“后部加载”叶型气动性能的研究

为了对具有“后部加载”叶型叶栅的气动性能进行了深入的了解,本文在环形叶栅低速风洞上对具有“后部加载”叶型的常规直叶片栅和弯叶片栅进行了吹风帝验,实验结果表明：采用先进的“后部加载”叶型和弯曲叶片较大地改善了静叶栅的气动性能。     

高效宽负荷汽轮机通流气动技术研究

文章针对高效宽负荷汽轮机中的通流气动技术进行了研究,包括高中压亚音速叶型设计、低压超音速叶片优化和低压排汽缸气动优化。亚音速叶型设计的主要目的是提高其宽负荷性,对新设叶型进行了叶栅试验和多级透平试验,新设的亚音速叶型不仅能量损失得到了降低,且攻角适应性更好;优化末级动静之间的匹配参数、静叶流型和弯曲规律及动叶型线的扭转规律,并对末级变工况性能进行分析,末级收益达到了预期收益效果;对低压排汽缸汽流的流动机理进行了深入分析,以削弱或消除通道涡为目的对排汽缸进行优化,极大程度改善了排汽缸的性能。     

具有后部加载叶型的环形静叶栅的旋涡结构

为了详细研究具有后部加载叶型的环形静叶栅的流场结构，在环形叶栅低速风洞上对具有后部加载叶型的环形弯曲叶片静叶栅上、下端壁以及叶片型面进行了墨迹显示实验，同时应用拓扑学原理分析了叶栅的壁面流谱，并据此分析提出了本实验叶栅的二次流动的拓扑示意图。     

可控扩散叶型振荡叶栅边界层转捩特性分析

为研究某重型燃气轮机的压气机叶栅在振荡条件下的非定常响应特性,采用基于γ-Reθ转捩模型的雷诺时均方程对可控扩散叶型组成的振荡叶栅进行了数值计算,研究了折合频率、来流攻角和前缘造型对叶片气动性能及表面边界层发展的影响。结果表明：叶片吸力面发生分离前存在较大的压力波动,边界层转捩后叶片表面压力波动减小;叶片振动对可控扩散叶型的分离转捩特性影响较大,随着叶片振动折合频率的增大,叶片吸力面边界层分离转捩位置向叶片前缘移动;通过优化前缘曲率造型能抑制边界层转捩位置的前移,同时改善振动状态下的前缘压力波动特征。     

905毫米长叶片跨音速平面叶栅试验研究

一、试验目的及要求研制905mm长叶片,需对叶片的特征截面叶型进行气动性能研究。为此,对叶片五个特征截面叶型进行平面叶栅试验模型设计,模型制造和吹风试验。通过对这五个截面叶型的叶栅吹风试验,可以得到气流流经叶片型面的叶片表面速度分布以     

多级轴流压气机级间参数测试的叶型受感部设计

针对某重型燃气轮机压气机的模化机级间测试需要,完成了压气机4级叶型受感部的设计,测点按流线布置在各级静叶前缘处,能够进行动叶出口的总压、总温测量,用于分析压气机的性能及内部流场特性。     

IGCC与联合循环用蒸汽透平叶片数值模拟及试验研究

介绍了通过全三维数值模拟,在IGCC使用的蒸汽透平的叶片设计中采用后加载叶型和弯曲成型静叶栅,并以空气动力试验来考察其性能,试验研究的结果表明设计达到了预期目标。该成果可应用于一般联合循环用的汽轮机设计中。     

前加载和后加载叶片气动性能的数值研究

采用数值计算的方法对后加载和前加载叶片的气动性能进行了详细的分析,研究了无扭曲的叶片与弯曲叶片的压力系数分布以及负荷分布特性,分析了后加载和前加载叶栅内总压分布规律和总压损失沿叶高的变化情况.数值计算得到的后加载和前加载无扭曲的叶片中部压力系数分布与平面叶栅试验数据吻合良好,后加载弯曲叶片和前加载弯曲叶片的近叶顶、中部和近叶根处的压力系数分布与试验数据基本吻合.     

叶片吸力侧反曲率设计对流道内激波强度影响的研究

现代航空燃气轮机负荷升高,流道内马赫数提高,激波损失增大,流动熵增增加,气动效率下降,能量损失增加.在大功率高负荷航空燃气轮机中,激波对气动性能影响更加明显.本文对某型航空发动机涡轮叶型进行了改型设计,分析了在不同出口马赫数条件下激波的结构,研究了通过控制激波强度以减小叶型损失的方法.研究发现,吸力侧带有反曲率弧段的叶型对于控制激波强度、减少能量损失作用明显.     

采用后部加载叶型的国产200MW汽轮机高压级弯曲叶片的壁面静压场

将具有后部加载叶型的叶片应用于汽轮机中在我国还是一个崭新的课题,本文对采用后部加载叶型的国产２００ＭＷ汽轮机高压级弯曲叶片的壁面静压进行了详细的测量,并与直叶片进行了对比。     

Design and performance of a double-pitch wind turbine with non-twisted blades

A new design has been proposed for inexpensive wind turbine blades with high power coefficients.The new wind turbine blade has been subdivided into two, each with a different pitch angle, to optimise aerodynamic flow, absence of twist, and carries a variable chord along the blade itself.The new blade reveals some energy loss due to the tip vortices of each blade part (which can be minimised by winglets), yet proves that it is possible to create a wind turbine with high power coefficients.To design and evaluate the performance of the new wind turbine a numerical code, developed by the authors and based on blade element momentum theory, was implemented after validation by experimental measurement found in scientific literature. The code led to better choices of layout to maximise turbine performance.     

基于滑移网格的垂直轴潮流水轮机的三维数值模拟

为了探究翼型对垂直轴水轮机水力效率的影响,基于叶素理论分析建立了垂直轴潮流水轮机在水槽中的物理模型,采用滑移网格技术在Fluent软件中对模型的流场进行了三维数值模拟。在保持转速一定、更改来流速度即改变叶尖速比的条件下,分析了两种不同NACA翼型直叶片的潮流水轮机内部流场以及水力性能。结果表明,翼型以及叶片安装角对垂直轴潮流水轮机的利用效率影响很大,其流动特性与来流速度、叶片布置形式有重要联系,为新型潮流水轮机的设计和翼型的选择应用提供了依据。     

Time‐accurate blade surface static pressure behaviour on a rotating H‐Darrieus wind turbine

Time‐accurate blade pressure distributions on a rotating H‐Darrieus wind turbine at representative tip speed ratios during start‐up are presented here, which allow blade dynamic stall and laminar separation bubbles to be observed clearly and which provide a rare experimental demonstration of the flow curvature effect inherent in H‐Darrieus turbine operation. The convection of a dynamic stall vortex along the blade surface at high reduced frequency has also been clearly identified. This study provides new information of the complex aerodynamics of the vertical axis wind turbines (VAWTs) and provides unique experimental data to validate the transient blade static surface pressure distribution predicted by CFD models. To the best of the authors' knowledge, this is the first time that the instantaneous pressure variation around the blade has been measured and recorded directly for an H‐Darrieus wind turbine.     

Effect of End Plates on the Performence of a Wells Turbine for Wave Energy Conversion

In order to improve the performance of the Wells turbine for wave energy conversion,the effect of end plates onthe turbine characteristics has been investigated experimentally by model testing under steady flow conditions.The end plate attached to the tip of the original rotor blade is slightly larger than the original blade profile.Thecharacteristics of the Wells turbine with end plates have been compared with those of the original Wells turbine,i.e.,the turbine without end plate.As a result, it has been concluded that the characteristics of the Wells turbinewith end plates are superior to those of the original Wells turbine and the characteristics are dependent on the sizeand position of end plate. Furthermore, the effect of annular plate on the turbine performance,which encircles theturbine and is attached to the tip,was investigated as an additional experiment.However,its device was not effec-tive in improving the turbine characteristics.     

Novel and optimal integration of SOFC-ICGT hybrid cycle: Energy analysis and entropy generation minimization

Integrating fuel cells with conventional gas turbine based power plant yields higher efficiency, especially solid oxide fuel cell (SOFC) with gas turbine (GT). SOFCs are energy efficient devices, performance of which are not limited to Carnot efficiency and considered as most promising candidate for thermal integration with Brayton cycle. In this paper, a novel and optimal thermal integration of SOFC with intercooled-recuperated gas turbine has been presented. A thermodynamic model of a proposed hybrid cycle has been detailed along with a novelty of adoption of blade cooled gas turbine model. On the basis of 1st and 2nd law of thermodynamics, parametric analysis has been carried out, in which impact of turbine inlet temperature and compression ratio has been observed on various output parameters such as hybrid efficiency, hybrid plant specific work, mass of blade coolant requirement and entropy generation rate. For optimizing the system performance, entropy minimization has been carried out, for which a constraint based algorithm has been developed. The result shows that entropy generation of a proposed hybrid cycle first increases and then decreases, as the turbine inlet temperature of the cycle increases. Furthermore, a unique performance map has also been plotted for proposed hybrid cycle, which can be utilized by power plant designer. An optimal efficiency of 74.13% can be achieved at TIT of 1800 K and r_p,c 20.     

Classical flutter analysis of composite wind turbine blades including compressibility

For wind turbine blades with the increased slenderness ratio, flutter instability may occur at lower wind and rotational speeds. For long blades, at the flutter condition, relative velocities at blade sections away from the hub center are usually in the subsonic compressible range. In this study, for the first time for composite wind turbine blades, a frequency domain classical flutter analysis methodology has been presented including the compressibility effect only for the outboard blade sections, which are in the compressible flow regime exceeding Mach 0.3. Flutter analyses have been performed for the baseline blade designed for the 5‐MW wind turbine of NREL. Beam‐blade model has been generated by making analogy with the structural model of the prewisted rotating thin‐walled beam (TWB) and variational asymptotic beam section (VABS) method has been utilized for the calculation of the sectional properties of the blade. To investigate the compressibility effect on the flutter characteristics of the blade, frequency and time domain aeroelastic analyses have been conducted by utilizing unsteady aerodynamics via incompressible and compressible indicial functions. This study shows that with use of compressible indicial functions, the effect of compressibility can be taken into account effectively in the frequency domain aeroelastic stability analysis of long blades whose outboard sections are inevitably in the compressible flow regime at the onset of flutter.     

Application of combined analytical/FEA coupled aero-structure simulation in design of wind turbine adaptive blades

This paper demonstrates the application of combined analytical/FEA coupled aero-structure simulation in design of bend-twist adaptive blades. A genetic algorithm based design tool, in which the power curve is predicted through a combined coupled aero-structure simulation, has been developed. A bend-twist adaptive blade has been designed to be used on the rotor of a constant speed stall regulated wind turbine. The bend-twist adaptive blade is assumed to be made out of anisotropic composite materials. The designed blade has the same aerofoil and chord distribution as the original blade used on the wind turbine, but with a different pre-twist distribution. The simulated results show a significant improvement in the average power of the studied stall regulated wind turbine when employing the designed adaptive blades.     

透平叶片的气动优化设计系统

发展了一个叶轮机械叶片全三维粘性杂交问题的气动优化设计系统。该系统包括分析技术与组合优化技术的耦合：前者基于高精度、鲁棒型的数值分析方法，已成功地用于蒸汽透平叶片的流动分析．并经详细考核已将其纳入到了实际的叶片气动设计体系；后者基于优秀的iSIGHT商用优化平台．通过对多种优化方法的集成从而发展了组合的叶片全三维气动优化策略。数值结果与试验数据的比较表明了这一气动优化设计系统真正纳入到工业设计体系是完全可能的。     

一种燃机叶片试板定向凝固过程的研究

明确铸件定向凝固过程中的温度变化规律．可以避免重型燃气轮机定向叶片铸造中出现的一些缺陷。文章选取了与某重型燃机第1级涡轮动叶尺寸相近的试板．采用定向凝固高温合金DZ445．研究了该试板在实际工业生产用定向结晶炉中的定向凝固过程,结果表明：在距离水冷铜盘位置〉50mm后固液界面形态将发生大的转变,温度梯度逐渐变小,〉100mm后温度梯度基本保持不变．这为后续制定叶片抽拉工艺给出了参考。该实验还通过热电偶获得的定向凝固过程中温度一时间曲线与ProCAST模拟结果基本一致．验证了模拟边界条件和设置参数的准确性．后续可以用于模拟结构复杂的叶片定向凝固过程．指导实际生产工艺.