mass decomposition vs pressure increase

[flaviochaves]

Hi,
I have the following problem:
i have a closed tube that was heated at 3.3ºC/h, and it has a energetic material inside.
so i have obtained the temperature and the mass decomposition profiles for this energetic material.
but i'd like to obtain the pressure increase inside this tube.
Does anybody know some way to do this?
Is it possible to make a thermal-mechanical simulation of this?

 

[btrueblood]

Sounds like a chemistry homework problem.

 

[MintJulep]

How about a pressure gauge?

If you can't do that, how about a strain gauge. There is a direct correlation between hoop stress and internal pressure.

 

[flaviochaves]

Hi MintJulep (Mechanical,
Thanks for your email, but i'm trying to simulate this on abaqus.
as i have said, i have done a thermal simulation and i have temperature and mass decomposition profiles (as results). But i would like to make a thermal-stress displacement simulation, and i don't know how can i calculate the pressure increase inside the tube, and to put it on simulation.
Best regards,

 

[blonde]

wouldn't an approach be to:
1)Create a balanced reaction for the decomp of this compond including gaseous and non-gaseous products
2)Calculate mMole of each gaseous product in your reaction
3)use patial pressures to develop your pressures at each increment of time over the reaction.

I think you will still need to know your reaction rate to calculate step 3. Do you have all this? I may be missing something yet.

 

[flaviochaves]

Thanks Blonde for your useful post.
i used a fortran subroutine to simulate the reaction rate, and with this routine i have calculated the fraction of energetic material that have beeen decomposed (from 1 to 0) at each node.
to simulate the pressure increase i suppose that i have to calculate the volume of each element and mMole of each gaseous product and partial pressure . do you know how can i put this on abaqus or in the routine?