What code or program can solve the equilibrium point temperature and composition accurately?CHEMKIN 4's EQUILIBRIUM MODLE is not accurate enough. Its temperature change rate obtained by using its API function is always very large -5000 at adiabatic temperature and constant pressure, its effective digits are only 5. I want to find a code can resolve the adiabatic flame temperature and composition accurately. So the production rate of species at this temperature is very close to 0, say 1.E-30.

Do you mean accurately for real fuels or accurately mathematically given a model for a fuel? Can you program?

For many years chemkin code was widely shared and most established combustion groups have derivatives for internal use. Since the commercialization these copies are no longer distributed on the internet but if you work with an established combustion group this code will be around. Since the commercialisation various "research type" alternatives have appeared. If you read German you can download one such here:

http://www.stanford.edu/group/pitsch/CES.htm

but there are others.

If you are only after equilibrium conditions the classical code is the Gordon and McBride NASA "ROCKET" program. Again, this is a widely shared code which most established combustion groups will possess. I think you might be able to download it from here (but have not tried myself):

http://www.grc.nasa.gov/WWW/CEAWeb/

Sad to see Bonnie McBride has passed away.

Thank you for you help, I know some codes such as CEC71(Now the CEA)and STANJAN deals with kind of problem. But the format of the input file was really a problem. It is a tedious process to learn. The ILDM method calculates from a equilibrium point, to ensure the point is on the manifold, all derivatives with repect to time should be very close or equal to 0, because it will influence the accuracy of the subsequent solution point, the more accurate the starting point, the more accurate the subsequent.