核电1000MW机组汽轮机高中压转子弯曲振动特性

Flexuous vibration characteristics of HP/IP rotor in a 1000MW nuclear power unit

以某核电1 000 MW机组HN1089型半速汽轮机为研究对象,采用高级旋转机械动力学软件ARMD,对8个支撑轴承分别进行建模计算,得到其静、动态特性参数;然后将轴系4根转子模化,并计入减震弹簧基础的影响,建立基础-可倾瓦轴承-转子的动力学模型;通过动力学计算分析获得轴系动力学特性,并通过现场实测轴系临界转速与计算值的对比验证了计算模型的准确性;基于此,计算了该高中压转子加配重时轴系的振动响应与一阶振型弯曲时的振动响应,并与同容量火电机组汽轮机转子的振动特性进行比较。结果表明:相比于同容量1 000 MW等级火电机组,核电机组汽轮机转子的加重响应敏感性仅为其1/6;核电高中压转子重心处弯曲值<0.06mm时,理论上从高中压缸的动平衡通道在转子轮毂专用加重螺孔处安装动平衡螺钉,即可满足机组运行要求,但当弯曲值超过>0.06mm后,需要揭缸检查并根据实际故障程度决定在高中压转子中部轮毂燕尾槽处加重处理或返厂维修,这将导致工期延长,给电厂带来较大经济损失。因此,建议核电机组的日常运行及启停机过程操作应更加严格规范,严防转轴发生弯曲事故。

Taking the half speed saturated steam turbine in a 1 000 MW nuclear power unit as the research object,modeling calculation for eight support bearings was carried out by using the rotor dynamic analysis software ARMD,to get the static and dynamic performance parameters. Then, four shafts of the unit were modelled considering the effect of spring foundation, and the foundation-bearing-rotor dynamics model was established. Through the comparison of dynamics calculation and measured critical speed of the shafting, the accuracy of the calculation model was verified. On this basis, the HP/IP rotor vibration response was calculated with a balance weight or first mode shape bending, then compared with the same capacity of thermal power units. The results show that, the response sensitivity of the nuclear power units was only 1/6 of that of the 1 000 MW thermal power units with the same capacity. For nuclear units,the HP/IP rotor with less than 0.06 mm bending in barycenter can make the unit meet the requirements of operation by dynamic balance screw in HP/IP rotor dynamic balance channels. But the HP/IP rotor with more than 0.06 mm bending in barycenter must carry out exposed cylinder inspection to add dynamic balance screw in rotor central hub or choice factory maintenance,which will cause extending time limit to a project. Therefore,to prevent the rotor shaft bending accident,the operation in daily running and start/stop process of the nuclear power units should obey more strict standards.