I am doing a combustion simulation with fluent. When post processing with fluent, I found the mole fraction of combustion product did not start from 0 from combustor inlet to outlet. It was a little bit above 0 instead.
I am wondering is it because the showed value is not from inlet boundary. Instead it's from the first cell center adjacent to inlet boundary. This is why combustion product mole fraction does not start from 0.
ps: I selected node values when post processing. My case is steady case.