Will "Hydraulic (Isothermal Liquid)" be replaced with "Isothermal Liquid"?

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I teach an introductory hydraulics class and for the past few years I have used the "Hydraulic (Isothermal Liquid)" for students to learn hydraulics and learn basic systems. I noticed that the 2020 version introduced "Isothermal Liquid" - will this eventually replace "Hydraulic (Isothermal Liquid)"? I ask because I have started to develop similar hydraulic models and the "Isothermal Liquid" package is less forgiving than "Hydraulic (Isothermal Liquid)". For example, I like to use constant displacement pump sources (as these sources are more realistic than constant pressure sources) and I can't seem to mitigate the errors associated with this block. For instance, I created the "Model an Isothermal Actuator" and it works as described... but when I replace the constant "Pressure Source" with a "Flow Rate Source" (set at constant volumetric displacement) errors are produced and I can't find a way to work around them. If MATLAB is going to phase our "Hydraulic (Isothermal Liquid)" I will need to find ways to work around these errors that appear when the model is replicated in the "Isothermal Liquid" environment.
(As an aside, having a pressure relief valve in the "Model an Isothermal Actuator" when there is a constant pressure defeats the purpose. You can remove the relief valve and it doesn't change the operation of the system.)
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Stuart Williams
Stuart Williams on 26 Jan 2021
Edited: Stuart Williams on 26 Jan 2021
Is MATLAB considering phasing out "Hydraulic (Isothermal Liquid)" elements?
For reference, I have attached the simulation of the "Model an Isothermal Actuator" with the "Flow Rate Source" incorporated instead of the "Pressure Source". I have tried a few things to have it run without success. I will update this post if I find my error.
Note: The pump flow is set at 0.00025 m^3/s which, if the DCV was completely open, would extend the cylinder in 4 seconds. That result doesn't happen either.

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Answers (1)

Steven Lord
Steven Lord on 26 Jan 2021
Take a look at the relevant entries in the Simscape Fluids Release Notes for more information about these two blocks.

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R2020b

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