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为保证汽轮机叶片安全运行,必须消除叶片-叶轮固有频率在工作转速附近出现共振的可能性。运行和制造部门对严格防止叶轮-叶片系统振动(以下简称为轮系振动)的临界转速,都予以充分的重视,但对合理的避开轮系低共振转速却往往重视不够,甚至有的制造厂在设计时缺乏考虑。捷制VK-50型汽轮机可作为这方面的典型事例。本文结合VK-50型机组叶片损坏实例,说明一阶共振转速的危险性。并指出,为确保叶片安全运行,除临界转速外,一阶共振转速也很重要,在改进和调频时,应使二节径和三节径的一阶共振转速避开一定的安全裕度。另外,对影响轮系振动频率的一些主要因素也作了扼要的叙述。
In order to ensure the safe operation of steam turbine blades, the possibility that the natural frequency of blade-impeller resonates near the working speed must be eliminated. The operation and manufacturing departments have paid sufficient attention to strictly preventing the critical speed of the impeller-blade system vibration (hereinafter referred to as the wheel system vibration), but often neglect enough to avoid the low resonance speed of the train wheel, and even some manufacture Factory lack of consideration in the design. Czech Republic VK-50 turbine can be used as a typical example in this area. In this paper, VK-50 unit vane damage examples to illustrate the risk of first-order resonance speed. It is also pointed out that in order to ensure the safe operation of the blade, in addition to the critical speed, the first-order resonance speed is also very important. When improving and adjusting the frequency, the first-order resonance speed of the two-path and three-path paths should be avoided. In addition, some main factors that affect the vibration frequency of the wheel system are also briefly described.