time????
Not to step on t-vago's toes... but I'm here so I thought I would try and help explain.

In this simplified example.
All the gasses share the 39.04cc of space ... the liquid water is only occupying the 0.96 cc of space.

The original hot gasses contracted when their temperature dropped ... causing their contribution to become the 82 t-vago wrote last time... this contraction happens to all gases in a fixed volume as they cool.

That drop in temperature was the heat energy transfer to the liquid water ... that heat energy transfer was what enabled the liquid water to phase change ~0.04g to steam ... the phase change itself does not change the temperature ... to change the temperature first you add the heat energy to get to the phase change point ... then you add more energy to do the phase change itself ... then you can add more energy to increase the temperature of the material in it's new phase... but you can't increase the temperature of the phase change material until you have added enough energy to phase change all the rest of the ~0.96g that is still liquid water just bellow the phase change point.

That water phase changed to steam ... expanded to fill the volume of the container ~39.04cc ... as any gas will do ... because there was not room for the full ~1700:1 expansion that would result at a lower ~14.7psi pressures the steam contributes a bit more than ~14.7psi ... I'm estimating ~26 psi.

Both gas forces ~26psi + ~82psi combine to make the total system ~108psi of gas in the ~39.04cc of volume... which with the still liquid water is now all the same temperature just bellow the phase change point.

If there was more thermal energy in the system more water would get converted to steam ... but to have more thermal energy without also having the same hot air contracts as it cools effect of giving up that thermal energy you need something with more thermal mass that doesn't change as much as a gas would.
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