Space Tech reject: A better catalyst Pack

Hello,
After reading John Carmack's results with getting the heating of his
catalyst packs sorted out I tried playing with some ideas with regenative
heating of the peroxide and catalyst to improve the decomposition rate.

As I have already ordered the materials needed make a test model, I thought
that I would just post my ideas here to see if anyone can spot a major fault
or has a better idea of a layout design to use before I start.

First, a basic H2O2 rocket design usually looks like this:

# = Support or filler material.
W = Wall material of rocket engine.
S = Screening to spread out the peroxide.
C = Catalyst packing.
| = Copper foil to conduct heat.

H2O2
IN
WWWWWWWWWW WWWWWWWWWW
W W
WSSSSSSSSSSSSSSSSSSSSW
WSSSSSSSSSSSSSSSSSSSSW
W W
WCCCCCCCCCCCCCCCCCCCCW -- Stays cool because of flow
WCCCCCCCCCCCCCCCCCCCCW cool peroxide entering pack.
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW
WCCCCCCCCCCCCCCCCCCCCW -- Gets very hot down here from
WW WW decomposed peroxide.
WW WW
WW WW
WW WW
WW WW
W W
W W
W W
W W
W W
W W
W W
W W

The basic problem with the above design is that the peroxide enters the top
of the catalyst pack cold. The cooler the catalyst/peroxide is the slower
the reaction that decomposes the peroxide. In the worse cases not all the
peroxide is converted before it leaves the bottom of the pack so you get a
poorer ISP and you have to clean up any of the peroxide spilled (or atleast
dilute with water). Additionally in the best case where all the peroxide is
converted because it is cold as it enters the pack and the H2O+O2 gasses are
very hot when they exit the packing, you will end up with a major thermal
stress across the catalyst pack and the walls of the engine. Which is not
good if you wish for repeated firings of the rocket.

H2O2
IN
WWWWWWWWWW WWWWWWWWWW
W W
WSSSSSSSSSSSSSSSSSSSSW
WSSSSSSSSSSSSSSSSSSSSW
W W
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WCC|CC|CC|CC|CC|CC|CCW
WW WW
WW WW
WW WW
WW WW
WW WW
W W
W W
W W
W W
W W
W W
W W
W W

Here is John's basic and simple solution to the thermal stress problem. The
copper foil is placed between the catalyst packing is used to conduct heat
generated at the base of the engine to the top. Because more heat reaches
towards the top of the catalyst pack the reaction of the peroxide is enhanced
and more of the peroxide is consumed/converted. This allow for a better
running engine in John's tests. Please note: the top of the engine still
stays a lot cooler than the bottom and thus the best results are still not
reached without extra steps.

What is needed is to move as much of the heat generated from the later stages
of decomposing peroxide to the peroxide as it is feeding into the catalyst.
The warmer the peroxide as it enters the catalyst the better (higher
percentage) it will decompose. Below are some ideas I have had about heat
exchangers to improve the process.

First we start with two sheets of metal and a sheet of catalyst foil.

|||||||||||||||||||||||||||||||||||||||||||||||||| |||||||||||||||
IN CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC CCCCCCCCCCCCCCC OUT
|||||||||||||||||||||||||||||||||||||||||||||||||| |||||||||||||||

Then fold it so that the heat of the decomposing peroxide can heat incoming
liquid.

IN
| C | ||||||||||||
| C | | |
| C | | CCCCCCCC |
| C | | C C |
| C | | C |||| C |
| C | | C | | C |
| C | | C | | C |
| C | | C | | C |
| C | | C | | C |
| C | | C | | C |
| C | | C | | C |
| C |||| C | | C |
| C C | | C |
| CCCCCCCC | | C |
| | | C |
|||||||||||| | C |
OUT

Above is shown to it to make it easy to understand the folding, infact we
need the full contact to transfer heat so it really would be folded as we see
below.

IN
| C |||||||||||
| C || |
| C || CCCCCC |
| C || C C |
| C || C || C |
| C || C || C |
| C || C || C |
| C || C || C |
| C || C || C |
| C || C || C |
| C || C || C |
| C || C || C |
| C C || C |
| CCCCCC || C |
| || C |
||||||||||| C |
OUT

You will notice that there are some double walls that will interfer with the
conduction of the heat to the fuild so we start with a small change in the
original foil layup. We start with.

|||||||||||||||||||||||||||||||||||||||||||||||||| |||||
IN CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC CCCCCCCCCCCCCCC OUT
|||||||||||||||||||||||||||||||||||||||||||||||||| |||||

And when we fold it we get.

IN
| C |||||||||
| C | |
| C | CCCCC |
| C | C C |
| C | C | C |
| C | C | C |
| C | C | C |
| C | C | C |
| C | C | C |
| C | C | C |
| C | C | C |
| C | C | C |
| C C | C |
| CCCCC | C |
| | C |
||||||||| C |
OUT

Now we are getting somewhere, as the peroxide enters it starts to break and
release heat, because of the folding peroxide that has decomposed further
down the flow can now heat up earlier protions of the flow and thus increase
the reaction.

IN
|C|||||
|C|CCC|
|C|C|C|
|C|C|C|
|C|C|C|
|C|C|C|
|C|C|C|
|C|C|C|
|C|C|C|
|C|C|C|
|C|C|C|
|CCC|C|
|||||C|
OUT

Because of the word wrap limit of most terminals here is a more compact form
of the same packing. I need this format to show the next step.

Now if we make this foil in long enought strip at the same time it can be
wrapped around in a spiral to fit inside a round rocket chamber.

IN IN IN IN IN IN
|C||||||C||||||C|||||####|||||C||||||C||||||C|
|C|CCC||C|CCC||C|CCC|####|CCC|C||CCC|C||CCC|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|C|C|C||C|C|C||C|C|C|####|C|C|C||C|C|C||C|C|C|
|CCC|C||CCC|C||CCC|C|####|C|CCC||C|CCC||C|CCC|
|||||C||||||C||||||C|####|C||||||C||||||C|||||
OUT OUT OUT OUT OUT OUT

Is the result we get if we do this simple wrapping up of the pack. Below are
some other design ideas to avoid the double walls we still see that cause
this to be a heavy design.

IN IN IN IN
| ||||||||| ||||||||| ||||||||| |||||||||
| C | | C | | C | | C | |
| C | CCCCC | C | CCCCC | C | CCCCC | C | CCCCC |
| C | C C | C | C C | C | C C | C | C C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C | C | C | C | C | C | C | C | C | C | C | C |
| C C | C | C C | C | C C | C | C C | C |
| CCCCC | C | CCCCC | C | CCCCC | C | CCCCC | C |
| | C | | C | | C | | C |
||||||||| ||||||||| ||||||||| ||||||||| |
OUT OUT OUT OUT

This design requires more folding but you will notice it has no double walls
to interfer with heat transfer. While I don't see a way to spiral the pack
to fit into a round chamber one can easyly build it out to a large flat pack
and either use a square chamber or cut it to fit.

IN IN IN
||||||||| |||||||||||||| |||||||||||||| |||||||||
| | CC | | CC | | CC | |
| CCCCC | CC | CCCCCCCCCC | CC | CCCCCCCCCC | CC | CCCCC |
| C C | CC | C CC C | CC | C CC C | CC | C C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C | CC | C | CC | C | CC | C | CC | C | CC | C | C |
| C | C CC C | CC | C CC C | CC | C CC C | C |
| C | CCCCCCCCCC | CC | CCCCCCCCCC | CC | CCCCCCCCCC | C |
| C | | CC | | CC | | C |
| |||||||||||||| |||||||||||||| |||||||||||||| |
OUT OUT OUT OUT

If you look carefully at this you will notice that it is just two U channels
nested into each other. With some care two spiral channels could be built
that will fit together and in a round chamber, or the U channels could be
uilt as rings that fit into each other.


Below are some possible chamber designs.

H2O2 IN
WWWWWWWWWWW WWWWWWWWWWW
W W
WSSSSSSSSSSSSSSSSSSSSSSSW
WSSSSSSSSSSSSSSSSSSSSSSSW
W W
WC|||||C|||||C|||||C||||W
WC|CCC|C|CCC|C|CCC|C|CCCW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WC|C|C|C|C|C|C|C|C|C|C|CW
WCCC|C|CCC|C|CCC|C|CCC|CW
W||||C|||||C|||||C|||||CW
WW WW
WW WW
WW WW
WW WW
WW WW
W W
W W
W W
W W
W W
W W
W W
W W



H2O2
IN
WWWWWWWWWWW WWWWWWWWWWW
W W
WSSSSSSSSSSSSSSSSSSSSSSW
WSSSSSSSSSSSSSSSSSSSSSSW
W W
W|||||CC||||||||CC|||||W
W|CCC|CC|CCCCCC|CC|CCC|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|C|CC|C|CC|C|CC|C|C|W
W|C|CCCCCC|CC|CCCCCC|C|W
W|C||||||||CC||||||||C|W
WW WW
WW WW
WW WW
WW WW
WW WW
W W
W W
W W
W W
W W
W W
W W
W W


Any suggestions on changes?

Earl Colby Pottinger

--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp

Opps, due to odd messages from my ISP's server I thought the previous post
did not make it into sci.space.tech

It appears to have gone thru ok. Please post in the thread there as it is
partly off-topic in this newsgroup.

Earl Colby Pottinger


--
I make public email sent to me! Hydrogen Peroxide Rockets, OpenBeos,
SerialTransfer 3.0, RAMDISK, BoatBuilding, DIY TabletPC. What happened to
the time? http://webhome.idirect.com/~earlcp