Combustion wave propagation through a bank of cross-flow cylinders

Combustion wave propagation through a bank of 12.7 mm diameter cylinders is investigated in a 76.2 mm tall, 25.4 mm wide channel using high-speed schlieren photography. Two cylinder geometries (staggered and inline) were tested with 50% channel area blockage. The staggered geometry was also tested with 67% blockage. Tests were carried out with hydrogen-air at atmospheric pressure. Flame propagation is highlighted by an initial flame acceleration phase driven by turbulent burning in the cylinder wakes. This is followed by quasi-steady flame propagation characterized by shock-flame interactions. Flame acceleration measured in the staggered and inline cylinder geometry, for the same blockage, was found to be similar despite the different flame pathways. In the fast-flame regime, the quasi-steady flame velocity was also found to be very similar. In the composition range where detonation initiation and failure was observed, often referred to as the quasi-detonation regime, the average velocity was significantly higher in the staggered cylinder geometry due to the higher frequency of detonation initiation. (C) 2015 The Combustion Institute. Published by Elsevier Inc. All rights reserved.