Skip to main content

Outward Propagation Velocity and Acceleration Charateristics in Hydrogen-Air Deflagration

Type of Publication
Year of Publication
T. Katsumi; H. Kobayashi; T. Aida; K. Aiba; S. Kadowaki

Propagation characteristics of hydrogen-air deflagration need to be understood for an accurate risk assessment. Especially, flame propagation velocity is one of the most important factors. Propagation velocity of outwardly propagating flame has been estimated from burning velocity of a flat flame considering influence of thermal expansion at a flame front; however, this conventional method is not enough to estimate an actual propagation velocity because flame propagation is accelerated owing to cellular flame front caused by intrinsic instability in hydrogen-air deflagration. Therefore, it is important to understand the dynamic propagation characteristics of hydrogen-air deflagration. We performed explosion tests in a closed chamber which has 300mm diameter windows and observed flame propagation phenomena by using Schlieren photography. In the explosion experiments, hydrogen-air mixtures were ignited at atmospheric pressure and room temperature and in the range of equivalence ratio from 0.2 to 1.0. Analyzing the obtained Schlieren images, flame radius and flame propagation velocity were measured. As the result, cellular flame fronts formed and flame propagations of hydrogen-air mixture were accelerated at the all equivalence ratios. In the case of equivalent ratio =0.2, a flame floated up and could not propagate downward because the influence of buoyancy exceeded a laminar burning velocity. Based upon these propagation characteristics, a favorable estimation method of flame propagation velocity including influence of flame acceleration was proposed. Moreover, the influence of intrinsic instability on propagation characteristics was elucidated.

We are professional and reliable provider since we offer customers the most powerful and beautiful themes. Besides, we always catch the latest technology and adapt to follow world’s new trends to deliver the best themes to the market.

Contact info

We are the leaders in the building industries and factories. We're word wide. We never give up on the challenges.

Recent Posts