In recent years, attention has been focused on fully reusable space transportation system with low operation cost for further promotion of space development. As part of this, the development of experimental winged rocket which is called WIRES (WInged REusable Sounding rocket) is being conducted at Space Systems Laboratory, Kyushu Institute of Technology. As one of its key technologies, a real-time guidance system that generates flight trajectories without reference trajectories using a DynDGA (Dynamically Distributed Genetic Algorithm) is studied. This guidance system can generate the flight trajectory even if the situation suddenly changes such as abort flight. The flight demonstration of this guidance system is currently planned using the WIRES#015 which is under development. For this guidance system validation, the 6 degree-of-freedom simulation, where DynDGA guidance system is applied to the gliding phase, is conducted. In this paper, the construction of guidance system for WIRES#015 and its simulation result are discussed.

In recent years, for further promotion of space development, reusable space transportation system with low launch cost per one has been researched and developed. However, there are some technical problems that must be solved in order to realize such system. One of these problems is the autonomous guidance system that can work under various flight environments. Therefore, onboard real-time optimal flight trajectory generation methodology using dynamically distributed genetic algorithm (DynDGA) has been studied. Its advantage is that it can cope with sudden changes in flight environment and mission by obtaining multiple optimized trajectories with diversity. While the general framework of this guidance system has almost been constructed, there is a problem that there are some performance indices of different importance and units, but the past algorithm sums up the raw values of performance indices with weight factor. Therefore, it was difficult to set appropriate weight factor such that fascinates the growth of the individual. In this paper, we propose a hierarchical fitness calculation method by fuzzy membership function so that performance indices grow according to priority order, and the performance of this guidance system is evaluated by numerical simulation.

The CO₂ recovery process used in thermal power plants has a running cost problem because the adsorbent must be heated at high temperature to desorb carbon dioxide. The new hydrogel-based absorbent used in this study may be the best way to reduce CO₂ emissions from thermal power stations as it absorbs and desorbs CO₂ in response to small temperature changes. Furthermore, since this absorbent can be fabricated as coating film, it can be applied not only to a flat surface but also to a complicated shape. However, a method for using it with high efficiency has not yet been developed. An aluminum reactor having many fine structures was manufactured by precision machining and several tens of micrometer absorbing gel films were formed thereon by spray coating. This method accelerates the absorption / desorption rate of carbon dioxide and reduces the size of the CO₂ capture reactor. In this paper, the influence of the film thickness and the carrier surface area on the absorption rate was investigated. CO₂ gas was guided into the reactor and the concentration of carbon dioxide contained in the gas after contact with the absorbent was measured. Comparisons were made between reactors with micro structures and reactors without them. The desorption step and absorption step were conducted once. As a result, it was found that the adsorption / desorption cycle improves as the membrane thickness decreases and the carrier surface area increases.

In recent years, as semiconductor products have been reduced in size and advanced in function, they are approaching the limit of ultrafine processing in the semiconductor surface, and it is inevitable that two-dimensional expansion of the substrate. In order to solve the problem, I focused on a three-dimensional structure that can achieve compactness and high density. Through Silicon Via (TSV) is a typical example of a three-dimensional structure, and in the resist film formation which is one of the steps of forming it, It is necessary to uniformly apply the resist to the edge portion, the wall portion, and the bottom portion of the prepared hole of the through hole called a via hole. However, this process has not yet been realized. In this paper, we attempt to control the resist coating thickness by combining an electrostatic induction type spray with an external electric field. The result of examining the shape of the external electrode for controlling its film thickness is reported.

Fluorescence correlation spectroscopy (FCS) is one of the fluorescence measurement methods, and it is possible to observe the dynamic characteristics of fluorescent molecules that perform Brownian motion in liquid. This measurement method has the potential to realize in-liquid measurement of nanoparticles with multimodality and polydispersity which is difficult to observe with conventional measuring instruments. In this paper, as a basic experiment for developing new nanoparticle sizing method, we report the result of investigation on the relationship between translational diffusion coefficient and solvent viscosity of a single fluorescent molecule.

Quartz glass is used as a material of flat panel display and a hard disk drive because of its optical transparency, heat resistance, dimension stability, high hardness and high surface smoothness. Recently, planarization of the glass substrate surface is demanded because electronic devices require higher performance and higher recording density. Therefore, CMP is used as a finishing process for quartz glass substrate polishing. Ceria slurry is widely used in glass substrate CMP because of its specific chemical characteristics of having extreme high removal rate(RR) comparing to other types of slurry. Colloidal Ceria is expected to be a candidate of alternative slurry for glass substrate CMP because the slurry particles are small and have a regular shape comparing to conventional calcined ceria particles. In the previous research, KOH additive makes colloidal ceria particles aggregate and improves removal rate(RR) close to that of calcined ceria. To reduce the consumption of slurry, in particular, experiments were carried out using low concentration slurry of 1 wt% or less. As a result, it was found that the lower concentration slurry can efficiently polish the glass substrate maintaining the good surface quality.

The purpose of this research is to apply high efficiency microfabrication with low fluence by near infrared femtosecond laser by applying carbon film to synthetic quartz. In order to examine the effectiveness of the proposed method, a single pulse was irradiated on synthetic quartz coated with C film and synthetic quartz not coated. By applying the C film, the damage threshold of synthetic quartz decreased by 59.1%. In order to investigate the excitation effect in the proposed method, double pulse processing was performed on synthetic quartz coated with carbon film. In double pulse processing, one laser pulse is used for the material of excitation and another pulse is used for processing. The fluence of the two laser pulses alone could not process synthetic quartz. The interval between the two laser pulses was set to 0.1 ps, 0.5 ps, 1 ps, 2 ps, 5 ps, 10 ps, 20 ps, 50 ps, 80 ps, 100 ps, 150 ps, 200 ps. The damage threshold increased after 1 ps by laser pulse irradiation as pulse interval increased.

The authors aim to develop a coordinate measuring machine equipped with a three-dimensional scanning probe in a dedicated gear measuring machine. This realizes a comparatively inexpensive measuring machine with high general versatility. In the development machine, it is calibrated using a calibration sphere calibrated with a higher standard instrument. It has been confirmed that certain variations will occur in the calibration results in previous studies. One of the factors may be the influence of contamination on the surface of the stylus tip ball. When observing the surface of the stylus ball with CLSM, there was dirt on the surface. Therefore, the stylus tip was cleaned with an ultrasonic cleaner and almost all contaminations were removed. When calibration was conducted with the cleaned stylus, the variation in the calibration result became small. It was found that it has been necessary to keep the stylus clean in the case of calibration and/or measurement with high precision.

The hypereutectic Al-Si alloy is a material in which crystal grains of primary crystal Si are scattered in the base material of an aluminum alloy, and processing by forging, casting, cutting is mainstream. However, due to the influence of Si crystal grains, tool wear is remarkable, so that cutting performance is poor and it is difficult to improve the surface roughness of the cutting surface. Al-Si alloy with high Si content is desired, however, it is currently difficult to precisely cut this material. Therefore, in this study, cutting of hypereutectic Al-Si alloy A390-T6 with a Si content of 17% was carried out. Then, the influence of cutting speed and tool material on width of flank wear was investigated. On this occasion, observation of the cutting edge of the tool using the digital microscope and measurement of cutting force at the time of cutting using the cutting dynamometer were performed. As a result, we found the characteristics of width of flank wear due to tool material and cutting speed. Also we derived the relational expression between the width of flank wear and the cutting distance.

The engine cycle of a Japanese next flagship liquid rocket applies an expander bleed cycle and it has a component called mixer. In the mixer, cryogenic hydrogen is vertically injected through the perforated plate into the high temperature hydrogen flow under supercritical pressures. It is important to complete mixing efficiently in the mixer because insufficient mixing may lead to non-uniform temperature distribution and thereby cause combustion instabilities in the chamber. The objective of this study is to investigate flow structures and mixing of a cryogenic jet injected into the crossflow under a supercritical pressure using a three-dimensional LES/RANS hybrid model. The results found that periodic vortex structures are formed around the jet and they have dominant role on near jet mixing processes. The shedding vortices penetrate into a region behind the jet, establishing a recirculation region. There are some differences in the jet height and the recirculation region, compared with those in a two-dimensional calculation.

In order to understand the detailed mechanism of galloping detonation of methane and oxygen, efforts were made to improve the cellular structure and propagation velocity of unsteady detonation. Firstly, as an alternative to smoked foil method, a new visualization of cell structure was attempted using CB film, mylar film covered by carbon black with spray-type adhesive. CB film succeeded in recording cell structure, and this result suggests a potential to apply for image recognition of the cell structure using strong backlight at scanning CB film. Secondly, the correlation between the cell structure and the propagation velocity in a galloping detonation was investigated by combining the detonation velocity measurement and smoked foil method. The propagation velocity distribution was measured using twice the sampling points in the same detonation tube length as in our previous research. This experiment revealed that, after the over-driven detonation started to decelerate, small non-uniform cell structure was formed and transited to spinning mode during the deceleration. Consequently, in galloping detonation, a strong correlation was found between wave-front acceleration and cell structure.

Condensation phenomenon in a high-speed flow field is, in general, induced through the non-equilibrium condensation process. In this process, condensation nuclei are generated by collision and aggregation of vapour molecules. The condensation of the vapour, so-called homogeneous condensation, takes place on the nuclei. On the other hand, in heterogeneous condensation, the condensation of the vapour takes place on foreign nuclei : smoke and vapour from fires and various industries, particulate products from chemical reactions. However, the effects of foreign nuclei on the high-speed flow field have not been clarified significantly. In the present study, the numerical investigation is carried out to clarify the effects of the heterogeneous condensation and relative humidity on the characteristics of the swirling flow field in a supersonic annular nozzle. In addition, the differences between homogeneous condensation and heterogeneous condensation are also explained.

Critical nozzles have been proposed as one of flowmeters that can be used under high-pressure conditions with stagnation point pressure of 70 MPa or more and can measure with high accuracy. The critical nozzle is a device for measurement of the mass flow using the flow-choking phenomenon at the nozzle throat and the theoretical mass flow rate is a function of the temperature, the pressure, ratio of specific heats at the stagnation point upstream of the nozzle and the diameter of the nozzle throat. In such a flow in the critical nozzle, the coefficient of discharge approaches 1 as Reynolds number increases. In previous studies, it has been shown experimentally and theoretically that the discharge coefficient of hydrogen gas in the region of high Reynolds number decreases with an increase of pressure at the stagnation point upstream of the nozzle. The objective in the present research is to investigate the effect of the stagnation temperature on the discharge coefficient of the critical nozzle.

The underexpanded free jet emitted from a micro convergent nozzle with an exit diameter of 1mm has been numerically solved by the axisymmetric compressible Reynolds-averaged Navier-Stokes (RANS) equations with the well-known Menter's SST k-ω turbulent model where the nozzle operating pressure ratio is held constant at 4.0. The computational models with 50,000, 170,000 and 200,000 meshes are estimated by a quantitative comparison with a recent experiment result using the rainbow schlieren deflectmetory. The commercial software ANSYS fluent with ver. 15.0 is used in the present simulation. It is found that the numerical results with both 170,000 and 200,000 elements show a Mach disk in the first shock cell clearly when compared to that with 50,000 elements. In addition, the centerline density profile in the shock containing free jet from the numerical result with 170,000 elements is in good quantitative agreement with that from the rainbow schlieren deflectometry. In this case, it is also found that SST k-ω turbulent model provides better simulated result than Realizable k-ε turbulent model.

The underexpanded sonic jet issued from an axisymmetric convergent nozzle with an inner diameter of 10 mm at the exit are experimentally investigated in which the nozzle is operated at a pressure ratio of 4.0 to produce a Mach disk in the jet plume. Multidirectional rainbow schlieren pictures of the jet acquired by rotating the nozzle about its longitudinal axis in equal angular intervals are utilized to reconstruct the jet three-dimensional density fields with both of the Abel inversion and convolution back-projection algorithms. The fine structure of the free-jet with a Mach disk in the first shock-cell is distinctly displayed with a two-dimensional density contour plot including the jet centerline. Furthermore, the jet centerline density profile obtained from the present rainbow schlieren is quantitatively compared with that from the background oriented schlieren performed by ONERA in the past. Summarizing, it is shown that the shocks reflected at the triple points of the Mach disk are gradually curved with convex facing downstream toward the jet shear layers, which lead to the downstream divergences of the slip lines generated at the triple points, therefore, the jet centerline density just behind the Mach disk continues to rise over a short distance.

The free jet issued from a Laval nozzle of a design Mack number 1.5 with a square area of 1 mm² at the exit is experimentally investigated to observe the flow characteristics of shock-containing microjets in which a Twyman-Green interferometer with a blue semiconductor laser is used and the reconstruction of the jet three-dimensional density field is performed by the convolution back-projection algorithm. It is found that the fine structure of the shock-containing microjet is quantitatively represented with the density contour plot at the streamwise cross-section including the jet centerline and the two-dimensional density field at the cross-section vertical with respect to the jet centerline just downstream of the nozzle exit shows the axis-switching phenomenon.

The unsteady flowfield in a two-dimensional transonic half diffuser has been simulated by the LES approach where the Reynolds number based on the critical conditions and the throat height was 1.11 × 10⁵, and the free-stream Mach number just upstream of a shock is around 1.03. It is shown that a shock wave generated downstream of the throat propagates beyond the throat in the upstream direction and a new shock germinates downstream of the throat and this series of shock motions are periodically repeated. The shock in the diffuser has a strength enough to induce the boundary layer separation. An unstable shock behavior in which a shock wave is generated just downstream of the throat, and then propagating beyond the throat in the upstream direction can be observed.

The underexpanded free jet issued from a rectangular convergent nozzle with an aspect ratio of 2.0 at the nozzle exit has been experimentally investigated using the rainbow schlieren deflectometry combined with the computed tomography where the nozzle operating pressure ratio was held constant at 4.0 to produce a flow-field including a Mach disk in the jet plume. Multidirectional rainbow schlieren pictures of the jet are acquired by rotating the nozzle about its longitudinal axis in equal angular intervals and the three-dimensional density field is reconstructed by the convolution backprojection algorithm.

The length of liquid slug and gas bubble, gas bubble velocity and pressure drop of gas-liquid two-phase flow in a rectangular channel were measured using a high speed camera and a different pressure transducer. Water and Glycerol-solution as the Newtonian liquids and Carboxymethyl cellulose, Xanthan gum and Polyacrylamide-water solution as non-Newtonian liquid were used as the liquid phase, and N2 gas was used as the gas phase. A rectangular channel was used, which has equivalent hydraulic diameter to 0.51 mm. The measured data were compared with unit cell model, which applied to gas bubble pressure drop prediction proposed by Kurimoto et al. (2017). The following conclusions were obtained: (1) Different flow pattern was observed only in Polyacrylamide-water solution. (2) Pressure drop gradient on two-phase flow increased as mean velocity of liquid increased. Pressure drop on two-phase flow can associate with effective viscosity of liquid except some experimental data. (3) Effects of elasticity of liquid on non-Newtonian two-phase flow should be accounted to predict pressure drop.

This study concerns with air-water annular flow across a grid spacer with mixing-vanes in a vertical 3×3 rod bundle channel. The rod channel consisted of one full rod (whose diameter is 1.5 mm ) in the center of the square duct (40 mm×40 mm) and four half rods on the side walls and four quarter rods on the corner. Four subchannels with hydraulic diameter of 15.3mm were created around the rods. The spacing between two rod was 4.85m. In order to investigate the effects of the vane on the spacer to the liquid film thickness on the center rod, a grid spacer without mixing-vanes or with mixing-vanes was placed in the rod channel. The film thickness distribution was measured with constant electric current method. The measurement results cleared that the film thickness downstream of the spacer becomes thicker for the spacer with mixing-vanes than that without mixing-vanes because the mixing-vanes enhance the position of liquid droplet in gas core to the rod wall.

In this work, the effects of surface tension and liquid viscosity on flow patterns, gas slug velocity and gas slug length in a horizontal circular microchannel with an inner diameter of about 530 μm have been investigated by using a high speed camera. As the working fluids, nitrogen gas for the gas and aqueous solutions of different concentration of glycerol of 26.0wt% to 33.5wt% and aqueous solutions of ethanol of 18.0wt% to 87.0wt% for the liquid were used. For their aqueous solutions the kinematic viscosities were from twice to 2.6 times and surface tensions were of 0.3 ~ 1.0 times as the ratios of their physical properties to those of distilled water. The superficial gas velocities, j_G, were ranged from 0.01 to 13.6 m/s, and the superficial liquid velocities, j_L, were from 0.05 to 0.30 m/s. The flow patterns of slug flow and disturbed ring film flow were observed. When the viscosities of the liquid were increased and the surface tensions of the liquid were decreased in the cases of the constant superficial velocities ratio of the gas to the liquid, the tendencies that the velocity of gas slug increases and the lengths of gas slug became short were recognized.

The present paper focuses on the effect of air flow on acoustic absorption characteristics of perforated plate. We experimentally measured the flow rate, acoustic pressure, and transfer function using an acoustic impedance tube. The normal incidence absorption coefficient was calculated from the measured transfer function using transfer function methods. As the flow velocity of air passing through the orifices increased, the peak level of the acoustic absorption coefficient increased for a wide frequency range. In addition, velocity measurements were performed around perforated plate by means of particle image velocimetry (PIV). The sinusoidal flow occurred near the center of orifices of perforated plate due to the acoustic particle velocity excited by using the loud speaker. The theoretical results used measured Mach number agreed well with the experimental ones qualitatively.

Laminar flowmeter with a measuring part formed by tied narrow tubes is a useful flowmeter because of its quick response time. Flowrate passing through the laminar flowmeter is calculated from a pressure loss in the tied narrow tubes and a flowrate coefficient. However, the flowrate coefficient depends on shape of the piping connected to the flow meter. In this paper, we focus on reduction of the effect of the expanded connection on the flowrate coefficients by means of perforated plates-type flow strainer. Three kinds of perforated plates were employed as flow strainer, and connected to each side of the measuring part of the flowmeter. Two types of connecting tube of a diameter of 4 mm and 10 mm were tested. The flowrate coefficient was experimentally determined by comparison to a standard flowmeter. The results suggested that a perforated plate in which the diameter of the holes gradually increases from the center toward the tube wall is effective in reducing the change of flowrate coefficient.

The purpose of this study is to control the jet diffusion by using the deforming nozzle. The shape of polypropylene nozzle can be changed from square shape to cruciform shape, again to square one smoothly and periodically. The velocity measurement of the jet flow was carried out using a PIV method, by changing the nozzle shape variously. The basic characteristics of the jet flow, such as the time averaging velocity distributions and the half value widths of the jet have been obtained. Due to the periodic deformation of the shape of the nozzle exit, the inducement of the ambient fluid into the jet becomes more activated. As a result, it has been found that the jet diffusion issuing from the deforming nozzle is consequently promoted in xOy-plane, but is suppressed in xOy'-plane.

A circular cylinder with tangential blowing is a type of the circulation control wing (CCW) that generates lift force by ejecting the jet flow from a slot. As an application example, the circular cylinder with tangential blowing has been used in the form of substituting the tail rotor of the helicopter called NOTAR (NO Tail Rotor helicopter). By applying the circular cylinder with tangential blowing to the helicopter, the interaction between the main and the tail rotor is eliminated, and noise reduction is realized. Because the circular cylinder with tangential blowing can control the flow direction without changing the geometric shape, its application to the inlet guide vanes in fluid machines has been expected. However, many of the research on the circulation control wing have been studied for the aircraft, and there are still few research examples for turbomachinery. This study attempted to experimentally elucidate the aerodynamic characteristics of a circular cylinder with tangential blowing it was placed in a jet flow. As an typical experiment result, it was confirmed that the deflection of the main jets can be controlled by the momentum from the tangential blowing.

In the situation of the swirling flow ejected to the semi-infinite space, the flow with the swirling jet structure is formed, when the swirl number relating to the angular momentum is small. On the other hand, under the condition that the swirl number is large, the flow does not become the jet flow structure but spreads in the radial direction by centrifugal force. Incidentally, the annular guide vanes are used as one method to generate the swirling flow. If the vane angle measured from the tangential direction set to be small, the flow instabilities with the vibration and the noise occur downstream of the annular guide vanes. It is known that such unsteady flow is essentially a two-dimensional phenomenon, and the vibrations occur due to the circumferential propagation of cell structure. However, there is no report about the behavior that the swirling flow with the instability of the cell structure generated downstream of the annular guide vane is released to the atmosphere. In this research, we tried to clarify experimentally the influence of the instability phenomenon on the swirling jets generated downstream of the annular guide vanes. Generally, it is known that the motion of the swirl flow for the same flow rate (momentum) depends on the angular momentum. However, the present results show that it depends not only on the angular momentum but also on the oscillation characteristics of the unsteady flow based on the rotation of the cell structure exists downstream of the annular guide vanes.

Over the past several decades, jet technology to control the flow field has been developed. Recently, research on the flow direction control of the jet has attracted attention. For synthetic jets, it has been reported that the jet vectoring is possible only by frequency adjustment, when the jets is produced with the beak shaped asymmetric slot. However, findings on detailed deflection mechanisms are still insufficient. Moreover, there have been few discussions on the optimal geometric shape for controlling the jet direction of synthetic jets. In this study, an attempt was made to elucidate the behavior of synthetic jet produced by an asymmetric stepped slot as a fundamental study of the flow direction control for the two - dimensional plane synthetic jet. As main results, it was shown that the degree of the jet deflection is determined by the step shape geometry of the slot exit. The influence of the geometric shape on the behavior of the jet flow was discussed.

Recently, the wind turbine design is developing for higher performance through taking into consideration the effects of velocity fluctuation and turbulence of installation location wind. It is necessary for the design to artificially generate natural wind and establish the wind turbine performance evaluation in natural wind. The paper describes a newly made active controlled multi-fan wind tunnel with cost reduction to generate natural turbulence wind. The authors plan to use it for measuring wind turbine performance in laboratory. The wind tunnel consists of 100 driving fans that are controlled by an original ICT embedded system. The fluctuating velocity wind is successfully generated with mean velocity 7m/s, turbulent intensity 2% and turbulent integral scale 5, 10, 20m, which is based on Karman’s power spectrum density function. Furthermore, power coefficients of a wind turbine in steady and natural winds are investigated. As the results, it is made clear that integral scale has large effect on the wind turbine performance. The maximum power coefficient in natural wind of integral scale 5m and 10m is 1.24 times as large as one of steady on the same mean velocity 7m/s.

Cavitation phenomenon in automotive torque converter causes various problems such as erosion, noise and performance deterioration. In this study, the mechanisms of cavitation occurrence and its effect on the torque converter performance are discussed by experiment and numerical analysis. It is found that the inception cavitation number decreases as the speed ratio increases and is less influenced by the pump rotational speed. Since the cavitation locally occurs at the inception condition and the local minimum pressure coefficient obtained by the numerical analysis well correlates with the incipient cavitation number, the cavitation inception based on the naked-eye observation is found to be not significantly influenced by the dissolved air. On the other hand, the performance degradation is found to be strongly affected by the amount of dissolved air. Many bubbles are observed in the whole flow passage at this condition. Since the averaged pressure inside the torque converter flow passage well correlates with the gas equilibrium pressure in the high dissolved air condition, it is found that the density decrease due to the huge amount of gas bubble generation deteriorates the performance of torque converter. However, at low dissolved air condition, the above correlation does not well hold, which seems to indicate that the performance degradation is caused by the local vaporous cavitation.

Small hydroelectric power generation using a Darrieus-type hydraulic turbine in agricultural channels etc can be mentioned as one of the expected utilizations of renewable energy. Channel conditions are different from place to place and also are dependent upon the seasons. A performance of Darrieus-type hydroturbine is strongly influenced by the channel and flow condition, and it is not clear how much electric power can be extracted from the turbine for each condition. In the present study, we propose a one-dimensional flow tube model and verify it’s validity through the comparisons with experiment. It is shown that the model can qualitatively predict in the high rotational speed range but not well in the low speed range.

By applying contra-rotating rotors in axial flow pump, compact size and better cavitation performance have been achieved. However, deteriorated performance has also been observed at off-design operations, which may be possible to be improved by applying rotating speed control and adjustable blade in front and rear rotors. In order to predict performance of contra-rotating axial flow pump with rotational speed and stagger angle controls, a model has been proposed on the basis of one-dimensional streamtube theory and the blade element theory with empirical flow angle deviations. Numerical simulations by Computer Fluid Dynamics (CFD) have also been conducted to compare with results of 1D model. In various operation conditions with changes in the rotational speed and stagger angle of rotors, total head evaluated by 1D model shows good agreement with that based on CFD from 0.8Q_d to 1.2Q_d. Small discrepancies are observed in the total efficiencies predicted by 1D model and CFD from 0.8Q_d to 1.0Q_d, while significant discrepancy occurs at larger flow rates.

Currently a syringe with a needle is mainly used as a parenteral medication method and it is disposable from the aspect of safety and sanitary. However, problems such as the risk of the infection by the needlestick injury and outbreak of expensive disposal cost occur. To solve them, therefore, a needlefree injection system has widely been investigated. In this study, characteristic tests for improvement of the repeatability of jet velocity and the penetration tests into the viscoelastic material simulated living body are performed for the development of the needlefree injection device which percutaneously administrate a liquid drug into the body with a microjet accelerated fast.

In the hydraulic transportation of solid-liquid flow in the conduits, the authors have proposed that to place the discharging plates in the flow area is valid to transport particles piled up. In the previous paper, we examined the effects of interval length of discharging plates while the plates were used under the experimental condition that was these plates were not inserted particles bed. However, practically the discharging plates have been used under the circumstance that is these plates are inserted particles bed. Therefore, in this paper, we examined the effects of interval length of discharging plates while the plates were used under the experimental condition that was these plates were inserted particles bed. As a result, it was found that the optimum interval length of discharging plates in current installation depth of the discharging plates. In addition, it was revealed by the visualization of particles behavior that the circumstances of the scouring boundary change by the interval length of discharging plates.

The authors proposed that using the compound swirl jet which is composed of an annular swirl jet and a coaxial free jet, as an injection flow of the push-pull ventilator which has push side on the coaxial extension of pull side. According to our previous reports, it was found that the collected flow rate increases by extending the length of swirl jet pipe. However, it was revealed that collected effect is suppressed, when the length of extension part of swirl jet pipe increases, or the diameter of extension part of swirl jet pipe decreases. This phenomenon is indicated by that the inner wall of extension part of swirl jet pipe interferes with compound swirl jet. Therefore, we carried out experimental investigation which purpose is to clear the effect of taper angle of swirl jet pipe on collected flow rate of compound swirl jet by enlarging taper angle of extension part of swirl jet pipe.

A vane-type vortex cup is a device attaining non-contact handling by rotating a vane inside a vortex chamber. In this paper, we investigate relation between shape change of intake hole and lifting force in a vane-type vortex cup. According to the experimental set up, the lifting forces of twelve cups with different intake radius and position were measured at three kinds of rotating speed. The result suggested that the maximum lifting force depends on the radius and position of the intake, the lifting force has maximum values when the ratio of the inlet radius to the swirl chamber radius r/R = 0.09 against the ratio of the inlet position to the radius of the vortex chamber l/R = 0.3, 0.5, and when r/R = 0.12 against l/R = 0.7. And the gap height against the same lifting force is increased in accordance with the increase of the intake radius and the closer the intake position is to the center of the cup.

A hybrid rocket is equipped with an engine consisting of two types of propellants with different phases. It is common to use liquid oxygen for the liquid oxidizer and acryl for the solid fuel. When liquid oxygen and acrylic are used, the gas temperature in the combustion chamber exceeds 3200 oC at maximum. Therefore, the nozzle of the rocket is exposed to high temperature and high pressure gas. In this study, we report the thermal barrier effect of thermal barrier coating （TBC） on graphite nozzle in firing test using acrylic for fuel and liquid oxygen for oxidizer. The temperature during the firing test of the nozzle outer surface with/without TBC was measured. During the firing test, the part where the coating was not applied showed a maximum of 500 oC and the part where the coating was applied showed 400 oC. As a result, sufficient thermal barrier effect was confirmed with TBC.

A hybrid rocket is equipped with an engine consisting of two types of propellants with different phases. It is common to use liquid oxygen for the liquid oxidizer and acrylic for the solid fuel. A hybrid rocket has merits including low cost, safety and environment-friendly. This is because no gunpowder for the propellant. However, it has a weakness of low thrust due to difficulty of burning fuel. The final objective of this research is to develop engines with a higher thrust. For this reason, research has been conducted to burn fuel more efficiently, nevertheless, it has not been commercialized yet. In this study, we used gaseous oxygen for oxidizer and acrylic for fuel. Firing test was carried out with three kinds of fuel; single-port type, convergent type, and divergent type. We studied the influence of acrylic fuel shape on thrust of hybrid rocket engine. As a result, as the contact area of the flame and the fuel increased, the thrust was improved for the convergent type and the divergent type compared to the single-port type.

This paper describes a regenerating system of living tissue combining culture promotion and capsule destruction by shock wave, and the development of the system. In this system, shock wave are applied to microcapsules containing bubbles for Drug Delivery System (DDS) to simultaneously stimulate cells and destroy capsules. The capsule have an important role as a medium for cell culture in regenerative medical. In this study, underwater shock wave is generated using short-time pulse laser with femtosecond for stimulating cells. The pressure of shock wave was measured at the positions by the pressure sensor. These positions are distances 0.3mm, 0.4mm, and 0.5mm from the focal point. An approximate expression was obtained from the peak pressure measured at each position, and the pressure at the focal area was obtained. As a result, the pressure at the focal area was estimated to be 2.4MPa at the 1Hz and 2.2MPa at the 100Hz.

The spherical shock wave in a rarefied polyatomic gas is analyzed based on extended thermodynamics (ET) with six independent variables; the mass density, the velocity, the pressure, the dynamic pressure. Appropriate new field variables, which transform the non-autonomous field equations into autonomous ones, are specified. A new system of ordinary differential equations, which depends on only one similarity variable, are derived in terms of the new field variables. The derived system with the boundary conditions obtained from the Rankine-Hugoniot conditions of the ET theory for a strong shock are solved numerically. It is shown that the similarity solutions are characterized by a dimensionless parameter and the dynamic pressure can essentially contribute to the profile of the physical quantities.

In recent years, nanobubble technology has drawn great attention due to their wide applications in various fields of science and technology, such as water treatment, biomedical engineering, and nanomaterials. This study focuses on the application to seafood long term storage. The nitrogen nanobubble water circulation may reduce the oxygen in water and slow the progressions of oxidation and spoilage. Our previous study showed the pressure reduction and shear stress are involved in nanobubble generation apparatus with honeycomb cells. In this work, the nanobubble generating performance is studied experimentally for honeycomb structures by varying the cell size and the flow velocity. Computational Fluid Dynamics analysis is also performed to simulate the experiment and find out the efficient nanobubble generation. It was considered that the maximum shear stress is the main controlling factor of the nanobubble generation.

Effects of nonequilibrium evaporation and condensation on expansion and contraction of a water vapor bubble under an oscillating large amplitude pressure induced by a strong ultrasound are numerically investigated based on bubble dynamics. A set of kinetic boundary conditions of interfacial nonequilibrium evaporation/condensation is taken into bubble dynamics account. The amplitude and frequency of the oscillating water pressure are set at -25MPa and 1MHz, respectively, considering the pressure in actual cavitation inception in the ultrasonic field. The comparison of the nonequilibrium case with the equilibrium one reveals nonequilibrium effects on the interfacial vapor temperature, the vapor pressure inside the bubble and the interfacial mass flux rate. The instantaneous magnitude correlation between the water pressure and a critical pressure, the latter of which is introduced as a criterion of expansion and contraction of the bubble, is found to be an important factor for expansion and contraction of the bubble. Furthermore, it is demonstrated that the interfacial mass flux rate in the case of nonequilibrium evaporation and condensation reaches a maximum value when the water vapor pressure equals to half the saturated vapor pressure.

An experimental study on the effect of Reynolds number (Re) on the flow normal to the two parallel flat plates was conducted by varying the gap ratio using the wind tunnel. For each of the Reynolds numbers velocity component were measured by using hot-wire anemometers and result were recorded. The interference of the wake on the downstream flow of two parallel flat plates were analyzed and expressed in the form of Strouhal number and pressure coefficient. Most of the cases show that the Strouhal number distribution was almost equally distributed at the range of 3000 ≤ Re ≤ 30000 except at lower Reynolds number of Re < 7000. Also, the pressure coefficient distribution slightly becomes unstable at relatively lower Reynolds number.

Easy control of turbulence intensity and scale is of basic importance for the experiments concerning effects of turbulence in a wind tunnel. Using a ‘multi-fan wind tunnel’, we devised ‘random-phase mode’, which makes use of shear layers generated between the outflows from adjacent ducts, and found that this driving mode realizes high intensity (12-16 %) and large integral scale (0.6-0.7 m). It is focused on the pressure characteristics deeply related to vortex formation and tried to clarify the dominant parameters of ‘random-phase mode’. In order to determine which parameter facilitates the turbulence control, we conducted measurements of pressure field immediately downstream of the inlet of the test section. As a result pressure drop depends on the r.m.s value u_e’ of the input velocity signal. It was confirmed that the turbulence intensity increases with u_e’.

Low head power plants are expected to be implemented increasingly in the future for economical, geographical and environmental purposes. Axial flow hydro turbines are well suited for the power plants, especially at higher flow rate, smaller head and faster rotational speed. The designs and performance improvement of the turbines are of great concern. In this paper, a runner blade of Kaplan turbine for micro-hydropower was designed and computed by using CFD tool. Computational results of the turbine runner were analyzed and evaluated in hydro-turbine characteristics such as the output, head and flow rate. It was confirmed that the higher the flow rate, the more output power can be obtained.

The low transduction efficiency is known as the disadvantage of electromagnetic acoustic transducers (EMATs) compared to standard piezoelectric ultrasonic transducers. In this research, copper coils are wired with different conditions for the purpose of increasing the amplitude of received signal while considering the lift-off effect and a lot of experiments are conducted by using copper coils with neodymium-iron-boron (NdFeB) magnets as shear vertical (SV) wave EMATs. Also, by using a resonance method, an ability to determine a surface defect are studied.