W-type Radiant Tube Burner
Abstract：By comparative test on the surface temperature distribution of W-type radiant tube with different burner structure，the main factors having effect on tube temperature uniformity for coaxially parallel jet burner are analyzed．The results show that the temperature of forepart tuber elevates while the temperature of posterior tube decreases with increase of gas speed；at the same time，the temperature of forepart tuber decreases while the temperature of posterior tube changes very little with increase of gas speed．When the proportion of second air increases，the tuber temperature decreases；however, the proportion of second gas has little effect on it．
Based on the principle of indirect heating radiant tube heating technology effectively avoids the heated surface oxidation and decarburization. Under protective atmosphere which creates the condition for the combustion gases and the product will not cause pollution to affect product quality, especially suitable for high quality requirements. The earliest radiant tube furnace invented and used was in Germany in the 1930s. The structure was single straight tube horizontally or vertically through the furnace. Until the early 1950s U-type radiant tubes came out, and on this basis, W-type radiant tube, casing tube type I, as well as exhaust gas recirculation of P and O type, etc. were developed. W-type radiant tube relative to other types of radiant tube has advantages of large burner space, large heat transfer area and high thermal efficiency. But at the same time W-type radiant tube burner also has difficult development problems because of the length of the tube, many factors influencing the length of the flame tube and the poor temperature uniformity along the length direction of W-type radiant tube.
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