Research On Two-dimensional Reconstruction Technology Of Combustion Product Concentration Field Based On TDLAS

Realizing the monitoring of combustion products helps to analyze the combustion process correctly,assists the design and improvement of thermal power machinery or combustion equipment,and is of great significance for studying combustion mechanism and improving mechanical efficiency.Most of the existing detection methods use sampling or contact analysis methods,which require preprocessing of the samples,which have poor timeliness,or may interfere with the combustion field itself;the currently relatively emerging optical detection methods can achieve high precision and Real-time monitoring of sensitivity,but generally using a test light path,the detected parameter value is the average value on the light path,which cannot meet the detection requirements of the internal conditions of the combustion field.In view of the above problems,this paper intends to carry out research on the two-dimensional reconstruction of the concentration field of combustion products based on tunable diode laser absorption spectroscopy（TDLAS）,aiming to realize the reconstruction of the two-dimensional concentration field of product water vapor,to make up for the shortcomings of the existing methods.The main work carried out in this paper is as follows:First,the technical mechanism of TDLAS is studied,and the feasibility of its application in the reduction of the concentration field of combustion products is explored.The research work on the principle of two-dimensional reduction algorithm is carried out,mainly including algebraic iterative algorithm and Tikhonov regularization algorithm.Secondly,a simulation program of combustion product concentration detection based on TDLAS technology is designed using mathematical software.The effects of system modulation parameters and environmental factors on the absorbance and test results were analyzed,and a temperature correction method was proposed.The reliability and accuracy of the two-dimensional restoration algorithm are verified,which lays the foundation for the software and hardware development of the two-dimensional field reconstruction system.Finally,a two-dimensional concentration field detection system of combustion products based on TDLAS technology is developed.Taking H₂O as the target gas,the time-division multiplexing method was used to scan the two lasers with the central bands of 1391 nm and 1468 nm alternately to obtain the absorption information.The system enables the measurement of the concentration field of combustion product water.The combustion field of a static flame was tested under laboratory conditions,and 2D reconstructed images of water vapor temperature and concentration were obtained.