We found the you "can" blow out a flame if things
are not just right and your not using a flame
holder which in our biprop tests was just
platinum coated spark plug. In all our runs we
never once had a detonation of any type even with .5 second delays.
Robert
At 05:33 PM 8/12/2016, you wrote:
Ok so you were using a evaporation for concentrating it, note taken.
I believe I've come across some work by Henry Spencer with regards to impulse density and a couple of other things. You say 14 ms is not good enough but our own tests with the 500N engine seems to say the contrary. Research from Purdue's zucrow lab seems to point towards the same conclusions. Could why henry had thought so back in time? Thanks!
IB
----------
From: johndom@xxxxxxxxx
To: arocket@xxxxxxxxxxxxx
Subject: [AR] FW: Re: "Direct" Hydrogen Peroxide engines
Date: Fri, 12 Aug 2016 23:12:55 +0200
From: <mailto:arocket-bounce@xxxxxxxxxxxxx>arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of ignacio belieres
Sent: vrijdag 12 augustus 2016 21:39
To: <mailto:arocket@xxxxxxxxxxxxx>arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
In those detonations you described, what temperatures did the peroxide reach? = the decomposition temperature of the mix predicted by the initial feed temperature, composition and pressure mentioned in literature.
_I hope you ran into those famous H. Walters Nazi decomposition graphs, still valid but rare. If you had a butane burner heating the peroxide then it was to be expected, especially if it was under atmospheric conditions. , The inhibitor type and purity matters; Mercks (not so cheap) pro analisi 30 % with pimelic acid inhibitor allows deep enrichment beyond 90 % with atmospheric evaporation. 50 % quality (to clean pig stables) is not OK for this procedure and detonates beyond 85 %.
Could you give me some sources on the claim that hypergolic engines lead to chamber fragmentation? Try Google. Or ask Henry S. who has encyclopedic literature know-how far beyond mine.
According to >10 years ago Henry S. regarded 14 s delay time too long for HTP/catalyst doped alcohol fuels. However, John Ruseks engine did work with such delays check with Google. We are of course using the latter types of mixtures you described. I described? which ones? there are hundreds of such compositions.
jd
From: <mailto:johndom@xxxxxxxxx>johndom@xxxxxxxxx
To: <mailto:arocket@xxxxxxxxxxxxx>arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
Date: Fri, 12 Aug 2016 15:53:42 +0200
From: <mailto:arocket-bounce@xxxxxxxxxxxxx>arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of ignacio belieres
Sent: vrijdag 12 augustus 2016 10:43
To: <mailto:arocket@xxxxxxxxxxxxx>arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
Yeah I would guess this comes up ever so often, but I searched the archives and could only find so little. Because too many emails were lost because of reorganisations. The amount of literature on H2O2 with Google and USPTO is vast but rarely useful.
H2O2 can detonate for sure, but only in vapor compositions yes at temperatures over 100 celsius AND in an enclosed environment. H2O2 is surreptitious, stabilizer types, metal contact, temperature, pressure ! It can detonate in an open tube like hell. I survived detonations of 6 L 85 % H2O2 in an open glass Erlenmeyer (open air evaporation field tests from a save distance) on a butane burner. Went whoosh without a bang but temp sensors had melted and glass stoppers went orbital. My other test was open air boiling at home with only 10 mL 90 %: that ended in a shocking bang like a shotgun and a big stink. Wall scrubbing job ensued I would assume the environment inside even a pre catalyzed biprop engine is harsher, but I havent heard of an explosion ever happening like that, so it would seem unlikely for it to do so under liquid-liquid injection. British Stentor HTP motors had their cat pack exhaust inside the chamber. Simplest and I dont think they ever exploded. Never read as to why.
We considered using a catalyst bed as many other successful programmes have, but they tend to take a while to learn run well and are somewhat expensive. Our experience with permanganate left a lot to be wished for too so the only option is silver catalysts, which are tricky to use with >90% h2o2.
I mentioned hypergolic ignition because that is what we are aiming for. The idea is to start the engine with a slug of a fuel that ignites with peroxide and then switch to kerosene for better isp density. What do you think? It is often mentioned (like on AR) hypergols are more prone to chamber fragmentation. A sufficiently short ignition delay matters there. We tested an engine running on our hypergolic mixture, a small one with only 500 N of thrust but its objective wasnt raw thrust either. Do you mean ww2 hydrazine/Cu2+ or a dissolved cat salt of the early 2000?
jd
From: <mailto:johndom@xxxxxxxxx>johndom@xxxxxxxxx
To: <mailto:arocket@xxxxxxxxxxxxx>arocket@xxxxxxxxxxxxx
Subject: [AR] Re: "Direct" Hydrogen Peroxide engines
Date: Fri, 12 Aug 2016 09:40:29 +0200
This thread comes up every 5 years or so on arocket, so was often discussed.
Mixtures of gaseous or liquid H2O2 > 80 wt. % have the nasty habit to detonate when heated and ignited. Add a fuel and the detonation is worse of course.
To have it deflagrate as a propellant you need to pre-decompose the H2O2, monopropellant wise, in a controlled manner with a catalyst bed in order to set free its oxygen as a gas, next spray a fuel in this hot gas. Then it becomes a bipropellant. Ignition is not necessary as the H2O2 decomposition gasses are typically hot enough to cause, say, kerosene ignition. Google Black Arrow launcher. Also the once operational AR2-3 peroxide bipropellant engine used a catalyst bed: <http://hydrogen-peroxide.us/uses-biprop-combustion/OSC-Peroxide-Propulsion-at-Turn-of-Century.pdf>http://hydrogen-peroxide.us/uses-biprop-combustion/OSC-Peroxide-Propulsion-at-Turn-of-Century.pdf.
There are ways to pre-decompose H2O2 thermally which has been done successfully. But so far it proved complicated compared to the simplicity of a catalyst bed and never made it for launching anything. As far as I know.
jd
From: <mailto:arocket-bounce@xxxxxxxxxxxxx>arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx] On Behalf Of ignacio belieres
Sent: vrijdag 12 augustus 2016 8:34
To: <mailto:arocket@xxxxxxxxxxxxx>arocket@xxxxxxxxxxxxx
Subject: [AR] "Direct" Hydrogen Peroxide engines
Hello everyone,
I have been lurking this list for quite a now, but not until recently had I read the discussions on peroxide propulsion. Leaving the supply problems aside, some have expressed doubts about being able to run a hydrogen peroxide-hydrocarbon rocket engine in a direct mode without a catalyst bed.
Why is that? Could any of you name some projects where it was attempted and found to be impossible or too difficult? I know a lot of you have direct experience with this so I was hoping some of you might help me clear some doubts. Perhaps a high characteristic length coupled with hypergolic ignition could work for this application, or not.
Well, I can't wait to see what many of you have to say.
Cheers,
IB
