Initial conditions solve failed to converge thermal simscape

I have set up a constant volume gas chamber to model the flow and I'm studying the variation of pressure and temperature within the chamber. I keep getting the following error.

An error occurred while running the simulation and the simulation was terminated Caused by: ['Charged_Cylinder/Solver Configuration']: Initial conditions solve failed to converge. all components and nodal across variables involved Cannot solve for one or more variables, including dynamic variable derivatives: Time derivative of 'Constant_Volume_Chamber_G.p_I' (Pressure of gas volume) 'Constant_Volume_Chamber_G.A.T' (Temperature) 'Constant_Volume_Chamber_G.Phi_A' (Energy flow rate into port A) 'Constant_Volume_Chamber_G.Q_H' (Heat flow rate into port H) 'Constant_Volume_Chamber_G.mdot_A' (Mass flow rate into port A) 'Constant_Volume_Chamber_G.rho_in_A' 'Controlled_Reservoir_G.A.T' (Temperature) 'Controlled_Reservoir_G.Phi_A' (Energy flow rate into port A) 'Controlled_Reservoir_G.mdot_A' (Mass flow rate into port A) 'Controlled_Reservoir_G.rho_in_A' 'Gas_Properties_G.A.T' (Temperature) 'Pressure_Temperature_Sensor_G.A.T' (Temperature) 'Pressure_Temperature_Sensor_G.T' (T)

Problems possible for transient initialization, as well as stepsize control for transient solve, due to equations of one or more components: all components involved 'Charged_Cylinder/Constant Volume Chamber (G)' Equation locations are: 'C:\Program Files\MATLAB\R2017a\toolbox\physmod\simscape\library\m\+foundation\+gas\+elements\constant_volume_chamber.ssc' (line 149) 'C:\Program Files\MATLAB\R2017a\toolbox\physmod\simscape\library\m\+foundation\+gas\+elements\constant_volume_chamber.ssc' (line 72)

'Charged_Cylinder/Controlled Reservoir (G)' Equation locations are: 'C:\Program Files\MATLAB\R2017a\toolbox\physmod\simscape\library\m\+foundation\+gas\+elements\controlled_reservoir.ssc' (line 43) 'C:\Program Files\MATLAB\R2017a\toolbox\physmod\simscape\library\m\+foundation\+gas\+elements\controlled_reservoir.ssc' (line 69)

I think the error is in the thermal reference used for the constant volume chamber. Can someone please confirm this and provide a solution for this problem? Thanks in advance.

[Arvind Narayanan]

Hi,

Can you please share the model that you are observing this error in? This will help us understand the issue you are facing. Also, are you using any PS Constant blocks in your model?

It is possible that there may be an algebraic loop in the Simscape network which can make the model more numerically sensitive and you should try to avoid it.

Thanks, Arvind

Answer 1

[Yasasvi Harish Kumar]

Hi. I was able to fix this problem by using thermal mass in place of thermal reference. I am not too sure why thermal reference was causing a problem. Thanks anyways.