Carbon residuals in hydrogen combustion
 

I am running a Fluent simulation of combustion of hydrogen for a turbine. I am using a K-omega SST model. For some reason, after running 500 iterations, 'co' residuals appear even though there shouldn't be any carbon present during hydrogen combustion. I have read in other posts that setting n2 as the bulk species can solve this issue, but in my case the issue persists. Does anyone havae any idea of what might be causing these residuals?

Residuals or mass fractions?

You should have residuals for all transported variables since you are solving transport equations for them


Try solving a problem with no flow, you also get residuals for continuity and momentum even with "zero" velocity