Evolution characteristics of vented gaseous ethanol-gasoline air explosions in a small cuboid channel

Vented explosion experiments with commercial E10 (10 vol% ethanol - 90 vol% gasoline) were carried out in an optically accessible vented 10 L, 100 × 100 mm2 cross-section channel. Liquid E10 was added to a channel preheated to 60 °C, and a plastic diaphragm initially covered the vent area located on the top wall near the end wall, at the opposite end of the spark plug. The measured peak overpressure and flame propagation phenomena were analyzed for different E10 liquid volumes and vent areas. As the volume of E10 added increased, both the inner and external peak pressure increased, but then decreased for larger amounts of E10 added. For a given amount of fuel, the pressure time-history was relatively smooth for the smallest vents, and highlighted by strong pressure oscillations for the largest vent openings. The peak channel pressure decreased monotonically with increased vent area because more of the fuel discharged and burned as a flame jet out the vent opening before it could combust inside the channel. The peak pressure and flame acceleration generated for gasoline only, measured for a single vent area, was only slightly lower than that produced with E10. From a process, storage and handling safety standpoint, this implies E10 can be treated similar to gasoline at 60 °C.