On building a better catalyst pack

Hope I don't get rejected again.

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

Hi!

Earl Colby Pottinger writes:
Any suggestions on changes?

You get two 180 degree bends in the flow, how much do that
add to the flow resistance?

Mad ideas:

Would it be possible to heat the peroxide withouth decomposing it?
First use it to cool the nozzle and then feed it pre-heated to the
catalyst pack.

Would it be possible to introduce a small flow of liquid catalyst
before the main catalyst pack to raise the temperature?

Would it be possible to use an injector before the catalyst pack to
suck decomposed peroxide from after the catalyst pack and mix it with
the flow before the catalyst pack?

Would it be possible to have some kind of pre-burner in the peroxide
flow?

What happens if a small ammount of fuel is mixed with the peroxide
before the catalyst pack?


Best regards,
--
Titta gärna på http://www.lysator.liu.se/~redin och kommentera min
politiska sida.
Magnus Redin, Klockaregården 6, 586 44 LINKöPING, SWEDEN
Phone: Sweden (0)70 5160046

Magnus Redin :

Hi!

Earl Colby Pottinger writes:
Any suggestions on changes?

You get two 180 degree bends in the flow, how much do that
add to the flow resistance?

I know know that is why I am building a proto-type tonight.

Mad ideas:

Would it be possible to heat the peroxide withouth decomposing it?
First use it to cool the nozzle and then feed it pre-heated to the
catalyst pack.

I have working on a cheap (sheet metal) design for the last cople of months,
so far I have not go a design that I like. However, yes cooling the engine
walls first help a lot in warmin up the peroxide before it hits the catalyst.

Would it be possible to introduce a small flow of liquid catalyst
before the main catalyst pack to raise the temperature?

While others have done it all my experiments with liquid catalysts have been
a big mess. I would like to avoid that is possible. But I will think about
again after building the test pack.

Would it be possible to use an injector before the catalyst pack to
suck decomposed peroxide from after the catalyst pack and mix it with
the flow before the catalyst pack?

This sound very hard to do, how would you do it?

Would it be possible to have some kind of pre-burner in the peroxide
flow?

This steps the problem of cold peroxide one step back but it is still the
same problem. You don't want to add more fuels and/or oxiders than needed.

What happens if a small ammount of fuel is mixed with the peroxide
before the catalyst pack?

That is exactly what they do at Armidillo and it seems to be working. You
should go to

http://www.armadilloaerospace.com/n.x/Armadillo/Home and read the last couple
of reports.

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

Earl Colby Pottinger wrote in message ...
Magnus Redin :

Hi!

Earl Colby Pottinger writes:
Any suggestions on changes?

You get two 180 degree bends in the flow, how much do that
add to the flow resistance?

I know know that is why I am building a proto-type tonight.

Mad ideas:

Would it be possible to heat the peroxide withouth decomposing it?
First use it to cool the nozzle and then feed it pre-heated to the
catalyst pack.

I have working on a cheap (sheet metal) design for the last cople of months,
so far I have not go a design that I like. However, yes cooling the engine
walls first help a lot in warmin up the peroxide before it hits the catalyst.

Would it be possible to introduce a small flow of liquid catalyst
before the main catalyst pack to raise the temperature?

While others have done it all my experiments with liquid catalysts have been
a big mess. I would like to avoid that is possible. But I will think about
again after building the test pack.

Would it be possible to use an injector before the catalyst pack to
suck decomposed peroxide from after the catalyst pack and mix it with
the flow before the catalyst pack?

This sound very hard to do, how would you do it?

Would it be possible to have some kind of pre-burner in the peroxide
flow?

This steps the problem of cold peroxide one step back but it is still the
same problem. You don't want to add more fuels and/or oxiders than needed.

I wonder if anyone has played with running electric current through
the catalyst pack, just before passing peroxide through it, to heat
the catalyst, increase the initial reaction which would then provide
enough heat to keep the catalyst at peak performance?

Bill Bogen wrote:
Earl Colby Pottinger wrote in message ...
Magnus Redin :

Hi!

Earl Colby Pottinger writes:
Any suggestions on changes?

You get two 180 degree bends in the flow, how much do that
add to the flow resistance?

I know know that is why I am building a proto-type tonight.

Mad ideas:

Would it be possible to heat the peroxide withouth decomposing it?
First use it to cool the nozzle and then feed it pre-heated to the
catalyst pack.

I have working on a cheap (sheet metal) design for the last cople of months,
so far I have not go a design that I like. However, yes cooling the engine
walls first help a lot in warmin up the peroxide before it hits the catalyst.

Would it be possible to introduce a small flow of liquid catalyst
before the main catalyst pack to raise the temperature?

While others have done it all my experiments with liquid catalysts have been
a big mess. I would like to avoid that is possible. But I will think about
again after building the test pack.

Would it be possible to use an injector before the catalyst pack to
suck decomposed peroxide from after the catalyst pack and mix it with
the flow before the catalyst pack?

This sound very hard to do, how would you do it?

Would it be possible to have some kind of pre-burner in the peroxide
flow?

This steps the problem of cold peroxide one step back but it is still the
same problem. You don't want to add more fuels and/or oxiders than needed.

I wonder if anyone has played with running electric current through
the catalyst pack, just before passing peroxide through it, to heat
the catalyst, increase the initial reaction which would then provide
enough heat to keep the catalyst at peak performance?

I wondered about a "drip-feed", which meters peroxide in at a millileter
or two a second.
Electricity is problematic, unless you'r on the pad.

Bill Bogen wrote:
Earl Colby Pottinger wrote in message ...

Magnus Redin :


Hi!

Earl Colby Pottinger writes:

Any suggestions on changes?

You get two 180 degree bends in the flow, how much do that
add to the flow resistance?

I know know that is why I am building a proto-type tonight.


Mad ideas:



Would it be possible to heat the peroxide withouth decomposing it?
First use it to cool the nozzle and then feed it pre-heated to the
catalyst pack.

I have working on a cheap (sheet metal) design for the last cople of months,
so far I have not go a design that I like. However, yes cooling the engine
walls first help a lot in warmin up the peroxide before it hits the catalyst.


Would it be possible to introduce a small flow of liquid catalyst
before the main catalyst pack to raise the temperature?

While others have done it all my experiments with liquid catalysts have been
a big mess. I would like to avoid that is possible. But I will think about
again after building the test pack.


Would it be possible to use an injector before the catalyst pack to
suck decomposed peroxide from after the catalyst pack and mix it with
the flow before the catalyst pack?

This sound very hard to do, how would you do it?


Would it be possible to have some kind of pre-burner in the peroxide
flow?

This steps the problem of cold peroxide one step back but it is still the
same problem. You don't want to add more fuels and/or oxiders than needed.


I wonder if anyone has played with running electric current through
the catalyst pack, just before passing peroxide through it, to heat
the catalyst, increase the initial reaction which would then provide
enough heat to keep the catalyst at peak performance?

You mean like a cat bed heater? These have been present on
virtually all catalyst decompsition engines built in the last 30 years.
Although, a short "pre-firing" followed by a off period to allow
soak-back works pretty well, and doesn't waste much propellant.

Maybe I missed the original post, but why is anyone messing with
these types of engines? They are only useful for small ACS thrusters,
and in these applications they have been refined to a high art. There
isn't a lot more to know.

Brett

(Bill Bogen) :

I wonder if anyone has played with running electric current through
the catalyst pack, just before passing peroxide through it, to heat
the catalyst, increase the initial reaction which would then provide
enough heat to keep the catalyst at peak performance?

For a flight weight craft the power source would be too heavy, but it seems
like a worth while idea for doing ground tests to find what temperature is
needed for good operation.

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