摘要
研究氢气/空气预混火焰加速过程的物理机理对氢气爆炸灾害预防和控制有重要意义。采用压力-时间记录法和纹影法两种测试方法,开展了常温常压下二元燃料氢气/丙烷和空气混合气体在带有阻塞比为0.5的孔板形障碍物、40 mm×40 mm×3 000 mm的方管中预混火焰传播物理机理的试验研究。结果表明,由压力传感器所测的火焰传播速度沿管道轴线方向先增加后逐渐减小。通过纹影法所测的火焰传播速度在可视化范围内逐渐增加。火焰加速初始阶段的主要物理机理是火焰表面积增加、燃烧产物膨胀和障碍物间的延迟燃烧等。
The present paper is aimed to experimentally probe into the features of the premixed flame propagation mechanism in the ini- tial stage of the binary fuel consisting of hydrogen/propane-air mix- ture. All the said experiments have been conducted in an obstructed square channel with a cross-section of 40 mm in width and 40 mm in height and a 3 000 mm in length in normal pressure and temperature. At the same time, we have arranged seven instrument ports on the channel surface and seven piezoelectric pressure transducers. In addition, we have adopted a series of perforated obstacles with the blockage ratio B. R = 0.5, a pitch equal to the channel width, the 31 mm diameter centrally round hole and a length of 1.5 m to speed up the flame propagation. To make sure the safety of the experimental facilities, we have made the equivalence ratio of the mixture and hy- drogen molar fraction in the binary fuel of hydrogen/propane 1.1 and 0.8, respectively. In proceeding with our research, we have careful- ly examined the mixtures in advance with the method of the partial pressure and then ignited them via an automotive spark plug at about 15-mJ discharge energy. As the result, we have achieved the pres- sure-time records of the flame propagation with the pressure transduc- er. Furthermore, we have resorted to the schlieren technique via a high-speed digital camera to check the variations of the flame front structure and record the time-of-arrival of Name front in the channel＇ s horizontal axis, which helps to deduce the flame propagation velocity accordingly. The results of our investigation and experiments demon- strate that it is possible to obtain the flame propagation velocity which augments initially, arrives at the maximal value in a distance of 80 cm from the ignition point and finally reduces gradually in the limited measuring range. As for the schlieren technique, we have found that the flame propagation velocity can be measured by the camera with the gradual increase in the visualized domain of 0- 300 mm from the
出处
《安全与环境学报》
CAS
CSCD
北大核心
2014年第1期56-60,共5页
Journal of Safety and Environment
基金
中央高校基本科研业务费专项(ZXH2012J001)
关键词
工程热物理
预混火焰
氢气
丙烷
火焰传播速度
孔板形障碍物
压力传感器
纹影法
engineering thermal physics
premixed flame
hydro-gen
propane
flame propagation velocity
perforatedobstacle
pressure transducer
schlieren technique
