Interesting. So if I'm understanding this correctly, you're talking
about something like an oxygen-rich preburner to make sure the oxidizer
is thoroughly vaporized as being useful for large hybrids.
Makes sense of what VG might be having methane onboard SS2 for. I'd
been wondering about that.
It sounds like the sort of thing one would come up with after already
committing to large hybrids, then hitting the (apparently fairly
typical) uneven combustion, to make them actually work. If you assume
from the start you'll need some sort of preburner with a separate fuel
system, I'd think large hybrids would lose their lower-parts-count edge
over biprops in the tradeoffs.
On 8/4/2015 11:37 AM, Bill Claybaugh wrote:
Mark:
It seems like an AN & ice water mix could be tailored to your temperature
goals. But why not go to a dry ice cooler and maximum density: a single pass on a
couple of coils should get you what you are seeking. LN2 is also obviously an
answer; both can be had in Mojave.
As Anthony has hinted, you will need a heat source at the head end to assure
the N2O fog is vaporized, otherwise combustion will be rough and unstable. At
Amroc we injected TEA throughout the burn to vaporize the Lox; I gather VG is
using Methane in the SS2 nylon motor.
Bill
Sent from my Commodore 64
On Aug 3, 2015, at 9:33 PM, Mark C Spiegl <mark.spiegl@xxxxxxxxx> wrote:
Wow... Im out of the office for a day and my inbox is full! :-)
Anyway.. Anyone who has followed my hybrid projects knows Im a fan of high
density Nitrous. Im looking to cool 20-50 lbs of Nitrous to 25-ish degF.
Goals:
(1) Flashing liquid to vapor to chill Nitrous is fine in a motor burning 10-20
lbs of Nitrous. Much above 20lbs (esp in the desert), flashing liquid to gas
becomes impractical. I would like to start a little closer to my target
temperature of 22 degF. The Peltier, Stirling Cooler, or whatever would chill
the supply tank, not the rocket tank.
I know ice is a quick-and-dirty answer, but I would like something a little
more elegant and deterministic. Bags of ice aren't a great answer at FAR or
Blackrock.
(2) I have had trouble igniting high density Nitrous in warm weather. Cold
weather is no problem. I cannot prove what is happening, but I suspect
temperature gradients in the long thin Nitrous tank are causing the problem. If
the Nitrous is 22 degF at the top of the tank, it may be much much colder at
the injector. Supplying Nitrous close to the final temperature should help
mitigate this problem, if Im correct.
A related question: Any simple ways to equalize temperature between the top
and bottom of the rocket's oxidizer tank???
--MCS
(Im an EE kind of person so my solutions tend to feel like electronics... ie
Peltiers)