Sulfide-oxide corrosion of the materials and coatings of gas turbine blades

Results from studies on analyzing the state of materials and protective coatings of gas turbine blade systems subjected to the sulfide-oxide corrosion are presented, and factors causing its occurrence are described. Data obtained from studies on analyzing the effect of doping on the resistance of nickel alloys to corrosion are given, as well as data obtained from studies of the corrosion longevity of thermo barrier coatings.     

Thermal barrier coatings on gas turbine blades: Chemical vapor deposition (Review)

Schemes are presented for experimental setups (reactors) developed at leading scientific centers connected with the development of technologies for the deposition of coatings using the CVD method: at the Technical University of Braunschweig (Germany), the French Aerospace Research Center, the Materials Research Institute (Tohoku University, Japan) and the National Laboratory Oak Ridge (USA). Conditions and modes for obtaining the coatings with high operational parameters are considered. It is established that the formed thermal barrier coatings do not fundamentally differ in their properties (columnar microstructure, thermocyclic resistance, thermal conductivity coefficient) from standard electron-beam condensates, but the highest growth rates and the perfection of the crystal structure are achieved in the case of plasma-chemical processes and in reactors with additional laser or induction heating of a workpiece. It is shown that CVD reactors can serve as a basis for the development of rational and more advanced technologies for coating gas turbine blades that are not inferior to standard electron-beam plants in terms of the quality of produced coatings and have a much simpler and cheaper structure. The possibility of developing a new technology based on CVD processes for the formation of thermal barrier coatings with high operational parameters is discussed, including a set of requirements for industrial reactors, high-performance sources of vapor precursors, and promising new materials.     

The effect of the alloying elements of a CoNiCrAlY system on the corrosion resistance of alloys for protective coatings of gas turbine blades

Results from testing for resistance to sulfide-oxide corrosion of model alloys used to make possible CoNiCrAlY system-based protective coatings are presented. The effect exerted by Ni, Cr, Al, and Y on the corrosion resistance of these coatings at different temperatures is determined, and equations for calculating the chromium equivalents of these coatings are obtained.     

Corrosive resistance of nitride coatings of steam turbine blades

Results from tests of multilayer nitride Ti _x N and (TiAlZrMo) _x N coatings resistance to downtime and high-temperature corrosion in steam are presented.     

某燃气轮机涡轮动叶片腐蚀疲劳失效分析

针对某燃气轮机涡轮第1级动叶叶身表面涂层剥落及尾缘转接R处产生疲劳裂纹的现象进行了失效分析,并对失效机理进行探讨。首先,对失效叶片开展了理化检查,包括外观检查、化学成分分析及显微组织分析;然后模拟了机组运行时涡轮叶片的温度场和应力场分布。研究结果表明:重油中的S和V燃烧后产生硫酸盐和钒酸盐,局部高温促使其加速穿过陶瓷隔热层中的空隙并产生反应,从而使涂层出现脱落;温度场计算获得的局部高温区域与涂层剥落区域吻合;叶片应力模拟计算结果显示尾缘应力水平较高,频繁的启停使尾缘转接R处产生疲劳裂纹。基于研究结果,得出此次叶片失效的主要原因是腐蚀疲劳失效,并对涡轮叶片使用提出了合理的建议。     

A choice of trailing edge diameter of gas turbine blades

A possibility of increasing the efficiency and profitability of gas-turbine installations by optimization of the geometry of trailing parts of the blades profiles is considered. This is done on the basis of actual data on characteristics of the blades of gas turbines manufactured by Western companies.     

Estimating the quality of coatings applied on the blades of a GTE-65 turbine

We present the results obtained from a comprehensive study of the plasma metalloceramic coating applied on the external surfaces and diffusion coating applied on the internal surfaces of rotor blades and guide vanes used in stages 1–3 of a GTE-65 gas turbine unit.     

水轮机叶片数控加工工艺技术研究

阐述了水轮机叶片数控加工工艺的技术方法,重点对毛坯余量控制、叶片划检、叶片装夹、叶片加工及叶片修磨等工艺环节进行了分析研究。实践证明,水轮机叶片数控加工工艺方法具有加工效率高、精度高等优越性,使转轮加工质量大幅度提高。     

汽轮机叶片点蚀现象的分析

分析了汽轮机叶片点蚀的宏观和微观现象,控制了点蚀产生和形成的过程。叶片点蚀产生的主要原因是：在含有氯离子的介质中,氯离子有选择地吸附在Ｃｒ１２不锈钢叶片表面钝化膜不完整的地方,由于潮湿空气进入,形成原电池,并与阳离子结合生成可溶性的氯化物溶在溶液中,形成点蚀坑。最后,提出在实际运行过程中防止点蚀的措施。     

An analysis of fatigue damage inflicted to the blades of gas turbine units during their long-term operation on gas mains

Results from studies of factors due to which fatigue damage is inflicted to the turbine and compressor blades of stationary gas turbine units operating at the compressor stations installed on gas mains of Russia are considered.     

风轮机桨叶生产工艺的现代化

指出了大型风力发电设备转轮叶片的结构特点和材料性能,提供了现代化制造工艺和装备。同时还介绍了降低风电机组成本的方法、风力发电开发方面的课题。     

Classification of lightning damage to wind turbine blades

Lightning damage to wind turbine blades is of great concern to wind power installations. We investigate various issues arising from lightning damage and assess the causes through actual lightning observations as well as from high‐voltage and large‐current experiments. Although installing lightning receptors and down conductors provide a good countermeasure, blade damage can still be caused by lightning still. New techniques are needed to better protect blades from lightning surges; these may include not only better performance and layout of receptors, but also independent lightning towers and new types of blade materials. This paper provides a classification of blade damage sustained in winter lightning, ranked in severity by analyzing the many incidents of damage that have actually occurred in Japan. Moreover, a list of possible causes of damage and relative countermeasures is also presented. © 2012 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

Depressing the torque vibrations of turbine blades using virtual inertia

Based on an electromechanical analogy, a turbine mechanical system can be transferred into an equivalent electrical circuit, allowing a phasor diagram to be used to evaluate the turbine shaft and blade responses to the electromagnetic (E/M) torque disturbance. After investigating six practical large-scale turbine units using frequency scanning, the dynamics of the blades were always found to be sensitive to system frequency excitation. Therefore, a system-frequency mechanical filter was designed and installed in the generator-and-rectifier section of the turbine set. This filter normally operates in a non-resonant state with only a low inertia constant such that the system operation is not affected. Only in the event of a fault, does the filter resonate and produce an extremely large virtual inertia that combined with the generator-rotor inertia to make the turbine system, especially the blades, less responsive to the system-frequency E/M torque disturbance. Using simulations, such a virtual inertia was proven to present excellent performance in improving the blade vibration behaviors.     

水轮机转轮叶片裂纹分析及处理

水轮机转轮的叶片出现裂纹会严重威胁水电厂的安全经济运行，通过对水轮机转轮叶片进行有限元计算分析，得出应力过于集中通常是叶片裂纹产生的主要原因，此外，叶片也存在设计、制造、运行方面的问题，为此，介绍了水轮机转轮叶片裂纹金属无损探伤的常用处理方法和一般工艺。     

Achieving better cooling of turbine blades using numerical simulation methods

A new design of the first-stage nozzle vane for the turbine of a prospective gas-turbine engine is considered. The blade’s thermal state is numerically simulated in conjugate statement using the ANSYS CFX 13.0 software package. Critical locations in the blade design are determined from the distribution of heat fluxes, and measures aimed at achieving more efficient cooling are analyzed. Essentially lower (by 50–100°C) maximal temperature of metal has been achieved owing to the results of the performed work.     

汽轮机动叶片氯腐蚀的分析与对策

汽轮机动叶片因腐蚀而引起的断裂事故严重威胁汽轮发电机组的安全经济运行，而氯腐蚀又是动叶片腐蚀的重要原因。为此，通过对某电厂300MW机组叶片断裂事故的分析，探讨动叶片氯腐蚀的机理与特点，并提出相应的对策，即通过对铬合金钢叶片进行表面强化．严格监视给水的pH值，加强水处理，降低氯离子的浓度，来防止汽轮机动叶片的氯腐蚀。     

Calculation of gas turbine characteristic

The reasons and regularities of vapor flow and turbine parameter variation depending on the total pressure drop rate π* and rotor rotation frequency n are studied, as exemplified by a two-stage compressor turbine of a power-generating gas turbine installation. The turbine characteristic is calculated in a wide range of mode parameters using the method in which analytical dependences provide high accuracy for the calculated flow output angle and different types of gas dynamic losses are determined with account of the influence of blade row geometry, blade surface roughness, angles, compressibility, Reynolds number, and flow turbulence. The method provides satisfactory agreement of results of calculation and turbine testing. In the design mode, the operation conditions for the blade rows are favorable, the flow output velocities are close to the optimal ones, the angles of incidence are small, and the flow “choking” modes (with respect to consumption) in the rows are absent. High performance and a nearly axial flow behind the turbine are obtained. Reduction of the rotor rotation frequency and variation of the pressure drop change the flow parameters, the parameters of the stages and the turbine, as well as the form of the characteristic. In particular, for decreased n, nonmonotonic variation of the second stage reactivity with increasing π* is observed. It is demonstrated that the turbine characteristic is mainly determined by the influence of the angles of incidence and the velocity at the output of the rows on the losses and the flow output angle. The account of the growing flow output angle due to the positive angle of incidence for decreased rotation frequencies results in a considerable change of the characteristic: poorer performance, redistribution of the pressure drop at the stages, and change of reactivities, growth of the turbine capacity, and change of the angle and flow velocity behind the turbine.     

汽轮机末级叶片水蚀防护技术

介绍了国内外常用的水蚀防护处理技术,并对其优劣性进行了对比,结果表明:堆焊硬质合金、表面涂镀氮化碳纳米复合涂层是一种较好的表面处理方法。     

贯流式机组桨叶与导叶全三维联合设计

为了充分反映水流经过导叶后的流态对桨叶入流的影响,本文建立了灯泡贯流式机组桨叶和导叶的全三维联合反问题计算模型。在包括桨叶和导叶的计算域中,求解联立的控制方程,同时设计得到了导叶和桨叶的空间叶型。采用联合设计和单独设计模型分别设计了一低水头贯流式机组的桨叶和导叶,并在设计工况下对其进行了全流道湍流数值模拟。性能预估结果表明,与单独设计相比,联合设计的桨叶进口边附近压力分布得到改善,导叶和桨叶段的联合损失减小,转轮效率提高。     

玻璃钢／复合材料风力机叶片的开发

随着风机单机容量的增大,对风机叶片的设计、制造提出了更高的要求。由于玻璃钢/复合材料具有强度高、容易成型、耐腐蚀性能好、抗震性能较高等特点,因而目前在大型兆瓦级风机叶片制造中得到了广泛应用。介绍了国内外风机叶片的发展概况,分析了玻璃钢/复合材料风机叶片的特点,并从气动设计、结构设计、工艺设计、认证规范和产业化等方面介绍了风机叶片的开发过程。