For the problem of test media vitiation associated with scramjet ground test facility

the effects of combustion heating vitiated air on kerosene-fueled scramjet performance were investigated with validated numerical approach. Under the simulating condition of flight Mach 6.0

the flow-field and performance of the scramjet were numerically calculated with clean free airstream and vitiated free airstream

respectively. Several matched parameter schemes for vitiated free airstream relative to clean air were considered. It indicates that among the pressure-interrelated parameters

the least discrepancy resulting from vitiation effects is found when the static pressure is matched

while the most discrepancy is found when the total pressure is matched; among the temperature-interrelated parameters

the least discrepancy resulting from vitiation effects is found when the static temperature is matched

while the most discrepancy is found when the total temperature is matched. As for the vitiation effects of combustion heating vitiated air

selection of pressure-interrelated parameters to be matched is more significant than selection of temperature-interrelated parameters. The present efforts can provide theoretical basis for understanding the vitiation effects on the scramjet and determining the simulation rules of ground test with vitiated free airstream.