EFFECTS OF SEVERAL PARAMETERS ON HEAT TRANSFER IN CIRCULATING FLUIDIZED BED BOILER

Analyses are carried out to study the effects of air velocity, particle circulating rate and fuel/air ratio on the profiles of temperature and heat flux in circulating fluidized bed boilers. The profile of particle concentration within the furnace is obtained by assuming the flow of gas and particles in the system as one-dimensional solid-gas two-phase flow and by considering that the particles are fed from the underside of the furnace with zero velocity, and are accelerated by the up-ward air flow. The radiative heat transfer in the two-phase flow system is solved by using the Monte Carlo method. In the heat-transfer analysis, the walls surrounding the system are considered as gray walls, and the two-dimensional heat transfer analysis is carried out in the one-dimensional two-phase flow field.