Purpose of this study is to improve the inter-laminar fracture properties of the carbon fiber reinforced plastic laminates by addition of fine particle to brittle matrix resin. In this study, vinyl ester was used for the CFRP matrix and two types of particle, alumina and silicon rubber were used for the modifier. Three point bending test, DCB test and ENF test was conducted to investigate the effect of mechanical properties of particle incorporated specimen. The mechanism of the difference in fracture behavior for these particle modified laminates was discussed on the bases of in-situ observation and fracture surface observation.

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This paper describes the method aiming for the stabilizing process in the electro-fusion joining of carbon fiber reinforced thermoplastic (CFRTP) composites when unidirectional carbon fiber sheet was used for resistance heating element whose matrix polymer was added a high thermal conducting ceramic particle. In this experiment, the effects of Boron Nitride (BN) particle adding to Poly-phenylene sulfide (PPS) polymer on the fusion behavior and single lap shear strength of electro-fusion joined laminates were investigated. The material used is 5H-satin woven CF/PPS laminate. The experimental results revealed that the electric resistivity of the laminates in electro-joining process was stabilized, but the welding area tends to decrease significantly with increasing the amount of adding BN particle, thus the resultant single lap shear strength was decreased.

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This study aims to fabricate the injection molded part using recycled carbon fiber reinforced thermoplastics (CFRTPs). The material used is chip crashed woven CF/PA66 laminate. In this experiment, a three point bending test specimen and a triangle scale were fabricated by injection molding machine, and the effects of the fiber content in recycled CFRTP on density, bending strength and bending elastic modulus were investigated. The experimental results revealed that the density, bending strength and bending elastic modulus were increased linearly with increasing the fiber content. The geometry of the triangle scale was investigated by a three dimensional digitizer. From the result of the measurement, the dimensional difference ratio was decreased with increased the distance from the gate.

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Recently self-healing materials are desired from the various applications. Since replying the desires, the self-healing researchers are required to organize the collaborating research group between universities, industry and national government. For the final goal, it is required to raise the name recognition of this area of research more. One of the examples is to conduct on information dissemination which utilized the IT environment.

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Self-healing fiber-reinforced ceramics (shFRC) are widely expected to be advanced structural materials for aerospace engineering. The self-healing function in shFRC appeared at 1200℃ for 1 h and 1000℃ for 50 h respectively. shFRC can appear autonomic self-healing if the shFRC is employed as turbine blade operated at temperatures between 1000℃ and 1200℃. However, 50 h healing at 1000℃ cannot be confirmed to ensure the mechanical reliability of ceramic composites. Also, TiSi_2 is a candidate of advanced self-healing agents which is able to produce the self-healing function at lower temperature than SiC self-healing agent. The self-healing function due to TiSi_2 oxidation appears above 400℃. TiSi_2/SiC composite is proposed as heterogeneous interlayer of shFRC to realize advantages both of lower temperature self-healing function and branching cracks. In this study, we created three kinds of shFRC with heterogeneous interlayer, which have different mass fraction of TiSi_2. Finally, at 30%-shFRC, which has 30 mass% TiSi_2 in heterogeneous interlayer, bending strength was recovered at 1000℃ for 60min and 1100℃ for 10min. Appearing self-healing function was successful in 200℃ lower and 50 times faster.

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Mechanical properties, especially high-temperature bending strength and bending creep strength, were investigated on self-healing fiber reinforced ceramics, shFRC, at elevated temperatures. shFRC consists of alumina continuous fiber bundle, Al_2O_3 matrix and SiC interlayer oriented along fiber bundle as self-healing agent. Bending strength of smoothed samples were obtained 82-120 MPa ranging at 1000-12000℃, higer than 85 MPa of ones at room temperature. Every specimens were deformed plasticaly. Bending creep was obtained over 100 h durability at 1000℃, weareas specimen was fractured for 2 h at 120℃. Both of specimen conducted high-temperature tests were broken from compressed surface at 1000℃, weareas and tensio surface at 1200℃. Different fracture mechanism would be resulted from tmeperature dependence of plasticity of Al_2O_3 matrix and leads higher bending strength than room temperature. Although bending test accomplished to evaluated the values of mechanical properties at high-temeprature, precise evaluation is expected using tensile test.

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A Kinetics model for strength recovery by oxidation-induced self-crack-healing in the alumina/SiC particles composites was proposed using the oxidation kinetics of SiC and process zone size fracture criteria on the basis of nonlinear fracture mechanism. Reported experimental results suggested that the strength recovery follows the mass gain of oxidation products. Thus, we estimated the remaining crack length using healing ratio, f_<CH>=ΔV_<CB>/V_C, where V_C is the volume of precrack, ΔV_<CH> is the mass gain due to the self-healing, which is estimated from oxidation kinetics of the sintered SiC together with microstructural features of SiC distribution. When f_<CH> &ge; 1, the crack is completely healed. When f_<CH>< 1, crack ealing is inadequate. Furthermore, we proposed the upper and lower limit model for recovered strength at f_<CH>< 1 as bridging and degeneracy models, respectively, and compared the proposed model with reported experimental results.

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The competition between crack self-healing and crack propagation induced by service stress in self-healing materials was investigated in the present study. Especially, it was succeeded that assessment on the displacement at the three-point bending load allows the time which crack propagation is arrested by self-healing to be evaluated. Although the bending stress of 70 MPa induced crack propagation form the pre-crack in alumina fiber reinforced self-healing alumina containing SiC interlayer as healing agent, which is typical self-healing fiber reinforced ceramics (shFRC), the crack propagation is arrested by self-healing effect for about 2200 s at 1100℃ in oxidizing atmosphere. Only self-healing progressed after the arrest and the complete strength recovery was attained for 1 h. From the above result and similar results at 1000℃ and 1200℃, the time which crack propagation is arrested by self-healing exhibits Arrhenius relation as a function of temperature. Therefore, the self-healing effect for crack propagation was found to be directly affected by oxidation reaction rate of SiC.

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Nano metallic particle-dispersed ceramic hybrids are promising candidates as ceramic-based composites with high mechanical strength and high fracture toughness at room temperature and high temperatures. Some of the metal/ceramic hybrids have a self-healing function against mechanical degradation by surface crack. In the present report, Ni nano-particle dispersed Al_2O_3 hybrids are discussed as high-temperature self-crack healing materials. At elevated temperatures in oxidizing condition such as 1200℃ in air, Ni nano-particles dispersed in Al_2O_3 matrix are oxidized into NiAl_2O_4 with Al_2O_3 matrix and oxide ions diffusing from the surface. On the other hand, outward diffusion of cations takes place simultaneously and causes the formation of NiAl_2O_4 on the surface of the hybrids. Surface cracks introduced to the hybrids are also filled with NiAl_2O_4, as a result, their mechanical recovery is achieved.

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Self-healing materials attract much attention because of their ability to repair the internal and external damages, thereby extending the lifetime of the material in numerous applications that we cannot repair easily. Diarylbibenzofuranone (DABBF), which is a dimer of arylbenzofuranone, can reach a state of radically thermodynamic equilibrium under air at room temperature without any stimuli. Furthermore, DABBF and arylbenzofuranone radical formed from cleaved DABBF are tolerant of oxygen. Here we report the preparation of polymeric materials containing DABBF units as exchangeable covalent bonds and their autonomous self-healing behavior at ambient temperature.

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Repeatable healing function of damaged materials is one of the promising topics in self-healing materials. As a solution of this challenge, we previously proposed the introduction of holes as stress-activated micro-channels on the surface of microcapsules as self-healing medium. Here, these micro-channels must be opened by stress field induced by micro-cracks and the healing agent (core material of microcapsules) will be repeatedly leaked from opened micro-channels. In this study, the method to apply channels, which are not broken by repeated loading-unloading and leak core material repeatedly, to microcapsules was studied utilizing the removal of glass beads treaded with release agent as secondary phase in membrane. In addition, the method to close these micro-channels during or after healing was also studied. Finally, the possibility to create stress-activated micro-channels was discussed.

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Polymer coatings have been widely applied as surface treatments for various metallic materials. The role of polymer coatings has generally been to provide a barrier against corrosion species in order to protect the surface of metallic materials from corrosive attack. One of the most important characteristics required of the coatings is the ability to self heal so that the damaged surface is automatically repaired by a chemical component of the coating. In the present study, multi-layer coatings consisting of superabsorbent fibers and vinyl-ester polymers were applied to carbon steel to prevent corrosion. The polarization resistance of a scratched specimen was monitored in a corrosive solution. The polarization resistance of a 3-layer coating, which consisted of a mixed polymer as the middle layer and a vinyl-ester polymer as the base and top layers, increased with time, resulting in a self-healing corrosion inhibition capability. A film, which consisted of spherical particles, was found on the scratched surface of a substrate. The film may have prevented the diffusion of oxygen to the scratched.

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Ni/Al_2O_3 nanocomposites have an excellent self-healing function because of the oxidation reaction of nickel particles in alumina matrix at high-temperatures. ZrO_2 particles were introduced into Ni/Al_2O_3 in order to improve their mechanical properties. In this work, self-healing of 5vol% Ni/(10vol% ZrO_2+Al_2O_3) was investigated as a function of temperature. Bending tests were carried out for understanding heat-treatment effects on crack-healing of the nanocomposites.

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This study focuses on the self-crack-healing process of Al_2O_3/30 vol.% SiC composites. Specimens with cracks were subjected to thermal treatment at 1000℃ and 1200℃, their strengths were measured by a three-point bending test, and nano/micro structural analysis of crack-healed zone was performed using scanning electron microscope (SEM) and focused ion beam (FIB) which are arranged orthogonally. A 100μm semi-elliptical surface crack healed completely at 1200℃ for over 5 hours in the air. The fracture origins of the complete crack-healing specimens were outside the crack-healed zone. On the other hand, the fracture origins of the specimen which did not accomplish complete crack-healing transit from the tip of crack-healed zone to the vicinity of a Vickers indentation as the strength of specimens become higher. As the result of analysis to the crack-healed zone nearing the indentation using FIB-SEM, it is found that main self-crack-healing process is the filling of the cracks by the oxidation formed from SiC reaction site and these oxidation formed bridge structure between interior surfaces of crack. Thus we revealed self-crack-healing mechanisms through the multi-scale structural analysis and established how to investigate the structure of crack-healed-zone.

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The machine perfusion (MP) technique can expand the donor pool for organ transplantation. The MP technique is able to eliminate toxins generated from cells and provide nutrition and oxygen to the tissues via the continuous supply of the preservation perfusate. Furthermore, the organ viability can be evaluated using screening techniques during MP before implantation in a recipient. In this study, the new visualization technique to evaluate the organ conditions of the flow distribution is proposed and discussed using porcine donated livers. This technique is employed the temperature difference of the perfusate for organ preservation to visualized the portal vein flow distributions during machine perfusion. As results, the flow distributions in the liver and the transitions of the temperature at the each measurement points can indicate the organ functions before implantation.

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In previous works, 3D-CT (Three Dimensional Computer Tomography) reconstruction of instantaneous 3D light emission distributions of turbulent premixed flames have been successfully obtained by a simultaneous photography with a custom-made 40-lens camera. Furthermore time-series 3D-CT distributions have been reconstructed by using a single high speed camera combined with a multi-mirror optical system. The techniques, in which light emission from target was captured, however, had an essential disadvantage for high speed detection of flames in terms of the shortage of the quantity of light, resulting in blurring image. In present study, in order to provide a suitable technique for 3D observation of high speed turbulent flames, non-scanning 3D-CT technique using a multi-directional quantitative schlieren system with flash light source, is proposed for instantaneous density distribution of unsteady premixed flames. This "Schlieren 3D-CT" is based on (i)simultaneous acquisition of flash-light schlieren images taken from numerous directions, and (ii) 3D-CT reconstruction of the images by an appropriate CT algorithm. In this paper, with custom-made 20 directional schlieren camera, instantaneous density distributions of a high-speed turbulent flame, which can be used as an industrial furnace burner flame, have been CT-reconstructed.

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New methodology of phase shifting digital holography has been implemented for particle depth determination of the 3D particle tracking velocimetry. Although the new phase shifting method requires multiple shot of hologram recordings, it enables more high speed and stable recording of phase shift images with respect to the conventional PZT (Piezoelectric Transducer) based method and is thereby more suitable for 3D particle motion analysis in fluid flows. Test results demonstrate the strength of the new method from the viewpoint of the reconstructed image quality and the particle depth accuracy.

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This study presents a novel alternative technique that can achieve simultaneous two-dimensional temperature and velocity measurements in the gas flow. This method is combining phosphor thermometry and PIV (Particle Image Velocimetry) operated by only one laser. The temperature distribution can be obtained from phosphorescence by using two-color method, and the velocity distribution can be obtained from two phosphor particle images which taken by the camera system in time series during the persistence of the phosphorescence. The camera system is composed of CCD Camera and I.I. (Image Intensifier). I.I. is used for the light intensity magnification and controlling the exposure timing by the gate system, and CCD camera is used for recording two particle images by double exposure. In addition, the seeded phosphor is Y_2O_3:Eu, which is usable for the two-color method at 611 nm and 587 nm wavelengths, and it also has enough photoluminescence decay time to take two particle images in time series. The developed measurement technique was demonstrated in a heated air flow for the temperature ranging from 300 K to 700 K. The result of demonstration, the measured temperature using two-color method showed qualitative conformance to the temperature measured by thermocouple, and Poiseuille flow distribution was also observed for each case.

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Needs of pressure field measurement by combining experimental results obtained by PIV and governing equations are rapidly increasing. On the other hand, PTV is one of PIV techniques, whose advantages are Lagrangian particle tracking and higher measurement resolution than PIV. In this study, we proposed the new methodology to estimate pressure distribution by using irregularly-distributed pressure gradient data. The first computing step is to calculate numerical integration to obtain pressure on the grids from scattered data points. The second step is to interpolate pressure on the scattered points by using Shepard scheme. The pressure distribution is converged by iterating these two steps. We chose Taylor-Green vortex flow as a model flow to validate the computation results. The difference of boundary conditions caused the different converged pressure value, so that it is difficult to estimate pressure with high quantitative accuracy, but it is possible to discuss the relative pressure distribution qualitatively. In addition we researched the effects of grid space, the number of referenced data and wave number for computing results by using correlation coefficient. We indicated that this method is particularly available in case of low wave number flow with high resolution grid in spite of the number of referenced data.

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As a new technique for visualizing three-dimensional air flow fields, multi-layer coloring of smoke-wire technique is proposed. This method is composed of four processes. (1)The specific plane of the flow is illuminated by sheet light to detect z coordinate. (2)Sheet light is shifted in z direction to detect z coordinates of the other plane of the flow and this process is repeated for whole layer of z coordinates in the measurement area. (3)To express z coordinates, the recorded gray-scaled image is colored differently in each layer. (4)The colored images are integrated into one image. In this integrated colorful image, we can understand the three-dimensional structure of the flow by the position and the color of the smoke. By means of this technique, three-dimensional flow field around a twisted Savonius wind turbine was visualized. According to the visualized image, in the convex side of the blade, the separation of attached flow is suppressed and in the concave side of the blade, with the move of the flow to +z direction, the angle of outlet flow is increased. Thereby it was concluded that twisted Savonius wind turbine is inferior in the drag characteristics and superior in the lift characteristics. This result suggests that the twisted Savonius turbines have advantages in conditions of the higher tip speed ratio, where the lift force has priority.

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Temperature is one of the important factors in polymer molding processes. A non-intrusive technique which obtains temperature distribution in dies or nozzles is expected. Electrical Capacitance Tomography (ECT) is a suitable system for satisfying the requirement to acquire two-dimensional capacitance distribution. However, it also draws relative permittivity distribution because capacitance is a function of relative permittivity. The relative permittivity distribution probably indicates the temperature distribution, because relative permittivity has temperature dependence. There are number of previous reports about temperature dependence of polymeric relative permittivity. The temperature ranges are usually lower than the point where polymers are melted. We describe polymeric relative permittivity under such high temperature. Capacitance is determined with an impedance analyzer which has a two-electrode cell, and relative permittivity is calculated from the capacitance. Sample polymers are polypropylene (PP), polycarbonate (PC) and polymethyl methacrylate (PMMA). The temperature dependence is changed complicatedly. It depended on the polarity existence or the measuring frequency. Some points where showed same values of relative permittivity in spite of different temperature were found. Capacitance distribution does not mean temperature distribution directly. There is necessary of considering new measurement method with a combination of relative permittivity and other electrical properties, such as dielectric loss or dielectric loss tangent.

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The flow characteristics of a new hybrid vertical axis wind turbine which has advantages of the drag type and the lift type wind turbine have been investigated by the conditional sampling PIV. The experimental apparatus is constructed using the PIV measurement system with a conditional sampling device and a new hybrid vertical axis wind turbine model installed in a circulating water channel. The flows around the turbine which influence the efficiency of the vertical axis wind turbine are clarified. And, the alternations of the mean velocities around the blade for the blade rotating position are calculated. Therefore, the influences over the tangential force generated on the blades by the alternations of the mean velocities around the blades are clarified. Moreover, it is clarified that the effectiveness of the hybrid blade for the new vertical axis wind turbine is increased by the influence of the alternations of the mean velocities around the blades.

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We report on the complex behavior of the shear flow induced by corotating disks stacked in a non-axisymmetric enclosure. The present study aims to investigate the flow structure leading to the fatal crash of a hard disk drive (HDD) for data storage. We developed a simplified HDD model which represents features commonly observed in real HDD products. The model is equipped with an imitating read-and-write arm and a shroud opening. The flow is driven by disk rotations and affected by the arm blockage and the partly opened shroud. A series of flow visualization was performed by applying refractive index matching technique, where the refractive index of the working fluid was matched to that of the transparent model. Flow behavior was observed on three different planes parallel to the disks at different Reynolds numbers and arm insertion angles. Polygonal structures were observed near the hub in a certain range of the Reynolds numbers and the vertices were observed to decrease with the Reynolds numbers. Variation of the flow behavior was identified near the arm and the shroud opening area. Generation of three-dimensional shear was observed near in the arm wake region, which would create complex flow behavior of the inner flow inside the whole enclosure.

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During these decades, the application of image processing to the flow measurement has made great successes such as PIV. But, the demands for the three-dimensional measurement are growing bigger and bigger. As holography can record three-dimensional structures, digital holography can be a good candidate for the three-dimensional measurement with a single camera. But, the commonly used in-line hologram suffers the influence of the zeroth diffraction, which is the real image of an object. Several techniques that can avoid the zeroth diffraction have been proposed by using so-called "shifting". In this study, the Doppler phase-shifting holography has been used to accurately calculate the three-dimensional structures. While this technique uses the Doppler phase-shift to extract the first order diffraction from others, the shift frequency is determined by the velocity of an object. This implies that the three-dimensional velocity can be measured directly by Doppler phase-shifting holography and the results are introduced in the present study.

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Typically, soccer balls are constructed with 32 pentagonal and hexagonal panels. More recently Teamgeist 2 and Jabulani balls have 14 and 8 panels, respectively, with dramatically different panel shapes and designs from conventional balls. The latest model called Cafusa, made with 32 panels, has been adopted by many soccer leagues. However, there are few studies on the aerodynamic characteristics of these balls. This study examined the trajectory and aerodynamic characteristics of soccer balls constructed with different numbers and shapes of panels. Results of wind tunnel tests indicated that the aerodynamic forces varied significantly according to the number of panels. The results of simulation showed that the ball trajectory changes according to panel orientation, suggesting that panel orientation has significant effects on the flight of the balls.

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The flexural oscillation of an archery arrow and its influence on aerodynamic properties are investigated by a free flight experiment. Two launching systems are developed. The first system utilizes compressed air as a power source and it launches an arrow without oscillation. The second system is an archery robot releasing an oscillating arrow from a recurve bow, in which a releaser is used to reduce the oscillation amplitude besides a finger-like mechanism. We also asked two expert archers to shoot arrows (72 shots in total). Using two high-speed video cameras, we record the trajectory of an arrow and analyze its velocity decay rate, from which the drag coefficient C_D is estimated. The third high-speed video camera records the flexural oscillation of an arrow, just after it is launched. The flexural oscillation induces laminar to turbulent transitions of the boundary layer on the arrow shaft. The standard deviation of the measured C_D of the arrow launched by the archers is found to be very small, suggesting that the oscillation of an appropriate amplitude is necessary to make the boundary layer turbulent and to improve the repeatability of the arrow trajectory.

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The lower limb motion to maximize the ball velocity in water polo was solved by an optimizing simulation in the present study. The simplified simulation model for the throwing motion was developed in order to reduce the computation time. The right hand velocity was used for the evaluation instead of the ball velocity. The Particle Swarm Optimization was used for the optimizing algorithm. The objective function consisted of the right hand velocity and a penalty term regarding the hip joint torque and power. The design parameters were the hip flexion/extension angles of four time frames around the time of ball release. From the simulation results, it was found that the throwing motion to increase the ball velocity was accompanied by the right leg swinging back more and both legs moving ahead more. These motions induce the rotation of the upper half of the body forward. This rotation contributes to the ball velocity.

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Wind tunnel tests were carried out with a full-size woman's discus. The experimental aerodynamic data D, L and M were obtained from wind tunnel tests as functions of the angle of attack. It was found that the drag, lift and pitching moment coefficients, C_D, C_L and C_M, increase with increasing the angle of attack up to a stalling angle of 29-30°. Beyond the stalling angle, C_L and C_M decrease suddenly and abruptly with increasing angle of attack. It was also found that there are three typical flow patterns around the discus. The 2D-PIV measurements were also carried out on the centerline of the discus at each region. The pressure fields were also derived on the basis of the velocity fields by the 2D-PIV. It was found that the low pressure appears on the suctions side at the angle of attack of 30°, where the largest lift coefficients appears.

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The panel architecture of the soccer balls used in the World Cup has changed in every four years' convention. It is understood that the change in the panel structure in the soccer ball exerts a big influence on the aerodynamic characteristics. It is well known that the non-rotating shot by "Team Geist" appeared in 2006 becomes a oscillating ball in the long or middle distance shot. In 2014, Brazuca, composed of 6 bending panels, became an official soccerball. The aerodynamic characteristics were investigated in this study. The specification of the ball was similar to that of the convetional soccerball.

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The flying discs used in "Ultimate" competition are not made in Japan. Therefore, it is expected to develop an inexpensive and highly efficient flying disc of Ultimate in Japan. In this research, the aerodynamic characteristics of the conventional flying disc were examined and three new-style discs were created with 3D-printer. The performance of these discs were evaluated by measuring aerodynamic forces and flow fields behind discs. According to the results of the aerodynamic forces measurement, the specifications of lift-drag ratio in these four discs were almost the same on the condition that flow speed and the number of revolutions are 9m/s and 1000rpm respectively. The good specification of the discs were obtaind in the followwing order: the original, smooth, concave groove and convex groove.

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The decrease in fluid resistance is one of the important keys for the purpose of shortening of the sports time record. By wearing of a low resistance swimsuit, it still reminds us that there were a lot of large time record shortening in swimming races of Beijing Olympic. The development of low resistance cloth as the application to sports is very important. The fluid resistance were investigated by the change of cloth materials, surface roughness, surface processing method, seam position and the difference in sewing. This study is intended to suggest the best piece of cloth in specific speed area of sports.

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Labyrinth seals have the potential to cause rotordynamic instability induced by the fluid force of seal flows. We conducted a computational fluid dynamics (CFD) study to investigate the rotordynamic characteristics of the turbine blade shroud seal of a steam turbine. The effect of swirl brake on the fluid force and turbine cascade performance was investigated. The predicted fluid force (stiffness coefficients) decreased with increasing the number of swirl brakes installed at the seal inlet, but the cascade performance degraded at the same time. When the swirling flow flowing into the seal portion strikes the swirl brakes, the flow is turned to the inner peripheral side and goes back into the cascade side, which may degrade cascade performance.

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An optimum aerodynamic design method for the new type of difiuser augmented wind turbine (DAWT) called "wind-lens turbine" has been developed. A blade loading distribution and a wind-lens shape is simultaneously optimized by the design method. Aerodynamic performances of the optimal and conventional cases are obtained from experiments and Reynolds averaged Navier-Stokes (RANS) simulations. The output power coefficients of the optimal case obtained from the experimental results are superior to those of the conventional case and the Betz limit. Three-dimensional flow fields of the optimal and conventional cases have been investigated by the experiments and the RANS simulations. The results show that the aerodynamic performance of wind-lens turbine is significantly affected by the interrelationship between the internal and external flow fields around the wind-lens. Therefore, the simultaneous optimization of rotor blade and wind-lens is important for the aerodynamic design of the wind-lens turbine.

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Displacement type pumps are often applied for micro-chemical plants, while the inherent pulsation natures of these pumps are undesirable to obtain efficient and continuous chemical reaction. We have proposed a multiple-disc pump as an alternative pump, since it is expected to have much less pressure pulsations. This could be confirmed in our previous experiments, while weak pressure fluctuations were still observed in the low flow rate range. In the present study, to investigate the possibility of occurrence of flow instabilities, unsteady numerical simulation with only two rotating circular disks considered is carried out. As a result, rotating cells with the cell number varying from four to nine are observed near the inlet of flow passage between the disks, which may be responsible for the observed pressure fluctuations. The cause of the rotating cells is discussed from the meridional pressure distribution.

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A practical numerical prediction of unsteady 3-D flows with nonequilibrium condensation is conducted for low-pressure final three-stage stator-rotor blade rows in an actual steam turbine developed by Mitsubishi Heavy Industry. Compressible Nervier-Stokes equations are solved by the MUSCL TVD scheme, Roe's approximate Riemann solver, and the LU-SGS scheme. The SST-model is used for evaluating the eddy-viscosity. The mass generation rate for water droplets is modeled as a sum of the mass generation rate of critical-sized nucleus and the growth rate of water droplets based on the classical condensation theory. In this paper, effect of unsteady flows on the nonequilibrium condensation in the long blade rows is briefly discussed from the obtained results.

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In order to reduce the noise of centrifugal blowers, the authors investigated the pressure fluctuation inside vaned diffusers using unsteady pressure measurement and compressible flow simulation. The number of revolution at which the pressure fluctuation in diffuser is highest matches the number of revolution of resonance obtained from the tracking analysis results of noise and is influenced by the acoustic resonance in diffuser. The pressure fluctuation in diffuser at resonant revolution has a node at the downstream of the overlapped region. The pressure fluctuation node at the inlet of the overlapped region, as well as the amplitude of the pressure fluctuation, varies with the number of revolution.

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General mixing machine which has rotor with blades have some problems such as influence on mixing fluids by share force at blade tip and occurrence of cavitation at high speed range. In order to solve these problems, the mixing rotor without blades had been developed. This rotor has very simple shape, which has 3 thorough holes in the mixing rotor. In the present study, the numerical analysis and experiment were carried out to know the basic characteristics of mixing rotor with columnar shape. As the results, the basic characteristics such as flow fields in the mixing tank, outlet velocity of rotor, mixing time and power consumption were clarified.

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Supersonic turbine for a rocket is sometimes designed as a partial admission turbine. However, few studies dealing with the partial admission turbine have been conducted in the past. So, there are a lot of unknown flow patterns and phenomena. This study focuses on nozzle admission layout and its influences on turbine flow pattern, loss production and efficiency. Two nozzle closing ways, (a): nozzle upstream closing, (b): block closing, are simulated by two dimensional unsteady CFD analysis. Different flow pattern and entropy production appear between (a) and (b) at 1^<st> stage behind of the nozzle closed sector. In the case (a), strong mixings are caused at closed nozzle passage outlet and closed sector end side. These mixings are due to velocity difference between high velocity circumferential flow and low velocity gas existing closed nozzle passages and high velocity jet from nozzle opened sector and low velocity gas at the end of nozzle closed sector. In contrast, in the case (b), these velocity differences do not appear and entropy production is low compare with case (a). As a result, turbine efficiency is about 1.7% higher in the case (b) than in the case (a).

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In order to improve the efficiency of high-lift low pressure turbines, this paper investigates two types of airfoils which have two-dimensional contouring with a small step or dimples on the suction surface to suppress the separation bubble that causes large aerodynamic loss, especially in the case of high stage loading. A linear cascade test facility is employed to investigate the aerodynamic performance of the two-dimensional contoured airfoil by use of miniature Pitot probes and RANS simulations are carried out to investigate the three types of dimple layouts. The Reynolds number based on the chord length was varied in the range of 40,000 to 170,000 to simulate a typical flight condition. It is found that the proposed methods are capable of reducing the profile loss, resulting in an improvement of cascade performance.

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In this research, we focus on supersonic impulse turbine designed for rocket engine and investigate optimal turbine blade profiles using genetic algorithms. To explore a design space, the computational requirement is quantified for CFD simulations can be lowered by reducing the number of grid points. In order to compensate for the reduced accuracy of the coarse grid simulations, the uncertainty of obj. functions by employing GCI.

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The present study investigates wake-induced bypass transition of boundary layers on a fiat plate subjected to favorable and adverse pressure gradients. The aim is to exploit unsteady effects in order to design a turbine blade without increasing the profile loss, as has been achieved for low pressure turbine blades. First of all, this fundamental study is to reveal the effect of wake passing frequency. Detailed boundary layer measurements were conducted using hot-wire probe. A passage-contouring device was employed to generate a pressure gradient on the test model, which was typical to that generated by a turbine blade. A wake generating squirrel cage was used to create periodic wakes in front of the flat plate. Computational fluid dynamics analyses are also applied to the flow field. It was found that the wake passage induces a temporary turbulence promoting in the flow over a flat plate surface.

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In a centrifugal compressor, the leakage flow through the tip clearance generates the tip leakage vortex by the interaction with the main flow, and consequently makes the flow in the impeller passage more complex by the interaction with the passage vortex. In addition, the tip leakage vortex interacts with the shock wave on the suction surface near the blade tip in the transonic centrifugal compressor impeller. Therefore, the detailed examination for the influence of the tip leakage vortex becomes seriously important to improve the aerodynamic performance especially for the transonic centrifugal compressor. In this study, the flows in the transonic centrifugal compressor with and without the tip clearance at the design condition were analyzed numerically by using the commercial CFD code. The computed results revealed that the tip leakage vortex induced by the high loading at the blade leading edge affected the aerodynamic loss generation by the reduction or the suppression of the shock wave on the blade suction surface.

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A multi-objective optimization system for Francis turbine runners was developed. The system considers the performances at multiple off-design points and a head at a design point as objective functions in order to obtain runner design candidates that meet required specifications. Furthermore, the number of CFD evaluations was reduced using the correlation between a head and an outlet opening area. The developed optimization system was applied to design a runner, and we obtained runner design candidates that were superior to the baseline in terms of the performances at all operating conditions with approximately half of the number of all CFD evaluations. Since an optimized runner showed runner efficiencies improved at the design point as well as both the partial load and the overload compared with the baseline by evaluating approximately half of all design candidates in the optimization, the availability of the optimization system was confirmed.

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Fluid machines for fluid food have been used in wide variety of fields i.e. transportation, the filling, and for the improvement of quality of fluid foods. However, flow conditions of it are quite complicated because fluid foods are different from water. Therefore, design methods based on internal flow conditions have not been conducted. In this research, a centrifugal pump with a small number of blades was used to decrease shear loss and keep wide flow passage. Furthermore a larger outlet angle was adopted. In this paper, the internal flow conditions at each axial cross section of centrifugal pump with four straight blades and blade outlet angle 90 degree was compared from numerical analysis results of low viscous fluids. In addition, design methods based on the internal flow were considered. Furthermore, the influences of viscosity on the performance characteristic and internal flow were investigated.

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Recently, the lattice Boltzmann method (LBM) is being applied in turbomachinery field, regarded as a good candidate for tool of flow simulation as well as aerodynamic sound analysis. For better prediction of broadband noise with high frequecy, which is generally generated in high Reynolds number flows, not only high grid resolution is required to capture very small eddies of the sound source inside the turbulent boundary layer, but also the computation of acoustic field is often needed. In such case, the direct simulation of flow field and acoustic field is straightforward and effective, and LBM is suitable for such simulation thanks to its advantages. In the present study, a large-scale numerical simulation of flow field around a half-ducted propeller fan is conducted with LBM, and its result is validated by comparing with the experimental result.

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In the operation of a centrifugal compressor of turbocharger, instability phenomena such as rotating stall and surge are induced at a lower flow rate close to the maximum pressure ratio. In this study, for the suppression of surge phenomenon resulting in the extension of the stable operating range of centrifugal compressor to lower flow rate, the compressed air at the compressor exit was re-circulated and injected into the impeller inlet by using the double injection nozzle system. The experiments were performed to find out the optimum circumferential position of the second nozzle relative to the fixed first one and the optimum inner diameter of the injection nozzles, which are able to most effectively reduce the flow rate of surge inception. Moreover, in order to examine the universality of these optimum values, the experiments were carried out for two types of compressors.

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The aim of this study is to design and propose the size and layout of buildings which provide the better wind distribution for the higher power generation of wind turbine. A building model whose layout is like nozzle is proposed to obtain the acceleration of wind blowing through buildings due to contracted flow between buildings, hi addition, the effect of the angle between two buildings on the power generation performance of the proposed building model is also investigated. For the feasibility check of installing the building model in some area actually, the power energy of wind turbine is investigated by considering the meteorological data such as wind velocity and direction distribution for Fukushima city as an example. If the proposed building model whose angle between two buildings is 135 degree is installed in Fukushima city, the ratio of power energy generated by wind turbine to electric consumption of households in a year is estimated to be approximately 21-22%.

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In order to put a surface-tidal power generation system into practical use, it should be easy to maintain and economically feasible. Besides, understanding of stakeholders suchlike as shipping companies and fishermen is essential. According to previous studies, the speed of a tide is the same regardless of depth, so a power generation system using surface-tidal power is feasible. The purpose of this industry-academic-government research is to put a surface-tidal power generation system into practical use. We have developed a wooden water wheel, moreover, we have been towing experiment. As the result, the wooden water wheel was rotated, it was able to power generation. However, the wooden water wheel was damaged, because it was not withstand the surface-tidal power. In this paper, an iron water wheel is developed. The iron water wheel is able to power generation, it is proved larger the wooden water wheel. These results are intended to show the effectiveness of the system.

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A wave power generator with an impulse turbine is installed in the breakwater and consists of the air-chamber, the turbine, the generator and the safety devices. The purposes of this paper are to construct the design method. As for the motion of water inside the air-chamber, that is, the oscillating water column (OWC) is solved by the eigenfunction expansion method. The characteristics of turbine and OWC for irregular wave are solved by assuming the Gaussian distribution for the probability density of the flow rate of turbine. The friction loss torque is considered by the simple assumption for the turbine and generator. An initial design decides the turbine size, the rotational speed and the rated generator power from calculation results for the several wave conditions.

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The effect of blade number to the performance on cross flow wind turbines was studied by Laminar Flow analysis. In this study, cross flow turbines include Savonius turbine. The equations are discretized by Finite volume method for space and Fractional step method for time. Turbine blade is thin and arc shape. Other important parameters are chord length, camber and setting angle of blades. The following are conclusions of analysis. Two blades turbine produce highest power coefficient, and four blades turbine produces lowest power coefficient. Suitable parameters for each blade number were clarified.

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