A tunable diode laser absorption spectroscopy (TDLAS) tomographic system was proposed via utilizing the wavelength modulation spectroscopy (WMS) method and distributions of temperature and specie concentrations in the dynamic flames were simultaneously reconstructed for the first time. A five-view fan beam tomographic sensor was applied to capture the absorption spectrum along the laser paths across the region to be imaged. Light intensities in all paths were collected in a custom specific TDLAS hardware. Different phantoms of the temperature and water vapor concentration distributions were fabricated to generate artificial data of the absorption spectrum acquired in the sensor. Reconstructed images of the phantoms in the simulations agreed well with the original distributions, in cases of different random noises that varied from 1% to 7% of light intensities at each wavelength. Experiments on a McKenna burner and the exit of a wind tunnel were carried out, and distributions of temperature and water vapor’s molar concentration were achieved by applying the proposed WMS based TDLAS tomographic system. A moving steel ruler was used to disturb the flame in the burner and temporal variations of the flame over a cross section of the burner were imaged in a tomographic way. Tomographic results on exhaust flows at the exit of a wind tunnel coincided with the variation trend of temperature in eleven different working conditions and verified the robustness of the proposed system under harsh conditions.

中文翻译：

---

基于 WMS 的 TDLAS 层析成像系统，用于动态火焰中气体浓度和温度的分布检索

利用波长调制光谱（WMS）方法提出了一种可调谐二极管激光吸收光谱（TDLAS）层析成像系统，并首次同时重建了动态火焰中的温度和物质浓度分布。应用五视图扇形光束断层扫描传感器来捕获沿要成像区域的激光路径的吸收光谱。所有路径中的光强度都在定制的特定 TDLAS 硬件中收集。制作了温度和水蒸气浓度分布的不同模型，以生成传感器中获取的吸收光谱的人工数据。模拟中幻影的重建图像与原始分布非常吻合，在不同的随机噪声的情况下，每个波长的光强度从 1% 到 7% 不等。对 McKenna 燃烧器和风洞出口进行了实验，并通过应用基于 WMS 的 TDLAS 层析成像系统实现了温度和水蒸气摩尔浓度的分布。使用移动的钢尺来扰乱燃烧器中的火焰，并以层析成像方式对燃烧器横截面上的火焰时间变化进行成像。风洞出口排气流的层析结果与 11 种不同工况下的温度变化趋势一致，验证了该系统在恶劣条件下的鲁棒性。通过应用所提出的基于 WMS 的 TDLAS 层析成像系统，可以实现温度和水蒸气摩尔浓度的分布。使用移动的钢尺来扰乱燃烧器中的火焰，并以层析成像方式对燃烧器横截面上的火焰随时间变化进行成像。风洞出口排气流的层析结果与 11 种不同工况下的温度变化趋势一致，验证了该系统在恶劣条件下的鲁棒性。通过应用所提出的基于 WMS 的 TDLAS 层析成像系统，可以实现温度和水蒸气摩尔浓度的分布。使用移动的钢尺来扰乱燃烧器中的火焰，并以层析成像方式对燃烧器横截面上的火焰随时间变化进行成像。风洞出口排气流的层析结果与 11 种不同工况下的温度变化趋势一致，验证了该系统在恶劣条件下的鲁棒性。