叶片型线对纯径流式向心透平气动性能的影响

以实验室的某纯径流式可调向心透平为研究对象，应用计算流体力学软件FLUENT,比较分析了几种不同曲线为动叶叶型对透平性能的影响；在此基础上，提出以阿基米德螺线为中弧线的叶片参数化造型方法，结果得到气动性能良好的叶片型线，阿基米德螺线叶型的叶轮效率比连锁螺线提高8%;参数优化后的叶型比原曲线叶轮效率提升5%左右。以优化后的曲线为叶轮型线，在不同操作参数下，得到了透平的轴效率特性曲线。研究可为小功率向心透平的叶片设计和优化提供指导。     

单级离心压气机气动性能预测与优化设计

为了提升低转速工况下压气机的气动性能,采用人工神经网络与遗传算法相结合的优化方法对某单级离心压气机离心叶轮的弯特性进行优化计算。利用NUMECA软件对该离心压气机进行了不同转速的数值模拟,得到压气机不同工况下的气动性能。通过设置不同控制参数和曲线形式对离心叶轮叶片进行参数化拟合,以8个改变叶片弯特性的参数为自由参数进行了叶型优化设计,最终得到了优化后的叶轮叶片。结果表明:优化后在低转速的设计工况下离心压气机压比增加了4.69%,稳定裕度拓宽了17.41%。     

叶片缝隙对叶片式波力发电叶轮转矩的影响

基于叶片式波力发电装置原型的特点,结合试验水槽的结构确定试验方案,采用高速摄影氢气泡技术测量了三种叶型不同叶片缝隙下的来流速度和叶型受力,并结合试验数据分析了不同缝隙对同种叶型叶轮竖置放置方式转矩的影响.结果表明,在试验来流速度0.165～0.270 m/s、叶片缝隙3 mm时的叶轮产生的转矩较其他缝隙大.     

叶片轴向进气的离心叶轮设计及分析

研究了位于叶轮0截面叶片轴向进气的离心叶轮气动设计方法和规律.采用四阶三次Bezier曲线生成叶轮子午流道型线,通过分段多项式函数给定叶片在轮盘和轮盖面上的角动量,并针对叶片轴向进气离心叶轮,提出了叶轮进口相对直径的修正公式,研究了其叶片安装角的分布规律.结果表明:轴向进气叶轮叶片安装角分布规律与径向进气叶轮的叶片安装角不同,其叶片安装角基本按单调方式增加;由叶轮进口相对直径修正公式计算后,在工况范围内的全压多变效率可以提高5%左右.     

表面粗糙度对透平叶片气动特性的影响研究

叶片为透平的核心部件,其气动性能直接影响透平的整体效率,叶片表面粗糙度的水平会影响透平级压力,导致叶型损失发生变化。应用数值模拟技术对某冲动式和反动式机组各4级透平级进行分析,考虑反动度、载荷分布以及旋转等多种因素,研究表面粗糙度变化对透平叶片气动性能的影响。CFD数值研究表明:叶型损失变化曲线的斜率随透平叶片表面粗糙度的增大逐渐变小;不同反动度的透平叶片受叶片表面粗糙度的影响存在差异,冲动式叶片相对反动式叶片受到的影响更为明显;吸力面上的粗糙度对气动性能的影响明显大于压力面粗糙度的影响,这种影响作用在反动度提高后相应变弱。研究成果可为透平叶片设计和加工提供参考。     

Bezier函数型弯叶片及其在带遮风罩垂直轴风力机中的应用

引入X弯度与Y弯度2个参数,提出了一种基于Bezier函数思想的叶型几何参数设计方法,通过分析传统垂直轴风力机效率低的原因,在此基础上提出了一种带有遮风罩的垂直轴风力机,并将基于Bezier函数生成的弯叶片应用于该风力机中.通过CFD数值模拟方法,研究了该风力机的气动特性,以及各种叶片的弯曲形式对其气动性能的影响.结果表明:遮风罩可以有效降低因来流对动叶轮吸力面的直接冲击而造成的阻力扭矩,风力机平均扭矩可提高107%;叶片的弯曲程度是由X弯度和Y弯度共同作用的结果,当X弯度与Y弯度在一定范围内具有局部最优值时,所形成叶片的垂直轴风力机的气动性能最佳,与普通半圆形叶片相比,风力机总扭转矩提高了33.8%.     

汽轮机调节级喷嘴组气动优化设计

采用叶轮机械优化设计平台FINE/Design3D对调节级喷嘴组汽道进行全三维气动性能优化设计,在保证工作点不发生偏离的前提下,提高其等熵效率。经过分析,优化后喷嘴组叶片由于采用加载叶型,有效的抑制叶片表面的附面层厚度,降低叶型损失;喷嘴组外端壁型线更加平缓,端壁损失和二次流损失得到了有效地抑制。额定工况下,调节级等熵效率提高了1.8%,并且在其它工况下调节级气动性能都有明显提高。     

冷却风扇变密流型扭叶片设计方法及其气动特性的数值研究

利用"径向平衡"原理,推导了轴流叶轮出口通流速度沿叶高的分布方程,并基于此提出了一种新的"变密流型"扭叶片设计方法.将该方法运用于某型叶轮的设计,并采用CFD技术,研究了该类扭叶片的气动特性.通过与传统的"等密流型"扭叶片及原始直叶片的气动性能的比较,发现"变密流型"扭叶片不仅能扩大小流量下风扇的稳定工况范围,而且其风压明显增加,有助于提高冷却风扇的散热性能.     

机翼型及板型叶片轴流风机气动性能计算及比较

采用数值模拟方法对机翼型及板型叶片的轴流风机的气动性能进行了比较.通过对比这两种叶型的风机在相同几何条件下的流量、全压升及效率,得到了不同叶片型线对风机气动性能的影响规律.数值模拟结果表明机翼型叶片的全压效率、通流能力和做功能力等方面比相应的板型叶片具有优越性.     

采用NURBS的某级透平叶片全三维气动最优化设计

用NURBS对叶轮机械叶片三维型面和基迭线进行参数化表达,实现了对叶片三维型面和基迭线弯、倾、掠、扭的变形控制.该方法为叶片的自动优化设计提供设计变量.把该方法构建的叶片全三维控制模块集成到基于商业软件iSIGHT的叶片粘性气动优化设计平台中,在该平台上选择优化算法对某级透平叶片进行了全三维气动优化设计实验,优化的目标是使级效率尽可能的高,同时流量不能降低并且动叶叶根前端的温度尽可能低.实验结果表明：优化后的叶型性能有所改善,同时也满足了流量和温度约束条件的要求.图23参5     

Experimental Investigation of Aerodynamic Performance due to Blade Tip Clearance in a Gas Turbine Rotor Cascade

This study examines how the complex flow structure within a gas turbine rotor affects aerodynamic loss. An unshrouded linear turbine cascade was built, and velocity and pressure fields were measured using a 5-hole probe. In order to elucidate the effect of tip clearance, the overall aerodynamic loss was evaluated by varying the tip clearance and examining the total pressure field for each case. The tip clearance was varied from 0% to 4.2% of blade span and the chord length based Reynolds number was fixed at 2×10⁵. For the case without tip clearance, a wake downstream of the blade trailing edge is observed, along with hub and tip passage vortices. These flow structures result in profile loss at the center of the blade span, and passage vortex related losses towards the hub and tip. As the tip clearance increases, a tip leakage vortex is formed, and it becomes stronger and eventually alters the tip passage vortex. Because of the interference of the secondary tip leakage flow with the main flow, the streamwise velocity decreases while the total pressure loss increases significantly by tenfold in the last 30% blade span region towards the tip for the 4.2% tip clearance case. It was additionally observed that the overall aerodynamic loss increases linearly with tip clearance.     

Optimization of Root Section for Ultra-long Steam Turbine Rotor Blade

This study presents the comparison of aerodynamic performances of two successive designs of the root profiles for the ultra-long rotor blade equipped with a straight fir-tree dovetail. Since aerodynamic and strength requirements laid upon the root section design are contradictory, it is necessary to aerodynamically optimize the design within the limits given by the foremost strength requirements. The most limiting criterion of the static strength is the size of the blade cross-section, which is determined by the number of blades in a rotor and also by the shape and size of a blade dovetail. The aerodynamic design requires mainly the zero incidence angle at the inlet of a profile and in the ideal case ensures that the load does not exceed a limit load condition. Moreover, the typical root profile cascades are transonic with supersonic exit Mach number, therefore, the shape of a suction side and a trailing edge has to respect transonic expansion of a working gas. In this paper, the two variants of root section profile cascades are compared and the aerodynamic qualities of both variants are verified using CFD simulation and two mutually independent experimental methods of measurements (optical and pneumatic).     

调节级局部进汽对下游动叶气动负荷影响的数值研究

基于舰船用主汽轮机多工况、变转速、变参数的特点,应用商业软件CFX对具有3组喷嘴的复速级叶栅进行全周数值模拟,着重分析了调节级局部进汽对下游动叶气动负荷的影响,数值模拟结果表明,各个喷嘴组边界壁面的存在对流动具有较大影响,同时喷嘴叶栅Ⅰ的叶片型线的不同导致边界畸变对流动的影响更敏感。动叶叶栅的压力分布特点表明了尾迹低速区和主流低压区是形成动叶流动参数不稳定的主要因素,从而形成了叶栅内特有的非定常流动现象。     

增压器压气机叶片结构/振动一体化优化设计

以废气涡轮增压器压气机叶轮为研究对象,创建了压气机叶片的三维参数化模型,通过全三维流场仿真分析,得到压气机的气动性能及叶片表面的压力分布.在不改变叶片形状、保证压气机气动性能的情况下,对叶片的静强度及振动特性进行了一体化优化设计.以叶片4个关键截面的叶顶、叶根厚度为设计变量,以离心力及气动压力作用下叶片的最大Mises应力、叶片的一阶动频为约束,以叶片体积为目标函数,在iSIGHT优化平台上集成了I-DEAS、ANSYS软件,采用混合整型优化和自适应模拟退火算法的组合优化方法,在满足叶片静强度小于屈服强度和一阶动频大于3倍工作频率的条件下,叶片体积(质量)减小了14.7%.     

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。     

大型湿冷汽轮机1450mm末级叶片CFD数值研究

针对火电全转速1450mm末级叶片进行了CFD数值研究。结果表明:在1450mm末级叶片的气动设计过程中,应用先进的全三维CFD计算分析方法进行合理的流型设计和气动匹配,保证了叶片具有优良的气动性能。     

倒角和间隙对跨音轴流压气机气动性能的影响

通过对一单级跨音速轴流压气机的流场进行数值模拟,研究了动叶根部倒角以及顶部间隙对流场气动性能的影响.结果表明:动叶叶顶间隙会造成顶部区域的通流阻塞并加重顶部分离损失,根部倒角会减小根部的气流折转角,降低做功能力,而且扩大根部分离区,减小根部流量,增大根部分离损失,因此为了提高数值模拟的准确性应考虑动叶叶顶间隙和根部倒角.     

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.     

几种超音速叶型的设计与比较

针对3种超音速叶型,基于遗传算法和人工神经网络,对这3个叶型进行单个工况点的优化设计,并对得到的所有叶型的气动性能进行多个马赫数工况点的数值分析以及综合比较,分析叶片型面的改变对多个工况下叶片气动性能的影响。结果表明,优化设计使2种叶型在超音速工况下的气动性能显著提高,1种叶型在临界及亚临界工况下的气动性能显著提高,从而获得每一工况点下的最优叶型。     

A Robust Blade Design Method based on Non-Intrusive Polynomial Chaos Considering Profile Error

To weaken the influence of profile error on compressor aerodynamic performance, especially on pressure ratio and efficiency, a robust design method considering profile error is built to improve the robustness of aerodynamic performance of the blade. The characteristics of profile error are random and small-scaled, which means that to evaluate the influence of profile error on blade aerodynamic performance is a time-intensive and high-precision work. For this reason, non-intrusive polynomial chaos(NIPC) and Kriging surrogate model are introduced in this robust design method to improve the efficiency of uncertainty quantification(UQ) and ensure the evaluate accuracy. The profile error satisfies the Gaussian distribution, and NIPC is carried out to do uncertainty quantification since it has advantages in prediction accuracy and efficiency to get statistical behavior of random profile error. In the integrand points of NIPC, several surrogate models are established based on Latin hypercube sampling(LHS) + Kriging, which further reduces the costs of optimization design by replacing calling computational fluid dynamic(CFD) repeatedly. The results show that this robust design method can significantly improve the performance robustness in shorter time(40 times faster) without losing accuracy, which is meaningful in engineering application to reduce manufacturing cost in the premise of ensuring the aerodynamic performance. Mechanism analysis of the robustness improvement samples carried out in current work can help find out the key parameter dominating the robustness under the disturbance of profile error, which is meaningful to further improvement of compressor robustness.