How the gas phase is calculated more accurately

Hi, developers. In my calculations, I found that when the case involved a complex geometric model, the gas flow rate between the inlet and outlet is not conserved. While the case of simple geometric model does not have this problem, how can I improve the accuracy of the calculation of the gas phase? Is it useful to raise the convergence criteria of the gas phase? Thank you!

You are encouraged to experiment with things like the convergence criteria.

If you want help with your case, please upload your project.