Research On Acoustic Measurement Technology In Temperature Field And Flow Field Of Power Plant Boiler Flue

At present,in coal-fired boiler of power station,the parameters of working fluid parameters of steam-water side are used to obtain parameters of furnace and to control relevant thermal parameters.After the pulverized coal enters furnace,change of the working fluid parameters on steam-water side is a hysteresis process with large delay and large inertia.It is known that in horizontal flue,change of flue gas temperature and flow velocity can reflect operating conditions of each main heat exchange surface,and it is an important basis for realizing feedback optimization.As a new non-contact measurement method,acoustic method can realize real-time monitoring of flue gas temperature and flow rate in boiler flue.Based on principle of acoustic measurement,this paper measures temperature field and flow field in boiler flue of power station and builds an acoustic measurement of simulated flue.The system test platform verifies feasibility of the system in measuring flow rate of medium through experimental research.Thus,the main research content includes three parts:1.In flue of power station boiler,considering actual situation of the coupling of temperature/flow field and requirements of acoustic simulation of flue multiphysics,the mathematical models of temperature field,flow field and sound field are established respectively.The finite element software Comsol Multiphysics is proposed to solve the temperature field and flow field.The acoustic model of the field is simulated under the condition of temperature field and flow field alone and coupled.Finally,the simulation results are quantitatively analyzed.2.According to acoustic measurement of three-dimensional temperature field/flow field in the flue,model temperature field and flow field distribution function are established.Based on arrangement of acoustic wave sensor,the measurement of flue temperature field and flow field is realized by least squares method.The restored temperature field and flow field distribution are compared with corresponding models and error analysis to verify effectiveness of the algorithm.3.The experimental platform for simulating flue acoustic measurement system is designed and built,and acoustic measurement experiments of cold and hot state are carried out under different experimental conditions.This paper focuses on acoustic measurement of gas flow velocity in simulated flue.Finally,feasibility of system platform in measuring flow velocity of medium by acoustic method is verified,which provides an experimental basis for measurement of actual flue flow field distribution.