Combustion parameters of gaseous epoxypropane/air in a confined vessel

Abstract

We present an ignition energy measurement system, which comprises a 5L explosion vessel, a transient pressure measurement sub-system, and a transient temperature measurement sub-system. Through a series experiments carried out with this system, the influences of the concentration of gaseous epoxypropane on the combustion pressure and temperature and on the rate of combustion pressure rise and combustion temperature rise have been analyzed, and the results are discussed. The combustion pressure and temperature of gaseous epoxypropane/air mixtures reached their highest values at a concentration of 7% within the studied range. Variation of the ignition energy within the studied range was found to have little effect on the combustion pressure or temperature of the gaseous epoxypropane/air mixtures. However, it had a significant impact on the upper flammability limit. The variation trends in the combustion pressure and temperature and the rate of pressure rise of gaseous epoxypropane/air mixtures with volume fraction appear similar. When the volume fraction of gaseous epoxypropane lies in the range 3.5–7%, the combustion pressure and temperature and the rate of pressure rise of gaseous epoxypropane/air mixtures increase with the volume fraction, while in the range 7–30% these parameters decrease with the volume fraction. The rate of temperature rise of gaseous epoxypropane/air mixtures shows a slightly different trend. It reaches the highest value at a volume fraction of 10%. The combustion pressure and temperature of gaseous epoxypropane/air mixtures reach their highest values near the lower flammability limit, which is in marked contrast to previous results on gaseous nitromethane/air mixtures.