Learning Forum

[majam]

Hi all,

 

I have a question about pressure distribution in a multiphase(gas-liquid) mixing tank. 

- first I wanted to mention that the pressure distribution is completely different when I use degassing BC for the liquid surface vs. when I use a Pressure outlet. can you tell me why? Presser outlet seems to be more realistic. 
-second, I think this has sth to do with the pressure reference location. Should I change that to a point at the surface of the liquid (0, tank height, 0) ? since in the manual it says it should be at the point where gauge pressure is 0.
-third, the pressure distribution is important for me since it affects the oxygen mass transfer by influencing the saturation concentration of oxygen (Henry's law). Is the total pressure of the liquid the gauge pressure? 

 

Thanks

[Rob]

Degassing only lets gas out (hence the name) so you can get a slightly odd pressure field. It's an old boundary condition and is there to avoid the need to model the free surface. 

Check the manual re operating pressure, reference pressure location and pressure boundaries.