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报道了激光诱导热光栅光谱测温技术的研究.通过两束相干交叉的脉冲抽运光,在NO2/N2混合气中诱导出热光栅,一束满足布拉格散射条件的连续探测光在交叉区域激励出相干的热光栅信号,经过空间和光谱滤波的信号光由光电倍增管探测,并由数字示波器显示和存储.该信号携带了丰富的流场信息,通过频域分析,对气体的温度进行了测量,热光栅光谱技术测量的温度与热电偶温度符合得很好.同时还利用热光栅光谱技术进行了气体声速的直接测量,在一定的温度范围内,测量结果与理论曲线基本一致,显示了该技术具有较高的测量精度与多参数同时测量的能力.对影响信号波形的因素进行了分析,结果表明,热光栅光谱测温技术在高压强环境下应用具有独特的优势,是一种应用前景广阔的激光燃烧诊断技术.
The research on laser-induced thermal grating spectroscopy temperature measurement is reported.The pulsed light with two coherent crossover pulses induces a heating grating in the NO2 / N2 mixture and a continuous probe light which satisfies the Bragg scattering condition is excited in the crossing region A coherent thermal raster signal, spatially and spectrally filtered signal light is detected by a photomultiplier tube and displayed and stored by a digital oscilloscope, which carries a wealth of flow-field information and analyzes the temperature of the gas by frequency-domain analysis The temperature measured by the thermal grating spectroscopy coincides well with the temperature of the thermocouple, and the direct measurement of the gas velocity is carried out by using the thermal grating spectroscopy. The measurement results are in good agreement with the theoretical curves in a certain temperature range, The technique has high measurement accuracy and multi-parameter simultaneous measurement capability.The factors affecting signal waveform are analyzed.The results show that the thermal grating spectroscopy temperature measurement technology has unique advantages in the application of high pressure environment, is an application Prospects of laser combustion diagnostic techniques.