Crawford Bomb (strand burner) calculations

[Oliver]

I am thinking of building a strand burner in order to characterize
propellants used in amateur rockets. For those unfamiliar with this device,
a strand burner (also called a Crawford Bomb), is a closed chamber in which
you burn a small amount of propellant to determine burn rate at various
chamber pressures.

I use a program called GuiPep (see http://www.lekstutis.com/Artie/PEP/) to
determine a lot of the thermodynamic properties of the propellant (see
attached), but I am not a chemist, so I don't know the meaning of a lot of
those numbers.

I would like to calculate the resulting chamber pressure when burning a
specific amount of propellant in such a closed system. I wondering, with
the information given by GuiPep, if this is possible?

Thanks

Oliver

[Marvin]

Post by Oliver
I am thinking of building a strand burner in order to characterize
propellants used in amateur rockets. For those unfamiliar with this device,
a strand burner (also called a Crawford Bomb), is a closed chamber in which
you burn a small amount of propellant to determine burn rate at various
chamber pressures.
I use a program called GuiPep (see http://www.lekstutis.com/Artie/PEP/) to
determine a lot of the thermodynamic properties of the propellant (see
attached), but I am not a chemist, so I don't know the meaning of a lot of
those numbers.
I would like to calculate the resulting chamber pressure when burning a
specific amount of propellant in such a closed system. I wondering, with
the information given by GuiPep, if this is possible?
Thanks
Oliver

GUIPewp is a graphics interface for Propep. According to
http://www.geocities.com/CapeCanaveral/Cockpit/1938/articles/Propep.PDF,
Propep calculates the following parameters: "Among other
things it calculates propellant density, chamber/exhaust
temperature,composition of the chamber/exhaust gases,
specific heat ratio, specific impulse (frozen
and shifting), characteristic impulse, and density impulse.
There is an option to calculate optimal nozzle expansion."
These are not chemical parameters, except for specific heat
(and specific heat ratio isn't). From chamber temperature
and chamber gas composition, you should be able to calculate
the pressure of the gas. Anyone who has taken Chemistry 101
should be able to show you how to do it, or you could get a
textbook and look for an equation like PV = NRT.

[Oliver]

Post by Marvin
GUIPewp is a graphics interface for Propep.

That is correct. I didn't want to bore the group with the details about the
ProPep vs. GUIPep.

Post by Marvin
These are not chemical parameters, except for specific heat (and specific
heat ratio isn't).

As I said, I am not a chemist.

Post by Marvin
From chamber temperature and chamber gas composition, you should be able
to calculate the pressure of the gas. Anyone who has taken Chemistry 101
should be able to show you how to do it

It has been a very long time since I have taken Chemistry 101 ;-). I didn't
think it was a very difficult question for someone with the right
background. That's why I posted this question here.

Oliver