Measurements of emissivity and temperature in hydrogen-air flames

This work presents a new emission measurement methodology that evaluates emissivity and temperature in hydrogen-air flames. Experiments were performed in premixed hydrogen-air flames at equivalence ratios (phi) of 0.85, 0.90, 0.95, and 1.0. Infrared emission emitted from the flames were measured using an infrared camera with a bandpass filter (1.325 mu m to 1.375 mu m). The methodology compares the measured spectral emissivity with the calculated one to determine the spectral emissivity and measure the temperature in the hydrogen-air flames. For the equivalence ratio of 0.85, the estimated maximum temperature is 2155 K, which agrees within 4 % with a thermocouple measurement of 2228 K and a NASA CEA equilibrium calculation of 2234 K. The emissivity increases with increasing the equivalence ratio and presents a maximum value at phi = 1.0 as 0.038. The large flame path length at the high equivalence ratio results in an increase in the emissivity. The new methodology could be applied to measure temperature and emissivity in hydrogen flames.