I have done a permeability experiment on LDPE in the presence of air using a 25mm circular specimen. At 30'C, the permeability was found to be 1.846 barrer.
Now I am trying to apply this permeability value to a calculation whereby I am trying to find what the change in pressure of a dunnage bag is (it is a bag that has the shape of a pillow) after 5 minutes. I have the following info of the dunnage bag:
- Volume of bag = 0.2064 m3 (This was calculated using the Paper Bag Problem)
- Approximate area = 1.35 m2 (this is just a quick approximate)
- Thickness of LDPE = 0.042 x 10-3 m
- Time = 5 x 60 s = 300 s
Is it correct if I convert barrer to SI units in the following manner:
1 barrer = 7.5005 x 10-18 m2s-1Pa-1
By using the following formula, I was hoping to calculate the change in pressure. However, my values don't make sense at all!
$$\text{Permeability} = \dfrac{\text{Volume}\cdot\text{thickness}}{\text{Area}\cdot\text{time}\cdot\text{Change in Pressure}}$$
