Fiber-coupled phosphor thermometry for wall temperature measurements in a full-scale hydrogen gas turbine combustor

Online wall temperatures were measured with fiber-coupled phosphor thermometry in a full-scale gas turbine combustor. The combustor was operated with natural gas and up to 100 vol% hydrogen at engine-relevant conditions. Two phosphors were tested for this application, namely YAG:Dy and YAG:Tm;Li. Although YAG:Tm;Li seemed to be the most promising phosphor for this application, it turned out to be incompatible with the used setup due to a strong interfering signal generated by the laser in the used fiber setup. A strategy to compensate for interferences from flame emissions during natural gas operation was developed. With this strategy it was possible to obtain single-shot temperature measurements at 15 Hz and a precision of 2-7 K for a 1 s average.