Difference betwwen (two) flow splitter and (two) fraction splitter?

Hello,
Could you please tell me the difference betwwen (two) flow splitter and (two) fraction splitter? Or where can I find the information?

Thank you,
Best regards,
João

Please have a look at the Models Guide under Models / Flow / Flow Splitters & Models / Flow / Fraction Splitters.

Basically the difference is that for the flow spitter one specifies the absolute value Q_Out2 of the 2nd outgoing flow (the 1st is then Q_In - Q_Out2). For the fraction splitter one specifies the relative fraction of the incoming flow f_Out2 that is to be associated with the second outgoing flow (Q_Out2 = f_Out2 * Q_In). Flow splitters do not affect the concentrations.

Flow splitters can be regarded as (ideal) [b]pumps[/b] whereas fraction splitters can be regarded as [b]valves[/b].
True pump models (for centrifugal pumps) are associated with the "pump" block.
An example of the use of a pump model was added to the latest release 2017.