An improved vertical-axis water-current turbine incorporating a channelling device

Water-Current Turbines (WCTs) are non-polluting electricity generation plants that harness the kinetic energy of natural water courses, using several kinds of rotors. At the School of Engineering of the University of Buenos Aires, researchers are developing a WCT whose particular characteristics improve technical and economic performance. A channelling device, integrated into the flotation system, is used to modify flow conditions in the neighbourhood of the rotor. This system was developed from theoretical modelling and small-scale model testing in a hydrodynamic test canal. The principal advantages of this kind of machine include reduced need for fixed civil works, ease of transport and relocation and autonomous, self-regulated operation, and it is expected to be a low-cost and long-lifetime system.     

Investigation of Extreme-Pressure and Antiwear Properties of Antimony Thioantimonate

Detailed studies including synthesis, characterization and evaluation of antimony thioantimonate, SbSbS₁, have been carried out. The amorphorus complex chalcogenide was prepared by a solution precipitation method. As a solid-lubricant additive in various greases, this material exhibits superior extreme-pressure and antiwear properties as demonstrated by the Four-Ball weld points and load-wear indexes on both AISI-52100 and AISI-440C steels. Antimony thioantimonate appears to be compatible with all the base greases investigated including a silicone grease in which very few additives show good response.     

Practical Algorithms for Online Thermal Stress Calculations and Heating Process Control

This article presents two algorithms for online mode thermal stress determination in machinery components based on Green's Function Technique approach and on the artificial neural network, respectively. A modification of the GFT algorithm is proposed involving the use of the component metal temperature rather than the temperature of the flowing fluid. The algorithms developed were used to calculate stresses in rotors and casings of new generation turbines. A possibility was also shown of using the algorithms to solve the inverse problem, i.e., to control the rate of temperature changes while keeping stresses within an allowable range.     

六甲1#、2#机组水轮机顶盖排水系统改造

六甲水电站1#、2#机组原主轴密封均采用橡胶平板式密封方式，设备运行期间顶盖漏水量大，时常因抽水泵故障导致水淹水导轴承，针对这一问题对水轮机主轴密封型式和排水方式进行改造。改造后，节省排水能耗和检修费用，运行3年效果良好。     

A Classifiers Based Optimization Technique for Designing Turbine Airfoils

The primary focus of this work is in the development of an evolutionary optimization technique which gets progressively 'smarter' during the optimization process by learning from computed domain knowledge. In the approach, the influence of the design variables on the problem solution is recognized, and the knowledge learned is then generalized to dynamically create or change design rules during optimization. This technique, when applied to a constrained optimization problem, shows progressive improvement in convergence of search, as successive generations of rules evolve by learning from the environment. This method is applied to a complex aerodynamic optimization problem involving turbine airfoil design. In this investigation, the 3D geometry of an airfoil is optimized by simultaneously optimizing multiple 2D slices of the airfoil. Results from the optimization of a low pressure turbine nozzle are presented in the paper. Results obtained using standard numerical optimization techniques are also presented for comparison purposes.     

Dynamic hydroelastic scaling of self-adaptive composite marine rotors

The objective of this work is to establish dynamic similarity relationships for self-adaptive composite marine rotors. Although scaling laws are well established for rigid propellers and turbines, relative little work has been shown for flexible marine rotors that are designed to interact with the surrounding flow. Considering recent interests in the development of large-scale, energy-efficient composite marine propellers and turbines, it is crucial to understand the scaling relationships to properly design and interpret model-scale studies. Explanations of the similarity requirements are presented, along with scaling factors for the various fluid and structural parameters that control the dynamic interactions between the flexible rotor and the surrounding flow. Finally, numerical results obtained using a fully coupled, three-dimensional, boundary element method–finite element method is shown to demonstrate the validity of theoretical scaling relationships and to investigate scaling effects. The results suggest that for most marine rotors where gravitational forces are negligible compared to other dominant forces and the boundary layer is fully turbulent, it is most practical to conduct model-scale experiments to satisfy Mach number similarity, even though the Mach number will be much less than one for most marine applications.     

大型汽轮发电机组误并列及其监测

本文结合国内第一台大型汽轮发电机组TSA—1系统的开发,研究了误并列判据和角度分析模型并给出部分误并列监测记录。可靠地监测误并角,为运行人员判别分析并列优劣提供了依据。     

Distortions induced in turbine blades by hot forging and cooling

Geometrical distortions of hot forged thin components are one of the main causes that force process designers to work with significant allowances. Their identification in the early stages of process design would permit changing the process parameters in order to compensate them during cooling after the hot forging process.This paper presents a novel approach to evaluate geometrical distortions of hot forged components characterized by complex and thin geometrical features, such as turbine blades. A thermo-mechanical–metallurgical model of both the forging and cooling phases is developed, in order to investigate the effects of different cooling rates after forging on the component final geometry and then to choose those cooling parameters that assure minimal distortions. The developed models are calibrated through extensive experimental campaigns, involving both laboratory experiments and on-field measurements during industrial productions. Thermal boundary conditions are identified through on-field measurements of blade surface temperatures, while material behaviour regarding flow stress determination and phase transformation-related parameters is obtained through compression and tensile tests with a dilatometer aid, all carried out in the range of temperatures of interest for the forging and the cooling phases.     

CC12型汽轮机低真空供热的安全经济性分析

通过汽轮机变工况计算及凝汽器的热力计算 ,分析了营口化纤厂自备电厂CC1 2型汽轮机低真空供热对汽轮机电功率、轴向推力、汽缸膨胀、凝汽器冷却管膨胀的影响 ,进而分析了CC1 2型汽轮机低真空供热的安全性和经济性 ,并对该汽轮机低真空供热的效益进行了计算及分析。该汽轮机经过 4个月的低真空供热运行 ,证明计算分析结果是正确的     

浅谈水头比例法在确定水轮机吸出高度中的应用

小型水电站水轮机转轮及叶片的汽蚀直接影响到水轮机的使用寿命和效率,正确地确定水轮机吸出高度是避免或减少汽蚀的主要途径之一。传统的方法由于采用统一的计算公式,而没有全面考虑具体电站的特点,导致转轮及叶片在运行中仍然发生不同程度的汽蚀。本文通过总结河南省小水电站设计中的应用情况,介绍确定水轮机吸出高度另一种方法即水头比例法,可供小水电站设计中参考。