For the real gas effects on the hypersonic boundary-layer flow stability of a flat plate

calculation was performed using the 7 species chemical equilibrium model

where viscosity and thermal conductivity were calculated using a mixing rule. The energy transport due to the species' diffusion was also taken into account. The flat plat base flow was computed under the conditions of Mach number of 10-20

wall temperature of 500-3500K

and flight altitude of 20-30.5km. The flow stability was analyzed

and the N number of relative growth rate of disturbance was given. The result shows that the second and third modes of instability waves are merged under high Mach numbers

taking their tolls on transition together. With the change of Mach number

the wall temperature

flight altitude

and variation trends of real gas instability model are almost the same as the perfect gas. Compared with the perfect gas model

real gas model's envelope line of N is lower

therefore affecting the transition prediction.