关键词: 污染空气;超音速燃烧;电阻加热;试验研究

Abstract: By comparative study for supersonic combustion experiments both in clean airstream and vitiation airstream,typically simulating the combustor entrance condition of Mach 4 flight,individual and combined influence of H2O and CO2 vitiation on hydrogen-fueled supersonic combustor performance was investigated.The total temperature,total pressure,oxygen mole fraction and fuel equivalence ratio are matched between the test runs with clean airstream and vitiation airstream.Hydrogen fueled combustion experiments were conducted in clean air and vitiation air of various levels,under two equivalence ratios of 0.53 and 0.42,respectively.The H2O vitiation levels examined were expected to be 7.5%,18% and 26%,respectively.The CO2 vitiation levels examined were expected to be 3.0% and 7.5% respectively.The experimental results suggest that the combustion induced pressure rise can be significantly inhibited by H2O and/or CO2 vitiation.The direct extrapolation of vitiated test results to flight condition may possibly result in overfueling combustion,even inlet unstart.The H2O and/or CO2 vitiation also influence the shock waves in the isolator,resulting in the tendency of supersonic combustion mode.

Key words: Vitiation air;Supersonic combustion;Resistance heating;Experimental investigation