Experimental study of vitiation effects on hydrogen/kerosene fueled supersonic combustor

Direct-connect tests were performed to determine the effects of vitiation on combustion in a supersonic combustor. Major combustion vitiation species (H2O and CO2) were added to the airstream. The tests were conducted in a direct-connect combustor with a Mach 2.02 inlet, hydrogen and kerosene were chosen as the test fuel. In the cases fueled with hydrogen, with an equivalence ratio of about 0.25, transition from cavity shear-layer combustion mode to combined shear-layer/recirculation combustion mode was observed in three test conditions, clean air stream, air stream with 4.5% H2O and 4.5% H2O + 4.5% CO2, but not occurred in the case with 4.5% CO2. In addition, in cases fueled with kerosene, the equivalence ratios were about 0.53 and 0.73 and tests with two matching types in vitiated air were conducted: A. matching total temperature and total pressure; B. matching static temperature and static pressure. Results show that the pressure profile decreased with the increasing H2O and CO2 contents, but the difference of pressure between the two matching types was not significant because of the small difference of two matching types.