FLNG多级液力透平转子临界转速的计算与分析
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摘要
为了研究9级FLNG液力透平转子在运行过程中的可靠性,基于ANSYS有限元仿真平台,采用模态分析方法对液力透平转子进行"干态"和"湿态"条件下数值模拟,并分析了轴承刚度、密封环间隙刚度和电机间隙刚度对转子系统的一阶临界转速的影响。结果表明,在"干态"刚性支撑条件下,转子各阶临界转速均大于相应的弹性支撑下的临界转速。"干态"和"湿态"条件下,转子的一阶临界转速分别为9 170r/min和21 179r/min,均超过工作转速2 965r/min,并留有不低于20%的安全裕度,表明所设计的9级FLNG液力透平转子在"干态"和"湿态"条件下均满足实际工程中结构动力学设计要求。此外,即使转子在实际运行过程中发生磨损,密封间隙增大至8倍设计值0.16mm,转子一阶临界转速仍远高于工作转速,不会影响安全运行。
In order to study the stability of the 9-stage FLNG hydraulic turbine's rotor in the actual operating environment,this paper uses the modal analysis method to simulate the rotor in"dry"and"wet"conditions based on the ANSYS simulation platform.Based on the simulation results,the 4 natural frequencies and the corresponding vibration model diagram are obtained.Besides,the influencing effects of the bearing stiffness,the clearance stiffness and the stator-rotor clearance stiffness to the first-order critical rotational speed are analyzed.The results show that the critical rotational speed under the"dry"rigid support is higher than that under the"dry"elastic support.The first-order critical rotational speed under"dry"and"wet"conditions is respectively9 170 r/min and 21 179 r/min,which are both higher than that under the working environment and have a safety margin bigger than 20%.It is shown that the 9-stage FLNG hydraulic turbine's rotor satisfies the structural dynamic design requirements under the both"dry"and"wet"conditions.Moreover,even if the sealing clearance is increased to 0.16 mm(8 times the design value)due to the abrasion in the actual operation progress,the first-order critical rotational speed is still well above the working rotational speed.It will not affect the safety of the FLNG hydraulic turbine's operation.
In order to study the stability of the 9-stage FLNG hydraulic turbine's rotor in the actual operating environment,this paper uses the modal analysis method to simulate the rotor in"dry"and"wet"conditions based on the ANSYS simulation platform.Based on the simulation results,the 4 natural frequencies and the corresponding vibration model diagram are obtained.Besides,the influencing effects of the bearing stiffness,the clearance stiffness and the stator-rotor clearance stiffness to the first-order critical rotational speed are analyzed.The results show that the critical rotational speed under the"dry"rigid support is higher than that under the"dry"elastic support.The first-order critical rotational speed under"dry"and"wet"conditions is respectively9 170 r/min and 21 179 r/min,which are both higher than that under the working environment and have a safety margin bigger than 20%.It is shown that the 9-stage FLNG hydraulic turbine's rotor satisfies the structural dynamic design requirements under the both"dry"and"wet"conditions.Moreover,even if the sealing clearance is increased to 0.16 mm(8 times the design value)due to the abrasion in the actual operation progress,the first-order critical rotational speed is still well above the working rotational speed.It will not affect the safety of the FLNG hydraulic turbine's operation.
引文
[1]陈杰.中国南海FLNG液化技术与关键设备方案研究[J].化工学报,2015,66(S2):300-310.
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[11]张宇,谢里阳,钱文学,等.深沟球轴承的载荷分布与刚度特征研究[J].机械设计,2012,29(3):45-49.
[12]姚建松,李一浩.一种计算深沟球轴承径向刚度的新方法[J].新技术新工艺,2009(6):52-54.
[13]平仕良.大功率高压多级离心泵转子动力学分析及其特性研究[D].浙江:浙江大学博士学位论文,2012:135-136.
[14]刘振萍.多级离心泵湿临界转速数值计算和测试技术[D].浙江:浙江大学硕士学位论文,2012:80-82.
[15]平仕良,吴大转,谭善光,等.大功率高压多级离心转子动力学分析[J].工程热物理学报,2010(7):1135-1138.
[2] Rankine W J M.On the centrifugal force of rotating shafts[J].The Engineer,1869,27:249.
[3] Myclested N O.A new method for calculating natural modes of uncoupled bending vibration of airplane wings and other types of beams[J].Journal of the Aeronautical Sciences,2012(11):153-162.
[4] Prohl M A.A general method for calculating critical speeds of flexible rotors[J].Journal of Applied Mechanics,1945,12(3):142-148.
[5] Kumar M S.Rotor dynamic analysis using ANSYS[J].Iutam Bookseries,2011,1011:153-162.
[6]秦然,张建伟.转子临界转速的求解方法比较[J].沈阳化工学院学报,2007(1):74-76.
[7]许艳,肖云峰,张志莲,等.基于ARMD的余热透平机组转子动力学分析[J].北京石油化工学院学报,2013,21(4):31-36.
[8]卢展雄,季燕羽,吴贤芳,等.八级离心泵转子临界转速分析[J].中国农村水利水电,2017(11):181-184,193.
[9]王猛.LMV-311型高速泵转子的临界转速计算与分析[D].南京:南京林业大学硕士学位论文,2014:71-72.
[10]郑赟,顾伯勤,邵春雷.离心泵转子-轴承系统临界转速的数值研究[J].煤矿机械,2013,34(5):76-78.
[11]张宇,谢里阳,钱文学,等.深沟球轴承的载荷分布与刚度特征研究[J].机械设计,2012,29(3):45-49.
[12]姚建松,李一浩.一种计算深沟球轴承径向刚度的新方法[J].新技术新工艺,2009(6):52-54.
[13]平仕良.大功率高压多级离心泵转子动力学分析及其特性研究[D].浙江:浙江大学博士学位论文,2012:135-136.
[14]刘振萍.多级离心泵湿临界转速数值计算和测试技术[D].浙江:浙江大学硕士学位论文,2012:80-82.
[15]平仕良,吴大转,谭善光,等.大功率高压多级离心转子动力学分析[J].工程热物理学报,2010(7):1135-1138.