Infrared radiation transfer analysis inside partially-premixed combustion chamber for wall temperature measurement

The risks of unstable combustion phenomena in gas turbine combustion chambers, such as flashback, have increased as further thermal performance improvements are pursued. This raises new requirements for more real-time and accurate monitoring of the combustor wall temperatures. In this study, we adopt the band-based Planck mean absorption coefficient to characterize variations in radiation properties across different spectral bands. Based on simulation data from hydrogen-enriched methane lean premixed combustion, the parameters of different radiation models and hydrogen mixing ratios are compared. To meet measurement demands, the wall temperature distribution is extracted and applied in a ray-tracing analysis to track the origins of regional incident radiation on the wall. The study indicates that the addition of hydrogen significantly affects the distribution of the combustion field, and that the radiation transfer process plays a critical role. Furthermore, radiation heat flux has a non-negligible impact on the total heat flux to the wall, especially in the head region, where the error in uncorrected non-contact temperature measurements can exceed 50%. However, after effectively monitoring the key radiation source regions, this error is greatly reduced. This analysis of the radiation transfer process within the combustor provides a theoretical foundation for the more effective application of non-contact temperature measurement techniques, such as infrared thermometry, in combustion chambers.