Vitiated Coflow Operation Range
A series of experiments were conducted to map out the operation range of this burner. The coflow was set at a mass flow rate of 40 g/s of air that has a cold bulk velocity of 1 m/s. The flame temperature and stoichiometry were measured for each case and the results are plotted in Figure 1 for the hydrogen-air mixture and in Figure 2 for the methane-air mixture. On both plots, the results are compared with those of an adiabatic reaction. As can be seen from the plots, there is a certain amount of heat loss that can be attributed to the heat transfer with the perforated plate and the water-cooled collar by the recirculation at these surfaces. Before getting to the blow off point, the hydrogen mixture had a stoichiometry of 0.17 and a temperature of 560 K compared to a stoichiometry of 0.53 and temperature of 1120 K for methane. The upper limit was constrained by the amount of heat produced by these flames that can generate on the order of several hundred kW of thermal power.
The data shows that a wide range of hydrogen-air turbulent premixed flames can be stabilized on the perforated plate burner. Accordingly, this combustor has the capacity for the exploration of a large range of Damköhler numbers.
Figure 1.
Temperature vs. fuel to air ratio for hydrogen-air coflow.
Figure 2.
Temperature vs. fuel to air ratio for methane-air coflow.
