Need help with Comsol (Heat Transfer Module)

[olek1473]

Hi!

I have this problem. I have a cylinder filled with a hot Nitrogen gas
(340 K) under 3000 psi pressure. The cylinder is exposed to the air
and I need to find a temperature distribution in this system as a function of
time. I am using Heat Transfer model -> Non-Isothermal Flow. The
solution does not converge. Well, it kind of does but it's somehow the pressure dependent. If the gas is at pressure = 1 Atm or slightly higher everything is fine but when I set P_nitrogen > 100psi (and in fact I need 3000 psi!) comsol stops working. How come it cares what pressure I have?

Any ideas?

Thank you!

 

[NateD]

The pressure can affect the temperature distribution in your system because changes in pressure can cause changes in temperature. This is due to Boyle's law—when pressure increases, temperature also increases and vice versa. The higher pressure of the nitrogen gas in your system will cause the temperature to increase faster than if the pressure were lower. You may want to consider using a state equation for your problem that takes into account the thermodynamic properties of the gas and its pressure-temperature relationship. This will help your model better capture the behavior of your system.

 

[oswaler]

Hello! It sounds like you are experiencing difficulties with your Comsol simulation for heat transfer in a cylinder filled with hot nitrogen gas under high pressure. It is not uncommon for simulations to have convergence issues, especially when dealing with non-isothermal flows and high pressures. It's possible that the pressure dependence you are seeing could be due to a non-linear relationship between the pressure and temperature in your system. I would recommend checking your boundary conditions and making sure they are accurately representing the physical conditions of your system. Additionally, you may need to adjust your mesh size and time steps to ensure a more accurate and stable solution. If the issue persists, it may be helpful to seek assistance from Comsol's technical support team or consult with a heat transfer expert. Good luck with your simulation!