Tuesday, July 28, 2009

Observations from the fireing

As shown in the camera death video we ran the H2O2 Kerosene motor last weekend. The chamber pressure port failed causing local loss of coolant and subsequent failure.

Even with the short run it answered several questions I've had about H2O2 Kerosene motors.

The Motor was built around 3 1"x  7" metal monolith platinum coated catalysts.

This gives it a large contraction ratio 7" to 1.9" . It was also designed with an L* of 60.

Test conditions:
~200 PSI chamber pressure.
~ 6:1 O:F by weight
90% H2O2


Observations:

From the previous mono-prop runs its clear the cat pack is not working very well The metal monolith seems like it needs finer channels.

Even with a partially working cat pack ignition was almost instant. Reading the available literature ignition seems to be a strong function of  contraction ratio.

One of my personal questions was can you run an H2O2 motor like a traditional bi-prop where the peroxide is thermally decomposed in the chamber?  With a generous L* of 60 and contraction ratio of  almost 4 at a chamber pressure of 200 psi the answer is no.  There was clearly undecomposed peroxide in the plume.

7 comments:

noel.wade said...

Paul - I'm curious about your summary: Do you think the "no" is due to the contraction ratio or the L* of 60? Or the fact that you weren't getting good decomp? Or after a practical test do you just think that this may be a dead-end? (I hope not)

Thanks, always love to see your work - even though its sometimes painful to watch!

Stevo Harrington said...

Since your cat pack has passages that are too big, does it make sense to use a swirl nozzle to create a fine peroxide mist upstream of the catalyst?

Can you use your broken engine to do a cold flow vis? Replace the wall with acrylic tubing and flow dye in the kerosene injection nozzles, flow water through the peroxide passages, get the right momentum ratio, and look for mixing.
Can you use a more volatile fuel, like gasoline or ether?

Steve

David said...

Often you can learn more from the failures than the successes. I am very interested in your future plans for the level 2 since this situation must mean its unlikely in the next three months epically with the second level 2 prise to capture.

I would think a new engine using a CSJ design with copper chamber. This could also use your other cat-pack design. This would be relatively easy to build. Provide more safety factor and could be converted to Lox/Al if the peroxide becomes to difficult for the higher performance required.

Just an idea though I am sure you are/have consider all options.

Paul Breed said...

Can't use copper with Peroxide.
Were uilding a Stainless version fowhat we just roke with our other cat pack design.

Paul Breed said...

Lets try that again, in English...

We can't use copper with peroxide.

Were building a Stainless version of what we just broke designed for our screen based cat pack.

David said...

Thanks Paul. The stainless makes sense. I was thinking maybe copper would react with the peroxide after I posted.

Given your using stainless for the other engine and Armadillo is using stainless there is a road well travelled.

You machining or thing of a spun chamber. Anyway, looking forward to the progress.

jacob.chancery said...

Yeah, the AR2-3 rocket had all the peroxide flow going through a catalyst pack injector. It looks like the LR40 and the Gamma rocket engines did too. I wonder if the Beal engine was fully catalyzed peroxide flow?

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20000033615_2000043589.pdf