为了精确测量吸收光谱, 并尽量减小温度与湍流波动对光谱测量结果的影响, 采用谱线模拟仿真模拟和20kHz高频扫描的方法, 选取中红外基频跃迁带内低温度敏感性谱线P(10), 进行了理论分析和实验验证, 取得了发动机CO吸收光谱及其体积分数随时间变化的数据, 变化范围为(153±123)×10-6。结果表明, P支谱线扫描范围内可降低48.28%目标气体温度变化对体积分数反演的影响。该方案能够为发动机尾气CO激光遥感测量提供一个高速、精准、实时的监测方案。

In order to measure the absorption spectrum accurately and reduce the influence of temperature and turbulence fluctuation on spectral measurement, the method of spectrum simulation and 20kHz high frequency scanning was adopted. The low temperature sensitivity line P(10) in mid-infrared fundamental frequency transition band was selected. The data of absorption spectra and volume fraction of engine CO with the change of time were obtained. The theoretical analysis and experimental verification were carried out. The results show that, the influence of target gas temperature change on volume fraction can be reduced by 48.28% within the scanning range of P branch line. The range of variation is (153±123)×10-6. The scheme can provide a high-speed, accurate and real-time monitoring scheme for CO laser remote sensing measurement of engine exhaust.