基于三维热弹性接触的汽轮机调节级叶片枞树型叶根轮缘结构的优化

在考虑高温热变形影响的前提下,对汽轮机调节级叶片枞树型叶根轮缘结构进行了优化研究．采用有限元分析软件Ansys的参数化设计语言APDL建立了枞树型叶根轮缘的参数化模型,以叶根轮缘的8个关键尺寸作为设计变量,以叶根轮缘处最大等效应力达到最小为目标函数,应用模式搜索算法进行优化控制,对叶根轮缘结构进行多变量的优化分析,获得了使叶根轮缘处最大等效应力大幅减小的枞树型叶根轮缘优化型线．结果表明：相对于原始结构,优化后,叶根和轮缘处的最大等效应力分别降低了19．84％和6．48％,提高了汽轮机运行的可靠性．     

透平机械枞树形叶根轮缘优化方法研究

枞树形叶根广泛应用于燃气轮机和大功率蒸汽轮机叶片,叶根的结构在一定程度上影响着整个叶片的安全性。本文基于参数化语言APDL,利用有限元软件ANSYS对具有复杂三维接触的枞树形叶根轮缘进行优化。以接触面倾斜角为优化变量,首先采用随机搜索方法得到较小的合理解范围,然后使用零阶算法和一阶算法分别进行优化分析,得到了接触面倾角最优值,使叶根轮缘的最大等效应力最小。优化结果表明在本研究中,初值对零阶算法影响不大,对一阶算法的收敛存在一定影响。通过优化前后结果对比,发现当接触面倾角从初始设计的25°变为最优值40.75°时,叶根及轮缘的最大等效应力分别减少了0.82%和11.2%。本文方法可以为枞树形叶根轮缘部分设计提供理论支持和基础数据。     

透平复杂阻尼结构叶片强度与振动特性优化研究

结合三维有限元分析方法和数学优化算法,构建了汽轮机叶片的结构优化体系。对具有复杂阻尼结构的汽轮机叶片枞树形叶根轮缘结构进行优化,使叶根和轮缘的最大等效应力分别降低了13.45%和12.26%,提高了叶片的强度性能;对某汽轮机整圈自锁叶片的围带结构进行优化,使叶片整圈振动各阶频率均满足振动安全性要求,改善了叶片的振动性能。建立的结构优化方法具有良好的工程应用价值,可以应用于叶片结构设计。     

考虑制造偏差的高温叶片热弹性接触应力研究

枞树型叶根广泛应用于燃气轮机和大功率蒸汽轮机叶片,其可靠性严重影响着叶片的安全运行.采用三维热弹性有限元分析技术建立了仅考虑离心力载荷及综合考虑离心力和温度载荷的数值模型,对4种不同的叶根轮缘接触面制造偏差状况下叶根应力进行了详细分析,发现常温下设计良好的枞树型叶根轮缘,在高温下由于热胀导致的变形,将使叶根承载分布不均,从而产生很大的应力,并且应力状况也随着制造偏差而不同.所以在设计高温级叶片枞树型叶根型线时,需要综合考虑叶根的制造偏差以及工作状态下的承载情况进行安全性校核.     

905毫米长叶片枞树型叶根光弹性实验

1 前言我厂最新开发的905毫米末级长叶片采用三对齿的圆弧枞树型叶根。枞树型叶根能利用各对齿逐对承担叶片离心力载荷,同时逐步缩小齿根截面,从而减小了叶根及轮缘的尺寸,而叶根与轮缘配对时,齿的非工作面存有间隙,这样使叶根与轮缘在受热后能自由膨胀,以减少热应力;对于松装结构的枞树型叶根,它还能自动定心。但枞树型叶     

基于差分进化算法的枞树型叶根测量数据处理方法

结合枞树型叶根的型线特点,将某一大功率汽轮机末级动叶枞树型叶根的测量数据拟合处理,转化成多约束条件下多参数单目标最小值优化问题,并采用差分进化算法进行求解。拟合结果表明这种处理模式是合理的,差分进化算法能够很好地应用于该类工业测量数据的拟合。     

700毫米长叶片枞树型叶根各齿受力分布的计算分析

一、引言枞树型叶根能利用各对齿逐对承担叶片离心力载荷,同时逐步缩小齿根截面,从而充分利用材料强度,减小了叶根及轮缘的尺寸,因此这种叶根型式主要用在叶片离心力载荷较大或大功率机组的调节级及末几级长叶片中。     

五叉等强叶根型线设计

一、前言长叶片是汽轮机的关键部件之一,对于长叶片,不仅要求其气动性能、强度振动特性优良,而且要求叶根必须安全可靠。为此,长叶片叶根的设计是一项很重要的工作。目前,随着国内外大功率汽轮机的发展,末级叶片的长度也在不断增加,使得叶根承受的离心力显著增大。解决这一问题的途径是:采用枞树形叶根,增加叉型叶根的叉腿及轮缘宽度,增加叉型叶根的叉腿数量,采用等强叉型叶根或者采用外包式叉型叶根     

用三维有限元确定枞树型叶根的结构

枞树形叶根在强度性能上的主要优点是它能利用各对齿逐对承担叶片离心力荷载,同时逐步缩小齿根截面,从而充分利用材料强度,减小叶根及轮缘尺寸。所以在汽轮机设计中,对末级叶片离心力荷载较大的情况下,大多采用枞树形叶根。从以往一些电厂叶片     

700毫米长叶片枞树型叶根的各齿受力分布实验研究

本文用电测和光测方法对700毫米长叶片各齿的受力分布进行了实验分析,得到了该叶片各齿的受力分布情况,为枞树型叶根的强度计算和改进提供了基础。一、引言枞树型叶根能利用各对齿逐对承担叶片离心力载荷,同时逐步缩小齿根截面,从而减小了叶根及轮缘的尺寸。而叶根与轮缘配合时,齿的非接触面存有间隙,这样使叶根和轮缘在受热后能自由膨胀,以减少热应     

斜齿枞树型叶根倾斜角度对叶根接触影响分析

文章针对不同倾斜角度，对斜齿枞树型叶根透平叶片的叶根和轮槽的接触状态进行了分析。通过三维建模和有限元分析，发现斜齿枞树型叶根各齿栽荷分布随角度变化不大，且各齿栽荷分布没有直齿枞树型各齿载荷分布均匀。叶根最大应力随叶根倾斜角增大而增大，对低温区叶片来说，由倾斜角度增大引起的叶片应力增大可忽略不计。但对于高温区叶片，减小倾斜角度以使叶片应力降低是很有积极意义的。本研究可为枞树型叶根的设计提供理论支持。     

围带及拉筋间隙装配的汽轮机末级长叶片的试验研究

阐述了汽轮机末级长叶片围带及拉筋的设计方法,通过对叶片的有限元分析确定围带及拉筋间隙,同时通过试验来验证有限元分析结果的精确性,掌握该结构叶片的设计原理和分析方法,为开发该结构的新叶片提供理论依据,以便满足汽轮机安全、可靠、高效运行要求。     

单晶涡轮叶片强度分析与结构优化设计

为提高某型燃气轮机的工作可靠性,对单晶涡轮叶片进行了强度分析与结构优化设计。采用第四强度理论,考虑了晶体取向、温度载荷、气动载荷和转速的影响,得到叶片的应力分布、典型截面的强度储备系数;根据诺顿蠕变方程计算关键节点的持久寿命;基于分析结果对叶片局部结构进行优化改进,将叶片质心向叶背侧偏移,调整进气前缘气膜孔的排列方式,并对新结构进行强度复算。结果表明：优化后的叶片静强度符合设计要求,消除了局部结构处的应力集中现象,叶身结构强度储备系数高于1.3,叶身两侧应力分布更加均匀,叶片在设计转速10%裕度范围内无共振现象发生。     

300MW汽轮机设备增容及系统优化改进

为降低机组热耗水平,提高机组整体安全性、可靠性和经济性,提高机组额定出力,实现机组节能降耗,针对1台300MW汽轮机机组采取了汽轮机设备及系统优化技改,实现了汽轮机提高额定出力并取得良好效果。     

某涡轮增压器涡轮叶片断裂故障分析及改进

针对某涡轮增压器涡轮叶片断裂问题,基于ANSYS有限元软件对该涡轮进行强度分析和振动特性分析.结果 表明:该涡轮一阶自振频率较低,一阶倍频比不满足设计要求,共振导致涡轮叶片断裂.在此基础上对涡轮整体结构进行了优化,优化后涡轮叶片一阶自振频率得到提升,叶片断裂问题得到解决.     

On the structural topology of wind turbine blades

As wind turbines continue to grow in size, it becomes increasingly important to ensure that they are as structurally efficient as possible to ensure that wind energy can be a cost‐effective source of power generation. A way to achieve this is through weight reductions in the blades of the wind turbine. In this study, topology optimization is used to find alternative structural configurations for a 45 m blade from a 3 MW wind turbine. The result of the topology optimization is a layout that varies along the blade length, transitioning from a structure with trailing edge reinforcement to one with offset spar caps. Sizing optimization was then performed on a section with the trailing edge reinforcement and was shown to offer potential weight savings of 13.8% when compared with a more conventional design. These findings indicate that the conventional structural layout of a wind turbine blade is sub‐optimal under the static load conditions that were applied, suggesting an opportunity to reduce blade weight and cost. Copyright © 2012 John Wiley & Sons, Ltd.     

Efficient incorporation of fatigue damage constraints in wind turbine blade optimization

Wind turbine design is a challenging multidisciplinary optimization problem, where the aerodynamic shapes, structural member sizing, and material composition must all be determined and optimized. Some previous blade design methods incorporate static loading with an added safety factor to account for dynamic effects. Others incorporate dynamic loading, but in general limit, the evaluation to a few design cases. By not fully incorporating the dynamic loading of the wind turbine, the final turbine blade design is either too conservative by overemphasizing the dynamic effects or infeasible by failing to adequately account for these effects. We propose an iterative method that estimates fatigue effects during the optimization process while quickly converging to the true solution. We also demonstrate an alternate approach where a surrogate model is trained to efficiently estimate the dynamic loading of the wind turbine in the design process. This surrogate model, once trained, was then incorporated in the optimization loop of the wind turbine blade. In contrast to the iterative method, there is significant upfront computational cost to construct the surrogate model. However, this surrogate model has been generalized to be used for different rated turbines and can predict the fatigue damage of a wind turbine with less than 5% error for baseline wind turbines of the same family. These methods can be used instead of the more computationally expensive method of calculating the dynamic loading of the turbine within the optimization routine.     

透平叶片弯、扭、掠联合造型规律及其气动性能研究

为研究静叶弯、扭、掠联合造型对流场结构的影响,以某高压透平首级叶片为研究对象,借助计算流体力学与正交优化方法,基于动静叶最佳匹配原则（即对于每种静叶构型,动叶都进行了相应的扭转规律变化,使得动静叶气动性能处于最佳匹配状态）,研究了静叶不同复合构型方式对流场结构的影响。结果表明：在合理的静叶弯曲规律下,静叶扭转改型对透平性能有较大影响,掠改型对透平性能影响有限;在一定的扭转规律下,对静叶进行掠改型对轮周效率的影响较小,仅后掠改型会提高透平的轮周效率;对弯扭掠静叶匹配扭动叶进行联合优化,得到的最佳透平的轮周效率为87.12%,与原始透平相比,轮周效率提高了2.09%。     

Reliability design method for steam turbine blades

Based on theories of probability and statistics, and taking static stresses, dynamic stresses, endurance strength, safety ratios, vibration frequencies and exciting force frequencies of blades as random variables, a reliability design method for steam turbine blades is presented. The purport and calculation method for blade reliability are expounded. The distribution parameters of random variables are determined after analysis and numerical calculation of test data. The fatigue strength and the vibration design reliability of turbine blades are determined with the aid of a probabilistic design method and by interference models for stress distribution and strength distribution. Some blade reliability design calculation formulas for a dynamic stress design method, a safety ratio design method for fatigue strength, and a vibration reliability design method for the first and second types of tuned blades and a packet of blades on a disk connected closely, are given together with some practical examples. With these methods, the design reliability of steam turbine blades can be guaranteed in the design stage. This research may provide some scientific basis for reliability design of steam turbine blades. __________ Translated from Chinese Journal of Applied Mechanics, 2007, 24(3): 331–335 [译自: 应用力学学报]