Application of time-division-multiplexed lasers for measurements of gas temperature and CH4 and H2O concentrations at 30 kHz in a high-pressure combustor.
Application of time-division-multiplexed lasers for measurements of gas temperature and CH4 and H2O concentrations at 30 kHz in a high-pressure combustor.
复制标题
应用时分复用激光器测量高压燃烧器中 30 kHz 的气体温度以及 CH4 和 H2O 浓度。
作者：
A. Caswell;T. Kraetschmer;K. Rein;S. Sanders;Sukesh Roy;D. Shouse;J. Gord
在实际的高压燃气轮机燃烧器测试物品中，使用基于光纤布拉格光栅的两个时分复用 (TDM) 源来监测气体温度、H(2)O 摩尔分数和 CH(4) 摩尔分数，并使用视线吸收光谱法。总的来说，这两个光源每 33 μs 循环一次 1329-1667 nm 范围内的 14 个波长。虽然它基于吸收光谱，但这种传感技术与典型的基于二极管激光器的吸收传感器有根本不同，并且具有许多优点。具体而言，TDM 激光器能够以非常高的速度（通常为 30 kHz）在宽光谱范围内高效、灵活地采集离散波长信息，从而以高速提供大量精确数据。对于目前的燃气轮机应用，使用模拟温差光谱选择 TDM 源波长。该方法用于选择接近最佳值的 TDM 波长，以实现精确的温度和物质浓度测量。还预测了 TDM 激光器在高压、湍流反应流中的其他测量以及温度和物质浓度场的二维断层扫描重建中的应用。
Two time-division-multiplexed (TDM) sources based on fiber Bragg gratings were applied to monitor gas temperature, H(2)O mole fraction, and CH(4) mole fraction using line-of-sight absorption spectroscopy in a practical high-pressure gas turbine combustor test article. Collectively, the two sources cycle through 14 wavelengths in the 1329-1667 nm range every 33 μs. Although it is based on absorption spectroscopy, this sensing technology is fundamentally different from typical diode-laser-based absorption sensors and has many advantages. Specifically, the TDM lasers allow efficient, flexible acquisition of discrete-wavelength information over a wide spectral range at very high speeds (typically 30 kHz) and thereby provide a multiplicity of precise data at high speeds. For the present gas turbine application, the TDM source wavelengths were chosen using simulated temperature-difference spectra. This approach is used to select TDM wavelengths that are near the optimum values for precise temperature and species-concentration measurements. The application of TDM lasers for other measurements in high-pressure, turbulent reacting flows and for two-dimensional tomographic reconstruction of the temperature and species-concentration fields is also forecast.