Research on flame temperature measurement method based on water vapor emission spectrum

Internal temperature monitoring of high-speed propulsion systems is highly important for engine performance evaluation and lifetime prediction. As a passive optical measurement method without the need for an external light source and without flow field interference, the emission spectrum measurement technique has good application prospects for harsh measurement environments. As the main combustion product, high-temperature water vapor shows a strong emission intensity that is highly suitable for temperature measurement applications. We propose use of the band integral ratio to remove the high resolution measurement requirements for the spectrum acquisition system. In addition, the temperatures of methane-oxygen flames with different equivalent ratios are measured successfully under the condition that the influence of self-absorption on the measurements is considered.