John,
I did some related work during grad school that may be of use to you. I did
visualization experiments looking at the blowdown of N2O tanks using a
quartz tube as a pressure vessel. I mainly looked at pure N2O, but I also
studied the case where the N2O was "supercharged," meaning the tank was
initially pressurized with another gas (eg O2) above the vapor pressure of
the N2O.
I found that you can definitely achieve the "soda like frothing" that you
describe, but it depends strongly on how you add the O2 (which is probably
what you'd expect anyway). In short, if you add the O2 from the top of the
tank and do so shortly before you ignite the motor, you don't need to
worry. If you wait a while, or add the O2 from the bottom so it bubbles
through the liquid, or add N2O to a tank that already has O2 in it, you'll
get significant O2 dissolved into the liquid and if you encounter a
pressure drop the O2 begins to bubble out ("soda like frothing").
One caveat to my research - I used CO2 and N2 as simulants for N2O and O2
and there are likely some differences in this type of test. I did extensive
comparisons of N2O vs CO2, but did not evaluate the N2 vs O2 question.
My thesis is available here (you'll want section 4.4, pg 218):
https://purl.stanford.edu/ds271zh2987
A screenshot of one of the relevant figures is attached.
-Jonah
On Mon, May 23, 2016 at 3:12 PM, John Lyngdal <john.lyngdal@xxxxxxxxx>
wrote:
Wonderful. Just the type of information I was looking for.
John
On Mon, May 23, 2016 at 2:15 PM, Craig Strudwicke <cstrudwicke@xxxxxxxxx>
wrote:
http://arc.aiaa.org/doi/abs/10.2514/1.B34768
http://www.spg-corp.com/nytrox-propellants.html
On Tue, May 24, 2016 at 6:06 AM, John Lyngdal <john.lyngdal@xxxxxxxxx>
wrote:
Looking for something that is the reverse of this paper:
The solubility of Nitrous Oxide in Liquid Oxygen
http://pubs.rsc.org/en/content/articlelanding/1959/tf/tf9595500239#!divAbstract
I'm looking for a pressurizing gas for a blow down feed nitrous oxide
hybrid motor. I could use helium, but would like to explore the use of GOX
in this application.References on the topic discuss the Poynting effect,
but direct the discussion towards the effects when the mixed gasses are
used in anesthesia, not the discharge of the liquid phase. It's clear that
nitrous oxide will dissolve in the oxygen pressurizing gas and cause a drop
in the head pressure over time, I can deal with that. The more important
question is if GOX dissolves into liquid nitrous oxide which would cause
soda like frothing in the delivery lines due to a pressure drop in the
fluid during delivery.
Before charging off into a dead end, I thought I'd make an inquiry to
the group.
Thank you
John
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