There is proper data from this black arrow/Gamma days. Local boiling can happen
on the micro scale in the regen boundary layer at temperatures >>150 degC. It’s
actually unavoidable in high heat flux engines where the hotside wall temp gets
to >400C. As long as the heatflux/velocity ratio of the coolant is high enough,
the boiling (decomposing, exothermic!) liquid/vapour mix in the boundary layer
mixes in with the rest of the coolant flow, recondensing and cooling and RUDs
are avoided. We found out the hard way a few times.
Stefan
From: arocket-bounce@xxxxxxxxxxxxx <arocket-bounce@xxxxxxxxxxxxx> On Behalf Of
Henry Vanderbilt
Sent: Wednesday, 21 October 2020 12:52 PM
To: arocket@xxxxxxxxxxxxx
Subject: [AR] Re: Hypothetical Lox cooling
I was already assuming Black Arrow avoided peroxide boiling in the cooling
passages. Sorry my question wasn't clear enough: Does anyone have any informed
comment on how absolutely necessary, or otherwise, that might be in using h2o2
as a coolant? As I said, my limited info on the lower stability of peroxide as
vapor is anecdotal.
Hmm. Per Wiki, "The boiling point of H2O2 has been extrapolated as being 150.2
°C (302.4 °F), approximately 50 °C (90 °F) higher than water. In practice,
hydrogen peroxide will undergo potentially explosive thermal decomposition if
heated to this temperature. It may be safely distilled at lower temperatures
under reduced pressure.[7]"
So, possibly there's a practical upper temperature limit even if you do
pressurize it to raise the boiling point.
Does anyone know? Thanks in advance...
Henry
On 10/20/2020 12:05 PM, roxanna Mason wrote:
Maybe boiling, at the feed pressure, was avoided. Possible.
K
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On Tue, Oct 20, 2020 at 11:32 AM Henry Vanderbilt
<hvanderbilt@xxxxxxxxxxxxxx<mailto:hvanderbilt@xxxxxxxxxxxxxx>> wrote:
Speaking of possibly exciting hobbies, what happens if you boil peroxide in
cooling passages? Is that another one of those things one should avoid?
I gather peroxide cooling worked in Black Arrow, but I have the impression from
various distillation tales of woe that peroxide vapor is much less stable than
the liquid. I might guess both that preheating the peroxide could help with
catalyzing or directly combusting it, and also that making sure it stays liquid
till then is indicated, but those are just guesses.
Henry
On 10/20/2020 11:09 AM, Doug Jones wrote:
A supercritical positive-heat-of-formation oxidizer with oily contaminants
leached from every step of the distribution chain. What could possibly go wrong?
On Tue, Oct 20, 2020 at 11:04 AM Bruno Berger
<bruno.berger@xxxxxx<mailto:bruno.berger@xxxxxx>> wrote:
Am 20.10.2020 um 19:53 schrieb roxanna Mason:
Is your fuel even less satisfactory?Yep, we discussed that at ARIS for cooling the nozzle with N2O for their
Perhaps it's a LOx/solid fuel hybrid and you want to cool your nozzle.