2-Phase Translational Mechanical Converter Without Mass Inlet

Dear Mathworks Community,

Does anyone know how to modify a 2-phase translational mechanical converter block in Simscape to eliminate the mass inlet port ? That is, can the block be modified to model a system that does not undergo mass transfer with the surroundings but can undergo heat transfer with the surroundings and whose volume, pressure, and temperature (and phase) are coupled with the displacement of piston ?

I ask because such system are quite common, for example, when a sealed flexible container containing a fluid is heated resulting in thermal expansion and vaporization and displacment of the 'piston' although no mass is exchanged with the environment , e.g. heating of a balloon, plastic pouch, or syringe

Thanks,

-Kirk

Answer 1

[Yash]

Hi @Kirk Roffi,

In the Translational Mechanical Converter (2P) block (https://www.mathworks.com/help/simscape/ref/translationalmechanicalconverter2p.html) port "A" represents the inlet through which fluid enters and exits the converter. To model a system that does not undergo mass transfer with the surroundings, set the input to port "A" as 0.

The mass conservation equation used by the block to calculate the internal pressure in the converter given the mass flow rate through the inlet is:

Refer to the documentation for the meaning of the terms here (https://www.mathworks.com/help/simscape/ref/translationalmechanicalconverter2p.html#:~:text=in%20the%20converter.-,Mass%20Balance,-The%20fluid%20mass). The system can be modeled by the above equation with .

I hope this helps!

[Kirk Roffi]

Hi Yash, thank you for that guidance, I did not realize the input can be zero! It works.