不同推力级高涵道比涡扇发动机结构与力学特征定量评估

Quantitative Evaluation for Structure and Mechanical Characteristics of Different Thrust High Bypass Ratio Turbo Fan Engines

针对不同推力级高涵道比涡扇发动机的结构设计与定量评估的需求,修正了弯曲刚度轴向分布系数和变形协调性参数的计算公式。对不同推力级的典型高涵道比涡扇发动机CFM56与GE90采用结构效率评估方法进行计算与对比,结果表明:GE90高压转子的弯曲刚度分散系数高出CFM56高压转子的17.7%,大尺寸发动机高压转子应当增强局部刚度;在承载能力设计中大尺寸发动机重点关注风扇处可能引起的转静件碰摩,小尺寸发动机重点关注间隙变化带来的气动效率损失;两台发动机低压转子的弯曲应变能系数均大于20%,对连接结构的设计应当避免应变能集中处;GE90转静间隙变化量范围[-4.5mm,2.3mm],明显高于CFM56的[-1.4mm,1.0mm];在不平衡量作用下,整机振动动力学响应及敏感度分析中,需同时关注不平衡量的大小和相位的影响。

Aiming at the requirement of structural design and quantitative evaluation for high bypass ratio turbofan engines with different thrust, the formulas for calculating the axial distribution coefficient of bending stiffness and rotor-to-stator deformation coordination parameters are modified. The compare results by structural efficiency method for two different thrust high bypass ratio turbofan engines of CFM56 and GE90 exhibit that the flexural stiffness coefficient of GE90 HP rotor is higher than that of CFM56 by 17.7%, so HP rotor for largesize engines should enhance local stiffness. In the load capacity design, largesize engines focus on potential rub-impact in fan location, small size engines focus on the pneumatic loss of caused by the gap. Bending strain energy coefficient for LP rotor of CFM56 and GE90 are both over 20% , so the design of the connection structure should avoid the location of strain energy concentration. Rotor-to-stator clearance variation of GE90 ranges of [ -4.5mm, 2.3mini, significantly higher than the CFM56, which ranges of [-1.4mm, 1.0mm]. Phase of imbalance is as important as the amplitude in the analysis of the whole engine vibration response and sensitivity under the load of imbalance.