# Flux and Flow rate conversion

1. Jul 28, 2010

### AlexN07

Hi,

I am performing a helium leak experiment in which the detector outputs a number in mbar.L/s which is the amount of helium permeating through a specimen at a given pressure per unit of time.

I am interested in obtaining a permeability coefficient (K) for this specimen for the given pressure with helium as the working fluid.

My equation is: -K = J . delta x / delta P (rearrange Fick's 1st Law)

I know delta x (thickness) and delta P (pressure), however I am having trouble converting the mbar.L/s (leak rate) to a flux J (which I believe is in (mol /m^2 . s) for the equation.