| The goal of this project was to study the flame acceleration characteristics and detonation properties for various fuel-air mixtures at elevated initial temperatures. Flame acceleration distances were measured for the fuels hydrogen, acetylene, ethylene and JP-10 in air from 300K to 573K at initial pressures of one and two atmospheres. Two sets of experiments were conducted to investigate flame acceleration and deflagration-to-detonation transition (DDT) in a sealed tube. In the first set a tube 3.1 meters in length and completely filled with obstacles having a blockage ratio of 0.43 and spaced one tube diameter apart was used, and in the second set of experiments the tube was 6.2 meters long with the initial 3.1 meters lined with an identical orifice arrangement and followed by a smooth walled section. The 6.2 meter configuration allowed for detonation cell width measurements of JP-10-air mixtures.; Experiments performed using hydrogen-air mixtures demonstrated an increase in the distance for the flame to reach sonic velocity with increasing initial temperature. (Abstract shortened by UMI.)... |
