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为建立超燃发动机燃烧模态定量判别准则,针对马赫数3.0,总温1500K,总压2.1MPa的来流,完成了燃烧模态的实验和数值模拟研究。对比分析了不同当量比条件下燃烧室马赫数分布和隔离段激波结构,确定了燃烧模态判别采用的两个压力测点特征位置,研究了燃油增加过程中特征位置壁面压强比值的动态特性。结果表明,随着当量比的增加,燃烧模态由超燃模态转变为亚燃模态,当量比0.6是超燃模态过渡到亚燃模态的转换点。特征位置压比变化率最大时刻的比值1.5可以作为定量判别燃烧模态的依据,当特征位置壁面压强比值小于1.5时为超燃模态,大于1.5时为亚燃模态。
In order to establish the quantitative criteria for determination of the combustion modes of a super-heated engine, the combustion mode experiments and numerical simulations were completed for Mach 3.0, total temperature 1500K and total pressure 2.1MPa. The Mach number distribution and the shock structure of the isolation section under different equivalence ratios were compared and analyzed. The characteristic locations of two pressure measuring points used in combustion mode determination were determined, and the dynamic characteristics of the wall pressure ratio at the characteristic location in the process of fuel increase were studied. The results show that as the equivalence ratio increases, the combustion mode changes from the super-combustion mode to the sub-combustion mode, and the equivalence ratio 0.6 is the transition point from the super-combustion mode to the sub-combustion mode. The ratio 1.5 of the maximum ratio of the characteristic pressure ratio at the maximum change rate can be used as the basis for quantitatively determining the combustion mode. When the wall pressure ratio at the characteristic location is less than 1.5, it is the super-combustion mode, and when it is greater than 1.5, it is the sub-combustion mode.