Effects of gas state equation on n-dodecane jet combustion
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摘要: 选取正十二烷作为航空煤油的替代燃料,应用大涡数值模拟方法和详细化学反应动力学相结合的方法对该燃料在超临界环境下的射流燃烧进行计算,研究其射流、燃烧及排放特性。重点考察了气体状态方程对射流形态、贯穿距、温度、混合分数等的影响。结果表明:理想气体和真实气体状态方程对仿真得到的射流贯穿距和宏观形态影响不大,而真实气体状态方程可以更好地反映在超临界环境下的液体燃料射流内部特征,如混合分数、温度;燃烧方面,仿真的点火延迟与实验存在10%的误差,火焰浮起长度、火焰形态、碳烟等均得到很好的预测,NOx与OH分布与温度场具有高度一致性。Abstract: The n-dodecane was selected as an alternative fuel of aviation kerosene in this study. Its jet combustion characteristics under supercritical condition were studied by using large eddy simulation and detailed chemical reaction kinetics. The effects of gas state equations on jet morphology, penetration, temperature, and mixing fraction were also investigated. The simulation results showed that ideal gas and real gas state equations had negligible effect on the jet penetration and macroscopic shape, while the real gas state equation had advantage to reflect the liquid fuel jet characteristics under supercritical condition, such as mixing fraction and temperature. In terms of combustion, there was an error of 10% between the simulated ignition delay and the experiment, the flame lift-off length, flame shape and soot were also well predicted, and the distribution of NOx and OH was highly consistent with the temperature field.
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