Abstract
A simulation method on characteristics of spray combustion for a Pitch-Water (PWM) and Coal-Water mixture (CWM) has been developed which was composed of the following seven frames; 1. the modified k-ε two equation model was used to estimate the flow pattern of recirculating zone in the swirling flow. 2. a trajectory of fuel droplets was calculated in the Lagrange method. 3. the interaction between fuel droplets and gas flows was considered by PSI cell model. 4. the combustion rate of PWM and CWM was determined by experiments for a single droplet combustion. 5. the combustion rate in gas phase was estimated by a eddy-dissipation combustion model. 6. NOx and Soot formation rates were computed by the previous models, respectively. 7. radiant heat transfer rate was obtained by the flux method.
Production rates of NOx and Soot in the two-stage combustion of PWM, the relation between a swirling number and unburned ratio and between atomization characteristics and unburned ratio of CWM were simulated in three different furnaces, respectively. Their computed results were successfully fitted with experimental ones. The simulation method was thus useful to predict the influence of various operating conditions on the combustion performance.
