How can I measure Gas Density in a Simulink model?

I'm modelling a gas network in Simulink using some Simscape components. I'm measuring the mass flow, temperature and pressure at different nodes in the network. As the pressure and temperature vary inside the network, I know that the density may vary too. 

I'd like to know how I can measure the density of the gas at a particular node in the gas network (rather than an assumed constant). 

 

Answer 1

[MathWorks Support Team]

• As you are already measuring the pressure and temperature at specific nodes in the network, you could calculate the density using the relationship provided by Boyle's law for ideal gases. The relationship is described by the expression - Density = Pressure/(Temperature*Gas constant). The gas constant value can be the same as that specified in the 'Gas Properties' block in the model.
• Alternatively, in MATLAB R2017, a new block called 'Thermodynamic Properties Sensor (G)' has been introduced that allows you to determine the gas density. You could therefore consider upgrading to MATLAB R2017a to use that block.