Abstract: The ignition and flameholding characteristics of liquid single component hydrocarbon fuels were investigated in a model supersonic combustor，and n-dodecane and methylcyclohexane were chosen as the tested fuels. The results may provide some basis for the preparation of the scramjet engine fuels. All investigations were performed in the direct-connect supersonic combustion facility with regenerative storage air heater. High enthalpy clean air was heated up to the total temperature ranging from 1040K to 1100K through regenerative storage air heater，entering the isolator entrance at a Mach number of 2.03 through a convergent-divergent nozzle. The inflow mass flow rate was approximately 2.0kg/s. A gas-pilot flame acted as the igniter. Two serial cavities acted as the flameholder. The fuels with ambient temperature were transversely injected into the combustor upstream of the first cavity. The experimental results show that compared with the n-dodecane，the methylcyclohexane was easier to achieve the ignition and flame stabilization under lower inflow total temperature. It should be noted that the ignition and flameholding characteristics of the cold liquid fuels were relatively bad with the inflow total temperature less than 1100K. Theoretical analysis indicate that the evaporation characteristics of methylcyclohexane was better than n-dodecane’s within the same incoming flow parameters. Based on the wall static pressure profiles，combustor inlet Mach number and air flow rate that tested in the experiments，a one-dimensional analysis code was established to calculate the stagnation temperature distribution and combustion efficiency of n-dodecane and methylcyclohexane at different operating conditions.

Key words: Single component hydrocarbon fuels；Supersonic combustor；Ignition；Flameholding；Evaporation characteristics；One-dimensional analysis

摘要： 主要研究了液态单组份碳氢燃料在超燃燃烧室中的点火和稳焰性能，所用燃料为正十二烷和甲基环己烷，研究结果可以为超燃冲压发动机的燃料制备提供部分依据。试验在以蓄热式加热器为核心的直连式试验台上进行，超燃燃烧室进口总温在1040～1100K范围内，进口马赫数2.03，进口空气流量2.0kg/s左右，点火器为燃气发生器，采用串联凹腔作为火焰稳定装置，在第一个凹腔前常温燃料垂直喷射到燃烧室中。研究结果表明:与正十二烷相比，甲基环己烷在来流总温较低的超声速流中更容易被点燃和实现稳火，但总体来讲，当燃烧室进口总温低于1100K时，常温液态燃料的点火和稳焰性能较差。理论分析了两种燃料的蒸发特性，计算结果表明在来流参数相同时，甲基环己烷的蒸发特性优于正十二烷。利用一维分析方法结合试验测量的壁面静压、燃烧室入口马赫数和空气流量，得到了正十二烷和甲基环己烷不同工况时的总温分布和出口燃烧效率。

关键词: 单组份碳氢燃料；超燃燃烧室；点火；稳焰；蒸发特性；一维分析