尾气透平膨胀机部件改造效果分析

针对云南云天化国际化工有限公司云峰分公司硝铵厂尾气透平机轴承、静叶调节机构、承缸叶片等部件存在的问题,分别进行改造,提高了该设备的运行周期,取得了很好的经济效益。     

Modal-based damage identification for the nonlinear model of modern wind turbine blade

In this paper, the modal-based indices are used in damage identification of the wind turbine blade. In contrast of many of previous researches, the geometric nonlinearity due to the large structural deformation of the modern wind turbines blade is considered. In the first step, the finite element model (FEM) of the rotating blade is solved to obtain the modal features of the deformed structure under operational aerodynamic loading. Next, the accuracy and efficiency of the various modal-based damage indices including the frequency, mode shape, curvature of mode shape, modal assurance, modal strain energy (MSE) and the difference of indices (between the intact and damaged blades) are investigated. To adapt the MSE index calculation in nonlinear modeling, a new approach is introduced to include the effects of the structural nonlinearity. Furthermore, the effect of the damage length, its location and severity and also the effect of rotational speed and amplitude of loading are studied. The generic 5-MW NREL blade is used for the simulation study. The results show enough sensitivity of the mode shape curvature and MSE indices to the local damages. Moreover, the importance of geometric nonlinearity in the damage detection of the modern wind turbines is demonstrated.     

Effect of shallow-angled skins on the structural performance of the large-scale wind turbine blade

Two shallow-angled symmetric and asymmetric skins, with off-axis fiber angles of less than 45°, were proposed and employed to a 5 MW wind turbine blade. For the symmetric configuration, shallow-angled skins were applied to both the pressure and suction sides of the blade, while, for the asymmetric configuration, only the pressure side was implemented with a shallow-angled skin, keeping the conventional 45-degree-angled skin for the suction side. The blade tip deflection, modal frequencies, buckling stability, and failure index were computed for off-axis fiber angles of 45°, 35°, and 25°. The use of shallow-angled skins improved blade bending stiffness and strength. The buckling resistance decreased for symmetric skins and remained unchanged for asymmetric skins; the former case was compensated for by increasing the core thickness. For both skin configurations, a reduction in the blade failure index of up to 18% and 38%, and mass reductions of up to 8% and 13% were demonstrated for the 35° and 25° shallow-angled skins, respectively.     

Multiscale modelling and simulation of single crystal superalloy turbine blade casting during directional solidification process

As the key parts of an aero-engine,single crystal（SX）superalloy turbine blades have been the focus of much attention.However,casting defects often occur during the manufacturing process of the SX turbine blades.Modeling and simulation technology can help to optimize the manufacturing process of SX blades.Multiscale coupled models were proposed and used to simulate the physical phenomena occurring during the directional solidification（DS）process.Coupled with heat transfer（macroscale）and grain growth（meso-scale）,3D dendritic grain growth was calculated to show the competitive grain growth at micro-scale.SX grain selection behavior was studied by the simulation and experiments.The results show that the geometrical structure and technical parameters had strong influences on the grain selection effectiveness.Based on the coupled models,heat transfer,grain growth and microstructure evolution of a complex hollow SX blade were simulated.Both the simulated and experimental results show that the stray grain occurred at the platform of the SX blade when a constant withdrawal rate was used in manufacturing process.In order to avoid the formation of the stray crystal,the multi-scale coupled models and the withdrawal rate optimized technique were applied to the same SX turbine blade.The modeling results indicated that the optimized variable withdrawal rate can achieve SX blade castings with no stray grains,which was also proved by the experiments.     

浮动式液压剪的结构特点及参数计算

本文结合作者的浮动式液压剪的设计、调试体会,分析了液压剪的结构组成,并对液压剪设计所需的一些重要参数进行确定。     

Exploratory Study on Cyclones of Modified Designs

This paper introduces a new design of cyclone, named triple cyclone, created by adding two more cylinders to the conventional cyclone. The performance of the triple cyclone was evaluated systematically together with the previously reported double cyclone. The tests showed that the collection efficiencies of double and triple cyclones were lower than those of the conventional cyclone with the same body diameter and identical gas inlet and outlet size. Of the three designs, the collection efficiency of the triple cyclone was the lowest. Accordingly, the highest pressure drop was observed for the conventional cyclone, and the pressure drop for the triple cyclone was the lowest. These results are probably attributed to the relatively weak vortices formed within triple and double cyclones.     

一种叶片安装角可调的离心泵设计

将叶片设计成若干带有凸形槽的长方块和带有凹形槽的长方块凸凹相对镶嵌、依次连接组成可伸缩叶片,将叶片的两端轴固定在轮盘的内、外两边缘,将轮盘的内边缘做成可以转动的,通过转动内边缘(圆环)改变叶片在轮盘的长度,从而改变叶片的内、外安装角。     

Simultaneous neutron transmission and diffraction imaging investigations of single crystal nickel-based superalloy turbine blades

The integrity of turbine blades is at the heart of every operating aerospace engine or land-based gas turbine. In the most demanding environments, they are cast as single crystals. Whereas traditional neutron imaging is an excellent tool for the non-destructive testing in search of cracks or residual core material, it is insensitive to variations in crystallographic properties. In this work we show that by simultaneous imaging of the diffracted neutrons, one can also probe variations in crystal orientation. In a matter of seconds, different dendritic growth in two industrial turbine blades could be ascertained.     

铁精粉环境中圆形料场堆取料机的设计与应用

冶金行业的铁精粉属于大密度的散状物料,目前其存储大多采用露天条形料场的形式,存储过程中存在严重的物料浪费和环境污染问题。本文将在煤炭行业广泛应用的圆形料场系统引入到铁精粉环境中,详细介绍了铁精粉环境中的圆形料场堆取料机设计的关键点、运行工艺、使用维护等。实际工程应用表明,该系统可以很好地运用在铁精粉环境中,减少了铁精粉的浪费,并降低对环境的污染。     

风力发电机组独立变桨鲁棒自适应桨距角跟踪控制

在全面考虑风力发电机组桨叶所受各种载荷的情况下,建立了含有时变不确定项、未知载荷干扰的桨叶动力学数学模型,该模型精确描述了桨叶系统的非线性动力学行为。模型存在很多不确定时变参数和未知干扰项,针对这一复杂多变的桨叶模型,采用鲁棒自适应控制方法,成功设计了独立桨距角跟踪控制器。利用李雅普诺夫(Lyapunov)稳定性理论,证明了系统的稳定性。采用Matlab/Simulink仿真软件,建立了风力机组桨叶动力学仿真模型。仿真结果表明,所设计的桨叶桨距角控制器,在系统参数和所受干扰完全未知、不确定且时变的情况下,能够快速跟踪期望的桨距角,表现出良好的鲁棒性。