Three-Dimensional Temperature Field Reconstruction Of Burner Based On Infrared Radiation

At present,thermal power generation,nuclear power generation,hydropower generation and wind power generation are the main power generation methods in China.The main fuel of thermal power plants is coal,and coal-fired power plants are one of the main factors in polluting the environment,especially nitrogen oxides in tail flue gases,the main components of which are nitric oxide and nitrogen dioxide,expressed in NOx.In order to reduce environmental pollution,it is necessary to intervene in coal-fired boilers,which not only ensure the full combustion of coal,but also reduce the emission of pollutants such as soot,SO₂,and NOx.Presetting the new low-nitrogen burner at the front end of the boiler is an effective means to solve the above problems,in order to ensure the safe operation of the burner and effective pre-pyrolysis,it is necessary to monitor the flame combustion status inside the burner in real time,so the research on temperature field reconstruction technology in this area is of great significance.Infrared radiation temperature measurement is a typical non-contact temperature measurement,which has the advantages of fast response speed and wide temperature measurement range.In order to realize the reconstruction of the three-dimensional temperature field in the burner,the calculation of the temperature value corresponding to the pixel interval of the burner section becomes a key problem.This paper introduces the principle of infrared radiation temperature measurement and the basic law of infrared radiation,and analyzes the error of infrared temperature measurement.The method of finding the temperature value of the pixel interval and the regularization solution method of the undetermined equation are compared,the combustion characteristics of the burner temperature field are analyzed,and the solution method suitable for the burner temperature field is selected.By analyzing the internal working state of the burner and the principle of infrared radiation temperature measurement,this paper proposes the prediction and reconstruction of the burner temperature detection and the three-dimensional temperature field inside the burner.Using infrared radiation temperature measurement technology,the burner temperature field reconstruction algorithm was studied and derived.Firstly,the horizontal section in the burner is divided into many pixel regions,assuming that the average temperature of each pixel area is the temperature of the center point of the pixel area,the internal temperature field of the burner under different working conditions is numerically simulated by COMSOL finite element physics simulation software,and then the average temperature of the pixel area is calculated according to the obtained data,and the temperature field is constructed by spline interpolation method with the help of MATLAB.The three points of plasma side,intermediate measurement point and nozzle side and the corresponding cross-sections of the three points obtained by the simulation results were selected,the actual temperature of the three measurement points measured by the thermocouple in the experiment was compared,and the temperature value of the infrared thermometer was set as the three sections,the cross-section was divided into several pixel areas,the average temperature of each pixel area was solved according to the least squares method and the Tikhonov regularization method,and the temperature field of the section was established by the spline interpolation method of MATLAB.The feasibility and accuracy of infrared radiation temperature measurement technology for burner temperature detection and temperature field reconstruction are verified,and the prediction and control of pyrolysis products in the burner are realized indirectly through temperature control,which provides a reference for future in-depth research.