Innovations to improve thermal efficiency, to reduce exhaust gas emissions, and to utilize alternative fuels in diesel engines are necessary to prevent global warming, to save energy resources, and to reduce the impact on the environment Introduction of the latest materials and technologies for control and sensing is essential to achieve the innovations, including concepts which could not be realized previously but can be at present The diesel engine will remain as the main power source of automobiles in the long term as they have superior efficiency, performance, and cost This overview will detail the development and prospects of diesel engine technologies and alternative fuels, including bio-diesel fuels, dimethyl ether (DME), and gas to liquid (GTL) fuels.

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Supercharging the intake air is one of the effective methods for increase the operating load of Homogeneous Charge Compression Ignition (HCCI) engine. In this study, the influence of boosting the intake air pressure on combustion characteristics of HCCI engine fueled with dimethyl ether (DME) was investigated. The experimental results revealed that the combustion became more moderate with boosting the intake air pressure because recombination reaction of CO and 0 becomes gradually and the operating load extended more upper load ranges. However, too much increase of intake pressure decreases the combustion efficiency because the decrease in the maximum gas temperature in cylinder.

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To control the ignition timing in accordance with operating conditions is crucial for utilizing homogeneous charge compression ignition (HCCI) combustion engines. Hydrogen and carbon monoxide, both main constituents of reformed gases, are known to retard the autoignition of dimethyl ether (DME). The ignition control effect expands the operable range of equivalence ratio and engine load in HCCI combustion. This paper newly investigates the effect of ethylene, which can be reformed from ethanol, on DME oxidation in HCCI combustion.

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In this study, ignition and combustion characteristics of biomass gas in a HCCI engine was investigated experimentally. Imitation biomass gas consisted of H_2 CH_4, CO, N_2 and CO_2, was used assuming wood pyrolysis gas. Test engine was a 3cylinder 1.6L gas engine by modifying compression ratio from 9.5 to 24 and equipping intake air heating system. Experiments were carried out by changing fuel composition and fuel/air mixture condition. As results, knocking was not occurred at higher equivalence ratio 0.4, because the fuel had much dilution components. Indicated thermal efficiency was achieved 47%. It was also clarified that H_2 advanced ignition timing but CO retarded it.

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In order to utilize biomass resources effectively, one of the effective methods is considered to be the diversion of the automotive engine as a small-distributed generation system due to its low cost. Therefore, it is necessary to understand the combustion characteristics of the biomass gas because the composition of the biomass gas generated from gasifying biomass resources fluctuates with the gasifying method and the operational condition of gasifying plant. So, an investigation on the combustion characteristics was carried out by a simulated biomass gas. In addition, operational tests were also conducted using real biomass gas that was supplied by gasifying plant. Air-fuel ratio was controlled by twin throttles for air and fuel on this occasion to realize stable operation.

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Micro Gas Turbine system is required to be stable for unpredictable fuel component fluctuation while maintaining the control performance. By using supply system of generating simulated biomass gases, experiments of operating biomass gases were realized. We used the way called two-stage combustion in order to achieve low NOx combustion. And we used two kinds of controllers, one is depending on H infinity optical control theory and the other is depending on PID control theory. After confirming the stability of both the controller and the system by the simulation, it was equipped to the Micro Gas Turbine experiment system. This development made the Micro Gas Turbine stable against finer fuel control, and this realized higher controllability under fluctuating low calorific gas fuel such as biomass gases.

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By combustion of a fossil fuel, human beings have raised the carbon dioxide levels in the atmosphere by about 100 ppm. On the other hand, oil and natural gas are considered that the amount of supply gradually decreases with a peak of around 2030, and need to provide an insufficiency with atomic power and renewable energy. We have done research for making liquid fuel and gaseous fuel generate from a waste plastic or the waste biomass using thermal cracking technology. We introduce this time about the process (BTG: Biomass to Gas) of generating natural gas (methane), from the woody biomass. When such a process will put in practical use from now on, it has a possibility that the substitution to the renewable energy of town gas is raised greatly. Furthermore, this method becomes applicable also when town gas is changed into hydrogen gas from natural gas in the future.

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To realize thermal recycling of waste plastic resin as one of alternative fuels, detailed microscopic observation is made of the multiphase process in a micro spherical PET particle under abrupt heating. It is observed that multiple internal micro bubbling occurs within the micro PET-droplet independent of its initial diameter and is triggered by flash vaporization of thermally decomposed products of PET resin. Internal random explosions of micro bubbles follow and blow up multiple irregular micro jets from the micro droplet. The latter forces the micro droplet to move around irregularly on the fine wire, while micro diffusion flames are randomly established behind them. Based on the observation results, the key factor to such a violent burning process of PET particles as to exceed that of well-known volatile liquid fuels can be attributed to the internal multiple micro bubbling due to the flash vaporization of thermally decomposed products.

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This paper describes a new process to produce a clean fuel from wood wastes mixed with synthetic polymer materials such as plastics or adhesives. The process will consist of several components. The three main components of the process are as follows: (i) Pyrolysis Wood wastes mixed with synthetic polymers are dried and pyrolyzed to lower molecular weight products at mild conditions.; (ii) Hydrogen production The solid residue produced from the pyrolysis reactor is converted to hydrogen under coexistence of water and the alkali compound.; (iii) Hydrogenation - The liquid heavy compounds produced from the pyrolysis reactor is hydrogenated to light hydrocarbons. Light hydrocarbons produced by hydrogenation will be used as gas fuel or can be further converted to liquid fuel by reforming and synthesis processes.

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New rapid extraction method has been developed to measure quantity of brominated flame retardant in thermosetting resin such as an epoxy circuit board. The epoxy board was solubilized almost completely in many organic solvents at 300 ℃. However, only two solvents, benzyl alcohol or N-methyl-2-pyrolydone, were effective at 250 ℃ for solubilization of the epoxy board. Solubilization of the epoxy board in benzyl alcohol was promoted by sodium hydroxide. Even at 200 ℃, more than 70 % of epoxy board was dissoluble in the presence of sodium hydroxide. Conversion of TBBA increased with temperature, and 40% of the TBBA was decomposed in benzyl alcohol at 250 ℃. Removal of bromine from TBBA was accelerated by sodium hydroxide significantly.

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This paper describes product distribution from hydrogenation of model materials as heavy liquid elements by pyrolysis of wood wastes mixture containing adhesive, plastics, and so on. The mixing effects of materials on reaction were also discussed. As a result, product distribution was differed by hydrogen pressure. It was shown C_6H_6 and C_2H_6 influenced as middle products which could be converted to CH_4. Whole reaction was enhanced by pressure increase. The effects of mixing on increasing in product yield were observed even it was small. It is possible to say exothermic reaction promotes endothermic reaction in a short time.

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The aim of this study is to clarify the appropriate reaction condition for the thermal decomposition of the glycerol, in order to utilize wasted glycerol produced as a by-product of biodiesel fuel. The effect of the reaction temperature on decomposition products were examined by the experiment and the chemical equilibrium simulation. In addition, the effects of steam addition and partial oxidation on thermal decomposition were also investigated. Results shows that both steam addition and partial oxidation are effective to improve the gasification ratio with relatively low reaction temperature, while the heat value of product is decreased when the partial oxidation is adopted.

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In recent years, the rotors for small wind turbines designed to have low tip speed ratio are increasing in number because of their reduced noise. The development of generators and controllers suitable for low rotational speed is largely accelerated these years. While there are many papers on the small wind turbine rotors with high tip speed ratio adjusted for conventional generators, a number of the paper systematically dealing the rotor shapes applied for low tip speed ratio is very small. In this study, two types of experimental models are prepared to compare the performance at low tip speed. One has a rotor with tapered blades designed by the combined blade element and momentum theory, and the other has a rotor with inversely tapered blades in which the calculated chord lengths are applied in an opposite way. In this paper, the authors report a result of a performance test in a wind tunnel on experimental models.

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This paper proposes an application of Flywheel Energy Storage System for wind generation system to improve the power system stabilization. Then, the output variation of wind generation system is a serious problem. Therefore, when the wind generation system connected the power system, the voltage variation and the harmonic component problem causes. The validity of proposed method is evaluated by a small examination.

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In this paper we will present some novel results of our research and development in the filed of wind energy utilization. Our effort in this filed is mainly concentrated to the conceptual design of optimum airfoil sections for the blade of Darrieus Savonius Rooter wind turbine which undergo cross wind motion. This concept was embodied in the design of a family of airfoil sections designated as Tokai Wind Turbine sections and a series of wind tunnel testing was conducted to confirm its desired aerodynamic characteristics. Then, we designed an experimental Darrieus Savonius Rooter wind turbine system with blades to evaluate system performance and structural analysis results, and furthermore to collect operating experiences under real, fluctuating wind conditions. We are now working for evaluating operational feasibility of five sets different Darrieus Savonius Rooter wind turbines system, which are partially in service as pilot plants of regional energy development.

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In recent years, various information about the importance of solar and wind power is getting around, and with growing awareness of environmental problems, the use of renewable energy is increasing. The construction of small wind generators is developing more and more worldwide to meet demand for new natural-energy power generators. Small wind turbines must meet safety, low-noise and high efficiency requirements at low wind speed, too. Various studies have been carried out in Japan and abroad. Most of these, however, are just additional work on blades made by using common design techniques that follow the Blade Element/Momentum Theory (BEM). By the switch of the idea, therefore, we decided to investigate blade shape starting with basic notions such as the leverage principle, the action-reaction law and Bernoulli's theorem, in order to address requirements for wind turbines used in urban environments.

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This Paper Presents a study of small scale wind powered generation systems (SW-VAWT) combined with solar cell generation unit as a reliable electric power source from Taiwan in Mingdao University. The subject of this study is a reliable and independent electric source powered by a small wind turbine which is intended to be deployed from Taiwan in Mingdao University. In these regions, wind is strong through a year and is constantly available and, if the wind turbine generation system is combined with solar cell unit, it will be an ideal independent electric source.The ultimate design concept was required for development and reliable operation for independent electric source powered. Therefore, the system was simplified. The system of straight wing non-articulated vertical axis wind turbine (SW-VAWT) has been shown good wind energy transform efficiency, by fixing a number of straight wings around vertical axis. Our experimental VAWT was designed based on the study and preliminary structural boundary to confirm them and collect operating experience under real, fluctuating wind with a number of loading devices. In this paper, a hybrid power system combined with the wind powered generator of 2kW output and the solar cell is described. We confirmed reliable and satisfactory operation of this small, independent power source.

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In this paper we will present some novel results of our research and development in the filed of wind energy utilization. Our effort in this filed is mainly concentrated to the conceptual design of optimum airfoil sections for the blade of straight wing non-articulated vertical axis wind turbine which undergo cross wind motion. This concept was embodied in the design of a family of airfoil sections designated as Tokai Wind Turbine (TWT) sections and a series of wind tunnel testing was conducted to confirm its desired aerodynamic characteristics. Then, we designed an experimental straight wing non-articulated vertical axis wind turbine system with straight blades to evaluate system performance and structural analysis results, and furthermore to collect operating experiences under real, fluctuating wind conditions. We are now working for evaluating operational feasibility of five sets different straight wing non-articulated vertical axis wind turbines system, which are partially in service as pilot plants of regional energy development.

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This paper proposes the wind generator system with wind screen for large automobile. The wind screen for the car is used in the large truck. In this paper, shutter and vertical-shaft wind power generator are introduced into this wind screen. The shutter of this wind screen opens, when it becomes the case in which the car stops or deceleration condition. Then, the deceleration energy is recovered in the wind power generation. The proposal system was introduced into the wind screen for the small truck, and the experiment was carried out using the air blower. As the result, the deceleration energy got possible recovering possibility by the proposal system.

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Recently, a wind turbine utilizing the Magnus effect is appeared in Russia and Japan. Akita Magnus Association in Japan proved that the Magnus effect could rotate a wind turbine, their cylindrical rotors were necessary to rotate by an electric motor. Therefore, the authors proposed a Magnus wind turbine that utilize Savonius wind turbines of high aspect ratio instead of the cylinders, since the Savonius wind turbines rotate without using electricity; we also looked into the technical feasibility of this system. In this paper, the authors report a result of a performance test of the Savonius type Magnus wind turbine in a wind tunnel test.

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Savonius turbine is known as a wind power generator that is driven by drag force acting on two cylindrical blades. The drag is, however, insufficient to maximize the power efficiency because of interaction of fluid around the pair of blades. In order to see and evaluate detailed flow structure, PIV technique is used and applied to Navier-Stokes equations for obtaining pressure field information. With the results, the use of low-pressure region on convex surface of the blade is suggested so that lift force reinforces the torque as drag is lacked. Moreover, streamwise and lateral oscillatory forces around the turbine are discussed in the safety point of view, which need to be investigated to prevent from bending and collapse of the turbine main shaft.

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NEDO (New Energy Industrial Technology Development Organization) has developed the systems which forecast wind power for the purpose of increasing the quantity of wind power which can be installed in Japan. ITOCHU Techno-Solutions Corporation carried out the development of the wind power forecasting system for the control area of power grid. The forecasting system is made up by numerical weather prediction (NWP) model and statistical model. This paper describes the overview of wind power forecasting system for the control area of power grid and the results of accuracy evaluation.

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Gearbox failures are caused by various reasons, for example, absolute gear rating, bad load distribution across teeth and between planets, uncontrolled power input, rotor loads imposed on gear case etc. To reduce in these failures, it is important to define concept design robust. During the concept design, components layout which includes demanded torque, type of gearbox for torque split, calculation of power flows, gear sizing with K&C factor, bearing selections with bearing catalog and gearbox suspension systems to support the gearbox. To be optimized gear design, mechanism of flexible pin concept which can be approached by gear test of analytical method is introduced. This paper introduces concept design procedure of the wind turbine gearbox. Some kinds of design parameter are introduced and compared initial concept design with final concept design of gearbox system.

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In this paper, we discuss effects on aerodynamic sound generated from an NACA0012 airfoil by the airfoil tip flows mainly at a Reynolds number of three times ten to the fifth and angle of attack of lifting condition. Some results of far-field sound spectra suggest that tip flow noise affect the sound of frequency range of 2.5 kHz to 8 kHz. Accordingly, we investigated unsteady flows around the airfoil tip by hotwire measurements and obtained some possibilities of noise reduction by reduction tip flows rolling up or its fluctuation from pressure side to suction side from the results that it was observed of high turbulence on the same range of frequency of velocity in the tip flows. Then, it was cleared that the appropriate flat plate could reduce the tip flows rolling up and the turbulence level, and could reduce the noise level of 3 dB (Max.) in the frequency range of 5 kHz to 8 kHz.

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In the current wind turbine generation system, no optimized system is found in terms of the matching between wind turbine and the generator. Recently, new wind turbine generator optimized for the wind turbine output is proposed. This wind turbine generator is made of PM generator and is using neither control circuit nor PWM converter. From the experiment result and review, it has been confirmed that the matching of the wind turbine and new generator is high.

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The analytical and experimental evaluations of the newly developed panel type solar cooker are performed in the study to show its practicality and efficiency especially for the use in the areas with various sun elevations. Due to their low cost and simplicity, panel type solar cookers are considered to be one of the effective tools to prevent deforestation and to create jobs in the developing countries. The proposed panel type solar cooker is foldable and made of durable cardboard with water-resistant surfaces intended for the use in the areas where the fuels are insufficient. Analyses, experiments and several demonstrations in the developing countries show that our cooker works effectively for the all sun elevations.

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An actual renewable energy house, equipped with a geothermal heat pump (GHP)-powered floor heating system was investigated and analyzed. It emerged that the GHP-powered floor heating system is sufficient for space heating and with the maintenance of near-uniform room temperatures even during the coldest days in a very cold region like eastern Hokkaido. Annual heat loss from the house estimated by the numerical simulation showed almost agreement with the measured annual thermal demand for mom heating by consideration of heat recovery from floor heat loss. Measurements of actual ground temperature distribution started from the last summer showed a new issue, requirement of heat recovery of ground.

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A Low-grade Thermal Energy Conversion (LTEC) is paid attention in saving energy and generating power as environmental friendly energy. Over a long period of time, the thermal cycle efficiency has been used as mainly standard evaluation for energy system for generating power system, for example, a fossil fuel power plant, a nuclear power plant, a geothermal power plant, a wasted thermal energy conversion (WTEC) plant and an ocean thermal energy conversion (OTEC) plant, etc.. For the power plants using heat source below nearly 100℃ (WTEC, OTEC, and so on), a evaluation including pumping powers and net power etc. In this paper, the power plant using heat source below nearly 100℃ is called as LTEC. The thermodynamic analysis including pumping powers and net power is performed for LTEC. In this research, the ratio of net work to maximum work and some evaluation including using effectiveness-NTU are proposed on LTEC.

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An Ocean Thermal Energy Conversion (OTEC) is one of the renewable energy. The non-azeotropic mixtures have been utilized as working fluid for enhancing the thermal efficiency of OTEC system. In this paper, it was conducted an experiment on the characteristic of the OTEC system using a new evaporator for low pressure drop, and evaluation of turbine power, net power and the ratio of net work to maximum work. New plate type evaporator has lower pressure drop. As an experimental result of comparison with previous type evaporator, higher net power is obtained. In the case that warm source temperature is 31℃ and cold source temperature is 8℃, around 24% of the ratio of net work to maximum work is achieved.

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An analysis of performance of the power system utilizing ocean energy and waste heat energy from marine engine is presented. The working fluid was using Trifluoroethanol (TFEA). A procedure is developed to maximize a net power of power system using of shell and plate type heat exchanger under the condition of designate power system. The maximum net power is given by minimizing of heat transfer area of the heat exchangers which consume most cost in total cost of a power system. The minimum value of objective function is about 3.1 m^2/kW and the thermal efficiency of Rankine cycle of this power system is 24.4 % when the inlet temperature difference of exhaust gas and sea water is 376 ℃.

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Recently DME is focused as alternative fuel because DME could be made from natural gas, bio-mass gas and coal. Now DME is investigated fuel for Diesel engine because Cetane number of DME is almost as same as light oil. On the other hand, DME can be blended with LPG because characteristic of DME is similar as LPG. LPG is usually used as gas fuel for small gas engine, cooking equipment and stove. LPG small gas engine drives generator and heat pump system. If mixture fuel of DME and LPG can be used instead of LPG in the market, energy security will be safe in the world. However, the knocking limit of DME is very low comparing LPG because the auto ignition temperature of DME is almost as same as light oil. This research is investigated on knocking limit of mixture fuel of DME and LPG on each ratio of DME. The test engine is natural aspirated small spark ignition gas engine which is used for micro cogeneration system. The bore size of test engine 88mm and stroke is 96mm. The displacement of the test engine is about 1.6 liter. The engine speed is 1500 min^<-1>. The result showed that the knocking limit using DME mixture fuel could be improved by retarded ignition timing and A/F ratio under the limit of blend ratio without EGR is less than 30%. The limit of DME blend ratio should be less than 40% by retarded ignition timing and controlling EGR ratio in improvement of knocking limit.

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This system consists of a 1MW class gas engine of which generating efficiency is 42.5%LHV, that is the best level of this class in the world, and HRSG (Heat Recover Steam Generator) with re-burning system to expand heat/power ratio. The total thermal efficiency of this system is 10-20 points higher than that of conventional variable heat and power gas turbine systems or current gas engine systems in combination with independent package boiler in a range of heat/power ratio of 0.5-1.5. In this paper, features of this gas engine system which is eco-friendly and has high electrical efficiency and moderate steam output, and the energy saving effect of this system based on a field test result in some mining factory for two years are described.

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We have proposed the energy networks which carries out the cross-supply of electricity, hot water, and hydrogen for effective use of fuel cell systems. We started the demonstration in existing apartment building from May 2007. The demonstration system consists of three fuel cell systems, a hydrogen generator, the hot water pipe, Electricity grid, demand measurement sensors, experiments for detached houses model and apartment building model are enabled. The effects of the energy network were confirmed by demonstration through one year. We report outline and results of demonstration.

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Many believe that bulk utilization of fossil fuel influences to the damaging environmental effects. In recent years, it is noticeably shown that global warming and climate change is mostly due to man-made emissions of the fuel utilization in various purposes and sectors. The particular purpose of this paper is to support the selection of cogeneration system (CGS) and technologies by applying with total energy efficiency in various periods. The optimal heat recovery, exhaust energy and electrical power are also hourly investigated to provide the selecting operational mode in micro gas turbine with absorption heat exchanger. Total fuel energy saving amount and its related CO_2 emission are also simulated to determine the capacity of the CGS for comparing with the conventional separated system. Eventually, this CGS will reduce the fuel consumption and CO_2 emissions in operation, when the system will gain the high total energy efficiency and the low emissions level with respected periods.

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Reduction of CO_2 emissions and energy saving are the urgent issues for many fields of industries at present. Steam, occupying considerable energy consumption rate in the whole industry, is generally generated using combustion gas being higher than 1,000 centigrade at boilers. However, the temperature loss is large at boiler process in the case of generated steam of 100 something centigrade. Therefore, we thought that energy saving could be accomplished if steam could be generated using low temperature heat resources. This presentation reports the development of steam generator in the case of low temperature difference between generated steam and heat resources. The steam generator was designed employing method of vaporization using falling films on heat transfer tubes, so that the size of the generator became compact The size was calculated in the case of generated steam flow late being 2,000 kg/h. The development requirements and the possibility will be discussed.

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Biomass ethanol is CO_2 free fuel. Consequently, biomass ethanol attracts attention as renewable energy with few amounts of greenhouse gas discharge. Therefore, in this study, steam reforming of the biomass ethanol is carried out using the heat source of sunlight. The produced hydrogen is supplied to a proton exchange membrane fuel cell, and is generated. The meteorological data in Sapporo, Tokyo, etc. was introduced into this system, and the amount of hydrogen generation, the amount of greenhouse gas discharge, and power of purchase and sale were investigated by numerical analysis. Moreover, it is testing in the condensing collection of heat using the commercial sunlight condensing solar collector. This paper reports the scheme and test result of this system

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Chemically Recuperated Gas Turbine (CRGT) is an advanced GT cycle that can increase power generation efficiency by recovering the exhaust heat with endothermic reaction of steam reforming. The CRGT fueled by Dimethyl Ether (DME) was demonstrated using 30kW Micro GT (MGT) as a project funded by METI from 2003 to 2007 and accomplished both 10% reduction of fuel consumption compared with steam injected GT cycle, which is similar proven technology, and NO_x emission level of less than 10ppm. Alternative fuel nozzle had concentric double pipe, one of which was designed to burn DME directly with diffusive combustion, and the other was premixed combustion of low-BTU reformed gas. The reformer, which was designed to fit into the MGT and consisted of 96 SS316-tubes filled with Pt catalyst and alumina balls, top and bottom headers and rectangular duct, recovered 15.3kW heat from exhaust gas and increase fuel heating value by 7.9%. This report provides not only these results but also a lot of useful information including concise specification, designing process and verification test of each mechanical and electrical component, and relevant issues and solutions as well.

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A capacitance sensor was developed to measure the static dielectric constant of heavy crude oil under the high temperature and high pressure conditions. The static dielectric constant of heavy oil level of steam atmosphere was measured by using this sensor on 320-390 degrees Celsius and 10-25MPa conditions. As result, in about 20 degrees Celsius high temperatures side than saturation temperature, the difference between calculation value and experimental data was within 10%. These results, we got the prospects of a tar level control system by capacitance sensor.

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It is very important to measure gas flow rate transported by pipeline for city gas distribution. Though, the gas flow rate is measured at thousands of point where flow meters have been installed such as regulating stations, Tokyo Gas has developed tracer gas method as a new approach for simple flow rate measurement at the point where the flow meters have not been installed at present to realize more efficient gas distribution. In this paper, we report diffusion behavior in the city gas pipeline and accuracy of gas flow rate measurement by means of tracer gas, resulting from actual full-scale experiments and diffusion analyses.

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A impedance CT for solid liquid two phase flow has been developed by simulation. First, we solve forward problem. It is solved the next Laplace's equation to find electric potential and current density distribution of the duct line inside. Second, inverse problem was solved. Resistivity was found by electric potential and current density distribution. The state in the pipe is simulated by this resistivity.

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Friction drag accounts for 80 % of the total drag for large ships, and hence microbubble drag reduction is expected as one of the most feasible ways to reduce it because of less environmental impact. The demonstration experiment using 127m-ship is carried out and its turbulent boundary layer is measured by UVP for the first time. This report mainly describes the measurement method of seawater velocity profiles beneath the ship and some typical results on the influences of bubbles on their statistic values.

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The photo resist stripping process in photo lithography plays an important role in manufacturing large-scale integration. In the present study, experimental information is obtained to establish high-concentrated ultra pure ozonized water technology for stripping the photo resist, in stead of chemicals such as sulfuricacid or hydrochloric acid. In the experiment, rotating flow of the ozonized water on the photo resist is irradiated by excimer light, wave length is 222 nm. Ozonized water supplied by cleansing nozzle on the rotating wafer forms liquid film flow. After the process, the thickness of unremoved photo resist on the wafer is measured by ellipsometer. As the result, it is clarified that adjusting the irradiation of excimer light and the control of flow on silicon wafer is inevitable to accomplish high efficiency of photo resist removal rate.

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The aim of this study is to reveal the basic flow characteristics, especially downward velocity, of the free surface vortex. The flow field at the vertical cross section in a cylindrical vessel was measured by using PIV. The measurement results showed the inclined vortex center due to the un-axisymmetric structure of the vessel. Therefore, the maximum downward velocity on the cross section was discussed with the depth. The relation between the maximum downward velocity and the depth showed the tendency where the downward velocity increased with the depth non-linearly. By using dye, the downward velocity was also measured but its results showed a little difference from that by PIV.

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To develop the numerical simulation of PEM fuel cell, verification experiments and data acquisition of physical parameters were conducted by mechanical and electrochemical measurements. The mechanical measurement showed that the GDL deformation due to clamping by separator lands is important phenomenon to estimate an actual flow in the cell, and the unique deformation behavior of GDL with fabric construction was clarified. From the electrochemical measurement, the methods to acquire the parameters used in the simulation, proton conductivity σ_m, electrochemically active Pt area a, exchange current density i_o and cathode transfer coefficient α_c were established. Furthermore, the possibility to analyze flooding phenomenon by applying this electrochemical measurement was presented.

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The deformation of gas diffusion layer (GDL) plays an important role on the performance of polymer electrolyte fuel cell since the physical properties such as porosity and permeability of the GDL and the cross sectional area of the gas channel are affected by the structural deformation of GDL. Non-uniform deformations of GDL are taken into consideration and are chosen as in the experimental data. A transient, non-isothermal and three-dimensional numerical model has been used to find the solutions for a wide range of porosity and permeability values. Further, the effects of these parameters on the pressure distribution are measured. It is found that there is an effective range of porosity and permeability values for which these parameters have a very strong effect on the pressure drop (difference of pressure from inlet and outlet).

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Water management is the most important subject in the development of the Polymer Electrolyte Fuel Cells (PEFC) with high performance and high reliability. Experimental and numerical study has been done for the serpentine channel. Two kinds of the channel width, 2 mm and 8 mm, were selected. It is found that the rib of each separator plays as the coverage to reduce the escaping of the water content from the GDL to the channel.

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To maintain the high performance in PEFC, water management which keep an electrolyte film to the adequate wet is necessary. The gas diffusion layer (GDL) fulfils large role in it. In this study cell characteristics was tested using GDL with various characteristics. As a result it was showed that the rigidity was necessary for GDL to keep the contact resistance stably low. In GDL with the same carbon-fiber direction, the difference of the cell performance occurred by changing the channel direction. It was thought that the gas diffusion under the separator rib was changed, because the difference could not be seen in both of the visualization image.

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High power density enhances polymer electrolyte fuel cell with widely varied applications. Our investigation focused on the refinement of the reactant gas flow field at the bipolar plate in order to increase the fuel cell performance. Applying a porous material to the reactant gas flow field is one possible method. Expected advantages of a porous flow field are an increase in reactant gas diffusivity and electron conductivity allover the electrode. An investigation was carried out to evaluate the feasibility of a porous flow field. The Lattice Boltzman simulation indicated that surface wettability and pore structure control have prospect of gas and water flow field separation. The experiment of porous flow field showed same level performance of channel type.

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It is important to reduce the diffusion polarization at high load conditions for achieving higher performance in direct methanol fuel cell. Previous research by the authors has shown that a porous stainless flow field improved cell performance at higher load conditions. This research applied the porous stainless steel to the gas diffusion layer (GDL) of a direct methanol fuel cell, and experimentally analyzed its effect on the cell performance. The result shows that porous stainless steel GDL enables direct methanol fuel cell to operate with higher output than carbon-paper type GDL especially at higher current densities.

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A model is developed to explain the water movement in a hydrophilic gas diffusion layer (GDL) of PEFC. In the model, a fine hydrophilic columnar fiber is set perpendicular to the surface of the catalyst layer covered by water film. The fiber stands in the channel air flow of the PEFC. The water climbs along the fiber surface up to several tens micron meters for fibers with a diameter range between 3 to 30 micron meters. The calculated results of the evaporation rate from a set of parallel fibers simulating GDL with a void fraction of 0.5 are shown to be much higher than the water generation rate at the catalyst layer with a power density of 1A/cm^2.

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