超超临界1000MW汽轮机低压转子叶片装配

百万等级汽轮机低压转子是集多种叶根形线于一身的一种特殊结构,因此,装配过程十分复杂。文中详细介绍了每种叶片结构特点与装配要求,并给出了科学有效的装配方法,保证了叶片装配质量和机组运行的经济性与可靠性,为同类型机组装配提供了可借鉴的经验。     

325MW空冷汽轮机低压缸末级动叶片Z型拉筋凸台及拉筋孔的加工

论述了325MW空冷汽轮机低压缸第6级(末级)动叶片上结构新颖、型面构成复杂的Z型拉筋凸台及凸台拉筋孔的加工工艺,并结合工厂的实际情况,分别对叶片内、背弧拉筋凸台的型线、凸台端面以及拉筋孔的加工进行了详细的分析研究,提出了切实可行的加工工艺方案.     

汽轮机转子动叶围带滚压机的设计与实践

针对公司汽轮机转子动叶围带的产出供应不足问题,指出铸钢动叶围带制造工艺的局限性是影响动叶围带生产效率的关键原因。根据动叶围带的特点,设计了一台简单实用的动叶围带滚压机,通过结构改进提高了设备的性能。经过实际使用,证明滚压的动叶围带成本低、质量可靠、性能稳定,完全可以取代铸钢动叶围带。     

Study of applying reverse engineering to turbine blade manufacture

A turbine blade has complex shaped free-form surfaces that can be modelled as surfaces with variable curvature by high-degree polynomials. Industry typically utilizes a turnkey system and special-purpose machine tool to manufacture turbine blades. A turkey system is a closed form design. Users need only input relevant data to this system to manufacture the product directly. However, users are unaware of the internal operation of the system. With rapidly advances in computing technology, commercial CAD/CAM systems can be utilized to design freeform surfaces and generate a tool path for the designed surfaces. This study uses a reverse engineering technology that is used to reconstruct the CAD model for a turbine blade. The prototype is measured by a coordinate measuring machine to obtain the geometrical control data points that are used to generate the CAD model in the UniGraphics (UG) CAD/CAM system. The UG/GRIP (GRaphics interactive Programming) language is used to generate the cutter location data rather than using the default UG CAM module. A five-axis NC code is acquired by the developed postprocessor and verified by the solid cutting simulation software VERICUT®. Real turbine blade machining is performed on a table/spindle tilting five-axis machine tool, demonstrating the effectiveness of the proposed approach.     

低压两级涡轮叶片修缘对涡轮效率影响研究

运用三维数值模拟技术,对一个多级轴流空气涡轮的低压两级原型4排叶片进行了数值计算和流场分析.然后分别对低压一、二级前缘和尾缘进行修缘的修缘叶片两级涡轮进行数值计算,并与原型叶片的计算结果进行比较,确定其对低压涡轮效率的影响.计算结果表明:采用修缘叶片的涡轮效率均小于原型叶片的效率,涡轮效率随着修缘量的增大逐渐降低.     

LP compressor blade vibration characteristics at starting conditions of a 100 MW heavy-duty gas turbine

In this paper are presented the blade vibration characteristics at the starting conditions of the low pressure multistage axial compressor of heavy-duty 100 MW gas turbine. Vibration data have been collected through strain gauges during aerodynamic tests of the model compressor. The influences of operating modes at the starting conditions are investigated upon the compressor blade vibrations. The exciting mechanisms and features of blade vibrations are investigated at the surge, rotating stall, and buffeting flutter. The influences of operating modes upon blade dynamic stresses are investigated for the first and second stages. It is shown that a high dynamic stress peak of 120 MPa can occur in the first stage blades due to resonances with stall cell excitations or with inlet strut wake excitations at the stalled conditions.     

小型风力发电机叶片设计与制造的研究

叶片是风力发电机(简称风机)的关键部件,为了制造出优良的小型风机叶片,对小型风机叶片的设计、材料的选择以及模具制造进行了研究。根据当地风能资源的情况,风机的设计功率为300W。首先设计出风轮的基本尺寸,选择NACA4412翼型,经过计算和分析,确定叶片剖面翼型和具体尺寸;其次根据风机叶片的受力情况及其他要求,选择玻璃纤维增强复合材料制作叶片;然后运用CAD和CAM技术,设计了一套小型风机玻璃钢复合材料的叶片并制作了模具。为风机玻璃钢叶片进一步实现规模化生产奠定了良好的基础。     

Investigation of blade failure in a gas turbine

A gas turbine abruptly tripped to a stop during its daily morning start-up period. Out of a total of 81 blades in the first row only one blade was broken at its root. Prior to this accident, there were three blade failure accidents in the same plant during the last 10 years. First, the fracture surface of the troubled blade was investigated. Stress analysis of the blade showed that the maximum stress occurred due to the pressure profiles developed during operation. Modal analysis for one blade and the assembly of blades was performed and Campbell diagram and Interference diagram were drawn to check the dynamic characteristics of the blades. The vibration of the turbine was measured using accelerometers during the operation condition. The result shows that the fatigue fracture of the blade was originated during transient events internal to the combustion chamber which was close to the resonance condition of the assembled blades.     

CFD investigation on the flatback airfoil effect of 10 MW wind turbine blade

The flatback airfoil effect on the inboard region of a large wind turbine blade was investigated by numerical analysis. Complicated flow phenomena in wind turbine blade with flatback and non-flatback airfoil were captured by Reynolds-averaged Navier–Stokes flow simulation with shear stress transport turbulence model. Although both airfoil blades were designed using blade element momentum theory to produce identical shaft power, results of three-dimensional computational fluid dynamics (CFD) flow analysis indicated that at a specific location of the root area, the flatback airfoil improved the inboard force by approximately 6 % compared with the non-flatback airfoil. We were also able to confirm that by using the flatback airfoil, the overall shaft power throughout the blade increased by 1 %, thereby restraining the bending moment exerted by the thrust force on the hub by 0.5 %. Moreover, numerical analysis results indicated that the flatback airfoil blade reduced the size of the secondary vortex around the blade root area and its progress in the secondary direction in comparison with the non-flatback airfoil blade. The shape of the flatback airfoil on the trailing edge weakened the adverse pressure gradient migrating from the lower to the upper surface. Regardless of the flatback airfoils, the tip vortex core of the outboard region formed on the suction surface leading edge and strongly rolled up by the pressure surface boundary layers due to the large pressure difference between the suction and pressure surfaces in the blade tip region. This remarkable strong tip vortex developed downstream and raked up the boundary layer of the blade trailing edge with low energy.     

燃气轮机动态仿真容积效应法研究

针对燃气轮机动态建模容积效应法运用过程中,使用真实体积运算时计算结果振荡较大,无法对燃气轮机动态过程进行实时有效的运算的问题,对容积效应法的原理进行分析,提出了采用虚拟容积计算方法计算容积大小.采用面对对象的模块化建模方法,基于Matlab/Simulink平台,运用容积效应法建立了燃气轮机动态仿真模型,解决了在常规建模时迭代次数太多的问题.分别计算了在相同工况变化条件下,采用真实容积和虚拟容积方法建立的两种模型的仿真结果.研究结果表明,采用虚拟容积的仿真模型更稳定,并且计算结果更准确.     

600MW汽轮机组基于ANSYS的低压转子轴承系统的模态分析

针对600MW汽轮发电机组低压转子-轴承系统,建立了整轴模型和低压转子模型,采用有限元分析软件ANSYS进行模态分析,计算汽轮机转子的固有频率和临界转速,从而避免工作转速达到临界转速产生共振现象.最后通过临界转速和振型图分析了低压转子的特性.     

汽轮机叶片汽道的结构模型研究

叶片作为汽轮机的重要组成部分,决定着能量的转换效率。对汽轮机动叶片的结构特征进行了研究,从叶型的特点,结合国际标准化组织颁布的工业产品数据交换标准的要求,选取了三次均匀有理B样条和2×3次非均匀有理B样条为叶型的数学模型,推导了各自的矩阵表达式,证明了曲线的连续性,实现了叶片的数字化表示。由矩阵表达式可以看出,明显的三次均匀有理B样条比2×3次非均匀有理B样条方法的计算量小、简单和便于控制等,为后续的插补算法研究提供了理论支持。     

Single wavelength and ratio pyrometry reflection errors in temperature measurement of gas turbine blade

Radiation thermometers are the instruments most opted for when measuring surface temperatures of high speed rotating parts non-intrusively in many industrial applications. However, reflection of ambient radiation from the measured target goes against the operating principles of most of these thermometers thus introducing errors to the temperature measurements. Reflection errors introduced into single wavelength and ratio pyrometer temperature measurements of a rotating cooled gas turbine blade were investigated in this work through simulation. Errors for the two pyrometers based on varied target surface emissivity, view factor and ambient temperature were calculated. At high ambient temperatures, high view factors and low surface emissivity, errors exceeding 70% and 30% were realized for single wavelength and ratio pyrometers respectively. Thus temperature measured on reflective targets surrounded by surfaces at much higher temperature should be corrected for reflection errors if its reliability is to be guaranteed.