| OCR Text |
Show SIMULATION A computer simulation was conducted to predict the gas velocity distribution and particle trajectory in the combustor in order to increase slag capture rate. Fig. 4 shows a simulation of the particle trajectory, considering combustion, in the experimental slagging combustor, as well as in a Inrger slagging combustor, as predicted by a FLUENT model. In both combustors, coarse particles collide with the wall of the combustor immediately after injection from the burner by the centrifugal force of the ash particles imparted by the swirling flow. On the other hand, fine particles follow the recirculating flow at the combustor center, and are kept in the combustor for a relatively long period of time. The results of the simulation indicate that since it is important to prevent the escape of the fine particles from the combustor and to keep the temperrature of the combustor uniform in order to improve slag capture rate, it is therefore necessary to use a high ratio of primary to secondary air flowrate. Particle Size 50 Ilm 8 ~500 __ ¢ 2000 · 1---1 Q) c ~ Particle Size 2 Ilm ~ ~ I _ I I Q) c o N c o .~ ~ ""S u L- ·u Q) a:: 1 ~ I ~I Test Furnace (~500xlll001lln) Scale Up Furnace ( ¢ 2000 x l4400 mm) Test Furnace ( ~500xlll 001lln) Scale Up Furnace ( ¢ 2000 x l4400 nwn) F ig.4 Predicted particle trajectory in slagg ing combustor ( Tg =1600°C, Non-combustion) -5- |
