TDLAS波长调制压力测量法参数优化

使用TDLAS技术进行动态压力测量已经成为压力测量领域的研究热点。波长调制法实验装置较为复杂,需要对多个参数进行设置,选择出最优的预设参数能够取得更好的实验效果,获得更高的测量精度。目前波长调制法的实验参数设置基本凭借个人经验,使用Matlab程序仿真结合波长调制法的TDLAS测量技术,能够对实验中需要进行预设的重要参数进行了分析。通过计算4990cm-1波段和6330cm-1波段附近的多条吸收峰,发现4990.09cm-1波段处的吸收峰更适合作为波长调制法的测量波段。以4990.09cm-1处的吸收峰为研究对象,进行了波长调制法压力测量仿真建模,计算了调制度、调谐频率和调制频率对二次谐波幅值和对称性的影响并深入地分析了影响因素,总结了其变化规律。在综合考虑抗噪性能和测量精度的情况下,选择了调制度为2.5,调谐频率30Hz,调制频率5kHz为最佳实验参数。基于Matlab的仿真模型能够快速计算大量参数点,更加直观地分析出对参数的影响趋势,为实验仪器和预设参数的选择提供依据。

Parameter optimization of TDLAS wavelength modulation pressure measurement method

Dynamic pressure measurement using TDLAS technology has become a research hotspot in the field of pressure measurement. The experimental device of wavelength modulation method is complex. It needs to set many parameters. Choosing the optimal preset parameters can achieve better experimental results and higher measurement accuracy. At present, the choice of experimental parameters of wavelength modulation method is based on personal experience. Using the Matlab program to simulate the TDLAS measurement technology combined with the wavelength modulation method, it is possible to analyze the important parameters that need to be preset in the experiment. The absorption peaks near 4990 cm-1 and 6330 cm-1 bands are calculated. It is found that the absorption peaks at 4990.09 cm-1 bands are more suitable for the measurement band of wavelength modulation method. Taking the absorption peak at 4990.09 cm-1 as the research object, the simulation model of pressure measurement by wavelength modulation method was established. The effects of modulation degree, frequency and frequency on the amplitude and symmetry of second harmonic were calculated, and the influencing factors were analyzed in depth, and the changing rules were summarized. Considering the accuracy and anti-noise performance, the optimal experimental parameters are modulation degree of 2.5, tuning frequency of 30 Hz and modulation frequency of 5 kHz. The simulation model based on MATLAB can quickly calculate a large number of parameter points, more intuitively analyze the trend of influence on parameters, and provide a basis for the selection of experimental instruments and preset parameters.