[AR] Re: Peltier specifications

  • From: Andrew Burns <burns.andrew@xxxxxxxxx>
  • To: arocket@xxxxxxxxxxxxx
  • Date: Wed, 5 Aug 2015 06:54:58 +1200

Is there a reason while traditional like on like impinging injectors can't
be used to atomise and subsequently vaporise LOX or nitrous in a hybrid? Is
it something to do with getting the droplets to interact with the fuel
boundary layer?

Andrew

On Wed, Aug 5, 2015 at 6:37 AM, Bill Claybaugh <wclaybaugh2@xxxxxxxxxx>
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)






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