Economical Design of Wind Generating Plants

A definitive analysis technique is proposed for designing wind generating plants to produce electrical energy at minimum cost. The method employs variation in essential design parameters: rated power level, rated wind velocity, design wind velocity, and number of generator poles. These parameters in turn define wind turbine radius, turbine speed, rated torque at step-up gear input, and step-up gear ratio. When these are combined with site (or region) specific wind statistics, appropriate wind plant cost functions, and criteria by which to compute annual cost of ownership, the result yields the cost of produced energy for the several design variations. The selected design is that one for which the cost of produced energy is minimum.     

航改大功率、高效率舰船燃气轮机的

为适应舰船战术性能和舰船吨位级别提高的要求,迫切需要研究大功率、高效率舰船燃气轮机.通过对国内外战舰主动力装置进行分析,认为中国开发40000kw的大功率燃气轮机是十分必要的,利用现有航空发动机的技术资源优势,采用先进的间冷技术是发展大功率、高效率舰船燃气轮机的1条现实可行的技术途径,既可以提高燃气轮机在设计工况下的功率和热效率,又能保持在低工况下的高效率.     

Energy Control for Microwave Amplifier Arrays

In large systems using microwave amplifier arrays, the size, weight, and cost of individual energy sources require consideration of the use of a common power supply and energy storage bank. Complex energy control techniques may be necessary to protect the RF amplifier and to provide isolation of the faulted amplifier from the common energy source. Four approaches are discussed. Three of these are dependent on either the development of reliable arc-free microwave amplifiers or special isolator tubes, gas or vacuum types. A practical circuit using available components is suggested. Its advantages and limitations are discussed. Calculations are presented showing this approach can result in increased system efficiency, improved regulation, and large decreases in the size of the secondary capacitance bank for each microwave amplifier.     

Energy sources for the world's post-petroleum era

Growth of industry and commerce during the last century have been accompanied by a significant increase in the use of natural gas and petroleum. Today's growing consumption of fuels indicates that, in the next SO years, the world's petroleum resources will be approaching exhaustion. For example, suppose that every family in China had two cars that are driven everyday as far as American family cars are driven today. Then, China would need 80 million barrels of petroleum each day. However, the world's current production of petroleum is only 74 million barrels per day. China's approach to their air-pollution and energy problems is constructing new nuclear power plants plus the 18.2 gigawatt Three Gorges hydro-power-plant. The increasing carbon dioxide content in our atmosphere, and a rising global temperature, accompany the world's growing fuel consumption. Archeological evidence relates the growth and decline of the ice ages to air temperature. Many popular techniques for reducing carbon-dioxide emissions have defects. For example, replacing nuclear power plants with wind-power plants is proposed in Germany. During no-wind conditions, hydropower would be imported from Switzerland. At night, the Swiss would pump, with nuclear power from France, water from the lake back up into the high-elevation storage reservoirs. These and other power-generation technologies are evaluated in this report.     

Designing a power plant with highest efficiency:results from SFB 561

The goal of Collaborative Research Centre(SFB) 561 "thermally highly loaded,porous and cooled multi-layer systems for combined cycle power plants" is to expand the current technological and scientific knowledge on power plants in order to achieve total efficiencies of 65% in a combined cycle power plant in the year 2025.Therefore,the aero-thermomechanical,structural-mechanical,materials' scientific and production fundamentals for the development of steam and gas turbine components that are able to withstand highest thermal loads are being worked out within this SFB.This means for the gas turbine that combustion chamber outlet temperatures of 1520℃ at 1.7MPa are to be attained.In order to control these high temperatures,it is not only required to develop new materials' solutions,including thermal barrier coatings,but also to apply improved cooling techniques,as for example effusion cooling.This novel cooling concept is to be realised through open-porous structures.These structures can consist of drilled open-porous multi-layer systems or open-porous metallic foams.The development of graded multi-layer systems is also extremely important,as the grading will enable the use of coolant in dependence of the requirements.The live steam parameters in the high pressure turbine are expected to be increased up to approximately 700℃ with pressure of 30MPa.These elevated steam parameters can be encountered with Ni-base alloys,but this is a costly alternative,associated with many manufacturing difficulties.Therefore,the SFB proposes cooling the highly loaded turbines instead,as this would necessitate the application of far less Ni-base alloys.To protect the thermally highly loaded casing,a sandwich material consisting of two thin face sheets with a core of a woven wire mesh is used to cover the walls of the steam turbine casing.The current state of the research shows that by utilising innovative cooling technologies a total efficiency of 65% can be reached without exceeding the maximum allowable material temperature,thereby prolonging the life-span.      

Processing feasibilities of enhancing the GTE-based electric power plant efficiency

In this paper, a layout of an electric power plant that uses the gas turbine engine as a source of energy is presented. We give also the numerical analysis of this power plant and show its high efficiency.     

Future trends in space power technology

The status of the US Air Force Space Power Research and Development Program is summarized. Generic issues and requirements affecting the strategic planning of space power advances for the 1990s and beyond are described. The major thrusts of the Air Fore part of the Strategic Defense Initiative Office Space Power Program are highlighted, with emphasis on the ongoing advanced component technology development program. The status of these component technologies in the areas of power sources, energy storage, power management and distribution, and thermal management is described. Technology projections for the full range of envisioned technology options for the foregoing are used as the basis for a series of point designs for deriving the subsystem- and system-level benefits of the technologies. The primary focus is on baseload (CW) power systems operating in the range from 100 W for small satellites to 50 kW for potential large surveillance satellites. The secondary focus is on large, multimegawatt pulsed power systems and related components for potential applications such as directed energy. Potential `trump card' technologies related to energy conversion, storage, power electronics, and thermal management are identified     

三对转涡轮及其基本分析

本文对文献 [1]提出的三对转涡轮进行了较为详细的基元级分析。首先模拟常规涡轮分析,定义了 1 6种可能的典型级。按此定义以及本文建议的级独立自变变量,就可得到很简明的不同典型级的功率特性示式。针对这种级的可能应用场合—三轴涡轮发动机的具体要求,分析了各种典型级的适用情况。这种涡轮可得到比常规级高得多的功率系数而且效率也会有所改善。      

发电用燃气轮机使用寿命的影响因素分析

随着西气东输工程的实施、大型油气田的开发和中低热值燃料应用的发展,发电用燃气轮机在中国的应用越来越广泛。根据燃气轮机运行平稳、可靠性高等特点,基于燃气轮机电站的实际工作经验,对发电用燃气轮机寿命的影响因素进行了分析。     

A technique for selecting optimal engineering decisions in gas turbine plant design

A technique for evaluating the preferential usage of one or the other engineering decision is presented; for this, the objective function that represents the comparative profit of future GTP owners from realization of alternative power plant variants is used. The efficiency of the approach being proposed is shown by analyzing the possible modifications of the Siemens GT10C and GTX100 gas turbine plants operating in the Russian Federation.     

Fuel cell status: 1996

The technology of fuel cells is heating up. A world that, ten years ago, was unaware of the concept can now witness approximately 200 fuel cell units operating in 15 countries. Energy planners and decision makers are becoming aware that, in addition to a continual increase in installations, the reliability of early commercial units is outstanding and the cost is dropping. They have begun to ask whether fuel cells might fit into their future. While the fuel cell concept is simple, determining which type of fuel cell to consider may prove taxing. The multiplicity of fuel cells and their development programs, coupled with the amount of subject material and claims-versus-reality, may seem overwhelming. Fuel cell commercialization activities in North America are the focus of five manufacturers that are developing four types [fuel cells are typed by electrolyte: the 200°C phosphoric acid (PAFC); the 80°C proton exchange membrane (PEM); the 650°C molten carbonate (MCFC); and the 1,000°C solid oxide (SOFC) fuel cells]. Each fuel cell promises the attractive combination of fairly high efficiency and superior environmental performance compared to the presently available fossil-fueled electric generation technologies. As a result, fuel cells are particularly easy to site. There are additional advantages such as: excellent availability; electrical VAR control; quick ramp rate; remote/unattended operation; and redundancy when multiple units are installed. After earlier success in space, fuel cells are being applied to the commercial sector as on-site cogeneration units mostly fueled by natural gas. They are being considered for larger distributed generators (natural gas) and for vehicular power plants (methanol)     

Assessment of converting approach to efficient design of micro-turboprop engines

The design, manufacture and experiment of a shaft power unit for converting a micro-turbojet engine to a micro-turboprop in the class of less than 20 kW with the aim of obtaining maximum shaft power were described in this study. For this purpose, a Wren100 micro-turbojet engine was used as the gas generator, and the specifications of its outflow were measured. The optimal configuration of the inter-stage diffuser, which was an annular S-type diffuser, was selected based on its small total pressure drop and outlet flow uniformity. The power turbine was a single stage axial turbine that was designed based on the fixed nozzle angle assumption without any taper or twist in its stator. The turbine rotor was a bladed disk (Blisk) in which its unique blade profiles were designed based on the Wilson method. Subsequently, the shaft power unit was completed by designing and manufacturing an exhaust complex and gearbox. Finally, the micro-turboprop engine was tested with an overloading propeller. The results show a significant increase in the extracted power, an acceptable efficiency of the power turbine, and a significant reduction in the Specific Fuel Consumption (SFC) compared to other engines that use similar gas generators.     

Output Power Controller for a Wind-Driven Induction Generator

A constant stator power output controller for a wind-driven grid-connected induction generator is described. The load torque of the generator is controlled by varying the rotor resistance electronically. A dynamic model for the wind energy conversion system is proposed for both controlled and uncontrolled operation.The model is then used to predict the changes in shaft speed,turbine torque, and stator power output in response to change in wind speed. Data pertaining to a 60 kW commercial wind turbine generator is used in this investigation. Results based on analog computer simulation demonstrate the feasibility of the controller for scheduling a desired power output from the induction generator.Results of the tests on a laboratory induction generator driven by amicrocomputer-controlled dc motor drive simulating the characteristics of the wind turbine are included.     

Parametric cost model for solar space power and DIPS systems

A detailed cost model has been developed to parametrically determine the program development and production cost of photovoltaic, solar dynamic, and dynamic isotope (DIPS) space power systems. The model is applicable in the net electrical power range of 3 to 300 kWe for solar power and 0.5 to 10 kWe for DIPS. Application of the cost model allows spacecraft or space-based power system architecture and design trade studies or budgetary forecasting and cost benefit analyses. The cost model considers all major power subsystems (i.e., power generation, power conversion, energy storage, thermal management, and power management/distribution/control). It also considers system cost effects such as integration, testing, and management. The cost breakdown structure, model assumptions, ground rules, bases, cost estimation relationship format, and rationale are presented, and the application of the cost model to 100-kWe solar space power plants and to a 1.0-kWe DIPS is demonstrated     

Three Mile Island? Lessons for America

The great fear of a nuclear castastrophe is the prime lesson learned from the Three Mile Island accident. This fear is real and creates a major risk to our society. Although the probability of a major release of radioactivity occurring at a given plant in a given year is low, the rapidly increasin number of plants around the world increases the probability that such a catastrophe will occur someplace in the next few years. When a major release does occur, people will demand an end to the use of energy from nuclear power. We are at grave risk in not having an alternative, in not providing a choice in time. The alternatives are clearly defined. But we need to see that the resources are made available to develop them.     

WZ-5发动机改装高温涡轮的试验研究及分析

WZ- 5发动机改装 WJ5A- 1发动机的高温涡轮,在工程上单台发动机总寿命已安全运行达 10 0 0 0 h,现已证明 :结构设计及改进是成功的;WJ5A- 1发动机的前二级燃气涡轮与压气机基本上是匹配的;燃气涡轮第一级导向器与动力涡轮导向器面积调整是合理的;在相对换算转速为0.95时,其喘振裕度与 WZ- 5发动机基本上一样;动力涡轮导向器面积总共放大了 5.32 %,对燃气涡轮特性没有带来很大影响。      

空间站太阳能蓄热/吸热器轻量化研究

为了降低太阳能热动力发电系统中关键部件吸热器的质量,在NASA2kW吸热器样机的基础上建立了吸热器的物理和传热过程及流阻的数学模型,编制了吸热器传热及质量计算的数值模拟程序,分析了结构参数和特性参数对质量的影响。结果表明,在一定的设计要求下,合理的选取工质传热管的直径和数目、能量转换单元的转速、压缩机入口温度和回热器回热度等参数,可以明显降低吸热器质量的影响,为吸热器的设计提供了理论依据。      

Space power systems requirements and issues: the next decade

Some of the more important space power technology issues, requirements, and challenges of the 1990s are described, and the impact of new component technology on the overall performance of space power systems is assessed. Advanced component, subsystem and system technologies that will significantly affect the performance, reliability, and survivability of next-generation baseload and burst mode space power systems are emphasized. Technology disciplines related to power sources (solar/nuclear and chemical), power conversion, energy storage, power conditioning/distribution and control, and waste-heat acquisition, transport, and rejection are primarily addressed. For some of them, performance trends that can be used as the basis for projecting future advanced power-system performance are developed. Performance capabilities for several different types of space power system for both baseload and burst mode applications are postulated on the basis of evolving technology and point designs that incorporate projections of advanced component capabilities     

航空用燃料电池及混合电推进系统发展综述

随着世界范围内碳减排需求的日益增长及长航时飞机的发展需要,高效率的燃料电池航空电推进系统逐渐受到重视,氢能航空的理念被人们所熟知。可使用碳氢燃料的高温燃料电池还可与燃气涡轮组成混合动力系统,发电效率进一步提高至70%。本文首先回顾了燃料电池及燃料电池涡轮混合系统在航空能源、动力系统方向应用概况;接着,概述了几种突破现有涡轮发动机技术瓶颈的新概念混合电推进系统,如发电与推进一体化燃料电池涡轮混合动力系统和无涡轮燃料电池混合推进系统;基于此,本文分析了限制燃料电池混合系统实际应用的关键技术难题,主要体现在混合动力系统功重比较低、大分子碳氢燃料重整技术未突破两方面。     

Possible power generation with nature's high-efficiency technology

The rapidly growing fuel consumption in engines and turbine that power the world's transportation vehicles and power-generation plants will nearly exhaust the world's supply of petroleum by the end of the next century. These engines and turbines run at high heat-input temperatures because their efficiency is limited by the Carnot cycle. Muscles used for propulsion by animals are not limited in efficiency by the Carnot cycle, so we see dolphins getting 3,000 miles of travel from a food quantity that contains the energy equivalent of one gallon of gasoline. Leaves on plants capture the energy in sunlight to extract carbon from carbon dioxide in the air, and hydrogen form water, to manufacture carbohydrates. Scientists and engineers studying these processes are amazed by the computing power and data storage required to make these processes work. For example, a tiny grape seed contains the data and structural technology required for quickly constructing the plant's fuel-producing leaves and the structures that support them. Even the stiff thorn that discourages intruders from entering the grape bush has an effective design. The data stored in the seed specifies the color of the grape plant's blossoms, commands the production of the sugar-containing fluid that goes into the grapes, and even the data content of the next-generation seeds in the globules of each grape berry. In this report, we explore energy-conversion processes that nature has developed in plants and animals. We explore the possibility of adapting them into techniques that reduce our consumption of petroleum fuels.