ABSTRACT

Spray auto-ignition behaviors of the RP-3 jet fuel were compared to those of a conventional diesel fuel on a constant-volume combustion chamber. The experiments were conducted at changed ambient temperatures and oxygen concentrations, with adjusted fuel injection pressure and duration as well. Compared to diesel fuel, the RP-3 jet fuel exhibits less auto-ignition propensity and lower burn rate, its ignition delay, and combustion delay times are more sensitive to the change in temperature and oxygen concentration, and more obviously staged heat releases and pressure rises are observed at lower oxygen ambience. Also, the peak heat release rate of diesel fuel exhibits an apparent non-monotonic trend versus increased temperature at high oxygen environments, due to the reduced premixed burn intensity with increased ambient temperature, while this non-monotonic trend for the RP-3 jet fuel is less significant, as the peak burn intensity is less influenced by changed ambient temperature. Finally, both elevated injection pressure and extended injection duration significantly reduce the combustion delay time at lower ambient oxygen concentrations, because the interval between the two-stage pressure rises, that occur at lower ambient oxygen environments, are apparently shortened.

摘要

RP-3 喷气燃料的喷雾自燃行为与常规柴油燃料在恒定容积燃烧室中的自燃行为进行了比较。实验是在改变的环境温度和氧气浓度下进行的，同时调整了燃料喷射压力和持续时间。与柴油相比，RP-3喷气燃料的自燃倾向较小，燃烧率较低，其着火延迟和燃烧延迟时间对温度和氧气浓度的变化更敏感，更明显的分级放热和压力在较低的氧气环境下观察到上升。此外，在高氧环境下，由于预混燃烧强度随着环境温度的升高而降低，柴油燃料的峰值放热率随温度升高呈现明显的非单调趋势，而 RP-3 喷气燃料的这种非单调趋势不太显着，因为峰值燃烧强度受环境温度变化的影响较小。最后，提高喷射压力和延长喷射持续时间都显着减少了在较低环境氧气浓度下的燃烧延迟时间，因为在较低环境氧气环境下发生的两级压力升高之间的间隔明显缩短。