Simulation Research On Gas Temperature Measurement In High Temperature,High Pressure And High Concentration Environment Based On TDLAS

Compared with traditional temperature detection methods,tunable semiconductor laser absorption spectroscopy(TDLAS)technology will not interfere with the temperature field to be measured,and can also respond to temperature changes more quickly,and the non-contact temperature measurement is extremely high or extremely high in the measured object.The measuring equipment will not be damaged under low temperature,and it has the advantages of being able to measure a variety of information,and it shows great application prospects in temperature and concentration measurement.Based on the basic principle of the tunable semiconductor laser spectroscopic absorption technology,this paper takes the water molecular spectrum as the research object to study the temperature calculation method of the direct absorption method of gas at high temperature,high pressure and high concentration.First,an infrared spectrum absorption model is established,and the characteristics of the shape of the spectrum under high temperature,high pressure and high concentration conditions are analyzed by simulation using the water molecule spectrum line as an example,and the problems that need to be solved in temperature calculation under high temperature,high pressure and high concentration conditions are pointed out.In order to solve the selection problem under high temperature measurement spectrum overlay spectrum case,the temperature measurement method of combined spectral lines is researched.The influence of the interference spectrum on the main spectrum is explained through simulation,the principle of the combined spectrum temperature measurement method is introduced,and the conditions for the selection of the spectrum line are given.Comparing the temperature measurement performance of the four groups of spectral lines with the double-spectrum temperature measurement method and the combined spectral temperature measurement method,it verifies the high temperature measurement ability of the spectral line group near 6808cm-1 and 7195cm-1 of two methods,and simulates 7179cm-1 and 7182cm-1respectively to use two methods to calculate the integral absorbance.The maximum error of the combined spectral line temperature measurement method is 4.2%,which is better than the double-line temperature measurement method.In order to solve the problem of baseline extraction under high-pressure and highconcentration conditions,a baseline iterative algorithm based on the absorption model is researched.First introduced the basic principles of the iterative algorithm,and then through the simulation of the TDLAS measurement system in the ideal state,the algorithm was verified under simulation conditions.In order to test the effectiveness of the algorithm in the real measurement system,a 7179.75 cm-1 was built.The measurement system with 7182.95cm-1 as the main spectral line verifies the correction effect of the method on the baseline,and analyzes the total uncertainty of the entire measurement system.The temperature is 5.39%and the concentration is 8.25%.Finally,I summarized the innovative points and shortcomings of the paper,and planned the follow-up theoretical research direction and the next experimental plan.