gidge348
Senior Member
Joined: September 2010
Posts: 426 
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Post by gidge348 on Jan 22, 2015 0:53:07 GMT -5
John I remember a good, simple experiment from school that shows the principal of keeping the burning gasses in contact with water level of the container. www.youtube.com/watch?v=I9gKzea3Cno Ian... |
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Post by racket on Jan 22, 2015 3:26:47 GMT -5
Hi Ian
Thats a perfect demonstration of the situation :-)
Heh heh , I'm not too sure if an oxy flame would produce the same outcome though , there is a limit to heat transfer rates even for boiler plate , so any steam rocket would preferably have a "soft" flame to heat it with limited heat transfer rates per square foot of heating surface , especially if the metal is rather thick as would be the case with an oxy bottle .
At 500 psi the water is only at ~260 deg C , a normal gas burner ring would be more than enough to heat up the water if there was a bit of insulation to prevent heat loss during the process , we'd only be needing ~500 BTUs/pound of water , so even 50 lbs of water would only need 25,000 BTUs , or a couple of pounds of LPG theoretically , probably a few times that in reality .
Cheers
John
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gidge348
Senior Member
Joined: September 2010
Posts: 426
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Post by gidge348 on Jan 22, 2015 22:58:40 GMT -5
Hi John, Just wonder if you or any one else out there might have an answer to a "Reverse Engineering" problem that has been on my mind for years? I saw this clip some time ago www.youtube.com/watch?v=CDDI5h8JQE0&x-yt-ts=1421914688&x-yt-cl=84503534 and I thought this would be fun. I notice that when the kart takes off there is a small vent of steam before the main start, so I assume it is using the internal steam pressure to operate a main valve?  I found this picture of the business end but still can't work out how it works? The doo-hickey in the bottom left is a www.mro-supply.net/servlet/the-3691/FESTO-DSR-dsh-10-dsh-180-dsh-P-ROTARY-ACTUATOR/Detail with a key lock attached that uses a gas to turn a shaft through up to 90 degrees? So I assume the venting steam would probably be operating this that is turning another valve..... BUT..this valve is not near the nozzle?  I thought it must have some type of valve but nothing is visible from the back and other pics of the front don't show a "pull rod" through the tank. I guess it could be some type of rupture disc but that seems a bit dodgy if it needed to be shot down during the run, I am sure there must be a valve there bit I can't work it out? Cheers Ian... |
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Post by racket on Jan 23, 2015 0:34:58 GMT -5
Hi Ian
Mmmm, thats a tricky one , I've got a feeling theres "stuff" inside that large bolted on disc/flange at the end of the pressure vessel , its really "too big" just to connect a nozzle onto .........but I really have no idea :-(
Cheers
John
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gidge348
Senior Member
Joined: September 2010
Posts: 426
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Post by gidge348 on Jul 18, 2015 5:06:48 GMT -5
Just found some more pics of the valves on the steam rocket, still can't work out how they work.  Steam seems to vent from the small fitting on the edge, but not sure how decreasing the pressure in the rear (piston??) would cause it to pull the plunger unless maybe it is spring loaded??? Then how would you seal it while it was building up pressure??? Ian... |
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gidge348
Senior Member
Joined: September 2010
Posts: 426
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Post by gidge348 on Sept 17, 2016 6:32:17 GMT -5
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Post by racket on Sept 17, 2016 17:17:31 GMT -5
Hi Ian
Nice :-)
Cheers
John
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