关键词: 污染效应；超燃冲压发动机；煤油燃料；双模态；试验

Abstract: Through strict comparison tests in the clean and H2O/CO₂ vitiated air，the effects of H2O and CO₂ species on fuel ignition，flame stability，stable combustion performance and combustion mode in the kerosene-fueled dual-mode supersonic combustor were studied. The tests were carried out in the direct-connected scramjet facilities based on the clean air resistance heater. The conclusions are as follows. (1)The kerosene fuel ignition is restrained by the presence of H2O in the vitiated airstream. When the content of H2O is above 11%，reliable ignition cannot be achieved. (2)Compared with the clean airstream，the flame stability is reduced in the vitiated airstream. CO₂ has more influence on the flame stability than H2O of same mole fraction. (3)At fuel-off state，the wall pressure distribution along the flow direction in the vitiated air almost coincides with the clean air and there are little differences partly. (4)Both H2O and CO₂ have a certain inhibitory effect on the combustion. The wall pressure in the vitiated air is lower than the clean air and this drop of pressure，which is up to 12%，increases with the rising of vitiation levels. Moreover，CO₂ also has a greater impact on wall pressure drop than H2O of same mole fraction. (5)The vitiation changes the mode transition point of the combustor. Supposing the combustor working at the scramjet mode in the clean airstream，it will transit to ramjet mode in the high level vitiated airstream with the same fuel gas equivalent ratio likely.

Key words: Vitiation effects；Scramjet；Kerosene fuel；Dual mode；Experimental