Dissociation of burnt gases

roadracer

Dear all,

I have successfully implemented a modified version of Weller combustion model that is able to handle non uniform air fuel ratio and takes into account for residual gas influence. Part of the model is implemented via sorsca and part via scalfn. Now I have implemented a dissociation model that follows the one from Olikara and Borman. This model calculates the equilibrium composition given the temperature and imposes the various concentration values via scalfn.f I have checked for molar fraction consistency of the model, but after some timesteps the scalar equations don´t converge and I always reach 20 corrector steps. I have tried to modify urf for T and scalars, time step size, reduction residual per corrector step etc, but all these parameters seem to have no influence. It is too strong the coupling between concentration and temperature to be handled in this way? Any hint to overcome this problem? Any help really apreciated. Regards Roadracer