Hi Johannes,
I understand that you'd like to adjust the values of the pressure, temperature, and mass flow rate in a single line independently based on input signals, but when you change the mass flow rate, the changes in pressure and temperature are unexpected.
Which version of Matlab are you using? Without being able to verify the values in your model, I can't say for certain what the issue is, but I have a few questions and suggestions:
0) How different is the response from what you're expecting?
1) Is the behavior replicated when substituting a pump block, such as the Fixed-Displacement (TL) block?
2) Try adding a pipe block after the Controlled Mass Flow Rate (TL) block. This adds a dynamic component (another differential equation) that "softens" the model/solver response.
3) At the moment, your model is very stiff - check that you're using the most appropriate solver. See this page from our documentation more information: https://www.mathworks.com/help/physmod/simscape/ug/making-optimal-solver-choices-for-physical-simulation.html
HTH,
Sarah
