How to mix gases with different properties in Simulink ?

Hello everyone,

I work on a project where I have to use three different gases for mix them :

I use simulink for obtain the density of the gas mixed but I have this error message :

"Error compiling Simscape network for model labo.

Caused by: ['labo/Gas Properties (G)1', 'labo/Gas Properties (G)']: Failed to propagate domain parameters. Domain parameters are propagated to the same set of nodes from sources: 'Subsystem10.Gas_Properties_G1.A' and 'Subsystem10.Gas_Properties_G.A'. Each node may only have at most one source of propagation."

So, how can I mix different gases if I can't define a physical constant for each of them ?

As a reminder, I don't know gas properties for the mixed gas.

Thanks for your help

[soroush rastegarpour]

I have the same issue... Did you find any solution?

[Guillaume]

soroush rastegarpour, I'm still working on it

the only way I have found is calculate gas properties for the gas mixed and made this set up :

I really would like to not calculate gas properties for gas mixed but I have no choice

[soroush rastegarpour]

Thank you for your quick response.

As far as I know, the properties of the mixture depends on the concentration of each component in the mixture fluid. From this perspective, how do you manage the propoerties of the mixture if you change the contribution of one of the inlet components?

[Guillaume]

Precisely cause I know the composition of my gas

[Guillaume]

but except this simulation, the knowledge of this properties is useless for me and I lose so many precision by calculing gas properties

Answer 1

[Pramil]

Hey Guillaume,

Connecting three gases won’t mix them, rather it is perceived by Simscape as specifying the domain parameters more than once, as suggested by the error you received.

To obtain a mixture of gases in Simscape, you can use the “Moist Air Properties” block instead this block specifies data for “dry air”, “water vapor”, and “carbon dioxide”. However, you can replace them with your own gas properties so you will essentially have a mixture of up to three gases.

Here is the link to the documentation of “Moist Air properties” block for your reference:

https://www.mathworks.com/help/simscape/ref/moistairpropertiesma.html

Answer 2

[Alexander Szambor]

Too late, but you could use a Constant Volume Chamber to mix the gases. With 4 Connections where you use 3 as inputs and one as output.