Tutorials Manual

Chemkin 4.1.1
Chapter 2: Combustion in Gas-phase Processes
2.6.2.3 Project Results
The solution plots of a reactor network are difficult to interpret because the reactor
number does not necessarily correspond to its actual location in the flow field. In our
case, reactor C1_R6 actually represents the outer edge of the fuel jet and should be
physically located right next to the fuel jet nozzle in an upstream region. On the other
hand, reactors C1_R5 and C1_R7 are the flame zone and the post-flame region,
respectively, and are both located downstream from reactor C1_R6. Therefore, when
we look at the solution plots as a function of the reactor number, we should ignore the
sudden changes corresponding to reactor C1_R6.
The predicted temperature distribution is shown in Figure 2-39. The adiabatic flame
temperature of the stoichiometric CH 4 -air mixture is also given on the plot for
reference. We can see that reactors C1_R3, C1_R4, C1_R5, and C1_R7 have
temperatures close to the adiabatic flame temperature, which is a good indication for
the flame zone and post-flame region. The reactor temperature dropping when
coming from reactor C1_R5 to reactor C1_R7 is appropriate, since C1_R7 is in the
post-flame region. We can further confirm this speculation by checking the solutions
of other variables. We also think the jet flame is slightly lifted from the fuel jet nozzle
because the outer edge of the fuel jet (reactor C1_R6) stays at a relatively low
temperature.
Figure 2-39
Jet Flame Network—Temperature Distribution
Figure 2-40 gives the CO mole fraction distribution among the reactors. Again, the CO
mole fraction at the adiabatic flame condition is provided to show where the
combustion zone ends. The CO profile shows a spike starting from reactor C1_R3 to
reactor C1_R7. We ignore reactor #6 because it does not connect either to reactor
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