Research on the Pneumatic Spreader Stoker : 3rd Report, on the Ignition of Carbon Globule in Uniform Stream of Air

Abstract

Recently spreader stokers are used in many plants, and in the furnaces of these plants a part of the fuel burns in the state of suspension. In this paper, the ignition phenomena of the fuel located in the stream of the air are treated theoretically. On account of simplification of this problem, it was assumed that the gas flowing around the fuel was pure air and fuel was of carbon globules. The conditions for numerical calculations are as follows ; temperature of air stream=600∼1000°C velocity of air stream=0∼20 m/s radius of carbon globule=1∼15 mm termal-conductivity of carbon globule=0.22∼20 kcal/mh°C. From the results of these investigations, it has been concluded that (1) with the increment of the ignition temperature of carbon globule, the effect of temperature and velocity of air stream on the ignition time becomes remarkable, (2) the effect of thermal-conductivity of carbon globule on the ignition time is little.