Research On Resistance Characteristics And Structure Optimization Of Bell-type Hood In CFB Boiler

Circulating fluidized bed boilers have the advantages of wide adaptability to coal types and high combustion efficiency,so it have been widely used in China.The focus of the CFB boiler differs from other boilers is the fluidized combustion of the bed material.The primary wind passes through the hood above the air distribution plate to form a jet stream,making the bed material fluidized and ensuring sufficient gas-solid phase doping,which not only extending the residence time of the bed material in the furnace chamber,also enhances the heat transfer between the gas-solid two phases.The hood is the key to ensure uniform fluidization of the bed material.In actual operation,the hood is prone to wear,affecting the unit's safety,stability and economic operation.Therefore,research on the resistance characteristics of the hood is conducted,and the structure of the hood is optimized to reduce the wear rate of the hood.,to extend the service life,has important practical value.In this paper,the bell hood's wear and tear problem of a circulating fluidized bed boiler in Xinjiang is studied in depth.The resistance characteristics of active hoods are analyzed by three methods:theory,resistance characteristics experiment,and numerical simulation.Then,the optimization plan for active hoods is improved and improved wear and tear condition.Firstly,based on the classical fluid mechanics knowledge,the bell hood resistance test principle was analyzed.The bell hood resistance test system was initially designed.The structural parameters of the lab bench were determined by numerical simulation,and a bell hood test bench was built.Second,using CFD software to establish the hood model,through the comparison and verification of experimental data,the higher accuracy of the simulation model;comprehensive experimental and simulation of the two methods of conclusions,obtained the hood thickness,annulus area,exports The influence of structural factors such as small holes on the resistance of wind caps;on this basis,an optimization plan for active cap structure was proposed.Through the numerical simulation verification of CFD software,the final optimization plan was determined.