变转速运行静调轴流引风机叶片裂纹故障诊断分析研究

Fault Diagnosis of Blade Crack of Axial Flow Induced Draft Fan with Adjustable Stator Blades in Variable Speed Operation

本文对国内某1000 MW发电机组变转速运行引风机叶片裂纹问题进行了诊断分析。首先通过对引风机进行热态试验,对引风机失速的可能性及危害进行了探讨。其次,对引风机本体振动及进出口流场的压力波动进行了测试,得到了引风机本体振动频谱及其进出口流场内压力波动的特征频率,为叶片裂纹提供了更多的分析数据。然后,通过对引风机叶片进行敲击测试及固有频率分析,确定了在某些特定转速下引风机叶片存在共振问题.再次,通过对引风机进出口风道进行数值模拟发现,其进出口烟道布置不合理也时造成叶片裂纹的一个主要原因。最后,研究提出了一种有效的烟道优化及引风机转速优化方案,成功的解决了该引风机叶片裂纹问题,提高了设备的安全性。本文中所采用的分析过程为引风机故障诊断领域提供了一条普适性的分析方法。

In this paper,the crack problem of induced draft fan blades in variable speed operation of a domestic 1000 MW generating unit is diagnosed and analyzed.Firstly,through the hot test of induced draft fans,the possibility and harm of stall of induced draft fan are discussed.Secondly,the vibration of the induced draft fan and the pressure fluctuation in the inlet and outlet flow fields are tested,and the vibration spectrum of the induced draft fans and the characteristic frequency of the pressure fluctuation in the inlet and outlet flow fields are obtained,which provides more analysis data for the blade cracks.Then,through the knock test and natural frequency analysis of the induced draft fan blades,the resonance problem of the induced draft fan blades at some specific speeds is determined.Thirdly,through the numerical simulation of the inlet and outlet ducts of the induced draft fans,it is found that the unreasonable arrangement of the inlet and outlet ducts is also a main cause of the blade cracks.Finally,an effective flue optimization and induced draft fan speed optimization scheme is proposed,which successfully solves the problem of induced draft fan blade crack and improves the safety of the equipment.The analysis method used in this study provides a universal analysis methodology for the field of induced draft fan fault diagnosis.