steady-state calculation with WUFI2D

[Tommy So]

Hi,

I'm trying to calculate the water content of aerated concrete and compare the results with measurements from the lab.
For the 2D-simulation I have a 50 mm x 400 mm specimen. Both short sides as well as one longer side are sealed with metal foil, the other longer side is untreated.
The initial conditions for the material are 25 °C, 85% RH.
All the surfaces were treated as indoor surfaces with a heat transfer coefficient of 8 W/m2K and I assigned the same climate to every surface by changing the sine curves (25 °C, 65% RH, no amplitudes) into steady-state.
The untreated side dries out faster than the sealed side as expected. But it also looks like the material dries out faster on the short and sealed sides.
After changing the heat transfer coefficient from 8 to 0 W/m2K WUFIgraph (Isoline) is showing exactly what I was expecting with higher water amount on the sides and edges (sealed sides) but switched 180 degree.
If I look into one grid at the untreated surface it dries out but it gets a huge water content at the beginning which is not from the back. As I looked up a grid from the back side there is also increasing water content.

I hope someone gets my point and can help me on my issue!

[Christian Bludau]

Hello Tommy,
in laboratory tests there is a high influence of the transfer coefficient to the drying. The value of 8 W/m2K may not correct depending on the air movement in the climatic chamber. But 0 W/m2K is not possible.
Furthermore there should be no drying effect on the sealed sides.
What do you mean with the amount switched 180 degree?
I will send you a pm...
Christian