Aerodynamic Characteristics of a Stoker Furnace with Staged Combustion: Comparison of Cold Modeling Experiments and Numerical Simulations

A three-dimensional trial bed is established for a staged combustion boiler, and a modeling method based on similarity theory is proposed. The aerodynamic field of the 35 t/h layer combustion-composite combustion chamber-in the stoker boiler with staged combustion was evaluated. Further, a three-dimensional calculation model based on computational fluid dynamics (CFD) was used to simulate the aerodynamic field of the reformed boiler under normal operation, which facilitated convenience in the boiler design. Hot-wire anemometer and other instruments were used for the characteristic test of damper, a velocity field test in the furnace, wall wind test, temperature balance test at the outlet of the furnace, etc., and the law of motion for the flow field in the furnace was obtained. By analyzing the structure of staged combustion, the emission of nitrogen oxides and the combustion stability of a novel layer-fired boiler were studied. The calculated results are in excellent agreement with the experimental data. The results revealed that the combustion efficiency of the boiler and the reduction of nitrogen oxides were significantly improved by the staged combustion technology. There was no erosion on the water wall, and the flow velocity at the outlet of the furnace was uniform. This modeling method exhibits good adaptability to the combustion of stratified combustion boilers and is potentially useful for optimizing furnaces in a variety of applications.