Using air as exhaust gas
I'm trying to use FLUENT to simulate exhaust flow, temperatures and pressure. I've found this (Flow Through an Exhaust Manifold | Ansys Innovation Courses) very helpful video and many more about the topic. However I've yet to see someone specify the exact properties of exhaust gasses. Everyone seems to make the assumption ''regular'' air is being put out by the engine.
Now my question is: Is the difference in flow, temperature and pressure between exhaust gasses and ''regular'' air so minimal, it's not worth configuring the exact values for exhaust gasses?
Looking at the accuracy I'm already working with, it might really not matter at all. I would already be making the assumption of stoichiometric combustion and the ideal gas law. Which ends up that exhaust gas would simply be: 72% N2, 14% CO2 and 14% H2O, leaving away all types of other gasses and particles. So my ''exhaust gas'' would be inaccurate by itself already.
I've also seen that mixtures can be implemented within ANSYS (Species Transport) but I have no experience with that what so ever. If it's the case that it would be a good idea to specify the exact data for exhaust gas it would help me out a lot if someone could send me a link towards some information on how to do that as well.