基于双向流固耦合弹性环式挤压油膜阻尼器建模及动力学特性研究

利用数值方法建立了弹性环式挤压油膜阻尼器(ERSFD)的流固耦合模型,分别利用有限元方法以及有限体积法建立了弹性环和内外油膜的CFD数值模型,并进一步利用分时迭代的弱耦合方法实现了油膜以及弹性环控制方程的耦合求解,获得了内油膜的压力分布特性及弹性环的变形,并进一步识别了油膜和弹性环的动力学特性系数;研究了涡动频率、凸台数目、凸台高度、凸台宽度以及弹性环厚度对阻尼器动力学特性系数的影响。结果表明,弹性环的凸台高度对ERSFD油膜动力学特性系数的影响最为明显,ERSFD油膜阻尼与涡动频率无关。     

Numerical simulation on impact-contact between the tips of a pair of blades

To study the dynamic characteristics and damping mechanism of impact-contact between the tips of blades further more,the impact-contact between the tips of a pair of blades was studied through numerical simulation.In this paper,the dynamic equation of contact-impact between the tips was established and Newmark direct integration method was adopted in numerical simulation.The nonlinear response characteristics and damping mechanism of impact-contact system are obtained.The results of numerical simulation were obtained as follows:As the clearance between blade shrouds is smaller,the vibration amplitude is smaller.The clearance between blade shrouds has a great influence on the input energy of the aerodynamic-excitation-vibration force.As the clearance of blade shrouds increases,the input energy of the aerodynamic-excitation-vibration force increases rapidly.     

Numerical simulation of HP rotor cooling configuration using parameterized method

This paper implemented cooling configuration design on certain gas turbine HP rotor using parameterized method.It is convenient for complicated gas turbine blade modeling using parameters and also benefit for the geometry modify in later period.Parameterized modeling is the foundation of air cooling turbine blade design method engineering application.Mesh quality can be awarded when generated complicated cooling configuration blade grids,and also the increase of calculation error can arise by many mesh blocks.Film cooling and serpentine passage can effectively enhance the cooling effectiveness and protect blade.     

可倾瓦轴承瓦块摆动特性

研究可倾瓦轴承瓦块摆动几何关系,基于分离变量法建立了有限长轴承油膜压力模型及瓦块力矩平衡方程,获得瓦块摆角与轴承参数之间的函数关系;以瓦块包角为80°、支点偏移量为0.5的四瓦块可倾瓦轴承为研究对象,计算分析其瓦块的摆动特性.理论推导表明,瓦块静平衡摆角只与瓦块结构参数、轴颈相对瓦块偏心率、间隙比有关,而与轴颈转速、油...     

Rotordynamic forces generated by discharge-to-suction leakage flows in centrifugal pumps

In order to investigate the flow-induced vibration in the shroud passage of centrifugal pump and predict rotordynamic forces of centrifugal pump rotor system,an analysis of rotordynamic forces arising from shrouded centrifugal pump is presented. CFD techniques were utilized to analyze the full three-dimensional viscous,primary/secondary flow field in a centrifugal pump impeller to determine rotordynamic forces. Multiple quasi-steady solutions of an eccentric three-dimensional model at different whirl frequency ratios yielded the rotordynamic forces. The skew-symmetric stiffness,damping,and mass matrices were obtained by second-order least-squares analysis. Simulation of the coupled primary/secondary flow field was conducted,and the complex flow characteristics in the flow field of a shroud passage were achieved including the mean velocity and pressure,as well as the eddy in a large scale of flow field due to viscosity. The rotordynamic force coefficients were calculated,and the results were in good agreement with those of experiment except for the direct inertial coefficient without the consideration of whirling forces from the impeller primary flow passage.     

A recognition method of vibration parameter image based on improved immune negative selection algorithm for rotating machinery

To overcome the limitations of traditional monitoring methods, based on vibration parameter image of rotating machinery, this paper presents an abnormality online monitoring method suitable for rotating machinery using the negative selection mechanism of biology immune system. This method uses techniques of biology clone and learning mechanism to improve the negative selection algorithm to generate detectors possessing different monitoring radius, covers the abnormality space effectively, and avoids such problems as the low efficiency of generating detectors, etc. The result of an example applying the presented monitoring method shows that this method can solve the difficulty of obtaining fault samples preferably and extract the turbine state character effectively, it also can detect abnormality by causing various fault of the turbine and obtain the degree of abnormality accurately. The exact monitoring precision of abnormality indicates that this method is feasible and has better on-line quality, accuracy and robustness.     

轴弯曲故障特征分析

本文根据旋转机械经常发生的三类轴弯曲故障即初始弯曲、一般热弯曲和摩擦热弯曲故障,着重对由初始轴弯曲和摩擦热弯曲引起的振动响应进行了理论推导和特征分析。结合所做实验和现场汽轮机轴弯曲故障情况,得出轴弯曲故障的一些特征,为防止和诊断这种故障提供参考的方法和依据。     

超临界汽轮机高压缸有限元热应力分析

应用有限元分析程序对超临界600MW汽轮机高压缸方案进行三维有限元应力分析，提出采用带有一半圆槽的新型高压隔板套设计方案，可有效降低高压隔板套应力，采用椭圆形汽封结构形式，既可避免动静之间产生碰磨，又能使轴封和隔板汽封有较小的间隙，提高机组热效率，为超临界机组的研究与开发提供理论依据。     

燃气轮机滚动轴承故障及振动传递特性研究

针对燃气轮机动力涡轮转子系统中滚动轴承故障高发的问题,基于赫兹接触理论建立了滚动轴承故障激励力模型,并验证了其准确性。基于有限元法建立了转子-轴承-机匣-固定平台整机模型以揭示振动传递特性。频域分析结果表明：单故障条件下不平衡激励力与滚动轴承故障激励力是单向耦合的关系;双故障条件下,若故障点直径相同,加速度信号中滚子故障主要频率对应的加速度幅值最大,外圈故障主要频率对应的加速度幅值最小。     

重型燃气轮机转子启动过程热弯曲故障实验研究

重型燃气轮机频繁启停过程易发生热弯曲故障,严重的会影响机组及人员安全.本文模化了某型实际重型燃气轮机转子,搭建了拉杆转子热弯曲故障实验台,利用电涡流位移传感器采集了转子3500 r/min下不同运行时间的振动数据,给出了转子热弯曲故障振动规律,实验结果表明:转子一、二阶临界转速分别为1070 r/min和3180 r/min,转子存在热弯曲故障时,转子振动随着运行时间逐渐下降,对重型燃气轮机机组实际运行过程热弯曲故障的诊断和监测有一定参考价值.