Ignition studies of dodecane and binary mixtures of dodecane and tetralin

Abstract

The cool flame ignition characteristics of dodecane in air have been studied in a static system at temperatures in the range 523–623 K. The effects of initial temperature and pressure on the induction period preceding the first cool flame were determined along with the effect of initial pressure on the cool flame intensity. These results for dodecane are consistent with those for lower molecular weight alkanes. The aromatic fuel tetralin was added to dodecane in concentrations of 5, 10 and 20% by vol. In general, the addition of the tetralin increased the induction period. The pressuretemperature boundary which separates the regions of slow combustion and cool flames was determined for each mixture. At the higher temperatures the addition of the tetralin had little effect on the boundary over that of the pure dodecane/air mixtures. As the temperature decreased however, the tetralin began to have a significant effect, increasing the minimum pressure for the appearance of cool flames. At the lowest temperature studied, this effect on the pressure was proportional to the amount of tetralin added. Overall activation energies were determined, the values of which increased with an increase in tetralin. This suggests that the activation energy may be useful in characterizing the ignitability of these particular mixtures.