A Force generate by compressed nitrogen at different volume

[yudhi_chen]

Dear All,

I have a question regarding compressed gas. I'm doing some experiment for testing some seal (see hatch area on sketch below) at 10,000PSI by using nitrogen gas. in this experiment, i accidentally got some different result based on two different situation. you can see my experiment sketch in this https://drive.google.com/file/d/0ByzWTPTJnMGzTDlwbE1Ea0ItRzQ/view?usp=sharing.

case 1:
I apply nitrogen at confined space with volume 1 (V₁) to reach 10,000PSI at room temperature. the seal was able to sustain 10,000PSI without leakage.
case 2:
I apply nitrogen at confined space with volume 2 (V₂) which I'm sure larger than V₁ to reach 10,000PSI at room temperature. It took longer time to build up pressure than case 1 (longer time leads to more consumption of nitrogen gas occupied at confined space) and the seal was only capable to sustain up to 8,000PSI before it leak.

from this two experiment, one thing that I'm sure, even at the same pressure, the seal shall be exposed to higher load at case 2 with bigger volume. Any body can help me to explain why and what is load comparison [in force unit, e.g. lbf] that exposed to the seal?

I try to get some sense from ideal gas law PV = mRT. in this particular case, i can cancel out pressure (P), R, and temperature (T) since this experiment was done at room temperature ambient and same pressure 10,000PSI, which leaves volume (V) and mass (m).

then i compare case 1 and case 2: V₁/m₁ = V₂/m₂.
if V₁ = 1cu.ft, V₂ = 10cu.ft then m₂ shall be 10 times of m₁.

from this idea, I'm thinking that the load that exposed to the seal in case 2 shall be 10 times higher than case 1. Can somebody help me to cross check my understanding or correct me on how do i get load comparison between these 2 cases?

Regards,

Yudhi

 

[mfb]

Pressures and volumes like this can kill you, and based on your post you do not have the required knowledge to operate with them safely. Let an expert do this, please. We won't offer help with dangerous activities here.