Calculating Density of Gas from Combusted Solid w/ Known Wt, Pres, Vol

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SUMMARY

The discussion focuses on calculating the density of gas produced from the combustion of Bullseye powder in a firearm's barrel. The user provides specific parameters: a solid weight of 0.336954332 grams, a barrel volume of 0.39591921 in³, a pressure of approximately 29,000 psi, and a burn temperature of 2100 K. The user contemplates using the ideal gas law equation, ρ = MP/RT, to find density but questions its validity at high pressures, noting that the ideal gas law is not applicable at 2000 bars. The conversation emphasizes the need for alternative models to accurately assess gas density in this context.

PREREQUISITES
  • Understanding of the ideal gas law (ρ = MP/RT)
  • Knowledge of combustion chemistry and gas behavior
  • Familiarity with firearms and reloading processes
  • Basic principles of thermodynamics, particularly at high pressures
NEXT STEPS
  • Research real gas models applicable at high pressures, such as the Van der Waals equation
  • Explore the effects of temperature and pressure on gas density in combustion scenarios
  • Investigate the relationship between recoil dynamics and gas density in firearms
  • Study advanced thermodynamic principles relevant to gas behavior in confined spaces
USEFUL FOR

Firearms enthusiasts, ballistic engineers, and anyone involved in reloading who seeks to understand gas dynamics and density calculations in high-pressure environments.

tjhj
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Hello,
Thank you all for the help here.

Here we go, I have a known solid weight start of the propellent. I know the PSI of a known volume chamber(After combustion) and Temperature, can I find density?

So example
Bullseye powder has a load of 0.336954332 grams (5.2 grains)
The volume of the barrel is 0.39591921 in3
The pressure at this point is approx. 29,000 psi
Burn temperature = 2100k

I am thinking because the known mass of the air in the chamber, plus the mass of the powder can be used for the total mass in the density of the ideal gas equation. [itex]\rho[/itex] = MP/RT

Is this assumption correct? Will there be a substantial difference if I did not use the ideal gas law? I don't have the slightest clue what model would be appropriate to figure this as a "real" gas. Any suggestions?

This might make more sense in what it relates to. This is related to firearms and reloading. I am trying to figure out the density of the gas in the barrel just before it leave the chamber. This is part of a larger problem having to do with recoil and compensation, but this simple part I just can not seem to make connect.
 
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tjhj said:
Hello,
Thank you all for the help here.

Here we go, I have a known solid weight start of the propellent. I know the PSI of a known volume chamber(After combustion) and Temperature, can I find density?

So example
Bullseye powder has a load of 0.336954332 grams (5.2 grains)
The volume of the barrel is 0.39591921 in3
The pressure at this point is approx. 29,000 psi
Burn temperature = 2100k

I am thinking because the known mass of the air in the chamber, plus the mass of the powder can be used for the total mass in the density of the ideal gas equation. [itex]\rho[/itex] = MP/RT

Is this assumption correct? Will there be a substantial difference if I did not use the ideal gas law? I don't have the slightest clue what model would be appropriate to figure this as a "real" gas. Any suggestions?

This might make more sense in what it relates to. This is related to firearms and reloading. I am trying to figure out the density of the gas in the barrel just before it leave the chamber. This is part of a larger problem having to do with recoil and compensation, but this simple part I just can not seem to make connect.
Using the ideal gas law is not valid at 2000 bars.
 

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