작은 원형 노즐에서 메탄-수소 혼합 연료의 연소 특성에 대한 실험적 연구 (1) - 화염가시화

To investigate the combustion characteristics of methane-hydrogen mixed fuel, flame visualization was performed using small nozzles with diameters of less than 3 mm in a Bunsen burner. The following conclusions were drawn from schlieren imaging, direct photography, and infrared analysis under various combustion conditions for low-hydrogen-fraction fuels. When the nozzle size is small, flame presence is primarily influenced by size effects, while the number of nozzles has minimal impact. The minimum nozzle diameter capable of sustaining combustion as a burner is approximately 3 mm. At a hydrogen fraction of 0.20 or higher, backfire may occur when the equivalence ratio and Reynolds number are low. Additionally, as the hydrogen mixing ratio increases, a flame is more likely to form under conditions of higher equivalence ratios and lower Reynolds numbers. Furthermore, increasing the hydrogen fraction results in a reduction in flame height and reaction zone size. However, when the difference in hydrogen fraction is small, individual flame fluctuations may exceed the average variation expected based on the fraction.