Re: [Starlink] some post Starship launch thoughts

[Eugene Chang <eugene.chang@alum.mit.edu>]

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I like the simplicity of just H2O or LN2.

Ok for steel plate, we need to think about
the plate exposed to the exhaust gas and how that will wear
The thickness of the plate and the thermoresistance of the plate
The water behind the plate
heat of phase transistion of water from liquid to gas
heat of absorbtion of the H2O as gas
moving the water through the cavity (behind the metal plate)
how fast can we move the water
how much heat absorbing mass needs to be moved
how to manage the escaping steam and the pressure of the steam
the machiney to force the water into the cavity and keep replacing the steam

And whether H2O or LN2,
where does it come from
what is the cost of preparing the liquid
what is the cost of the tanks holding the liquid
I assume either liquid is completely vaporized.

This solution is approaching visualizing the rocket’s engine blasting into the cooling system jet “exhaust” with neutralized gas coming out of the two opposing jets. In many sense, two equal and opposite forces. That is the implication of neutralization.


Gene
-----------------------------------
Eugene Chang
eugene.chang@alum.mit.edu
+1-781-799-0233 (in Honolulu)





> On Apr 26, 2023, at 11:10 AM, Dave Taht via Starlink <starlink@lists.bufferbloat.net> wrote:
> 
> On Wed, Apr 26, 2023 at 1:41 PM Rodney W. Grimes
> <starlink@gndrsh.dnsmgr.net <mailto:starlink@gndrsh.dnsmgr.net>> wrote:
>> 
>>> As always I enjoy the flood of information we get on this list!
>>> 
>>> still, so far, my research on a nitrogen deluge system (instead of
>>> water) has come up empty for me, except as a fire suppressant. So it?s
>>> either crazy or brilliant. Or both! I really liked the idea of
>>> something cooler that was a natural byproduct of the LOX process...
>> 
>> I dont think cooler does much, isnt it the "energy of vaporization"
>> that is actually doing all the "work" in this type of system?
>> 
>> H2O is 40.7 kJ/mol and LN2 is 5.6 kJ/mol so you would
>> need ~7 times as much LN2 to do the same work.
> 
> Now that! was the kind of numbers I was looking for!
> 
> Still, water has to come from somewhere, and be stored. I will keep
> thinking about it. I like that they seem to think that a water cooled
> steel plate will suffice.
> 
>> And the reason N2 is used as a fire suppressant is again not
>> because of temperature, but because it displaces the O2 and
>> suffocates the fire.  N2 is also easier on our ozone layer
>> than the prior used Halon.  Finally, this is usually
>> compressed N2 gas, not LN2.
>> 
>> --
>> Rod Grimes                                                 rgrimes@freebsd.org
> 
> 
> --
> AMA March 31: https://www.broadband.io/c/broadband-grant-events/dave-taht <https://www.broadband.io/c/broadband-grant-events/dave-taht>
> Dave Täht CEO, TekLibre, LLC
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