To illustrate the use of solubility constraints, we can reconsider Cell Pathway Example #3, which simulated a volatile chemical diffusing across an air-w3ater interface. The only change we will make is to add a solubility constraint (of 0.5 mg/l) for the chemical in water. This particular example file, Cell7_DiffusionSolubility.gsm, can be found in the Contaminant Transport Examples folder in your GoldSim directory (accessed by selecting File | Open Example... from the main menu).
The output of this simulation, in the form of time histories of the concentrations of the organic in both Cells, is shown below:
This chart also show the amount of precipitated mass in the Cell.
Note that the concentration in the Water is initially held constant at the solubility limit, implying that the saturation capacity of the cell is exceeded. During this time period, the concentration in the air increases linearly, since the concentration difference is essentially constant (0.5 mg/l minus a very small number). Also during this time, the amount of precipitated mass decreases linearly. After about a half of a day, the water cell is no longer saturated (since sufficient mass has diffused out of the "Water_Side" Cell), the concentration falls below the solubility limit, and the amount of precipitated mass goes to zero.