# Leak Rates of Different Gases

1. Aug 25, 2010

Hi Everyone,

I have a problem that I've been working on and I'm having a little trouble. Essentially I have a tank with a known leak rate at a given pressure and temperature. We are currently using hydrogen, but I need to know what the equivalent leak rate would be if we changed the gas to say nitrogen or oxygen. Assuming I have the known values of pressure, temperature, and flow rate, would it be possible to determine the leak rate that we would be detect if we input a different gas and pressurized to the same pressure as before?

2. Aug 25, 2010

### drMS

Hi
if you know that leak occurs at tank sealing, it should be sufficient to compare the viscosity of the hydrogen and of the gas you are supposed to utilize. The leak (dot_q) decrease proportionally to the viscosity (eta) as dot_q propto 1/eta.

M

3. Aug 30, 2010

### darkside00

Basically, for a gas, you need to understand compressible flow
Fundamental equation
PV=nRT or see http://en.wikipedia.org/wiki/Ideal_gas_law

n is basically your gas constant that is different for the type of gas you have.

4. Aug 31, 2010