Combustion Phenomena of High Temperature Air Combustion - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 115

1373

1323

1273

1223

1173

1123

1073

973

873

573

13 12 10 8 5 3

Oxygen contents of air, %

FIGURE 2.78 Photographs of the spray flame in the high temperature preheated and diluted
air with the oxygen content in air ( T g = 300 to 1100˚C).

the color is, the lower the temperature. Based on this fact, it is easy to observe the
difference in temperature within the flame and the state of the flame in the violet
color that is peculiar to combustion in the high temperature, preheated, diluted air.

2.4.1.3.2 Flame Form and Flame Color
The flame turned to form clearly a lifted flame at a distance from the nozzle, and a
red flame generated on top of a violet flame. An orange flame was generated at first,
and then a violet flame was generated from the bottom portion. As the temperature
went down, the violet flame gradually expanded to the top, and the flame turned all
violet, then blew out. The states of the flame at 1050, 1000, and 950˚C, when the
oxygen content was 8%, are observed in Figure 2.79 . Further, it has been made clear
that, under the conditions where the in-furnace temperature was more than 1000˚C