The wind turbine industry has seen innovations leading to growing size of turbines of currently over 160 min diameter. However, as pointed out by some recent studies, up-scaling of blades has its limitations and therefore advantages of multi-rotor system concepts have been suggested by Jamieson et al. The so-called wind lens turbine, which was developed by Kyushu University, shows increased power output using a brimmed diffuser to augment the approaching wind flow. In the presented research we are investigating the aerodynamics of wind lens turbines spaced closely together comprising a multi-rotor system. We placed up to three of these turbines closely in an array perpendicular to the flow and measured power output. The total power output of multiple turbines was then compared to the power of the stand-alone setup. Several different wind lens configurations have been used, mainly varying the brim height. We observed that the performance of the turbines is influenced by the width of the gap between the brims and the brim height of the wind lens configuration. The best performance was at a gap of 0.15 D with 10% brim height which leads to a power increase of more than 9% in a three turbine side-by-side arrangement. Further it was observed that the individual power output doesn't follow the trend of the cumulative power output. These phenomena can be explained with flow patterns observed in gap flow analysis of bluff bodies. Further research is necessary to fully understand which mechanisms in three dimensional gap flow cause the effect on the performance of the turbines.

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The increasing concentration of carbon dioxide in the atmosphere is one of the causes of greenhouse effect. In order to control the concentration of CO_2 in the atmosphere, the technology of recovering the emitted CO_2 and isolating from the atmosphere is considered to be effective. In this viewpoint, the solution and diffusion process of CO_2 in seawater is important in the research and development of CO_2 ocean sequestration technology to mitigate global warming. In this study, solution process of CO_2 bubble in seawater and pure water were experimentally studied under various pressures, temperatures, and initial bubble diameters to evaluate the transport process of CO_2 in seawater. Experimental conditions for the temperature ranged from 278 K to 293 K, and the pressure ranged from around 1 atm up to 4 atm. It was obtained that the complete solution time decreases with the increase in pressure due to its higher solubility at a higher pressure. It decreases with an increase in temperature arising from a higher diffusivity at a higher temperature. It was clarified that the complete solution time for CO_2 in seawater is higher than that in pure water due to its relatively lower solubility compared with pure water.

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The topcoat of the thermal barrier coating (TBC) applied to hot gas path parts of a gas turbine has a risk of delamination during operation. A nondestructive testing method based on active thermography has been developed to inspect for such delamination, using a laser beam as the heat source. With this technique, the laser beam is scanned over the surface to be inspected, and delamination is detected based on both the temperature peak attained when the delaminated part is heated, and a residual thermogram shaped with a trail behind it. This technique was applied to a disk-shaped TBC testpiece, in which simulated delamination was caused artificially. Inspection results with higher precision than conventional techniques were obtained, and it was shown that there are proper heating conditions for obtaining a high temperature peak and clear residual thermogram.

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Transient forced convection heat transfer due to exponentially increasing heat input to a heater is important as a database for safety assessment of the transient heat transfer process in a Very High Temperature Gas-cooled Reactor (VHTR). Forced convection transient heat transfer for helium gas flowing over a cylinder in a narrow channel at various periods of exponential increase of heat input was experimentally studied. The test heater was mounted horizontally along the center part of a circular test channel with a diameter of 5 mm. The heat generation rates of the heater, Q, was raised with exponential function, Q = Q_0 exp(t/τ). By using a narrow channel, relatively high flow velocity was achieved and experiment data at large Reynolds number were obtained. As the results, the surface temperature and heat flux are increasing exponentially with the time. It was clarified that the heat transfer coefficient approaches the quasi-steady-state one for the period longer than about 1 s, and it becomes higher for the period shorter than about 1 s. The heat transfer coefficients show high dependence on the flow velocity of helium gas and heater diameter.

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A dynamic cycle simulation model of a multi-split type electric air-conditioning system for buildings is developed. The target air-conditioning system is an air-source heat pump system using a vapor compression cycle and composed of multiple indoor and outdoor units. The developed model consists of performance characteristics of components, digital feedback control algorithm, constraint for refrigerant charge amount, and connecting and boundary conditions. For the refrigerant side of the components with long transit times, dynamic balance equations for mass, momentum, and energy are formulated. Static balance equations are applied to the components with short transit times. The model results in nonlinear differential algebraic equations, which are solved by our hierarchical combination of the Runge-Kutta and Newton-Raphson methods. Then, the dynamic behavior to stepwise changes in the set points of the operation controls in the target air-conditioning system, i.e., the set points of the compressor inlet and outlet pressures and the air flow rate of the outdoor unit fan, is analyzed for the development of an active operational management approach.

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Optimization approaches based on the mixed-integer linear programming (MILP) have been utilized to design energy supply systems. In this paper, an MILP method utilizing the hierarchical relationship between design and operation is extended to search not only the optimal solution but also suboptimal ones which follow the optimal one without any omissions, what are called K-best solutions, efficiently in a multiobjective optimal design problem. At the upper level, the values of design variables for the K-best solutions are searched by the branch and bound method. At the lower level, the values of operation variables are optimized independently at each period by the branch and bound method under the values of design variables given tentatively. Incumbents for the K-best solutions and an upper bound for all the values of the objective function for the K-best solutions are renewed if necessary between both the levels. This method is implemented into a commercial MILP solver. A practical case study on the multiobjective optimal design of a cogeneration system is conducted, and the validity and effectiveness of the method are clarified.

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Heat transfer, pressure drop and thermal performance characteristics in ellipsoidal dimpled tubes fitted with twisted-tape swirl generators have been studied experimentally. Ellipsoidal dimpled surfaces function as the turbulence promoter near the tube wall while twisted-tapes act as the swirling flow generators. The experiments were performed by using twisted tapes with different twist ratios (y/W = 3.0, 4.0 and 5.0) and water as the working fluid for Reynolds numbers between 5000 and 15,000. The experimental results of the dimpled tubes equipped with twisted-tape were compared with those of the dimpled and plain tubes without twisted tape. Evidently, the dimpled tubes fitted with twisted-tapes consistently yield higher Nusselt numbers and friction factors than the dimpled and plain tubes without twisted tape. It is also found that the average Nusselt numbers of the dimpled tubes equipped with twisted-tapes at y/W = 3.0, 4.0 and 5.0 are higher than those of the dimpled tube alone up to 40.7%, 32% and 26.7%, respectively which correspond to the higher thermal performance factors up to 10.8%, 6.7% and 3.6%, respectively. Depending upon Reynolds number, the dimpled tube with twisted-tape at the smallest twist ratio, y/W = 3.0, give higher thermal performance factors than those at y/W = 4.0 and 5.0 by around 3.9% and 6.7%.

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The article presents the heat transfer and friction factor characteristics of turbulent flow in a uniform wall heat flux tube inserted with delta-winged dual twisted tapes. The typical dual twisted tapes (DTs) with constant twist ratio of y/W = 3.0 and delta-winged dual twisted tapes with delta-winged attack angle of α = 30° and β = 30° were carried out. Influences of the delta-winged arrangements in (1) the parallel direction (DT-PW) and (2) the counter direction (DT-CW) on the thermal performance characteristics were also described. The experimental results found that the use of the dual twisted tapes with parallel wing arrangements (DT-PW) provide the heat transfer higher than those the typical dual twisted tapes (DTs) and dual twisted tapes with counter wing arrangements (DT-CW) around 6.6-7.3% and 5.5-8%, respectively, due to stronger of dual-swirling/turbulent flow leading to better fluid mixing between the core and near tube walls while the friction factor is increasing up to 10.9 times above the plain tube. The typical dual twisted tapes (DTs), dual twisted tapes with parallel wing arrangements (DT-PW) and dual twisted tapes with counter wing arrangements (DT-CW) performs the highest thermal performance factor up to 1.2, 0.9 and 0.85 at Reynolds number of 6000.

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The heat transfer coefficient and pressure drop characteristics of turbulent flow through micro-fin tubes fitted with twisted tape in co/counter-arrangement have been studied. In the experiments, water as the tested fluid is passed in a Reynolds number range of 7800 to 17,650. The results reveal that, the Nusselt numbers in the system with a micro-fin tube and twisted tape are considerably higher than those in the system without tape. Evidently, the tape with the smaller twist ratio gives higher heat transfer rate, friction factor as well as thermal performance factor than the one with larger twist ratio as a result of a larger contact surface area, and stronger turbulence intensity and thus better fluid mixing which leads to a thinner thermal boundary layer. The result reveals that for using the micro-fin tube with twisted tape, the increases in the mean Nusselt number and friction factor are, respectively, up to 181% and 3.86 times of the plain tube and the maximum thermal performance factor is 1.52. It is also obvious that the heat transfer and friction factor obtained from the micro-fin tube with twisted tape in counter-arrangement is higher than that from the micro-fin tube with twisted tape in co-arrangement.

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This paper presents the numerical study of the turbulent flow and heat transfer in the round tubes equipped with multi-channel twisted tapes (MC-TT). A finite volume method with the RNG k-ε turbulence model was applied for the simulation. The effects of the twist ratio (defined as a ratio of twist length to tape width: y/w = 1.5, 2.0, 3.0, and 4.0) and number of channels (N = 2 and 4) on the fluid flow and heat transfer characteristics were investigated in a turbulent flow regime (5000≤Re≤15000). The computations show that the circular tubes with multi-channel twisted tapes give higher heat transfer rate than the plain tube by around 22-30%. Heat transfer enhancement by the multi-channel twisted tapes is strongly dependent on twist ratio (y/w) and number of channel (N). For the present study, the tape with N = 2 with twist ratio, y/w= 3.0 offers the best heat transfer enhancement with the maximum thermal performance factor of 1.02.

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Turbulent flow characteristics and heat transfer performance of heat exchanger tube fitted with annulus circular-rings (A-CRs) are experimentally studied. The d/D_o = 0.1, 0.15 and 0.2 were inserted into a round tube at constant space length ratio (s/D_o) of 1.0. For optimization, the A-CRs at different annulus diameter ratios of d/D_o = 0.1, 0.15 and 0.2 were comparatively tested. The experimental data of the tube with A-CRs are compared with those of the tube with a typical circular-rings (CRs) and also the plain tube. The results show that using the A-CRs with d/D_o = 0.1, 0.15 and 0.2 improves heat transfer rates by around 210%, 244% and 303%, respectively over that of the plain tube. The enhanced heat transfer rates are respectively accompanied with the increased friction factors of around 28, 47 and 90 times of the plain tube. Both friction factor and heat transfer caused by the A-CRs are considerably higher than those caused by the CRs. However, the tubes with A-CRs yield lower thermal performance factors than the one with CRs. In order to understand the heat transfer enhancement mechanism of the heat exchanger tube fitted with A-CR, the numerical results of streamlines and fluid temperature distributions are also reported.

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In order to achieve higher thermal efficiency and decreased emissions, Advanced ultra supercritical (A-USC) steam power plant in which the main steam temperature is raised above 700℃, is developing. Ni-base superalloys have been considered as a candidate material for use in the high-temperature section of an A-USC plant. Since these materials are exposed to the high-temperature steam, it is important to investigate environmental effects on material degradation. There is only limited knowledge about the environmental effects on the cracking behavior of Ni-base superalloys in the temperature range proposed for an A-USC plant. In this study, the crack growth rate of alloy 625 at 750℃ in a steam environment was obtained under cyclic loading using a compact tension specimen. Results were compared with those obtained in a dry gas environment, and it was found that crack growth rates in the steam environment were faster than those in air. According to the observation of oxides formed at the crack tip region, it was thought that steam oxidation enhanced intergranular crack growth. In a longer cyclic period, the cause of the enhancement in the growth rate is probably due to the interaction between environmental fatigue and creep.

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To improve the rate performance of the manganese dioxide positive electrode of the fuel cell/battery systems, we fabricated electrodes by adding small amount (5 and 10 wt%) of nickel hydroxide to the manganese dioxide. Electrochemical characterizations such as galvanostatic measurements and electrochemical impedance spectroscopy were carried out to determine the discharge rate performance and electrical resistance. Scanning electron microscope and X-ray diffraction were also used to observe the crystal structure and morphology of the electrode before and after the electrochemical test. The electrochemical results indicated that the positive electrode with nickel hydroxide has better rate performance than the pure manganese dioxide electrode. It is considered that the electrical path in the electrode was improved owing to the low electrical resistance of the nickel hydroxide and the bimodal effects between the nickel hydroxide and manganese dioxide particles. Additionally, X-ray diffraction confirmed that the formation of δ-MnO_2, which results in electrochemically unreactive Mn_3O_4 after electrochemical discharging, is inhibited in the presence of nickel hydroxide.

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Some ash particles from solid fuels adhere to heat exchanger tube surfaces, which causes some trouble, such as heat transfer inhibition, operational problems and hot corrosion in coal/biomass-fired boilers. Thus, monitoring techniques for deposition and corrosion are important in order to maintain plant conditions and keep boiler thermal efficiency high. In this study, the corrosion and the ash adhesive properties in corrosive conditions were evaluated through an Electrochemical Impedance Spectroscopy in order to develop monitoring techniques. Moreover, corrosion and deposition characteristics of coal ash were evaluated on site using a new monitoring probe. The major conclusions were drawn as follows: A positive correlation between the polarization conductance and the corrosion current density was obtained in the hot corrosion tests for sulfate ash with simulated gas. Although the standard deviation of the impedance data was influenced by temperature, gas and ash composition, the ash adhesive properties was confirmed to estimate using the standard deviation of the impedance Z_<SD>. The corrosive property of solid fuel on-site could be evaluated qualitatively with the polarization conductance. It is possible to monitor ash adhesive properties on-site using the measurement values of the Z_<SD>, temperature conditions and gas compositions.

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In the stator windings of large rotating machines such as the turbogenerators and the hydrogenerators, the conductor bars are divided into strands to reduce the eddy current loss due to the leakage magnetic flux which are mainly induced inside the slot. Moreover, in the case of the strands which are shorted in the most end of the stator bar, inter-strand circulating current is induced due to the leakage flux and it causes additional heating. Therefore the strands are usually transposed in the stator core region and sometimes in the end region in the generators of large output. In order to enhance the efficiency of the generator and/or to avoid the additional heating, it is important to evaluate the loss in each part of the machine and the circulating current loss should also be calculated precisely to evaluate the effect of transposition. In this paper, magnetic field analysis method using multi-slice finite element method is proposed to calculate the circulating current in the stator bar which includes strands transposed in the coil end region. Then circulating current loss analyses of transposed stator bars are performed and the effect of the transposition is discussed for some variations of transposition. The end transposition "90-360-90" is the most effective for the coilend internal leakage flux and circulating current loss increase for "0-360-0" case is reduced to around 3/5 by the coilend transposition and it is around the same level as "0-450-0" case.

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The purpose of this study is to find a way to increase power generation by wind power generators. For wind power generators, cogging torque operates to resist generation. Firstly, a core-less coil generator to have smaller cogging torque was considered and developed. Such wind power generators are thought to be useful as self-powered street lights in case of disaster occurrence such as earthquakes, which may cause electricity system trouble. When an earthquake occurs at night, people may not be able to easily escape without lights. Today, more than 70 units of self-powered street lights with a solar sell and a wind power generator had been installed mainly in Kochi, Shikoku. As wind power wing, savonius-type and gyro-type ones were considered. The prior stage of generator development was to study inside of generators by products dissection. The obtained information was combined with the knowledge obtained during development of eddy current brakes. The eddy current brakes were used in Japan as retarders for trucks and buses. Through the analytical study, non-magnetic material for a drum is found to be preferable. Therefore, core-less coil for wind power generators was selected. The next stage is to obtain more power generation with cored coil generators.

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This paper presents an investigation of forces acting on particles used CFD-DEM simulation method in a rolling Circulating Fluidized Bed. In the simulation, the discrete particle phase is solved by the DEM approach and each individual particle motion is described by Newton's equations of motion; the continuum fluid phase is solved by the Navier-Stokes equations at a computational cell scale. Conclusions obtained from the simulation results are shown as follows. The behavior of particle movement in the radial direction is mainly dominated by unsteady forces including pressure gradient force F_<PG,Y> and virtual mass force F_<VM,Y> in a static CFB and by the component of gravity force F_<g,x> in a rolling CFB. The rolling motion of CFB has a large influence on the axial velocity of air phase, which is caused by the instantaneous change of the relative pressure and the distribution of discrete particles. By comparing forces acting on particles, as the magnitude order of electrostatic force F_E is extremely lower than that of any other forces, F_E is not taken into consideration. Furthermore, Van der waals force F_<VDW> as a adhesive force is also disregarded on account of the little particle number and low particle concentration at the present work.

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In this study, Organic Rankine cycle (ORC) to recover wasted heat of metallurgy plants was evaluated. Several types of ORC systems, such as the direct evaporation, the indirect evaporation and their combined cycle were picked up and their operational parameters were optimized. The results showed all of these ORC systems indicated better gross power generation efficiency than that of the conventional steam power generation system. It is also indicated that the direct evaporation is most effective and the indirect evaporation is preferable to the combined cycle in case that the direct evaporation system cannot be installed

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To reduce both the power output fluctuation and the platform motion, a feedback control algorithm based on blade pitch and generator torque manipulations for a spar-type floating offshore wind turbine-generator system was developed through numerical analysis using the aeroelastic simulation model (FAST), observed high wind speed data, and irregular sea waves. The blade pitch is collectively manipulated to maintain the generator power at a rated value, and the generator torque is manipulated to dampen the nacelle fore-aft motion. The concept of this control approach is to increase the generator torque in response to the platform motion to the leeward side and to provide a positive damping effect immediately to the platform motion. The sensitivity analysis of the feedback control parameters showed the effectiveness of the generator torque manipulation and the filter of the nacelle fore-aft speed for the reduction in the platform motion. This feedback control approach had an advantage in not only the power output fluctuation and platform motion but also damage equivalent fatigue load characteristics over previous control approaches.

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This study is concerned with the development of a hollow micro-hydraulic turbine excellent in foreign matter passage performance. The runner has a circular hollow around the central (rotating) axis so that foreign matter included in water can easily flow without blocking the turbine. The laboratory experiments are conducted to investigate the turbine performance. The guide vane successfully heightens the turbine efficiency. Though the maximum efficiency decreases with increasing the hollow ratio ε when ε>0.25, it remains unchanged when ε≦0.25. The hollow of the runner effectively heightens the passage performance of the polyester fibers entrained into the turbine. When employing the guide vane, the developed micro-hydraulic turbine of ε≧0.375 is not blocked by the fibers and maintains its function.

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As the wind farms are constructed in complex terrain in recent years, the wind resource analysis is becoming more important. The purpose of our study is optimizing wind turbine placement in complex terrain for more AEP. In this paper we performed validation of CFD wind analysis. The validation method is comparison of measured and calculated wind profiles. The wind speed and direction were measured by "WINDCUBE" at the altitude from 40m to 260m by 20m for about one month in Nagashima-Kuronoseto wind farm in Nagashima island, Kagoshima prefecture. "RIAM-COMPACT", which is a CFD software based on an LES turbulence model, was used for wind flow analysis. We compared the 10min averaged data by measurement and all time averaged data by CFD on the wind profiles of speed, direction, and standard deviation of north-west and north-east winds.. It is confirmed that the CFD results reproduce the difference of topographic effects depending on wind direction and that "RIAM-COMPACT" is able to predict the actual wind affected by complex terrain.

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Three-dimensional numerical simulation was conducted to investigate the enhanced cooling performance caused by ridge-shaped tabs located along the upstream edge of the film cooling holes. Three covering ratios of ridge-shaped tab on film hole and four blowing ratios were considered in the present. The results show that the presence of ridge-shaped tabs in the nearby region of the primary film cooling holes mitigates the primary vortices due to mainstream-coolant jet interaction and transfers the higher coolant jet momentum flux to streamwise direction mainly. The coolant jet penetration along vertical direction is suppressed and the peak velocity along streamwise direction is augmented under the action of ridge-shaped tabs, providing an increment in the film cooling effectiveness and enhancement of heat transfer coefficient over the baseline case. The ridge-shaped tabs provide enhancements in cooling effectiveness, but this is at the expense of larger pressure drop. It is suggested that the ridge-shaped tab with middle covering ratio should be the best choice in the present study.

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Coal can be classified according to fixed carbon and calorific value, and each coal has different combustion characteristics. Anthracite is the most difficult coal to burn, because it has low volatile matter and high fixed carbon. Also, the temperature for starting devolatilization of anthracite is higher than that of the other coal. As a result, anthracite firing boiler is an arch firing type or fluidized bed type normally. In Vietnam, electric power demand is increasing year by year together with high economic growth. In view of energy security, it is important to use fuel produced in own country and to reduce imported fuel. Vietnam has many reserves of anthracite. Therefore, there is a strong demand to use it for coal firing power plant. IHI developed a new type of burner for low volatile fuel. The feature of this burner is that coal can be pre-heated in the chamber of the burner by the high temperature gas in the furnace. Preheating can help devolatilization and promote combustion of anthracite. In this year, IHI's low volatile fuel burner was installed to an existing boiler in Vietnam, which capacity is 100 t/h. This boiler is opposed firing with four burners and water tubes in burner zone are covered with refractory to increase the temperature around the burners. Only one burner was changed to IHI's low volatile fuel burner and demonstration test of anthracite firing was conducted. As the result of test, anthracite firing succeeded in the boiler to which IHI's low volatile fuel burner was installed. In this paper, the result of this demonstration test will be introduced. The improvement of the burner for anthracite combustion will be discussed.

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Ground source heat pumps (GSHPs) use buried pipes to extract heat from the ground and to release heat to the ground. In the conventional GSHP system, which uses an indirect heat exchange method, vertical systems use two long pipes connected by a U-shaped fitting at the bottom of a hole bored in the ground. These pipes form part of a closed loop, called the ground loop, through which a mixture of water and antifreeze circulate. In contrast, a GSHP that uses a direct expansion method circulates a mixed refrigerant through the ground loop. In our tests of this method, the depth of the borehole was 30 m, and the refrigerant was R410A. The heat exchanger of a ready-made air-conditioner was replaced by an underground heat exchanger. In the direct expansion GSHP, the underground heat exchanger consisted of narrow copper tubes inserted into the bottom end of a long pipe filled with water. The coefficients of performance (COP) were obtained for the direct expansion type of GSHP running in the cooling and the heating mode. The amount of heat transferred was evaluated by obtaining an enthalpy difference at the indoor unit. It was found that the COP in the cooling mode was over 10.

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Recently, the new wind farm has been successfully built in Nagashima island, Kagoshima prefecture. This site is located in complex terrain and, the flow above the ground is also thought to be complex. We analyzed the flow here using the RIAM-COMPACT (Uchida 2014)natural terrain version software, which is based on an LES turbulence model. The accuracy of this software was proved in previous studies. In addition to the CFD analysis, we also conducted airflow measurements using hot wire technique in the boundary layer wind tunnel of the Research Institute for Applied Mechanics, Kyushu University. In this experiment, the vertical wind velocity profile were obtained at 3 locations as time step data, from which we calculated turbulence. The value of scalar wind speed and turbulence by CFD and experiment generally has same tendency at each height of each location. These agreements demonstrates the validity of this CFD software based on LES turbulence modeling.

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In 1989, a pilot plant of a solar chimney was erected in Manzanares Spain to evaluate the feasibility of the solar tower as a new source of renewable energies. Since then, the solar tower was discussed in the press, but no commercial plant succeeded the research. A reason for this could be the relative low power output compared with other renewable energy production systems. However, the power generation system of a wind solar tower can be designed and constructed at relatively low cost. A solar tower consists mainly of three components. The collector area is a glass roof, above ground with increasing height towards the center. Attached to the center of the collector is a vertical tower inside which a wind turbine is mounted at the lower entry into the tower. When solar radiation heats the ground through the glass roof, the uprising warm air is guided to the center into the tunnel. A wind solar tower that can generate electricity in a simple structure, and enables easy and less costly maintenance, has considerable advantages. Since the solar tower reaches several hundreds of meters into the sky, the tower exit is at a level of higher wind speeds compared to the ground. If wind passes over the tower exit, it can induce air flow inside the tower. Hence, the solar tower could be capable of producing electricity at night when the solar radiation is not available. In our research we are aiming to improve the overall performance of the solar tower focusing on the tower component. We consider airflow caused by thermal updraft and air flow in the tower induced by wind flowing over the tower exit at the top. We conclude that the shape of the tower has a significant effect on the performance of the solar tower. Therefore, our future research will focus on further optimization of the shape of the tower.

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Out-of-phase thermo-mechanical fatigue (TMF) tests and low cycle fatigue (LCF) tests were performed on Nibase single crystal superalloy, CMSX-4. LCF tests were performed at 800℃ and TMF tests were performed under 200-800℃ out-of-phase conditions. In both tests, tests were performed under fully reversed, total mechanical strain controlled conditions, and specimens whose axial orientations were [100] and [011] were used for evaluating the influence of crystal orientation on deformation behavior and fracture life. As the results, deformation behavior and fracture life were strongly influenced by specimen crystal orientation and temperature-strain range. To evaluate these effects, γ/γ' unit-cell finite element (FE) analysis were performed. Simulations revealed that even if macroscopic inelastic strains in hysteresis loops were small, inelastic strains were clearly occurred in γ phase microscopically. And the simulations under TMF conditions revealed that microscopic deformation shows tension/compression asymmetry and these asymmetric deformation causes ratcheting deformation in γ and γ' phases.

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Recently, the transient technique using infrared thermometer has widely been used for measuring the distribution of local heat transfer coefficient. In this study, To obtain high-precision measurement of the rotating disk surface temperature field, we have proposed a phase-locked method. The effects of two parameters, on the heat transfer phenomena the rotational Reynolds number Re_<r0> from 0 to 1.8×10^6 and the penetration flow Reynolds number Re_s from 2×10^4 to 7×10^4, were observed. These dimensionless parameter is possible to reproduce the range of actual and the same order. Non-dimensional disk casing gap-to-radius ratio (s/2r_0) fixed 0.026. The present results showed that as the rotational Reynolds number increases, nusselt number tends to 2×10^3 to 3×10^3 increase at test condision.

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This paper presents the results of the operation and performance evaluation obtained from the first stage of the experiments that have been performed with the hybrid power test plant built in Awaji Island, which consists of a Concentrated Solar Power (CSP) system, biomass boilers and wind turbine. This pilot plant is the first CSP based power station in Japan and followed the requirements of Japanese Electric Utility Industrial Law. The results clearly showed that the changes in thermal performance of the pilot plant are strongly depending on solar intensity and climatic conditions specific for the site location. In addition, adjusting the amount of the biomass fuel supplied to the boilers is found effective to stabilize power output.

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Ocean current power generation is expected to be renewable and stable energy source. Floating type ocean current power generation system is under development by joint research consortium comprised of TOSHIBA, IHI, the University of Tokyo and Mitsui Global Strategic Studies Institute. This system will be mainly operated at a depth of 50m in one of the largest ocean current Kuroshio, which flows along Pacific coast of Japan. However degradation data of materials have not been obtained sufficiently. In order to obtain material degradation data for development of ocean current power generation system, corrosion test and bio fouling test were achieved at depths of 1.5m - 70m in sea-water. Carbon steel and stainless steels were used for corrosion tests. Carbon steel with antifouling coating, stainless steels and fiber reinforced plastic were used for bio fouling test. Enormous amount of aquatic organisms were observed on specimens at near the sea surface, and the amount was significantly decreased at depths of 20m or deeper. Antifouling coating significantly decreased the amount of aquatic organisms even near the sea-surface. Species of aquatic organisms on specimens also changed significantly with time, depth and substrate. Corrosion rate at a depth of 70m tended to be lower than that at a depth of 1.5m - 35m. Crevice corrosion was observed on some part of SUS316, though general corrosion of SUS316 and SUS329 was not significant.

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Reduction of greenhouse gases has become the centre of public concern with existing coal fired power plants having a significant role to play. One solution is biomass co-firing at high ratio, such as 50 cal%, in order to reduce CO2 emissions from coal firing. Such high ratio co-firing is already utilized in some power stations overseas but not in Japan due to lack of comprehensive analysis and evaluation in domestic power stations. For the realization of this solution, we examined the characteristics and behavior of biomass (wood pellets) as fuel for coal-fired boilers. As a result, we confirmed that there are no significant technical difficulties in high biomass co-firing ratio in existing pulverized coal-fired boilers. Utilizing this knowledge, a demonstration test is planned at an existing 150MW commercial plant in 2015. During the test, all aspects of biomass will be studied as potential fuel for boilers, including transportation, storage, grinding, firing and so on.

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In recent years, expectation for the renewable energy has been increasing from the standpoint of environmental impact reduction. As for hydro electric generation, improvement of the energy utilization is demanded and high efficiency of the power generating system is required. In order to design high efficiency generators, it is necessary to improve the estimation accuracy of the losses. The electrical loss of hydrogenerators includes the iron loss caused by the magnetic flux in the iron core, the eddy current loss induced by the leakage flux as well as the copper losses by the armature current and the field current. In this paper, as a result of the numerical analysis of the loss of the end structure in the no load operating condition, at which only the field coil is excited, are described.

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Although polymer electrolyte fuel cells (PEFCs) are commercially available, there are still many problems that need to be overcome to further improve their performance and increase their usage. The cell performance depends strongly on water management in the PEFC. In this study, two schemes for optimization are proposed to improve the water management in gas channels and GDL. One was a combination of novel gas channel with micro-grooves, which are manufactured inside gas channel walls, and novel GDL with wettability distribution. The cell performance was examined by changing the cell temperature, relative humidity of gas and air velocity. The other was a novel design of cathode channel with sub-channel. The main-channel was fed by moist reactant while the sub-channel supplied by dried reactant with the whole reactant flow rate invariable. Three positions of sub-channel inlet and the dried reactant flow rates were experimentally studied to evaluate the cell performance. It was shown that the both schemes could improve the cell performance. That is, the PEFC with micro-grooves and hybrid GDL showed higher performance than the conventional PEFC without grooves. Especially, the value of maximum current density was increased by about 19.5% when air velocity is 8.0m/s. Meanwhile, as the position of the sub-channel inlet was 30% of the cathode channel length, the dried reactant flow rate was 70%, the cell with sub-channel achieved the best performance.

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As a countermeasure against global warming, CO2 capture and storage (CCS) technology represents the core technology, and its early realization is expected. CSS technology consists of CO2 capture technology, transport technology, and compression and storage technology. One of the major issues of CCS technologies is the large amount of energy required for CO2 capture. If part or all energy could be supplied from waste heat, significant energy savings would be achieved. With our proposed CO2 capture system (KCC System: Kawasaki CO2 Capture system), an energy-saving system for easily utilizing the waste heat was constructed to capture CO2 using low-temperature steam. In this study, we have performed bench tests on a moving-bed system suitable for large-scale plants and verified the performance of an adsorbent. The system successfully captured 3.1 t/day of CO2 from the exhaust gas and confirmed the viability of an energy-saving moving-bed system. We also performed a feasibility study of a system for capturing CO2 from the exhaust gas of a gas engine and found that the energy required for the KCC system utilizing waste heat from the gas engine was 1.3 GJ/t-CO2. This shows that the moving-bed system using an adsorbent is an effective means for CO2 capture.

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In this paper, an industrial gas-turbine combustor was numerically investigated by applying large-eddy simulation for turbulent model and 2-scalar flamelet approach for combustion model. In the combustion model, the structures of premixed and non-premixed flame are expressed by conservative scalar and levelset function respectively. These two concepts are coupled for partial premixed combustion field. Flow field properties inside the flame (temperature, density, laminar flame speed) are determined by "flamelet data". The flamelet data is mainly divided in "premixed-like flamelet data" and "diffusion-like flamelet data" in this study. The premixed-like flamelet data is based on chemical equilibrium assumption and is evaluated by 0-dimensional chemical reaction calculation. On the other hand, the diffusion-like flamelet data is based on laminar flamelet assumption and is evaluated by 1-dimensional counter flow combustion calculation. In this study, for the diffusion-like combustion field in the industrial combustor, diffusion-like flamelet data was newly applied. The predicted gas temperature showed a little higher value than the temperature calculated by using the premixed-like flamelet data. However, the predicted temperatures underestimated measured one. Therefore, in this case, it was cleared that difference of flamelet data is insignificant for improving analysis accuracy.

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This paper discusses the effects of hydrogen addition on soot formation in iso-octane pyrolysis using a shock tube. In the experiments, 1% iso-C_8H_<18> + 99% Ar and 1% iso-C_8H_<18> + 1% H_2 + 98% Ar are used as a test gas in the temperature range of 1800-2600 K and in the pressure of 1.2 ± 0.1 MPa behind a reflected shock wave. Soot formation process was characterized by induction time and soot volume fraction, which is obtained from laser light extinction measurement. In addition, time history of soot particles temperature was calculated based on spectral dependence of monochromatic emissive power from thermal radiation from the soot particles. The experimental results show that soot formation had bell-shaped temperature dependence exhibiting maximum at 2000 K with and without hydrogen addition. Adding hydrogen to iso-octane, soot volume fraction reduced for T_5 = 1800 K. Additionally, induction time increased for T_5 = 1800 K and 2000 K. Soot particle temperature T_P was higher than T_5 by about 200-400 K except for around 1800 K. Consequently, hydrogen addition to iso-octane suppressed soot formation for T_5 = 1800 K, while no distinct effects of hydrogen addition were observed for T_5 = 2000 K and 2500 K.

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We made the partial load performance tests of recently developed GHP VRF systems with rated cooling and heating capacities of 45kW and 50kW, respectively. COPs were measured at 37 test points for cooling operation and 31 test points for heating operation to make clear their detailed partial load performances. Based on the measured COPs and thermal load models for detached shops, the annual energy consumptions of these air conditioners were evaluated. They were compared with those obtained with conventional GHP VRF systems, and their energy-saving performances were demonstrated. Next, we applied a new calculation method of the annual energy consumptions of air conditioners, which was originally developed for EHP VRF systems, to the present GHP VRF systems. The variations of COP to the outdoor air temperature and the indoor thermal load were predicted based on COPs measured at 8 test points in the partial load performance tests. The annual energy consumptions of the tested VRF systems were calculated based on those predicted COP characteristics. It was confirmed that the errors included in the annual energy consumptions and resulting annual average COPs predicted by the proposed method were less than 7%.

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Ammonia is regarded as one of the possible alternative fuels for industrial furnaces because of its high transportability and storability. In the industrial furnaces, it is important to understand the radiative characteristics of flame. However, the knowledge of the radiative characteristics of ammonia flame is extremely limited. In this study, the radiative heat flux and the radiation spectra from the ammonia flame were measured to understand the radiative characteristics of ammonia flame. A slot burner was used for stabilizing the laminar ammonia/N_2/O_2 premixed flame. The concentration of O_2 in the oxidizer and equivalence ratio were varied for increasing the flame temperature. The results showed that radiative heat flux of ammonia was lower than that of methane/air premixed flame in all condition of that has the same net heating values per unit time. Ammonia/N_2/O_2 premixed flame doesn't have any intensity in the spectra band of CO_2 absorption. In addition, oxygen-enriched ammonia/N_2/O_2 premixed flame showed higher intensity than that of methane/air premixed flame in the spectra band of H_2O at around 2.7 μm band.

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The effect of the non-equilibrium plasma superposition on the ammonia/oxygen/nitrogen unburned premixed gas was investigated to improve the laminar burning velocity as the combustion characteristics. When ammonia was used as a fuel, it was necessary to improve the laminar burning velocity of ammonia premixed flame because the combustion characteristics of ammonia were too lower than those of fossil fuel. The plasma-assisted combustion was the one of the methods to improve the combustion characteristics. Especially, the effect of the dielectric barrier discharge (DBD) on the burning velocity as the indicator of combustion quality of ammonia was experimentally investigated in this study. In experiments, a slot burner was used to measure the burning velocity. DBD was superimposed on ammonia/oxygen/nitrogen unburned premixed gas just before it was entered into the flame zone. To understand effects of the condition of the electric power source of DBD, the peak to peak voltage of DBD was varied from 0 kV to 30 kV. The equivalence ratio was varied from 1.0 to 1.2. The results showed that the burning velocities became faster with increasing the peak to peak voltage of DBD, the largest increase of the burning velocity was observed at the stoichiometric condition in all conditions of the DBD power source.

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In Tanegashima, the sugar mill, which is the main industry recycles sugarcane bagasse as a fuel but concurrently generates the massive amounts of unused heat at 200℃. Raw sugar is shipped to a sugar-refinery in Osaka where the sugar products are produced. The sugar-refinery uses a city gas boiler to generate a massive quantity of heat at 150℃ for refining. In order to resolve this spatial and temporal mismatch, we propose the application of chemical heat storage. Steam adsorption and desorption cycle of zeolite was employed in this work. Process flow diagram of the sugar mill was developed and potential heat storage capacity, the transport capacity for zeolite and reduction rates of city gas consumption at Osaka were calculated. From the results, it was revealed that the transport capacity for zeolite was restricting factor in the heat storage and transport system. In fact, heat storage capacity depends on desorption amount and regeneration rates, so potential heat storage capacity, the transport capacity for zeolite and fuel reduction rates at Osaka were recalculated using the results of the adsorption/regeneration tests.

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Hybrid Electric Vehicles (HEVs) and Electric Vehicles (EVs) are the typical electric prime movers installing an on-board battery. The vehicle traction battery deteriorates in chemical degradation both cycle lifetime and preservation lifetime. A battery is focused on a Nickel-metal hydride (Ni-MH) battery which is widely used as traction energy storage in HEVs. The verification is done in two types of battery which is the most accepted AB5 alloy type and the other is a super lattice alloy type. This study investigates, (1) a verification method of the AC impedance response analysis is able to discriminate the battery deterioration level in progress of lifetime cycle, and (2) the two types of experimental battery potential are verified in the lifetime cycle experience. The goal of this study is to establish a method to verify a battery state of health (SOH) on-board operating conditions. The battery examination load condition is to drive JC08 mode to estimate a real world usage.

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For the designing of the pulverized coal firing boiler, the char reaction rate is an important parameter to consider the residence time of the particles inside the boiler. The char reaction rate is influenced by the coal type. Therefore, it is profitable to predict the char reaction rate by the properties of its parent coal. The purpose of this paper is to investigate the char reaction rate experimentally, and to render the data useful for the boiler designing. The type of coal was covered from lignite to anthracite. Experiments were conducted by the Drop Tube Furnace. As the results, it is clear that the magnitude of the deviation in the char reaction rate is about two digits in the region around 1000 K, and it is less than one digit in the region above 1600 K. The char reaction rate is still below the diffusion limited rate at 2500 K. Therefore, usage of the diffusion limit to the boiler designing may induce an optimistic estimation concerning the residence time of the particles. This paper also indicates the possibility to use the ash fluid temperature as the index for the char reaction rate in high temperature.

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The progress of the 2011 Fukushima Daiichi nuclear disaster has been calculated by severe accident analysis codes in order to understand the causes of accidents and the current status. However, effects of seawater are not considered in these calculations, although the seawater was attempted to inject into the reactors to cool down the nuclear fuels. In the present study, the objective is to understand the basic physical effect of the seawater on the thermal-hydraulic behavior without boiling. To achieve the objective, we measured and compared the thermal-hydraulic behavior of pure water, NaCl solution with the concentration of 3.5wt% and artificial seawater with the concentration of 3.5wt% in an internally heated annulus. In the comparison of the pure water, the NaCl solution and the artificial seawater, the correlation between Nusselt number and Reynolds number was the same with each fluid above Re = 2300 [-]. Moreover, the correlation can be predicted by Dittus-Boelter equation. Below Re = 2300 [-], the Nusselt numbers of each fluid correlated with the Rayleigh number. Therefore, considering physical properties of the pure water, the NaCl solution and the artificial seawater, the thermal-hydraulics behavior without boiling was not different for each fluid.

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As the number of installed wind turbines has increased, location suitable for wind power generation has been reduced. Then complex terrains like the mountainous regions are sometimes selected for the wind farm. In this case, the wind flow variation in the speed and direction will be severe by the complex terrain profile. So, we have conducted a wind speed measurement at actual wind power plant in Nagashima Island of Japan's Kagoshima Prefecture. In this paper, we conducted a CFD analysis of the same area with two sub-grid model of LES and compared the wind speed distribution with the measured results.

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The objective of this research is to study the attack angle effect of elongated orifice with aspect ratio of AR = 8 on the flow and heat transfer characteristics of jet impingement array. Both the inline and staggered arrangements, having arrays of 6×4 nozzles and attack angles at θ = 0°, 15°, 30° and 45°, were examined. The jet-to-plate distance (H) and the jet-to-jet distance (S) were fixed at H = 2D_E and S = 3D_E, respectively (where D_E is the equivalent diameter). The experiments were carried out under jet Reynolds number at Re = 13,400. Temperature distributions on the impingement surface were measured using Thermochromic Liquid Crystal sheet (TLCs). Flow characteristics on the impingement surface were visualized using the oil film technique. Numerical simulation was employed to gain insight into the fluid flow via Computational Fluid Dynamics (CFD). The results indicate that the average heat transfer on the impingement surface tends to decrease when the attack angle becomes larger. However, local heat transfers at impingement regions in the upstream channel with attack angles of θ = 30° and 45° are higher than those at θ = 0° and 15°, especially in the case of staggered arrangement.

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A demonstration test with the aim to show the potential of an ammonia-fired power plant using a micro gas turbine is planned. A 50 kW-class turbine system firing kerosene is selected as the base model. A standard combustor is replaced by a prototype combustor, which enables a bi-fuel supply of kerosene and ammonia gas. Diffusion combustion is employed in the prototype combustor to ensure flame stability. The demonstration test with kerosene and ammonia gas co-firing was conducted to verify the functionality of each micro gas turbine component. The gas turbine started firing kerosene and increasing its electric power output. After achieving a stable power output, ammonia gas was supplied with a gradually increasing flow rate. 17 kW of power generation was achieved with a 38% decrease of kerosene, replaced by ammonia gas, which increases NOx in the exhaust gas dramatically. However, a decrease of the NOx can very well be obtained by the supply of ammonia gas to the catalyst.

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Condominiums which satisfy the Japanese standards determined by laws have the seismic resistance to withstand an earthquake with an intensity of six to seven because the condominiums have to save the life of occupants. The condominiums also can contribute to the safety of cities as they provide one of the shelter for the neighboring people. However, the condominiums locate at the high-performance and high-density residential district. For that reason, in the emergency, all occupants experience the difficulty to maintain their daily lives without the supply of electricity, gas, water and other utilities. Additionally, the occupants who live in high-rise buildings feel greater inconvenience just like refugees because they are unable to use elevators. Shortly after the Great East Japan Earthquake, the metropolitan areas had an electric shortage; then these areas implemented the scheduled blackouts. This implementation affected the majority of condominium occupants. They reaffirmed the importance and convenience of electricity by the scheduled blackouts. Eventually, people have raised the awareness of power saving following the seismic disaster. This paper describes the community formation among the occupants by visualizing the electric power consumption, in real-time, with smart meters. In the emergency, it is very important to take care the elderly or physically-challenging peoples. Especially when they live alone, the visualization system for their household contributes to know their safety and welfare.

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The discharging flow rate from safety or relief valves is restricted with the minimum flow area between disk and seat. The flow rate is usually smaller than the calculation with the minimum flow area due to the vena contraction. The clarification of vena contraction is very important but actually difficult to visualize as the rapid radial expansion occurs just after the minimum flow area. It has a possibility that the rapid flow-directional change of disk-seat contraction enhances the non-equilibrium behavior. The simple disk-seat flow contraction was fabricated to measure the discharging flow rate at different valve lifts, seat and nozzle configurations. Furthermore the two kinds of nozzles used in actual safety valves were installed instead of the simple straight nozzle to verify the effect on vena contraction. The discharging flow rate of water was affected with the lift, seat and nozzle configuration due to the different formation of vena contraction. The adequate shape of nozzle was effective to increase the vena contraction ratio to the minimum flow area. The air flow rate could be well predicted with the expansion delay model by using the vena contraction ratio as same as the water flow and the adequate expansion delay factor.

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This paper describes on new solutions for energy issues and town development. The new social system instead of the conventional energy supply system has been discussed. The renewable energy is eagerly expected but the electrical output is too unstable to use. In this situation, the new system with three functions was proposed in 2004. The first is to provide the best circumference to use the renewable energy. The electricity is exchanged between grid and demand-side with distributed generation, heat storage and electric battery. The second is to provide the visualization tool to cooperate with citizens. The advanced demand-side control promotes the energy saving and accepts the fluctuating output of renewable energy. The third is to provide the electricity from ships or EV at the emergency. The system contributes to the early recovery in the case of anticipated disaster. With these, a strong town based on the renewable energy can be realized. In addition, it has a possibility that visualization of electricity demand can be used to detect the abnormal condition or sudden illness of elderly person who lives alone in a house. These technologies, with combined information and mobility, are important to develop the future safety and saving energy town.

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We manufactured a Ground Source Heat Pump (GSHP) system of the test model and investigated the Coefficient Of Performance (COP) of a fabricated GSHP system by experiment in the laboratory. This GSHP system was fabricated using common commercially available equipment. Using such equipment helps to provide at a low price for the market. The COP was estimated by using the refrigerant enthalpy method with pressure and temperature fitting. Furthermore, we evaluated the COP by using the calorimetry method that measures the heat transfer rate of the chilled water in the evaporator and the cooling water in the condenser. As a result, while the estimated COP using the refrigerant enthalpy method decreases with increasing mass flow rate of chilled water in the evaporator, the estimated COP using the calorimetry method showed a peak at 4 kg/min.

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