Numerical calculation of heat transfer distribution in a 600MWe supercritical circulating fluidized bed boiler

Abstract

The water wall heat transfer and heat flux distribution in a 600MWe supercritical CFB boiler with water-cooled panel in the furnace was numerically studied. The water wall was made of smooth tube membrane. The solid suspension density ρ, heat flux q and heat transfer coefficient K distribution in the furnace were predicted at rated boiler load (100%BMCR), 75% of turbine heat acceptance load (75% THA) and 50% THA. The results show that for a large-scale CFB boiler, the convection is the main part of heat transfer in the lower furnace, and radiation is the main in the upper lower. The ρ, q and K have the similar axial and radial distributions. Their radial distributions depend on the position of the water wall and boiler load, and show a peak value in the corner. The ρis a sensitive to K. With increasing of the height in furnace, ρdecreases, thereby the q and K decrease. The radial distributions of q and K are similar at different height. The study shows that the three-dimensional model is valid to predict the heat transfer in the furnace of the 600MWe supercritical CFB boiler.