Flame Acceleration in Fuel-Air Mixtures at Elevated Initial Temperatures

Abstract

Flame propagation experiments were performed in a 3.1-m long, 10-cm diameter heated detonation tube equipped with 0.43 blockage ratio orifice plates equally spaced at onetube diameter. The influence of initial temperature, over the range of 298K to 573K, on flame acceleration and detonation initiation was investigated in mixtures of propane-air and hydrogen-air. The results show that initial temperature has very little effect on the flame acceleration process except for off-stoichiometric propane-air mixtures where flame acceleration at the elevated temperature was much stronger than at room temperature. Also, the DDT limit for hydrogen-air mixtures at elevated temperatures was found not to follow the classical DDT criterion based on the mixture detonation cell size and the orifice plate diameter.