Simscape Fluids model of closed system

I am attempting to model a closed, pressurized system with an accumulator to set the static pressure and allow for expansion. I have not been successful configuring the system to be completely closed. I can solve it with reservoirs (see example).

Answer 1

[Yifeng Tang]

Hi Jeremy,

Looks to me like an initialization issue. I don't have R2020b on my computer so I tried this on R2021b, the oldest version I have.

Change that PS constant to a step + some filtering. You can do this as PS step + PS transfer function, or as Step + Simulink-PS Convert (with input filtering). I did the latter and it seems to give reasonable results.

Some other suggestions, but totally optional.

(1) I personally found that gas-charged accumulator a bit confusing to set up, especially the initial conditions. I prefer the Tank (G-TL)

(2) since you are using a torque source, it may make sense to attach an inertia to the shaft, just to avoid any chance of F=m*a while m=0.