Study on relationships between detonation characteristics and molecular structure parameters of hydrocarbon fuels

Detonation characteristics of hydrocarbon fuels are important indexes for their safety evaluation and protection. To investigate the detonation characteristic of alkane homologs series and the influence of different molecular energies, alkane homologs series’ critical energy to direct detonation (hereinafter related to as critical energy) and detonation cellular width were measured by a self-designed shock tube. Then, the molecular total energy (E) and bond dissociation energy (BDE) of fuel molecules were calculated by the quantum chemistry method. After the comparison between detonation characteristics and molecular energies, it is found that for alkane homologs series, molecular total energy was found to have a good exponent relation between critical energy and detonation cellular width, which indicated that the detonation sensitivity of alkane homologs series can be predicted based on total energy of fuel molecules with preferable accuracy. Extra experiment and calculation was also carried out on gaseous hydrocarbon fuels (ethane, ethylene and acetylene) with same carbon atom number. Results indicated that the bond dissociation energy may have the impact on the detonation cellular width for these three gaseous fuels. The bigger bond dissociation energy leads to smaller cellular width.