Ignition delay times in ethylene oxideoxygenargon mixtures behind a reflected shock

Abstract

A great deal of work has been conducted on the ignition delay times of fuel-oxygen-argon mixtures in shock tubes to investigate the complex combustion processes. Recently, the authors have studied the ignition behavior of nitromethane-oxygen-argon mixtures in the region behind a reflected shock wave. It was found that increasing concentrations of CH[sub 3]NO[sub 2] inhibits detonation and that the role of O[sub 2] as a detonation promoter is reduced in the reaction of the nitromethane mixture. This result could be due to the substituted NO[sub 2] group. The present study was undertaken to investigate the kinetics of the ethylene oxide combustion process. A single-pulse shock tube with 24.3 mm i.d. was used in this study. The shock speed was measured with two Kistler 6031 pressure transducers: one was mounted at a distance of 0.233 m from the other which was flush with the inside wall of the end plate. A detailed description of the experimental apparatus has been presented in previous work. The test gases were prepared by mixing vaporized ethylene oxide with oxygen and argon manometrically and the mixture was stored in a Pyrex flask connected t the driven section of shock tube. Reflected shock temperatures were computed frommore » the measured incident shock speed and the other input data making the assumption that the composition of the mixture is fixed in any thermodynamic process by the initial composition to be shocked. The program, originally written by Gordon and McBride, has been modified to run on an IBM/PC. Thermodynamic properties of ethylene oxide, oxygen and argon were computed from polynomial fits to JANAF thermodynamical data.« less