How to calculate pressure increase from expanding gas 3

[CamaroFan]

It has been over 20 years since I studied Thermo. I am trying to run safety calculations on a pressure vessel. The PV contains batteries than may generate gas under certain conditions. I know the size of the PV and the volume of gas generated by the batteries.

How do I determine the change in pressure inside of the PV? The phyical size of the chamber does not change so Boyle's Laws do not fit (P1V1=P2V2) because V1 = V2.

The problem sounds easy ie the volume of gas inside of the cylinder increases by say 100 cu in so what is the new pressure? What are the governing equations?

 

[MintJulep]

Don't forget n, those pesky moles.

You are creating gas that wasn't there before, the number of moles of gas is not constant.

P1V1/T1n1 = P2V2/T2n2

 

[rb1957]

presumably the volume of gas created is at STP conditions, then P1 = normal atmosphere pressure and V1 = tank volume + battery gas volume and V2 = tank volume, so
P2 = Psl*(Vt+Vg)/Vt

 

[CamaroFan]

Aerospace:
Can I assume you meant to type: P2 = P1*(Vt+Vg)/Vt

 

[rb1957]

yeah P1 = standard pressure = sea-level pressure = 1 atm