变叶片数和长短叶片对某跨音速向心汽轮机气动性能的影响

利用三维数值模拟的方法对一跨音速向心汽轮机进行了气动设计优化分析,通过改变叶片数和采用长短叶片结构等方法分析其对叶轮内流场的影响,分析了TC-4P叶型的气动特点。结果表明:TC-4P叶型虽然只是普通的渐缩型流道的叶栅,但利用其斜切部的膨胀能力,对超音速工况一样具有良好的性能;叶轮采用长短叶片的方法可以有效地降低余速损失,并改善流动状况。     

Numerical Investigations of the Influence of Unsteady Vane Trailing Edge Shock Wave on Film Cooling Effectiveness of Rotor Blade Leading Edge

Unsteady numerical simulations of a high-load transonic turbine stage have been carried out to study the influences of vane trailing edge outer-extending shockwave on rotor blade leading edge film cooling performance. The turbine stage used in this paper is composed of a vane section and a rotor one which are both near the root section of a transonic high-load turbine stage. The Mach number is 0.94 at vane outlet, and the relative Mach number is above 1.10 at rotor outlet. Various positions and oblique angles of film cooling holes were investigated in this research. Results show that the cooling efficiency on the blade surface of rotor near leading edge is significantly affected by vane trailing edge outer-extending shockwave in some cases. In the cases that film holes are close to leading edge, cooling performance suffers more from the sweeping vane trailing edge outer-extending shockwave. In addition, coolant flow ejected from oblique film holes is harder to separate from the blade surface of rotor, and can cover more blade area even under the effects of sweeping vane trailing edge shockwave. As a result, oblique film holes can provide better film cooling performance than vertical film holes do near the leading edge on turbine blade which is swept by shockwaves.     

Innovative design approaches for large wind turbine blades

A preliminary design study of an advanced 50 m blade for utility wind turbines is presented and discussed. The effort was part of the Department of Energy WindPACT Blade System Design Study with the goal to investigate and evaluate design and manufacturing issues for wind turbine blades in the 1–10 MW size range. Two different blade designs are considered and compared in this article. The first is a fibreglass design, while the second design selectively incorporates carbon fibre in the main structural elements. The addition of carbon results in modest cost increases and provides significant benefits, particularly with respect to blade deflection. The structural efficiency of both designs was maximized by tailoring the thickness of the blade cross‐sections to simplify the construction of the internal members. Inboard the blades incorporate thick blunt trailing edge aerofoils (flatback aerofoils), while outboard more conventional sharp trailing edge high‐lift aerofoils are used. The outboard section chord lengths were adjusted to yield the least complex and costly internal blade structure. A significant portion of blade weight is related to the root buildup and metal hardware for typical root attachment designs. The results show that increasing the number of studs has a positive effect on total weight, because it reduces the required root laminate thickness. The aerodynamic performance of the blade aerofoils was predicted using computational techniques that properly simulate blunt trailing edge flows. The performance of the rotor was predicted assuming both clean and soiled blade surface conditions. The rotor is shown to provide excellent performance at a weight significantly lower than that of current rotors of this size. Copyright © 2004 John Wiley & Sons, Ltd.     

Influence of Hub Contouring on the Performance of a Transonic Axial Compressor Stage with Low Hub-Tip Ratio

The rotor blade height with low hub-tip ratio is relatively longer,and the aerodynamic parameters change drastically from hub to tip.Especially the organization of flow field at hub becomes more difficult.This paper takes a transonic 1.5-stage axial compressor with low hub-tip ratio as the research object.The influence of four types of rotor hub contouring on the performance of transonic rotor and stage is explored through numerical simulation.The three-dimensional numerical simulation results show that different hub contourings have obvious influence on the flow field of transonic compressor rotor and stage,thus affecting the compressor performance.The detailed comparison is conducted at the rotor peak efficiency point for each hub contouring.Compared with the linear hub contouring,the concave hub contouring can improve the flow capacity,improve the rotor working capacity,and increase the flow rate.The flow field near blade root and efficiency of transonic rotor is improved.The convex hub contouring will reduce the mass flow rate,pressure ratio and efficiency of the transonic rotor.Full consideration should be given to the influence of stator flow field by hub contouring.     

跨声速串列转子叶型流动特性分析

串列叶片技术可以突破常规压气机叶片的负荷极限,因此成为下一代高负荷压气机设计技术的研究热点。为了拓展串列叶片的使用范围,采用数值模拟的方法对跨声速串列转子叶型（来流马赫数1.2）流动特性及前排叶片尾迹发展演化规律展开研究。得出结论：全工况范围内,前排叶片总压损失占比超过50%,前排叶片激波系结构的优化设计是影响串列叶型性能的关键因素;随着出口背压提高,前排叶片尾迹厚度先增加后减小,导致尾迹厚度不同的根本原因是流出前排叶片通道时尾迹的初始速度亏损不同,后排叶片通道的扩压对初始速度亏损有进一步的放大作用。     

高压比跨音速离心叶轮的三维叶片型线优化

应用Fine／Design3D软件,采用CFD方法对某一高压比跨音速离心叶轮进行三维叶片型线优化设计,优化结果是效率提高了1．05％,压比和流量也都得到了提高。从几何变化分析,相对于根部、中径截面叶片型线,叶片顶部型线优化是提高跨音速离心叶轮效率的有效措施。     

Reconstruction method for running shape of rotor blade considering nonlinear stiffness and loads

The aerodynamic and centrifugal loads acting on the rotating blade make the blade configuration deformed comparing to its shape at rest. Accurate prediction of the running blade configuration plays a significant role in examining and analyzing turbomachinery performance. Considering nonlinear stiffness and loads, a reconstruction method is presented to address transformation of a rotating blade from cold to hot state. When calculating blade deformations, the blade stiffness and load conditions are updated simultaneously as blade shape varies. The reconstruction procedure is iterated till a converged hot blade shape is obtained. This method has been employed to determine the operating blade shapes of a test rotor blade and the Stage 37 rotor blade. The calculated results are compared with the experiments. The results show that the proposed method used for blade operating shape prediction is effective. The studies also show that this method can improve precision of finite element analysis and aerodynamic performance analysis.     

高负荷扩压串列转子的设计技术探讨

对高负荷串列转子的设计技术进行了探讨,通过速度三角形分析与可控扩散叶型的反问题设计技术相结合,完成了二维高负荷串列转子的设计方案。数值计算表明:所设计的串列转子有优越的气动性能,效率能达到91%,并且在50°的气流弯折角和1.68的增压比情况下无分离流动,保证了其做功能力达到了原始两级的做功能力。     

A practical approach for selecting optimum wind rotors

The main objective of this paper is to categorize practical families of horizontal-axis wind turbine rotors, which are optimized to produce the largest possible power output. Refined blade geometry is obtained from the best approximation of the calculated theoretical optimum chord and twist distributions of the rotating blade. The mathematical formulation is based on dimensionless quantities so as to make the aerodynamic analysis valid for any arbitrary turbine models having different rotor sizes and operating at different wind regimes. The selected design parameters include the number of blades, type of airfoil section and the blade root offset from hub center. The effects of wind shear as well as tower shadow are also examined. A computer program has been developed to automate the overall analysis procedures, and several numerical examples are given showing the variation of the power and thrust coefficients with the design tip speed ratio for various rotor configurations.     

Aerodynamic Loading Distribution Effects on the Overall Performance of Ultra-High-Lift L Turbine Cascades简

The present paper reports the results of an experimental investigation aimed at comparing aerodynamic perform- ance of three low-pressure turbine cascades for several Reynolds numbers under steady and unsteady inflows. This study is focused on finding design criteria useful to reduce both profile and secondary losses in the aero-engine LP turbine for the different flight conditions. The baseline blade cascade, characterized by a standard aerodynamic loading （Zw=1.03）, has been compared with two Ultra-High-Lift profiles with the same Zweifel number （Zw=1.3 for both cascades）, but different velocity peak positions, leading to front and mid-loaded blade cascade configurations. The aerodynamic flow fields downstream of the cascades have been experimentally in- vestigated for Reynolds numbers in the range 70000〈Re〈300000, where lower and upper limits are typical of cruise and take-off/landing conditions, respectively. The effects induced by the incoming wakes at the reduced frequency ./＋=0.62 on both profile and secondary flow losses for the three different cascade designs have been studied. Total pressure and velocity distributions have been measured by means of a miniaturized 5-hole probe in a tangential plane downstream of the cascade for both inflow conditions. The analysis of the results allows the evaluation of the aerodynamic performance of the blade cascades in terms of profile and secondary losses and the understanding of the effects of loading distribution and Zweifel number on secondary flows. When operating un- der unsteady inflow, contrarily to the steady case, the mid-loaded cascade has been found to be characterized by the lowest profile and secondary losses, making it the most attractive solution for the design of blades working in real conditions where unsteady inflow effects are present.     

高效低载的三维风力机叶片外形优化设计方法

常规风力机叶片的优化设计都是从二维翼型开始的,且翼型总是以升阻比最大为优化目标。然而,二维翼型的升阻比最大和三维叶片的高风能利用率与低气动载荷有本质的不同,采用以往的叶片优化方法常常会在提高风能利用率的同时,使叶片所受的气动载荷也提高。针对这一问题,提出基于多岛遗传算法和动量叶素理论,在给定风况条件下,以加权风能利用率最高与气动载荷最小为目标函数,以叶片各个截面的翼型型线及扭角作为设计变量,对三维叶片开展多目标优化方法设计研究。并对某实际NREL Phase VI叶片进行优化设计,结果表明：在给定风况下相比原叶片,优化叶片在风能利用率提升了3.06%的基础上,叶根弯矩降低了11.68%。在变转速与变风况下,优化叶片的气动效率整体提升,叶根弯矩明显降低。     

Unsteady rotor-stator interaction in high speed compressor and turbine stages

The blade row interaction can alter the time-mean flow and therefore be of interest for aerodynamic design analysis. Whereas results within low subsonic turbomachines are quite numerous in the literature, there have been far fewer works which give results of blade row interaction within high speed cases. Two cases are related in this paper. First, the effects of an incoming wake on the rotor flow field of a transonic compressor are analyzed. The blade row interaction proved to be positive regarding the total pressure ratio, but negative regarding the losses. The second case concerns a transonic turbine. Particular emphasis is placed on the assessment of the deterministic correlations included in the Averaged Passage Equation System.     

Aeroelastic multidisciplinary design optimization of a swept wind turbine blade

Mitigating loads on a wind turbine rotor can reduce the cost of energy. Sweeping blades produces a structural coupling between flapwise bending and torsion, which can be used for load alleviation purposes. A multidisciplinary design optimization (MDO) problem is formulated including the blade sweep as a design variable. A multifidelity approach is used to confront the crucial effects of structural coupling on the estimation of the loads. During the MDO, ultimate and damage equivalent loads are estimated using steady‐state and frequency‐domain–based models, respectively. The final designs are verified against time‐domain full design load basis aeroelastic simulations to ensure that they comply with the constraints. A 10‐MW wind turbine blade is optimized by minimizing a cost function that includes mass and blade root flapwise fatigue loading. The design space is subjected to constraints that represent all the necessary requirements for standard design of wind turbines. Simultaneous aerodynamic and structural optimization is performed with and without sweep as a design variable. When sweep is included in the MDO process, further minimization of the cost function can be obtained. To show this achievement, a set of optimized straight blade designs is compared to a set of optimized swept blade designs. Relative to the respective optimized straight designs, the blade mass of the swept blades is reduced of an extra 2% to 3% and the blade root flapwise fatigue damage equivalent load by a further 8%.     

Aerodynamic sweeping study and design for transonic compressor rotor blades

<正>The objective of the present paper is to study the sweep effect on the blade design performance of a transonic compressor rotor.The baseline to be modified and swept is a designed well efficient transonic single rotor compressor. The first part of the present study is concerning the sweep effect with straight leading edge.In this case fixing the hub section the swept blade is formed by tilting the leading edge with whole blade forwards and backwards axially.The second part is to use an optimization strategy with simple gradient-based optimum-searching method and multi-section blade parameterization technique to search and generate an optimal swept rotor with curved arbitrary leading edge.Its adiabatic efficiency is a little bit greater than that of the reference un-swept rotor.     

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。     

1 200mm叶片的非线性摩擦减振特性

根据国内外同行多年设计经验,综合考虑安全性、经济性与工艺性,设计了1200mm长叶片的结构,其中静叶为变截面空间三维弯扭联合成型叶片;动叶为考虑大变形、附加动应力最小的变截面空间反扭成型叶片;动叶的拉筋和围带设计成自带凸台拉筋和自带围带整圈软联接;叶根方案确定为斜四齿枞树型。在此基础上采用固定界面模态综合法计算了整圈叶片的非线性振动响应。设计与计算结果表明:采用自带凸台拉筋和自带围带整圈软联接结构形式的1200mm长叶片,在外激振力作用下,具有良好的摩擦减振性能。     

Blade Parameterization and Aerodynamic Design Optimization for a 3D Transonic Compressor Rotor

The present paper describes an optimization methodology for aerodynamic design of turbomachinery combinedwith a rapid 3D blade and grid generator(RAPID3DGRID),a N.S.solver,a blade parameterization method(BPM),a gradient-based parameterization-analyzing method(GPAM),a response surface method(RSM)withzooming algorithm and a simple gradient method.By the use of blade parameterization method a transonic com-pressor rotor can be expressed by a set of polynomials,and then it enables us to transform coordinate-expressedblade data to parameter-expressed and then to reduce the number of parameters.With changing any one of theparameters and by applying grid generator and N.S.solver,we can obtain several groups of samples.Here onlyten parameters were considered to search an optimized compressor rotor.As a result of optimization,the adiabaticefficiency was increased by 1.73%.     

The inverse design of the wind turbine blade sections by the singularities method

The aerodynamic characteristics of wind turbines are closely related to the geometry of their blades. The innovation and the technological development of wind turbine blades can be centred on two tendencies. The first is to improve the shape of existing blades; the second is to design new shapes of blades. The aspiration in the two cases is to achieve an optimal circulation and hence enhancing some more ambitious aerodynamic characteristics. This paper presents an inverse design procedure, which can be adapted to both thin and thick wind turbine blade sections aiming to optimise the geometry for a prescribed distribution of bound vortices. A method for simulating the initial contour of the blade section is exposed, which simultaneously satisfy the aerodynamic and geometrical constraints under nominal conditions. A detailed definition of the function characterising the bound vortex distribution is presented. The inviscid velocity field and potential function distributions are obtained by the singularities method. In the design method implemented, these distributions and the circulation of bound vortices on the camber line of the blade profile, are used to rectify its camber in an iterative calculation leading to the final and optimal form of the blade section once convergence is attained. The scheme proposed has been used to design the entire blade of the wind turbine for a given span-wise distribution of bound circulation around the blade contour.     

Effect of Bowed/Leaned Vane on the Unsteady Aerodynamic Excitation in Transonic Turbine

To investigate the effect of bowed/leaned vane configurations on the aerodynamic performance and aerodynamic excitation in transonic high-pressure turbine, the full three-dimensional viscous unsteady numerical simulation was performed by solving N-S equations based on SAS SST method.The influence of bowed/leaned vanes on turbine efficiency and efficiency fluctuation was investigated. The action of vane modelling to the overall aerodynamic fluctuation level and the amplitude of each vane passing frequency were analyzed. By comparing instantaneous pressure fluctuation contours in the blade passage with space-time maps, the link of the pressure fluctuation on blade surface with flow distortions was achieved, which can reveal the mechanism of the impact of the vane modelling. As the results suggest, the turbine efficiency is promoted with positively leaned and bowed vane modelling, and the fluctuation of stage turbine efficiency is repressed, which contributes to the smooth running of the turbine stage. The blade aerodynamic excitation on the rotor blade is characterized by the motion of vane trailing edge shock system, and the vane configurations can reduce the fluctuation level on the rotor blade surface effectively. For the positively leaned vane configuration, the aerodynamic excitations at the root and tip region are affected by the impact of the amplitude of the first harmonic, whereas they are reduced with the decrease of the amplitude of the second and higher harmonics at midspan. For the positively bowed vane, aerodynamic excitation is repressed by reducing the amplitude of the third harmonic at the root region, and the first harmonic at the tip region, and the amplitude of each harmonic is reduced at the middle region.     

Effects of Width Variation of Pressure-Side Winglet on Tip Flow Structure in a Transonic Rotor

Tip leakage flow has become one of the major triggers for rotating stall in tip region of high loading transonic compressor rotors.Comparing with active flow control method,it’s wise to use blade tip modification to enlarge the stable operating range of rotor.Therefore,three pressure-side winglets with the maximum width of 2.0,2.5 and 3.0 times of the baseline rotor,are designed and surrounded the blade tip of NASA rotor 37,and the three new rotors are named as RPW1,RPW2,and RPW3 respectively.The numerical results show that the width of pressure-side winglet has significant influence on the stall margin and the minimum throttling massflow of rotor,while it produces less effect on the choking massflow and the peak efficiency of new rotors.As the width of the pressure-side winglet increases from new rotor RPW1 to RPW3,the strength of leakage massflow has been attenuated dramatically and a reduction of 20%in leakage massflow rate has appeared in the new rotor RPW3.By contrast,the extended blade tip caused by winglet has not introduced much more aerodynamic losses in tip region of rotor,and the new rotors with different width of pressure-side winglet have the similar peak efficiency to the baseline.The new shape of the leakage channel over blade tip which replaces of the static pressure difference near blade tip has dominated the behavior of the leakage flow in tip gap.As both the new aerodynamic boundary and throat in tip gap have reshaped by the low-velocity flow near the solid wall of extended blade tip,the discharging velocity and massflow rate of leakage flow have been suppressed obviously in new rotors.In addition,the increasing inlet axial velocity at the entrance of new rotor has increased slightly as well,which is attributed to the less blockage in the tip region of new rotor.In consideration of the increased inlet axial velocity and the weakened leakage flow,the new rotor presents an appropriately linear increase of the stall margin when the width of pressure-side winglet increases,and has a nearly 15%increase in new rotor RPW3.