A radiation efficiency measurement procedure for gas-fired radiant burners

Radiant burners are used ill drying, preheating, curing, and baking processes in the manufacturing industry. High radiation efficiency is one of the most important performance criteria for these burners. A wide range of radiation efficiencies (varying by more than 200%) has been reported in the past for similar burners under similar operating conditions. The wide variation in reported radiation efficiencies appears to be due partly to the differences in the measurement techniques. If appropriate calibration source and procedures are used, the differences in data result from (1) nondiffuse emission from the burner and (2) nonuniform burner surface. The present article reports a technique for radiation efficiency measurements of diffuse and directional radiant burner surfaces. The technique is not sensitive to surface nonuniformities, which are common in commercial radiant burners. A calorimetric approach is used as a consistency check on the efficiency data obtained using the present technique. Companion measurements highlight the high degree of variability in the radiation efficiency results deduced from single-point radiation efficiency data, since they are based on the location of the sight tube with respect to the burner surface.