Development of a Fully Coupled Bed Combustion Simulation Method for Grate-Fired Furnaces Using Fluent UDF
In municipal solid waste (MSW) incineration simulation, the traditional FLIC-Fluent coupling method suffers from long iteration cycles across multiple operating conditions and significant errors due to data mapping at the coupling interface. This study developed a fully coupled bed combustion simulation program based on Fluent User-Defined Functions (UDF). By integrating four modules—dynamic regulation of particle emissivity, zonal motion control of the grate, bed drag shielding, and wall collision-induced fragmentation—the program achieved fully coupled calculation of solid waste particle movement, bed combustion, and furnace flow fields within a single Fluent platform, completely replacing the bed calculation functions of FLIC software. A 750 t/d reverse-inclined forward-feeding grate furnace in a Chinese waste-to-energy plant was selected for engineering validation. The model was calibrated using continuous operational data from 12 on-site measurement points. Results showed that the computational time per operating condition was reduced by 71.4% compared to the traditional FLIC-Fluent coupling method. The relative error between simulated furnace temperatures and on-site measurements was ≤4.10%, significantly outperforming the 9.68% maximum relative error of the traditional method. The proposed method provides a reliable engineering simulation solution for optimizing operating conditions and screening blending schemes in co-incineration of multi-source solid waste.