**5.3 Effect of the total pressure and total temperature distortion on the aerodynamic stability of fans**

The stability margin loss of the rotor increases under the total pressure and total temperature distortion when the total pressure distortion increases or the total temperature distortion decreases (see **Figure 17**). Binary linear regression is performed on the numerical simulation results, and the regression coefficient is about 84.1%.

The instability mechanism under the total pressure and total temperature distortion is generally similar to that under the total pressure and swirl distortion. **Figure 18** shows unwrapped blade-to-blade snapshots of the total pressure and velocity under the maximum stability margin loss at different spans. When the rotor is under the total pressure and total temperature distortion, stall and blockage appear at the tip first and then gradually spread to the midspan and root of the hub.
