乙醇燃烧加热空气污染物对煤油超燃的影响

Influences of vitiation air from ethanol-fueled heating on kerosene-fueled supersonic combustion

在燃烧室入口来流马赫数为2.5的条件下,研究乙醇燃烧加热空气污染物对煤油超声速燃烧的影响.在加热器中,采用预混稳态燃烧火焰模型和61组分388步详细反应机理模拟乙醇燃烧加热过程,获得与实验温度条件相同的详细污染出口组分组成.其主要污染空气作为煤油超声速燃烧室的入口组分,采用17组分30步反应机理模拟煤油超声速燃烧过程,研究了污染物组分对煤油超燃室性能的影响.通过化学动力学和热力学分析,对比了地面电加热、乙醇燃烧加热和25km高空三种工况.结果表明:由于自由基作用以及平均分子质量的减小和平均比定压热容的增加,乙醇燃烧加热污染空气造成超燃室的燃烧效率和内推力均上升.

The influences of vitiation air generated by ethanol-fueled combustion heating on the performances of kerosene-fueled supersonic combustion were studied numerically when the inflow Mach number at the inlet of combustor is 2.5.Premixed burner-stabilized flame model and ethanol-air reaction mechanism with 61 species and 388 steps were used to simulate the combustion in the heater,helping to obtain the components of high-enthalpy air fluid.The reduced reaction mechanism with 17 species and 30 steps were used to simulate the kerosene-fueled supersonic combustion.The contributions of seven main vitiated species such as H2O,CO2,O,OH,H,CO,H2 to the performance of the supersonic combustion were analyzed.Comparing with the cases of electric-heating on the ground and high altitude at the height of 25 km,vitiation air causes the increase of combustion efficiency and internal thrust because of the free-radical＇s function,decrease of averaged molecular mass and increase of averaged specific heat at constant pressure.