About the fluid velocity in the governing equation
Hi, everyone,
I'm currently studying the governing equations underlying TOUGHREACT, particularly in the context of the ECO2N module. The entire solution process is as follows：
（1）For the fluid flow field, the mass conservation equations established for CO2 and H2O（brine）, we first can obtain the pressure field distribution and velocity distribution for both CO2 and H2O.
（2）Subsequently, these obtained velocities can be substituted into the reactive solute transport equations to calculate the distribution of aqueous species and the corresponding chemical reactions. Now, I would like to know which velocity we use to calculate the solute transport equation？And maybe we use the total fluid pressure to calculate the equivalent velocity ？
I hope someone can tell me and explain the detail of the abovementioned governing eqution, thank you all ！
1 reply

（1）The results of pressure and velocity from flow simulation are phase pressure and velocity. They are for aqueous phase (water+small amount salt and CO2) and gas phase (CO2+ small amount water) respectively.
(2) In toughreact, transport equations are solved for both phases. For the aqueous phase transport, the aqueous phase velocity will be used. For the gas phase, the gas phase velocity will be used.