Comparative study on calculation methods and experiments of temperature measurement in gas analysis

In order to calculate the gas temperature based on the gas components of combustor outlet， nonlinear equations such as mass conservation equation， component balance equation， thermal dissociation equation， and energy conservation equation were solved using Newton’s method and Herv’s method. The gas temperature with and without thermal dissociation was calculated， and the above calculation methods were verified through gas analysis temperature measurement experiments and thermocouple temperature measurement experiments. Theoretical calculation results show that as the temperature increases， difference of the gas temperature calculated by gas analysis method between without considering thermal dissociation and with considering thermal dissociation increases. When the temperature exceeds 1 800 K， the temperature difference between considering thermal dissociation and without considering thermal dissociation exceeds 10 K， and when it exceeds 2 300 K， the temperature difference exceeds 50 K. The volume concentration of CO2 has a significant impact on temperature calculation， and its measurement accuracy is an important factor for the accuracy of temperature calculation. The experimental verification results show that the gas temperature calculated by the gas analysis method is roughly the same as the gas temperature measured by the thermocouple， and the trend is basically consistent. This indicates that the gas analysis temperature calculation method in this article is reliable， and that the gas analysis method is a reliable high-temperature testing technique. Moreover， when the temperature is high， thermal dissociation should be considered.