Combustion Phenomena of High Temperature Air Combustion - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 65

1600

1400

1200

1000

800

600

extinction (T a )
dropback (T f )

400

200

0

0 1000 2000 3000 4000 5000 6000

2V/R 1/s

FIGURE 2.39 Extinction and drop back temperatures (hysteresis).

Figure 2.40 shows the relationship between NO x concentration and flame tem-
perature T f at extinction when the flame strain rate is changed while the preheating
temperature is kept constant. As the strain rate increases, the extinction flame tem-
perature falls and its gradient becomes steeper. The lower the flame temperature

1700

24

1600

20

1500

1400

16

NOx (Ta=873K)
NOx (Ta=1073K)
T f (Ta=873K)
T f (Ta=1073K)

1300

12

1200

2000 4000 6000

2V/R , 1/s

FIGURE 2.40 Dependence of flame temperature T f and NO x concentration on the strain rate
2 V / R .