A gas turbine system using high humidity air is thought to be suitable for a distributed power supply because of the simplicity of composition, high efficiency, and the applicability of co-generation. The concept of the humid air turbine (HAT cycle) was reported 20 years ago, but it has not been used commercially yet. In this paper, influence of the suction air atomization on performance, mass flow restriction by methods of humidifying compressed air, and the optimum conditions of humidity are clarified, and the system performance is calculated. The AHAT (Advanced HAT) system shows efficiency which is 5% higher compared with the mid-size combined cycle, and the increment grows, even further for a small-size machine. The overall cycle efficency of the co-generation system is 80%.

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The operational strategy for cost saving is investigated for an existing gas turbine cogeneration plant with steam injection and inlet air cooling whose operation is difficult to determine because of its high flexibility. An optimization approach based on the mixed-integer linear programming is adopted to acquire the knowledge for the rational operational strategy. The on/off status of operation and energy flow rates of each piece of equipment as well as the adoption and amounts of steam injection and inlet air cooling of a gas turbine cogeneration unit are determined so as to minimize the hourly operational cost subject to performance characteristics of equipment and energy balance relationships. This optimization problem is solved for various combinations of power and steam demands under various ambient air conditions. The optimal operational strategy of the cogeneration unit is illustrated by operational maps, which clarify the conditions for the effective use of steam injection and inlet air cooling.

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In keeping with the current demand for energy conservation, Kobe Steel has commercially produced air compressors with a radial steam turbine, named "ECOCENTRI", which utilize excess or waste steam in factories and thereby save electrical power consumptions. In this work, we developed a high-efficiency compact superheater which is connected directly to the upper stream of radial steam turbine in order to enhance recovery power from excess or waste steam and extend available range of expansion ratio. The said integrated system was incorporated into the process steam line of Kobe Steel's Kakogawa Works and evaluated for turbine performance, heat efficiency of superheater and so on. We could recognize from these operation data that the integraeted system drastically improved its performance compared with conventional power recovery compressor.

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A prototype machine for a microturbine system using a simple humid air turbine system (electrical output : 150 kW; electrical efficiency : 35% LHV) was integrated for its laboratory evaluation. Systemdesign, main components and auxiliary components are described in the paper. One feature of the microturbine is to utilize water to improve the electrical efficiency and lubrication of bearings. Component tests were successful. Low NOx emission under 10 ppm was achieved at the rated load condition and sensorless drive of the permanent magnet generator controlled by the power conversion system was applied for starting operation of the microturbine system. The integrated machine is currently undergoing a motoring test to confirm its stable rotation and to check characteristics of the compressor. Design values for the compressor have shown good agreement with experimental results in the motoring test.

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Solid oxide fuel cell (SOFC) has been extensively developed in many countries as an ultra-high efficient energy converter. Such high temperature fuel cell can be operated as a hybrid system of integrating of turbo machinery. A major decision is whether to place the cell stack in pressurized or unpressurized section. This paper discusses the exhaust energy recovery from fuel cells by use of turbo machines under unpressurized conditions, working with inverted Brayton cycle in which turbine expansion, cooling by heat exchanger and draft by compressor are made in an open cycle mode. It is denoted as "atmospheric pressure turbine (APT)"

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The recovery of waste heat is an effective way of energy conservation, and the total amount of industrial waste heat is still notable. However, the value of the waste heat as energy source is low (low exergy). Therefore, its utilization requires larger recovery systems with increased costs. A concept of introduction of second, high-quality heat source in the form of H_2-O_2 combustion in order to improve the system's performance is presented. System analysis regarding obtaining combination effect (higher output from combined sources than from separate ones) is provided. The investigation results show possibility of remarkable merit of the considered systems under moderate conditions. The proposed combination of low-and high-quality heat sources makes reduction of systems' size and cost possible as well.

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Much of the new generation capacity installed during the next 10 years will be accomplished through the construction of IPP (Independent Power Producer) generating facilities. These facilities can take the form of small distributed generating (DG) units, or large capacity plants owned and even operated by non-utility personnel. It is forecasted that many of the distributed generating units will be at smaller industrial and commercial facilities and operating in parallel with the utility system to reduce energy cost through load sharing or "peak shaving." This paper discusses the protection requirements to interconnect these generators to utility systems, as well as methods to reconnect these generators after interconnect protection tripping.

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Economic advantage and CO_2 reduction extent of cogeneration system greatly depend on energy demand patterns, fuel costs and possibility of grid connection. The paper analyzes the basic characteristics of cogeneration system in economic and emission aspects and shows strategies necessary to maximize CO_2 reduction amount by the introduction of the system. The buildings analyzed in the paper are houses, offices, stores, hotels and hospitals, whose general energy-demand patterns are available. The result of the analysis shows that houses have the greatest potential to reduce CO_2 emissions among these building types, and reversed grid connection is the most important to maximize the potential. Combination of different types of buildings with energy network increases the economic and CO_2 reduction benefits, and the optimum combination of buildings is identified. The paper compares CO_2 emission amount for variety scenarios of strategies for introduction of cogeneration systems.

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An advanced co-generation system (ACGS) was built at Waseda University. The ACGS consists of a gas turbine, a steam turbine, an ammonia absorption refrigerator, an ammonia-water mixture turbine and an ice storage system. In this paper, at first, each component of the bottoming stage of the ACGS is modeled based on experimental data. Especially for the ammonia absorption refrigerator, we introduced the new characteristic modeling, which was expressed by some spaced straight lines, to improve the precision of operational planning. Secondly, we discuss the effect of the delay of components on the operational planning. In concrete terms, the delays of the output of both the AAR and the AWMT were considered based on experimental data. Further, the operational planning to various demand patterns of real civilian sector is studied. The calculation results show that the optimum operational planning is derived and the bottoming stage of the ACGS is available for actual demand patterns.

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The accumulated capacity of wind turbines in the world reaches 32GW at the end of 2003 March. Wind power is growing up to the big business now. The main feature of renewable energy is fuel free and less environmental impact. At COP3 in 1997,Japanese government agreed to cut down CO2 emissions in 2010 by 6% from the CO2 emissions in 1990. In order to attain this target of CO2 reduction, Japanese government starts promoting renewable energy, especially wind power. Wind turbines have been improved marvelously in recent years. Unit output and rotor diameter are increasing day by day. Mitsubishi Heavy Industries, Ltd. (MHI) has also produced several new turbines by it's own technologies. Recent trends about wind turbine generator systems are introduced in this paper.

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This paper provides a set of key-design equations for the preliminary phase of choosing the most appropriate wind generator to meet a given load at a particular site with known wind distribution. Efforts have been made to present a compendium of the important and useful results of research and development pertaining to the aerodynamics of horizontal-axis wind turbines (HAWTs), which generate the largest possible power output. Interpolating polynomials that best fit numerous airfoil design data are evaluated with all parameters expressed in appropriate dimensionless form so as to make the formulas applicable to a variety of wind turbine configurations. The best blade taper and twist, which can conform to manufacturing and production requirements, are obtained from refined distributions to the calculated theoretical variations. The derived formulas incorporate the influences of the earth boundary layer as well as the tower interference with the oncoming wind. Finally a practical study case is implemented and discussed, showing the usefulness of the given formulas in designing an efficient wind generator suitable for a specific site and energy needs.

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In the paper, the large eddy simulation of the flow fields around the NACA0012 airfoils and the MEL053 wind turbine airfoils developed by Mechanical Engineering Laboratory (MEL), Japan, is to be presented and discussed, with a special emphasis on the airfoil characteristics at the high angles of attack. As the subgrid scale models, the (conventional) Smagorinsky or dynamic subgrid scale model is used, and the numerical results are compared with the experiments. At high angles of attack, the quantitative agreement with the experiments is observed when the dynamic subgrid scale model is used. One the other hand, the Smagorinsky subgrid scale model over-predicts the subgrid stresses near the leading edge of the suction surface, poorly predicts the location of the re-attachment of the flow, and thus poorly predicts the static pressure on the airfoil. The difference in the numerical results between the Smagorinsky and dynamic subgrid scale models is less conspicuous for the MEL053 airfoils since the EML053 airfoils have more tendency to stall near the trailing edge.

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Woody biomass is a hopeful energy resource to reduce greenhouse gas emission, and it is widely used in North Europe. Although Japan has much forest, and emits large amount of greenhouse gas, little amount of woody biomass is utilized for energy production. One of the reasons is that most forests in Japan are located in steep mountain ranges. Therefore. we must reduce the labor and the costs for ingathering and transportation of the woody biomass energy to utilize it in Japan. The object of our research is to improve the calorific density of woody biomass pellets, and reduce the transportation cost per unit energy. We adopted the 'semi-carbonizing' method for the purpose. Woody biomass is generally used after desiccating because green woods include about 50% (mass fraction) of free water and it reduces the calorific value of the fuel. Woody biomass could be dehydrated more by decomposition of cellulose and hemi-cellulose during carbonization. The organic volatiles, however, are lost during the process, and the energy yield of the carbonized wood is reduced. Therefore, semi-carbonizing condition, on which maximum energy yield can be achieved, should exist. We examined the optimum semi-carbonizing condition for pelletizing in the present study.

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Fluidized bed technology is an established technology for energy generation due to low operating temperatures, high system efficiency, fuel flexibility, and easier control of pollutants such as NO_x and SO. This paper investigated combustion of biomass in a fluidized bed using numerical simulation. A recent model of fluidized bed combustion for high-volatile solid fuel was adopted to evaluate the biomass combustion in a fluidized bed combustor. The results of the model were compared with the experimental data from the literature to validate the model. Good agreement between the results of the model and the experiment was obtained. The model was then used to predict the performance of a fluidized bed combustor burning different types of biomass fuels.

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This paper focuses on the novel sensor system for measuring the moisture in biomass fuels, mainly in wood fuels, based on neural network models, which is low cost and a high performance. The sensor system for measuring the moisture in biomass fuels developed in this paper is quite different from the techniques before. In this new sensor system, the normal semiconductor humidity, pressure and temperature sensors will be installed in the fuel feeder in test facility, where the air humidity, pressure and temperature are measured. These signals will be fed together with operational data and ambient conditions in neural network models that have been trained by the experiment data in advance to estimate the moisture in biomass fuels. The information generated by the Neural Network will be used for the dynamic control system.

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In Japan, Waste-To-Energy Technology (WTE) has widely applied as the main waste handling technology because of its sanitation, disposal volume reduction, and obtainment of electric energy from the waste. However, in the conventional typed WTE, the efficiency level of obtaining energy has been as low as 10%. Therefore, the governmental projects started in early 1990s to discover the possibility of attaining higher efficiency. Consequently, governmental institutions introduced an advanced conventional type with efficiency level of 30% (i. e. High Efficiency Conventional Typed WTE. ). Along with such new Conventional Typed WTE technologies, two types of Gasification WTE technologies, equipped with an ability of efficient waste pyrolysis, were introduced. One is called as Pyrolysis and Combustion Typed WTE, and the other is called as Pyrolysis and Gasification Typed WTE. This paper presents the results and status of continuing R&D projects, analyzing the technical features of each WTE technology.

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Combustion of chloridated plastic such as PVC in solid wastes plays an important role in the HCl pollutant in air environment. The removal of HCl is classified as two sorts, i. e., the flue gas dechlorination and the reduction during combustion, of which the latter receives intensive concern due to its high economy and facility. In this paper, both HCl emissions and its removals by alkali-based sorbents during PVC combustion were conducted in an externally heated, quartz-tube fixed bed reactor. The conversion of HCl increased leniently from 83% to 88%, as temperature increased from 700 to 900℃. The calcium-based sorbents including CaCO_3,Ca(OH)_2,Ca(CH_3COO)_2 exhibited high HCl removal efficiencies from 68% to 79%, while magnesium-based sorbent less than that of 3%. Influences of operational variables, such as size of sorbents, Ca/Cl molar ratio and combustion fume compositions, on the HCl reduction were discussed.

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A small-scale gasification system for solid wastes has been developed and tested. In this innovative system, known as the STAR-MEET system, a fixed-bed pyrolyzer combined with a high temperature steam/air reformer is employed. From the experimental results using wood chips and polyolefin (PO) film as feedstocks, it has been demonstrated that injection of high temperature steam/air mixture into the pyrolysis gas can effectively decomposes tar components. As a result, the pyrolysis gas is reformed into tar-free clean gas contains CO and H_2. Experiments of direct steam injection into the pyrolyzer directly were conducted. For the wood chips, feedstock consumption, CO and CH_4 concentration in the reformed gas increased by direct steam injection into the pyrolyzer. For the feedstock which has low melting point like PO film, it was verified that the fixed-bed type of pyrolyzer was suitable for pyrolyzing. Also it was quite demonstrated that the produced reformed gas for a dual-fueled diesel engine was usable for power generation employing.

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This paper describes the deformation and breakup of a liquid bubble exposed to an airstream. Experiments were conducted using a vertical air-suction-type wind tunnel. Water and air were fed to a nozzle, and uniformly sized liquid bubbles were produced. Liquid bubbles vertically fell down, and entered the wind tunnel. A Liquid bubble has a larger surface area than a liquid drop for the same mass. So, the liquid bubble could be superior to liquid drop for heat exchange, combustion and so on. The displacement and the deformation of liquid bubbles due to airstreams were measured from photographs obtained by single exposure photography or consecutive photography. The liquid bubbles exposed to airstreams were deformed. The projected area a liquid bubble exposed to an airstream is expected to greatly influence such factors as the displacement, the drag coefficient, and the breakup time, etc., so the normal and the parallel liquid bubble diameters are measured in detail.

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The quantitative measurements of bed material movement and void fraction are indispensable for better understanding and formulation of thermal-hydraulics of fluidized bed. In this study the neutron radiography (NR) has been applied to the visualization of bed material movement and quantitative measurement of void fraction in the bed with 4×4 or 5×5 vertical tube banks. CT processing has also been employed to obtain void fraction distributions around the tube banks. The visualization data is expressed with the data of the heat transfer experiment, and the relationship between the heat transfer and void fraction is well correlated by Martin's correlation.

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In order to investigate the convection-condensation heat and mass transfer characteristics of the condensing heat exchanger of a gas fired condensing boiler, a single row plain tube heat exchanger is designed, and experiments have been conducted with vapor-air mixture used to simulate the flue gas. Colburn-Hougen method is introduced to analyze the heat and mass transfer process when the vapor in mixture condenses into water on the tube. The influential factors are found as follows : the partial pressure of the vapor, the temperature of the outer tube wall, the mixture temperature, Re and Pr. A new dimensionless number, which is called condensation factor, has been obtained by dimensional analysis. The experimental results show that the convection-condensation heat transfer coefficient is 1.5∿2.5 times that of the forced convection without condensation. Based on the experimental data, the normalized formula of convention-condensation heat transfer is obtained.

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An investigation of air-water counter-current two-phase flow in inclined pipe about flow patterns, the onset of flooding, pressure gradient and liquid hold-up were conducted experimentally. The pipe inclination angles examined were 30°, 45°and 60°from horizontal. The tube diameters were 16 mm and 26 mm I.D., the superficial velocities of air and water ranged from 1.0-25 m/sec and from 0.017-0.14 m/sec, respectively. As a result, it was found that (1) the flooding characteristics in counter-current two-phase flow in inclined pipe can be shown with variations of pressure gradient and liquid hold-up, where the pressure gradient was increased slowly in the pre-flooding then increased rapidly at the onset of flooding and gradually decreased in the post-flooding regime, while, liquid hold-up was decreased slowly in the pre and post-flooding regimes and increased rapidly at the onset of flooding, (2) an experimental correlation to predict the onset of flooding in inclined pipe was developed with error band ±10%.

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In this research, a critical power correlation is proposed for tight lattice bundle system. The correlation is developed from searching the relationship between local heat flux and critical quality based on JAERI axially uniform heating and axially non-uniform heated data. The proposed correlation is fit for the condition that mass velocity G<2500 kg/m^2s, with exit pressure in the range from 3 MPa to 8.5 MPa. The developed correlation is verified with BAPL data, JAERI axially uniform heated data and JAERI axially non-uniform heated data with good accuracy. The correlation also predicts reasonable parametric trends of mass velocity, pressure, inlet temperature and radial peaking factor on critical power.

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The new type of heat exchanger elements-Ni-based implanted spiral finned tubes (NISFT) has been studied and tested in this paper, which can contribute to increase the efficiency and reliability. The relations of Nu and Re with different fin pitch, fin height, transverse pitch and longitudinal pitch has been gained, which established basic foundation for the engineering application of NISFT.

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Performance of rectifier affects the coefficient of performance (COP) of an ammonia absorption refrigerator. Ammonia, namely refrigerant mass fraction, is one of the key parameters to discuss the performance of the rectifier. Focusing on the refrigerant mass fraction, this paper presents a method to estimate the refrigerant mass fraction with mass and energy balance and the results of the experiments which measures refrigerant mass fraction by sampling from the refrigerant receiver. Through out these investigations, the refrigerant mass fraction was lower than that of the expected value which is calculated from the condition of dry-saturated vapor at the top of the rectifier. The refrigerant mass fraction can be estimated within an accuracy of 0.7% from mass and energy balance equations around the separator at the inlet of the evaporator.

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A new type of heat storage materials combining high temperature molten salts (phases change latent heat thermal storage materials, PCM) with porous metals sensible heat thermal storage materials was developed in the authors' institute. The process of this technology is expressed as following : firstly, it is necessary to heat up the molten salts phases change materials to molten; and then the porous metals are put into the molten bath; after residing 1&acd;3 hours, the composite heat storage materials lumps are taken out of the molten bath and cooled to atmospheric temperature; the last step is to electrodeposit a layer metal coat on the surface of the material lumps. This new type of heat storage material integrates the advantages of both solid sensible heat thermal storage materials and high temperature phases change latent heat thermal storage materials. The metal-base heat storage materials enjoy some favorable characteristics such as higher heat charge-discharge rate, higher heat storage density and better mechanical strength.

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A new heat exchanger with latent heat transport for small and medium scale air conditioning system and industrial refrigerator was developed. This system consists of heated tube where coolant flows inside, wetted porous media layer and membrane which penetrates only vapor. Outside the membrane, forced convective air flow is applied. Most of heat from heated tube is transported by latent heat due to evaporation of water in wetted porous media and vapor penetrates membrane and is removed by air flow. In this way, very efficient heat transfer is realized. Moreover, in this system, water is kept by the thin layer of porous media and the membrane. Therefore, the quantity of water in this system is very small and no water circulation system needed. Then, very compact evaporative cooling system with latent heat transport becomes possible. Heat transfer coefficient of evaporative cooling system was measure at various flow conditions. The results showed that heat transfer coefficient augmented at least twice of that without evaporative cooling. The surface temperature of heated surface was maintained within the operational condition of practical heat exchanger. However, at some conditions, dryout phenomenon was observed due to the insufficient water flow in porous media.

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A three-dimensional numerical calculation has been performed on liquid-metal magnetohydrodynamic (MHD) flow through a rectangular channel in the outlet region of the magnetic field, including a region downstream the magnetic field section. The continuity equation, the momentum equation and the induction equation have been solved numerically by the finite difference method. Along the flow axis (i.e. the channel axis), the pressure decreases rapidly as a fully-developed MHD flow, drops more rapidly in the magnetic-field outlet-region, and finally decreases slowly as a normal non-MHD flow. The pressure recovery that was observed in the magnetic-field inlet-region does not appear in the magnetic-field outlet-region. The total pressure drop through the magnetic-field outlet-region is larger than that through the magnetic-field outlet-region is larger than that through the magnetic-field inlet-region. The flow velocity distribution also changes gradually from a flat profile of a fully-developed MHD flow to a parabolic profile of a non-HMD laminar flow.

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We designed the magnetic driving submersible pump (MDSP) to substitute ordinary one. Because of the eddy current and stray field, the power loss of the MDSP was increased 11-15% and these problems drop down the pump life same time because of the property of permanent magnets becoming worse by ultra warm. It can decrease the power loss 5-10% and magnetic materials volume 13% to use the optimizing magnetization permanent magnets to obtaining the maximal gradient force. There are 8 or more times longer life of the MDSP than the ordinary one.

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Natural convective flows of water induced around heated vertical cylinders have been investigated experimentally. Special interests were paid to the influences of cylinder diameter on the turbulent transition and also on the local heat transfer characteristics of the cylinders. The diameters of the cylinders were varied systematically from 10 to 165mm. Visualizations of the flows around the cylinder and of the surface temperatures of the heated cylinders have been carried out to determine the onset of turbulent transition. The result showed that the onset of turbulent transition shifts toward downstream with decreasing the cylinder diameters, when, in particular, the diameters are smaller than 60mm. Moreover, the local heat transfer coefficients of the cylinder show marked increase in the both regions of laminar and turbulent flows with decreasing the diameters.

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A research committee on steam turbine technology in the power & energy system division of the Japan Society of Mechanical Engineers (JSME) was established in the autumn of 1998. The primary functions of the committee were to investigate recent steam turbine technology and to discuss new technologies required for the power generating industry in the new century. This paper presents the results of the 3-years investigation.

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The general structure and purposes of the distributed control systems (DCS) are reminded in connection with the capability to use them for on-line optimization of the load distribution in large, multi-unit power stations. The basic assumptions, equations and structure of a model of backpressure extraction turbine are presented. The tasks, realized using this model in collaboration with the DCS's measuring and archive systems, are defined. The principles of using and correcting the input data for the considered tasks are described. Model calculation results and recorded measuring data are compared. The input data quality and influence of the DCS record mode on the abilities to use the model appropriately are discussed.

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This paper presents a method for the low cycle fatigue life expectation assessment with safety confidence of steam turbine components. The method is based on theories of probability and statistics. considering the low cycle fatigue life of steam turbine components to be a random variables : depending on concrete conditions. The low cycle fatigue life distribution parameters of the materials are estimated by statistical methods and low cycle fatigue test data. Low cycle fatigue life expectation with safety confidence of steam turbine components is calculated by applying the reliability theory. For low cycle fatigue life of steam turbine components with normal or a logarithmic normal distribution. a calculation method of the life expectation with safety confidence is given together with a practical example.

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To improve the reliability and the thermal efficiency of LP end blades of steam turbine, new standard series of LP end blades have been developed. The new LP end blades are characterized by the ISB (Integral Shroud Blade) structure, where the blades are continuously coupled by blade untwist due to centrifugal force. One of the most important technologies to design the ISB structure with high reliability is the analysis method of resonant stress of the blade. This paper presents the analysis method of the resonant stress caused for the the ISB structure by the lower engine order excitation force and the stage interaction force. The measured and calculated resonant stresses are compared to show the validity of the prediction method of the resonant stress.

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Modern steam turbines of Mitsubishi Heavy Industries, Ltd. (MHI) are based on advanced technologies, including advanced steam path design through fully 3-D viscous computational fluid dynamics (CFD) analysis, high efficiency seals, steam cooled casings, enhanced LP sections that include the world longest LP last blades such as 3600rpm 40-inch/3000rpm 48-inch steel blade, hetero material welded rotor, and state-of-the -art material technologies for high temperature up to 630℃. These advanced technologies result in more compact, cost-effective, opposed-flow HP/IP combined cylinder design that ensures high reliability, higher efficiency and ease of maintenance. This paper illustrates the features and operation experience of large steam turbines with MHI's new advanced technologies through two specific examples : a typical 240MW combined-cycle steam turbine recently developed for the American market, and a 700MW 3-cylinder steam turbine with 3600rpm 40-inch steel blades. HP/IP 1-cylinder design with 600℃ class high temperature steam conditions for 1000MW class turbine is also discussed.

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Because of incomplete historical records for the transient operation of steam turbine in power plant, data such as temperature of the steam, inner metal of HP, power output and time interval of a transient process, were not enough to accurately calculate the stress and life-loss of a turbine unit. The general way to evaluate the life-loss of an old turbine unit was to count transient process times under cool and warm as well as hot state to get accumulative total life-loss. Such general evaluation way was rough because of the neglects of the transient details in starting up or shutting down process. It was possible to use online life management system for more accurate evaluation of life loss of a turbine. The paper proposed a new method combining statistics and artificial neural evaluation of life loss of a turbine. The paper proposed a new method combining statistics and artificial neural network based on online lifetime management system, to evaluate past life-loss of the thermal turbine parts. First, the statistics of all previous typical transient operation and the concerned parameters for a year were made to be an operating sample. Second, an artificial neural network was applied to deal with these data, which need not set up accurate math model and carry out mapping between input and output. The life-loss could be output after historical data inputting and artificial neural network training. The new method overcame the constant life-loss caused by transient operation. This method was applied in a 125MW unit and basically satisfied results were achieved.

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A study of software development for steam turbine blade flow analysis was carried out as a cooperative project between a University and a steam turbine manufacture for the purpose of developing steam turbine aerodynamic technologies and enhancing efficiencies of subsonic and transonic turbine blades. A higher-order accurate robust computational fluid dynamic method, which includes an implicit LU-SGS-GE scheme and a higher-order, high resolution MUSCL TVD scheme, was developed. In this paper, we will report important applications of the steam turbine blade analysis, which include three cases of typical steam turbine blades. In contrast, a hybrid three-dimensional blade design method, coupled with optimization algorithms and viscous flow analysis, was developed in Tsinghua University. This can obviously reduce the level of aerodynamic loss of turbine blades. The comparisons between the numerical results and experimental data show the present study is able to become an efficient and robust tool to achieve high efficiency blade design.-

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This paper deals with an application of Computational Fluid Dynamics, CFD, to the design of a steam turbine of which working fluid is wet steam. Using a CFD code which can consider wet steam property, the present paper reports comparison between an ideal gas analysis and a wet steam analysis. Even in the wet steam region, the results of a single row analysis show good agreement, with respect to the loss coefficients and the outlet flow angles of blades, among the two CFD analyses and with the experiment of an air wind tunnel. However. However, the results of a multi-stage analysis in which state of steam intersects the saturated vapor line show difference. Results for stage analysis considering tip seal leakage are also described.

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New low pressure stages for 50 and 60 Hz steam turbines have been developed jointly by General Electric Company and TOSHIBA Corporation. The new low pressure stages feature 40" and 48" steel last stage blades for 60 Hz and 50 Hz applications, respectively. Last stage blades have been developed concurrently with the upstream stages, creating optimized low pressure turbine sections. This design has been further verified via a three stage scaled rig test of the 48/40 inch L-0,L-1 and L-2 stages. This model Turbine test measured both overall stage efficiency and detailed three-dimensional flow profiles through aerodynamic traverse and rake measurements. The measured stage efficiencies of the current design were clearly higher than the conventional design stages.

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Steam turbine generation has been around for a century now. Beside ongoing investigations aimed at improving economy in operation, the changed political scene as well as globalisation can be considered as prime movers associated with the development of modern power plant facilities. Based on a greater understanding of metallurgy and modern software solutions inner efficiencies above 96% and steam parameters of 620℃ underline the up-to-date STPP turbine technology ensuring net efficiency levels up to 47%. The power generation industry has mastered all these challenges in the past finally ensuring a head start to meet all future market demands and environmental pressures necessitating further steps for highly-efficient and reliable generating technologies. Further investigations on high temperature applications such as the European initiative E_<max> aiming for steam parameters up to 700℃ and net efficiency levels of above 50% have been initiated and are still under way. Besides presenting market developments and environmental requirements, state-of-the-art steam turbine technology as well as a future outlook for present R&D programs and design principles are key issues in the following paper. Focusing on the progress in material development, steam turbine blading technology as well as component design features are described in detail.

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A 3-dimensional finite element model (FEM) for vibration analysis of steam turbine blades is presented in this paper, employing a 3-dimensional incompatible solid element with 8 nodes for overcoming over-stiffening effect of the 8-node iso-parametric solid element. A skew coordinate system is introduced in the model for considering a cyclic symmetry of displacement constraints of blades. The vibration characteristics of a 4-blade group are analyzed using the proposed FEM. A running blade vibration test has been performed to measure natural frequencies of the blade group. The analysis results show a good agreement with measurements of the vibration test, and demonstrate that the proposed method is valid and effective for the blade vibration analysis.

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This paper describes the difference in aerodynamic stability between a free-standing blade (FSB) structure and continuous cover blade (CCB) structures for a steam turbine blade. Vibration modes and natural frequencies of FSB, CCB with tip cover only, and CCB with tip cover and tie-boss are calculated by a finite element code. The unsteady aerodynamic forces acting on oscillating cascades are calculated using two-dimensional, time-linearized Euler equation analysis. Aerodynamic work per blade is obtained by integration over radial sections of the blade. Aerodynamic damping is calculated from the aerodynamic work and the kinetic energy for the vibration modes of each structure. Finally, aerodynamic stability for each structure is evaluated and discussed.

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In this paper a new method for automatically detecting, localizing and classifying various types of disturbance waveshape fault is presented. The method is based on wavelet transform analysis, artificial neural networks, and the mathematical theory of evidence. The proposed detection and localization algorithm is carried out in the wavelet transform using multiresolution signal decomposition techniques. The proposed classification is carried out in sets of multiple neural network using a learning vector quantization networks. The outcomes of the networks are then integrated using voting decision making scheme.

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The paper first introduces the properties of circulating fluidized bed (CFB) ashes (fly ash and bed ash). Then it describes the new investigations about utilization progress of them. The properties of fly ash and bed ash are not identical, so the progresses of utilization are different, too. Usually, the low carbon and high CaO bed ash can be directly used as material for construction. But the high carbon fly ash must be treated with some process before being utilized, such as hydration for cement, pelletizing for re-burning.

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Through careful deduction, a steam-water distribution standard equation of thermo-system for coal-fired power plant is given, which depicts complicated thermo-system by system state parameters and auxiliary little steam-water flows. It is one of several accurate equations in thermo-system analysis. This paper also discusses two current equations, and analyzes their character and defect individually.

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An advanced-type compact water-tube boiler has been designed on the basis of the new concept of cooling flame by water-tube bank in the furnace, and is referred to as "tube-nested combustor". It realized drastic reduction in boiler size as well as in the NO_x emission. In this present study, aiming at further improvement of boiler efficiency and reduction of NO_x emission, the combustion characteristics in the furnace were investigated by using the test boiler of 0.5t/h steam output. Experimental results indicated that the NO_x formation was restricted in the narrow area close to the burner exit, and that the CO-concentration decreased drastically with the combustion gas stream through the tube-bank. These facts are closely related to the experimental evidence of the cross-sectional distribution of gas temperature being rather uniform owing to the agitation by the tube-bank. These experimental results verified the soundness of the boiler design and, in addition, gave relevant information on local combustion characteristics available for the R&D of the next generation tube-nested combustor.

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There is often residual whirl at the furnace outlet of the tangentially-fired furnaces. It has serious influence on the safe operation of the boiler. It is well known that the large temperature imbalance of the flue gas and steam may be a serious threat to the safe operation of the superheater and the reheater. In the counter-tangential operation, some counter-tangential air-streams are used to depress the residual whirl intensity. However, there is some misunderstanding in counter-tangential operation, which does not take account of the particularities of the tangential firing. It only eliminates the whirl by itself. The controlled whirl method is put forward in this paper, which not only keep the advantage of the corner tangential firing, but also effectively controls the residual spin intensity at the furnace outlet. The numerical simulation was used in this paper to discuss some basic principles. It is shown how the angular momentum flux is influenced when various layer second air is used to depress whirl.

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