Quote:
Originally Posted by drmiller100
take a closed volume of 40 cc's at 800 degrees F and 150 psi.
add one gram of liquid water.
water has an expansion ratio of about 1700 to 1.
I believe the pressure will rise.
Significantly.
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I know you believe. You believe that water will just magically flash into steam. Your belief is akin to a religious belief.
Again, you neglect the latent heat of vaporization.
Using your example of 1034 kPa and 700 K (or 427 C, if you will), and assuming that the liquid water was near 100 C, we find that:
The mass of your mystery gas in that closed volume is unknown. However, for a simplified exhaust gas containing 80% diatomic nitrogen, 11 percent carbon dioxide, and 9 percent steam, it's 0.2 grams.
It holds about 150 J of thermal energy. Of that, 91 J is available that can be used to vaporize water.
That gram of water needs 2260 J to completely turn into steam.
Roughly 4% of that gram flashed into steam, bringing the temperature of your closed system to that of the water, i.e. 100 C.
The pressure dropped, too. Ooooh, lookie - 101 kPa.
And you still have 0.96 grams of liquid water to deal with.
So, now you have 39 ccs of mystery gas, 1 cc of water, and it's all at 100 C and 101 kPa. Oh, excuse me - 212 F and 14.7 psia.
Quote:
Originally Posted by drmiller100
In order,
In order, pressure of steam at 100c is 1.0142 bar. which is interesting if the rest of the "atmosphere" is not at one bar.
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Given your example above, it's about 1/10th of the pressure you mentioned.
Quote:
Originally Posted by drmiller100
More interesting is what is the pressure of steam at 400c? I can't find the answer.
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That's because it's undefined. Water has a critical point of 373 C and 22064 kPa.
Quote:
Originally Posted by drmiller100
it is indeed a guess as a place to start based on an old timer I met who did this in the 70's.
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Why do we not know the name of this old-timer? If he could get this thingy to work, then his name ought to be at least as well known as Otto or Diesel or Brayton or Rankine or Carnot or Atkins or Wankel.
Quote:
Originally Posted by drmiller100
Pumping losses are significant. 10 to 15 percent. So if nothing else, we have magically found 10 to 15 percent possible gains.
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So how would you go about preventing ignition quenching?