! Yes! Thank You for your advice! However I knew that the solution is not converged because of a species (the solutions of other variables are already converged), is there any way which I can improve the solution of that species to be converged? I ran the calculation by giving 5000 iterations and 10000 iterations, and compared the results of velocity, temperature, and a species of a certain location, the results showed that the velocity is not changed at all, but the temperature and a species changed 1.6% . Please note that both 5000 iterations and 10000 iterations are not converged, but according to the residual line, all the solutions seems not to change anymore, in this case, are the solutions acceptable even the solutions are not converged? If it is not acceptable, please guide me another way! You can see my residual plot in the figure! Thank You in advance!nn