[AR] Re: Arocket Pump Progress
- From: Lars Osborne <lars.osborne@xxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Wed, 22 Jul 2015 22:38:26 -0700
Something we might get away with on a small engine they cant do on
larger ones is flame deposited ceramic coatings?
Those are certainly used on larger engines (in select locations)
Do anodize your aluminum. It is, after-all, a ultra-hard, well bonded
ceramic coating.
Thanks,
Lars Osborne
On Mon, Jul 20, 2015 at 8:40 AM, Monroe L. King Jr. <
monroe@xxxxxxxxxxxxxxxxxx> wrote:
Peter
Indeed all sounds good. I like 86% as a low number for peroxide.
Aluminum and stainless steel
I don't know yet what all the passages and piping pressure drops would
be. That part of the design will develop and I imagine it will change
the pump design somewhat.
Yes I like the closed design.
Wont start on the pump until I get back from Port O'Conner say the
first of August. Right now I'm tuning up my machines. I'm gonna install
a Vari-Drive bushing kit in the Bridgeport and put new belts on it. It's
just a bit noisy for my liking.
I like the XCOR style regen and I'm thinking stainless steel core with
aluminum casing. Perhaps nickel plated?
Something we might get away with on a small engine they cant do on
larger ones is flame deposited ceramic coatings? (same stuff they use on
racing engine piston tops and exhaust valves)
Just kicking around some thoughts.
Also it might be good to preheat the engine with a burst of peroxide
during the ignition sequence.
This is stuff that is getting way ahead of where we are at you know?
lol
-------- Original Message --------
Subject: [AR] Re: Arocket Pump Progress
From: Peter Fairbrother <zenadsl6186@xxxxxxxxx>
Date: Mon, July 20, 2015 3:53 am
To: arocket@xxxxxxxxxxxxx
On 20/07/15 01:00, Monroe L. King Jr. wrote:
I have not worried about it yet.
Peter- Can you run the numbers for the Barsky Peroxide Pump?
I was doing that, but I need to know what it is going to be made of
first. And the strength of the peroxide would help.
This is perhaps not simple - titanium would be perhaps favourite, but
peroxide and titanium don't mix well. I don't know whether that would be a
problem, a little decomp might not hurt anything as the peroxide is going
too be decomposed in a short time, but more than a little might cause the
temperature to rise too much. Corrosion of the pump might not be good
either.
Aluminium is another possibility, but unless it is pure (when it may
well be too weak), again they don't mix that well. Also, the oxide coating
may wear/flake off.
Does anyone have experience in materials for peroxide pumps?
Are you going to use a BLACK NIGHT / BLACK ARROW closed cycle type of
engine, where the peroxide is pumped up, then decomposed, then the
decomposed peroxide runs the turbine, the gaseous exhaust goes into the
chamber, where the fuel is added? If not the most elegant of rockets, BK
did get to spaaaaace after all.
Design and manufacture is fairly easy by comparison to most rockets
today, the Brits didn't have much money then, and it's 1960's technology at
the cheap-n'-cheerful end.
86% peroxide, Isp (vac) in the 280-ish range, not too shabby. You won't
get close to that with an open cycle peroxide/kero engine.
The best arrangement for this is probably a turbine on the bottom
feeding directly into the chamber, no ducts with bends, with the catpack
above it with the shaft running through it, then the peroxide pump above
that, then the fuel pump on top. You will need to regen cool the chamber
with peroxide, which sounds a bit hairy, but that's what BK did.
btw, it's Barske, not Barsky, after U M Barske, the inventor.
If you haven't started yet, here are some revised numbers for the fuel
pump, should give better efficiency and NPSH:
Mass Flow = 0.89 lb/s
DP = 870 psi
N = 50 kRPM
density 0.771
Impeller:
Diameter 38mm
6 blades.
Blade height 5.2mm at theoretical center, 3.4mm at edge
Center blade-free hole 12 mm diameter
Blade width 2.2mm
Output hole should in theory be 2.8mm diameter - but try 3.0 - 3.2mm
actual. A rectangular hole is good too, about 3.2 tall and 2.2 wide.
Impeller back plane: cutting away as much of the back plane as
practical, and/or drilling holes in it, will reduce end thrust and improve
efficiency a little.
Casing:
41.5 mm interior diameter, concentric
Volute:
Output taper 1 in 10 diameter, ie 1 in 3.16 area, at least 35 mm long.
Edges where taper meets casing interior should be sharp-ish.
-- Peter Fairbrother
Question, what are you going to make the peroxide pump out of?
ta,
-- Peter Fairbrother
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