Structure and dynamics analysis of low pressure rotor in geared turbofan

Takeing the low pressure rotor in geared turbofan as object, the influences of structural parameters (i.e., supporting scheme and stiffness of supporting point) of low pressure rotor on its dynamics were studied by building simplified model of low pressure rotor and quantifying its dynamics through structural efficiency evaluation parameters. Meanwhile, the optimization design of the supporting scheme and stiffness of supporting point was carried out based on the relationship of the structural parameters and dynamics of the rotor. The optimization design of the supporting scheme and stiffness of supporting point was presented. As a result, it indicates that the dynamics performance of the rotor is optimal when the supporting scheme is 1-0-1 and stiffness of supporting points is 5.84×10⁷ N/m and 5.90×10⁷ N/m, respectively. At that moment, the angular non-deformability of the rotor is pretty good, and the distribution of the first two critical rotational speeds satisfies the requirements for resonance margin design and is limited within a small speed extent as well.