Flame temperature and heat release rate sensor for active combustion control

• Real-time measurement of flame temperature and heat release rate. • Emission spectroscopy thermometry. • Designed for combustion oscillation active control systems. Accurate and real-time measurement of combustion chamber flame temperature and heat release rate (HRR) is critical for active control of combustion instability. This paper developed a flame temperature and HRR sensor based on radical emission spectroscopy. The sensor contains two optical acquisition channels with different responses to detect the spectral intensities of two different bands of hydroxyl (OH*). Optical acquisition channels contain optical filters, photodiodes, and photocurrent amplifier circuits. The single band spectral intensity can reflect the fluctuation of the HRR. The flame temperature can be calculated by the ratio of the spectral intensities of the two bands. The optimal detection bands are determined as 310.2–320.1 nm and 303.7–309.0 nm based on the genetic algorithm. In the temperature range of 1700–1900 K, the sensor achieved a precision of ±10 K, and the sensor successfully detects the HRR oscillation with a main frequency of 326 Hz.