Abstract: In order to study the torsional characteristics of the fan blade tip， a new dynamic measuring method for blade tip elastic deformation angle of an operating engine based on blade tip timing technology is proposed. The first stage blade tip torsional characteristics of a low bypass ratio two-stage fan were investigated under different operating conditions during rig test of the compressor. The results show that the elastic deformation angle increases with rotational speed and increases while the compressor characteristic curves approaching unstable region. The maximum deformation angle of 1.25° was recorded near the surge point at 100% corrected speed. Variable inlet guide vanes （VIGV） angle has a significant impact on the elastic deformation angle only when operating near the surge line. Elastic deformation angle oscillated sharply at surge point at 90% corrected speed with VIGV angle at -5°. It is estimated that the torsional amplitude of blade1 were 0.18° （before surge）， 1.05° （at surge point） and 0.11° （after surge）. It is possible to measure blade vibration by monitoring elastic deformation angle.

Key words: Fan blade;Torsional characteristics;Elastic deformation angle;Blade tip timing;Torsional vibration

摘要： 为研究风扇叶片叶尖扭转特性，基于叶尖定时技术，建立一种发动机运行状态动态测量叶片叶尖弹性变形角的试验方法，在压气机试车台对小涵道比双级风扇试验件一级转子叶片不同工况下叶尖扭转特性开展了试验研究。试验结果表明：叶尖弹性变形角表现为随着转速升高而变大及随着特性线向失稳区移动而变大的特点，在100%换算转速近喘点达到本次试验风扇稳定工作状态的最大值1.25°。可变进口导叶（VIGV）角度仅在喘振边界附近对叶尖弹性变形角影响较大。在90% 转速、VIGV角度为-5°喘点处，叶尖弹性变形角出现大幅振荡，经估算，1号叶片喘振前扭转振幅为0.18°，喘点处扭转振幅为1.05°，退喘后扭转振幅为0.11°，通过弹性变形角测量叶片振动具有可行性。

关键词: 风扇叶片;扭转特性;弹性变形角;叶尖定时;扭转振动