Enthalpy balance check

Julie

Hi,

I have two similar cases. One with gaseous fuel combustion, and the other one is with liquid fuel combustion. The calculations are steady-state. The fuel (n-heptane) mass values are equal for the both cases. The mass of air is about 30 % lower in the case with the gaseous fuel.

Checking the enthalpy balances in fluids in the .info file, I've found out that for the gaseous fuel the HDIFF is about 1.5 % of the entering enthalpy and for the liquid fuel the HDIFF value is about 6.9 %.

Now, the questions are:

1) What is an acceptable deviation range for HDIFF?

2) Why the difference between the two cases is so significant? (E.g., does the balance check account for the unburned fuel?)

Thanks in advance,

Julie