Design Guidelines for High Performance Industrial Furnaces - High Temperature Air Combustion: From Energy Conservation to Pollution Reduction - page 256

6.0
4.0
2.0
0.0
-2.0
-4.0
-6.0

0 %
43
63
73
83
90

0 0.5 1.0 1.5 2.0 2.5 3.0

Distance, m

FIGURE 5.14 Deviation of heat flux.

D-Burner C-Burner

B-Burner A-Burner A-Burner

300

1300

300 No. 4 No. 3 No. 2 No. 1

100

420 440 620 480

F-Burner E-Burner

Locations of insertion ion probes (No.1 to 4)
Locations of measuring steel temperatures
for comparison

FIGURE 5.15 The lower part of heating furnace structure for model testing and the locations
of inserted ion probes and of measurement steel temperature for comparison (units = mm).

measuring the ion current near the water-cooled skids, it was found that the improve-
ment of the steel temperature uniformity was mainly attributable to the increase of
the flame volume caused by HiTAC ( Figure 5.20 ) .
For the purpose of heating the material uniformly, it is possible to spread the
flames with the high temperature air to the entire area inside the furnace with HiTAC,
but at the same time it will increase the risk of releasing unburned components
outside the furnace. Perfect combustion inside the furnace is necessary for the
method to be applied to furnaces for industrial operation. The following experimental
studies were made to improve the uniformity of steel temperature satisfying this
condition: one study on the effect of the uniform heating of steel if the flames are
burned in the shorter direction of a furnace to change the locations where the flames
are formed; another on the effect of the heat transfer to the parts of steel near the
skids if a method is adopted that feeds fuel and air in such a way as to dilute them
near burners by the furnace gas, but under the condition of burning in the longer
direction of the furnace; and, last, on the effect of the heat transfer if the furnace
gas near the skids is agitated by some external force.