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Heat generation at the walls
Question: Without heat generation at the walls, the temperature remains constant throughout the reactor. By adding heat generation, will the final ammonia concentration be higher, lower, or no effect?
The heat generation will increase the temperature in the reactor, but not significantly, as shown below.
The contour plots look very
similar for all conditions; only the maximum temperature changes.
| Rate of heat generation | 0 | 0.1227 | 1.227 | 12.27 |
| Maximum temperature | 673 | 673.07 | 673.7 | 679.97 |
Graph 4.31 Graph 4.32 Graph 4.33
NOTE: There is no contour plot for heat generation=0 because the temperature is constant throughout the reactor.
Because the
temperature in the reactor is not significantly affected by the
heat generation, the minimum ammonia concentration is not
significantly affected either, as shown in the contour plots
below (heat generation rate increases from left to right).
| Rate of heat generation | 0 | 0.1227 | 1.227 | 12.27 |
| Minimum ammonia concentration | 0.24312 | 0.2459 | 0.23881 | 0.25836 |
Graph 4.34 Graph 4.35 Graph 4.36 Graph 4.37
To confirm that the slight increase in temperature to 679.97, for the highest heat generation rate, does not significantly affect the final ammonia concentration, the model was re-run with no heat generation but an inlet temperature of T=680. The ammonia concentration plot, shown below, indicates that the minimum ammonia concentration is 0.25527, which is similar to the value obtained for the heat generation=12.27 run.