Monitoring of oscillatory characteristics of pulverised coal flames through image processing and spectral analysis

This paper presents the monitoring of the oscillatory characteristics of pulverised coal flames using image processing and spectral analysis techniques. The instrumentation system employed in this investigation is as an integral part of a multi-functional flame monitoring system, being capable of monitoring oscillatory frequencies of a flame on a two-dimensional and concurrent basis. A quantitative flicker frequency is defined as the power-density-weighted mean frequency over the spectral range to represent the oscillatory characteristics of a specific region of the flame. A series of tests was undertaken on an industrial-scale coal-fired combustion test facility under a range of operating conditions. Relationships between the measured flame flicker and the process data including emissions are identified. Results obtained demonstrate that the flame flicker responds in predictable ways to the effects of operating conditions on the dynamic nature of the flame.