Henry's law when pressure changes fast

[mosafer1980]

Hello everybody,

I know that we can just apply Henry's law when there is a thermodynamic balance between for example air bubbles and liquid. Consider that we are having a liquid with some gas bubbles entrained in it. How can we apply Henry's law when we increase pressure rapidly. can we just say that in this case no air dissolves, because there is a rapid change in pressure and no time for the gas to go in solution. Any mathematical equations for it or any resource will be greatly appreciated.

Thank you,

 

[Achy47]

I would like to clarify that Henry's law is a thermodynamic relationship between the concentration of a gas in a liquid and the partial pressure of that gas above the liquid. It states that at a constant temperature, the amount of gas dissolved in a liquid is directly proportional to the partial pressure of that gas. Therefore, it is applicable in situations where there is a thermodynamic balance between air bubbles and liquid, as mentioned in the post.

However, when there is a rapid change in pressure, the conditions for Henry's law may no longer be met. In this case, the gas bubbles may not have enough time to dissolve into the liquid before the pressure changes. This can result in a deviation from Henry's law, and the amount of gas dissolved may not be directly proportional to the partial pressure.

To determine the effect of rapid pressure changes on gas dissolution, one can use the mass transfer coefficient (Kg) and the Henry's law constant (KH). The mass transfer coefficient represents the rate at which gas is transferred from the gas phase to the liquid phase, while the Henry's law constant represents the solubility of the gas in the liquid.

In situations where there is a rapid change in pressure, the mass transfer coefficient may increase due to the increased driving force for gas transfer. However, if the pressure change is too rapid, the mass transfer coefficient may not be able to keep up, and the gas may not dissolve into the liquid as expected.

In conclusion, while Henry's law can be applied in situations where there is a thermodynamic balance between air bubbles and liquid, it may not hold true in cases of rapid pressure changes. The use of mass transfer coefficients and Henry's law constants can help in understanding the effects of pressure changes on gas dissolution. I recommend consulting scientific literature on gas-liquid mass transfer for further information and mathematical equations.