How does FluidFlow work with regards to the different ‘modules’ i.e., Liquid, Gas, Slurry and Two-Phase. Is it three different software tools or theoretically could you have a system in one file that

You can model any type of system from within one single software environment. All you need to do is build a single model of a system and you can then simulate this as Liquid, Gas, Two Phase, Non-Settling Slurry, Settling Slurry, Pulp & Paper etc depending on what Modules you have purchased. 

The available Modules are:

1. Liquid (Liquid Calculations).

2. Gas (Gas Calculations).

3. Two Phase (Liquid & Gas Calculations).

4. Non-Newtonian  & Slurry Calculation (Non-Settling Slurry, Settling Slurry & Pulp & Paper Calculations).

5. Scripting (Dynamic Analysis)

The software uses one single user interface for all Modules.