Authors: Andrew J. Smallbone and Toshiaki Kitagawa

Fundamental measurements such as the laminar burning velocity are a key parameter for the development of reliable predictive turbulent combustion models/correlations. In this study, an optically accessed combustion vessel and high speed imaging were adopted to obtain laminar burning velocity measurements of spherically propagating hydrogen-air explosions at 0.06, 0.10, 0.175, 0.25 and 0.50MPa. Equivalence ratios of 0.4, 0.6, 0.8 and 1.0 are investigated and the influence of flame instability is discussed in terms of the Markstein number and flame instability burning velocity ratio (ratio of the laminar burning velocity at a flame radius of 60mm to the unstretched laminar burning velocity).