Optimized combustor performance based on the combination of bluff body and porous media

The direct emission of coal mine methane caused serious environmental pollution and resource waste. To improve the methane utilization, the porous media burner was regarded as an efficient method. In this paper, the bluff body was proposed to combine with porous media to optimize the combustion characteristics. The effects of bluff body position, size and shape on the temperature distribution and gas emission were studied at different operating conditions. The results indicated that the position of the bluff body greatly influenced the combustion characteristics, and the maximum temperature of 1295 K was obtained at the position of 62 mm. The increase of the bluff body diameter promoted the flame moving to the burner outlet. And the combustion temperature increased first and then decreased when the bluff body height increased. Moreover, the CO and NO_x emissions at the height of 20 mm reached 31 and 16.8 ppm respectively. The combustion temperature was significantly improved by increasing the equivalence ratio and velocity. Compared with the single porous media, the addition of the bluff body increased the combustion temperature and reduced the CO emission by 11%.