The heat transfer enhancement using the three impinging air jets crossing on heating surface was investigated. The convergent nozzles were used, and the diameter in the present study was 7.0 mm. As a result, the heat transfer was increased by using the three air jets crossing on heating surface in comparison with the single jet, especially in the range of high Reynolds number.

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By an improved transient calorimetric technique, total hemispherical emittance ε_h of glass sheets of borosilicate and fused silica has been measured. The temperature inside the glass-sheet specimen by the technique is analyzed, and it is confirmed that the effect of the temperature distribution inside the specimen on the measured ε_h is very little. Local total emittance ε_h on the specimen surface is also analytically obtained, and the effect of ε_h on the measured ε_h is examined.

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Natural convection heat transfer from a heater block in a rectangular vessel was studied experimentally and numerically A rubber heater heated up the heater block electrically. The vessel walls except bottom wall were maintained at an ambient temperature and the bottom wall was insulated. Numerical calculations took account of a combination of the natural convection and heat conduction in the heater block and vessel wall. Isotherms, streamlines, and temperature distributions at the measured lines were presented.

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In this paper, heat transfer for snow melting system was studied by numerical analysis. Temperature distribution in calculation region heated by equivalent square heating tube almost corresponded with the temperature field heated by circular heating tube. Surface heat flux for heated by equivalent square heating tube was calculated in two and three-dimensional models. Snow-melting system by road heating was examined.

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In this report, the heat conduction problems with Joule heat generation in precision electric film resistance are investigated by numerical simulation and experiment using infrared thermotracer. It is clear that a lot of heat transfer into nichrome film and a little heat flow to epoxy and alumina base.

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The turbulators have been studied as a device of the heat transfer enhancement in a tube. This paper presents the results of the heat transfer and the pressure drop in a round tube using a wire coil as the turbulator. The wire coil inserts are relatively low in cost and are easy to exchange. This paper is shown the experimental results, positional effects on the heat transfer and the pressure drop in a round tube, in the case that the diameters of the wire coils were made smaller than the inside diameter of the tube.

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We examined various technologies on the In-situ Lunar Orientation Measurement project, in hope that the project will be selected as one of next lunar exploration missions. In this project, a physical lunar libration will be measured with the accuracy of milliarcsecond using simple and light telescope on the lunar surface, a promising candidate of the telescope is Photo Zenith Tube using a mercury Pool as reflection mirror. In this study, we excuted thermal analysis of the telescope including the mercury Pool in order to check whether it is possible to keep the mercury liquid on the lunar surface.

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Experimental study was made to investigate the flame propagation within methane/air mixture with periodic concentration fluctuation in a stagnation flow. The following results were obtained: (1)Burning velocity differences between the flames propagating upstream and propagating downstream were larger than those estimated at the burner exit, meaning that the mixture concentration fluctuation in front of the flame was enlarged. (2)In some cases, giving a concentration fluctuation to the mixture outside the flammable region made the frame possible to propagate.

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The paper shows the result of fundamental experiments it applies the blended fuel of soybean oil which is producible vegetable on and kerosene to the diesel engine for the purpose of the reduction of the fossil fuel use. The mixing rate of the blended fuel was made to be soybean oil 20〜80vol%, and tried the application with them to the current diesel engine. As a basic experiment, the property of the fuel was examined in the beginning, and the ignition experiment was carried out, and in addition, the spray experiment of the spray distribution in the pressure vessel was done. As the result, it was possible to obtain the good result over the expectation with heating of the 20 and 40vol% blended fuel.

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The gas oil which is the main fuel of diesel engine is limited fossil fuel and the depletion in the future is doubted. As an alternative fuel of gas oil in addition fuel temperature injection valve opening pressure and fuel injection timing changed using the fuel in which producible soybean oil in the kerosene in which low calorific value is high mixed to 20〜80% is used and engine performance test was carried out and emission characteristic and change of thermal efficiency were examined.

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At present, it is necessary to suppress the discharge of the toxic substance (especially, NOx and black smoke) in automotive exhaust gas of diesel engine, which is one of the causes of air pollution. And, it is also important to cope with the depletion of the fossil fuel, which is the fuel of the diesel engine. So, in this study, combustion temperature was made to lower by the blending of the oxygenated fuel in gas oil, which was the fuel of diesel engine, and it was tried that the combustion of the fuel which and, it is perfect by the combustion aid action of the oxygen in the oxygenated fuel is promoted.

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The technology, which recycles heat energy in the exhaust gas reduction and the research which raises thermal efficiency of the toxic substance have been made over introduction present, diversity, and it recycles the effective heat energy of the exhaust, a heat regeneration internal combustion engine regeneration heat exchanger. Then, in order to sufficiently understand characteristics of the heat exchanger stainless steel ball free volume temperature effectiveness flow resistance characteristics.

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It has been known that the combustion chamber deposit (CCD) makes various problems on engine property. Especially, the CCD formation in the two-stroke cycle engines is more than four-stroke. In this report, we have studied about the relation between the CCD distribution and the temperature profile on the piston head in a small two-stroke cycle engine for getting the understanding CCD formation mechanism in this engine types. The temperature was measured using many fusible plugs (FP) which has different fusing point embedded on a piston crown surface.

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For the purpose due to find out indication of scuffing in a two-stroke cycle engine, cylinder temperature response was studied by numerical analyzing and experiments. As a result from the numerical model, the temperature increase of thrust and antithrust side of cylinder block were higher than that of cylinder head, when friction coefficient was increased. On an engine experiment, the same tendency about temperature behavior was observed when scuffing occurred.

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An experimental study of a plasma jet at a low pressure was carried out to examine the influence of strong magnetic field on the behavior of thermal plasma jet. The purpose of this study is to clarify the controllability of the plasma jet by the strong magnetic field and the possibility of enhancing the functions of plasma flow for the future application. The behavior of Argon plasma was observed by a digital video camera when strong magnetic field was applied to the jet by means of a pair of superconducting coils. It is shown quantitatively that the jet width decreases with increases in the applied magnetic field.

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The main objective of the present study is to clarify the effects of gas injection conditions such as gas mixing and gas injection location on the thermofluid characteristics and on the luminary areas of RF induction plasma flow. The gas temperature distibution shows the drastic variations due to the circulation by Lorentz force, the diffusion of mixed gases and complex flow patterns. On the other hand, the dissociation of N_2 or other secondary mixed gases cause the decrease in the temperature and the luminary area.

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An oscillatory motion of nonmagnetic object in magnetic fluid under the oscillating magnetic field was treated experimentally. Oscillating magnetic pressure is induced in a container of magnetic fluid with the oscillating magnetic field. This oscillating magnetic pressure causes the oscillatory motion of nonmagnetic object which is introduced into magnetic fluid. This oscillating system with a plexiglass column and a glass sphere as nonmagnetic object shows the similar characteristics to it of motion of the magnetic fluid itself under the oscillating magnetic field. The effects of some quantities such as the length and weight of column and the position of the object center against the center of the applied magnetic field on the oscillation have been clarified.

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In order to estimate the collection efficiency of the cyclone dust collector, it is necessary to consider thc radial distribution or thc mechanical equilibrium particle size X_B depended on the mean inlet velocity Vo in the inlet pipcon steady flow state. However the rotational gas flow in the cyclone dust collector is not always the stady now state but also the pulsating flow state. Thereforein this paper, the authors discussed the effect of the frequency of the pulsating rotational gas flow to the behaviour of the mechanical equilibrium solid parlicle on the steady flow state.

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An experimental investigation on the coherent structures of turbulent boundary layers at high and low Reynolds numbers is carried out. The effect of Reynolds number to the symmetry and the scale of the coherent structures is examined. The symmetry of the coherent structures is affected little by the Reynolds number, while the scale of the structures in the spanwise direction is found to decrease with the increase in the Reynolds number.

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The influence of the large-scale vortexes formed in the mixing layer of two concentric liquid jets upon initial deformation of gas-liquid interface of the outer jet was experimentally examined. The velocity ratio of the concentric liquid jets was changed, and the wavelength and amplitude of the liquid jet surface for each velocity ratio were measured. As the velocity ratio increases, the surface deformation of the liquid jet appears more upstream and its amplitude increases. However. The wavelength has a little dependency on the flow velocity ratio.

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A study of compressible turbulent Couette flow in a plane channel with isothermal wall was performed using large eddy simulation. Mach numbers, based on the wall velocity and sound speed at the wall, of 0.3 and 1.5 are considered; Reynolds number, defined in terms of the wall velocity and the channel half-width, is 1300. This paper addresses an effect of artificial viscosity both in cases with subsonic and supersonic wall-bounded turbulent flow to develop a highly resolute scheme suitable for large eddy simulation.

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In the internal combustion engine such as diesel engine, the combustion performance is strongly affected by the fuel spray characteristics. Especially, the disturbance of liquid now inside the spray nozzle due to cavitation may contribute to the disintegration of the liquid jet outside the nozzle. The objective of the present study is to investigate the effect of the nozzle dimensions (nozzle length L / nozzle diameter D) on the liquid breakup. It was confirmed that the cavitation bubbles in the nozzle passage promote the atomization of liquid jet in case that L/D is 3.

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In this study, a new condition of vortex shedding from the boundary layer of the flat plate was proposed. Vortices was directly arranged on the boundary of the flat plate and the strength of vortices were adjusted to satisfy the no-slip condition. And if the ratio of vertical componet of induced velocity at the outer boundary of the boundary layer to horizontal component cross above 0.2, then secondary vortices were shed from the boundary layer. In the case of the interaction of the primary vortex and the flat plate, the flow pattern is classified with the non-dimensionalised factor. And the interactions of the primary vortex and the secondary vortices was clarified.

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In this study, the decay of trailing vortex was discussed. The circulation by means of the turbulent vortex model was compared with the flight data. It was pointed out that in the core region the prediction is agreed well with the experimental data but in the o uter region not. The prediction with the viscous model was compared with the flight data too. But because the viscous model has only the molecular viscosity, the rapidly decay of circulation in a relatively short time scale was not predicted precisely.

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The purposeof this study is to examine the aerodynamic correlation between separation bubble on a blade and wake of stator blade. Test model used is a flat plate with the semicircular leading edge, in consideration of the generation of the separation bubble. In this experiment the position of the stationary bar, which imitates upstream stator blade, was changed. Measuring instrument was hot-wire measurement system. This investigation shows that the present method has a possibility to effectively reduce loss associated with separation bubble.

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A micro-downsized radial-flow fan (Sirocco Fan) was made for using in the local cooling of electronic devices and its performance tests were carried out on scale effects. The outer diameter of the rotor is 8mm, and the blade chord length, the blade width, and the blade thickness are about 2mm, 8mm, and 0.2mm respectively. Variable parameters to examine the scale effect are diameter ratios D_1/D_2 of the rotor inlet to the outlet(0.4〜0.75), the number of blades(8〜20), scroll angles(6°〜12°), and the number of rotor revolution(3750〜8500rpm). As a results, it was found that the optimum D_1/D_2 is about 25% smaller than that of a popular Sirocco Fan and a flow rate is considerably affected by both the blade thickness and the number of blades.

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An advanced cooling system for turbine blades is a key factor to realize supersonic transport propulsion system and utilize it practically. This study deals with heat transfer measurements inside of a cooling configuration designed for ultrahigh temperature turbine blades. The cooling configuration concerned integrates impingement cooling and pin-fin cooling devices into one body. A large scaled model employed in this study is constructed from acrylic resin materials to measure the heat transfer on the surfaces of the film cooling plate and pin-fins. The measurements are executed by a transient technique using thermochromics liquid crystal (TLC). This technique makes it possible to grasp quantitative information of the heat transfer distribution over the surfaces. A focus is on the effect of the pin height upon the local and averaged heat transfer characteristics.

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The characteristics of power output of Savonius wind turbine were examined under the condition of setting guide vanes. The configuration of tested guide vane is a flat plate and the number of guide vanes are two. When guide vanes are set in suitable positions and in good directions, the wind turbine is able to augment the power output about fifty percent at the largest compared with that without guide vane.

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An experimental and analytical investigation in cryogenic Mode II interlaminar fracture behavior and toughness of SL-E woven glass-epoxy laminates was conducted. End notched flexure (ENF) tests were performed at room temperature (R.T.), liquid nitrogen temperature (77 K) and liquid helium temperature (4 K) to evaluate the effect of temperature and geometrical variations on the Mode II interlaminar fracture toughness. The fracture surfaces were examined by scanning electron microscopy to verify the fracture mechanisms. A finite element model was used to perform the delamination crack analysis. The results of the finite element analysis are utilized to supplement the experimental data.

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It is confirmed that appreciable deflections occur in large brake disks after the braking due to having eyebrow-shaped holes as decoration when the number of braking under excess loading is more than several number. The purpose of this paper is to formulate a method of material design in order to reduce the plane-thermal stress and the centrifugal stress in a rotating disk composed of functionally graded material with an arbitrary mechanical and thermal nonhomogeneities in the radial direction and without holes, heated intermittently in the annular region near outer radius.

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Laminate that is constructed of helical cord and rubber is used inside of tire. The cord is usually used under the tensile load. However, the compressive load is applied when an automobile is driven under severe conditions such as sharp veering, stopping and starting. The compressive loading is one of the important factors for the fatigue failure in tire. In this study, the mechanical properties of the helical cord are investigated under compressive and bending conditions. A simplified mechanical model is proposed to explain the compressive and bending stiffness of helical cord and the composite material of the helical cord and rubber.

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A new porous carbon material, named RB ceramics, has been produced utilizing a natural structure of rice bran. Rice bran is one of the industrial wastes and is 0.9 million tons per year in Japan . In this study, two types of strengthening method are tried for RB ceramics . One is a carbon material that is made of fine RB ceramics particles and phenol resin (CRB). The other one is a carbon material that is made of fine RB ceramics particles, phenol resin and carbon fibers. The both materials are significantly strengthened.

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The buckling and post buckling behaviors of the short superelastic shape memory alloy (SMA) columns under repeated loading-unloading cycles are observed by experiment. It is found that for the first cycle the SMA column with slenderness ratio (L/k=28) shows two distinct modes of deformation and its failure load is higher than that of SUS304 column. Whereas, SMA column with L/k=38 shows two distinct peak loads. For each cycle, the SMA column can sustain much more deformation before failure compared to the SUS304 and Al columns. Compared to SUS304 columns, the cumulative residual strains are lower but the buckling loads are higher for the SMA columns after 2-3 cycles.

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Effect of Y_2O_3 content on high temperature strength of crack healed specimen has been investigated. Furthermore, the crystallization by the addion of Y_2O_3 under different healing conditions has been investigated. The semicircular crack (average diameter; 100μm) was made in the center of specimen using Vickers hardness indenter. Bending strength was measured from room temperature(R.T.) up to 1300℃ by 3-point bending test system. The results showed that the bending strength of Mullite/SiC composite with Y_2O_3 increased compared with that of the monolithic Mullite. This tendency was similar to the fracture toughness value. By adding Y_2O_3 the bending strength of Mullite/SiC composite increased from R.T. to 1200℃. The decrease of bending strength at 1300℃ of Mullite/SiC composite by the addition of Y_2O_3 is due to glass phase of crack healing material.

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It is said that the key parameters of the strength of graphites are the pore and grain sizes, and many researchers have been investigating on the brittle fracture of graphite. To investigate a relationship between the fracture toughness and the microstructure three kinds of graphites with different grain size distributions but having almost the same porosity were prepared, and the fracture toughness at room temperature was measured. Fracture toughness, K_<in> and K_<max>, of specimens contained with coarse grains was increased in comparison with a fine grained graphite. The K_<in> and K_<max> showed different relations with coase grain fractions. The distribution of K_<in> with coarse grains, derived from the load which seems crack growth started, was not affected by the fractions. On the other hand, the distribution of K_<max>, derived from the maximum load, were affected by the fractions.

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Plate impact experiment is conducted using a powder gun facility. Target-specimen is polycarbonate (PC) and is made of four disks which are laminated with three PVDF gauges by thin layers of adhesive. We have developed the unsteady-wave-sensing-system (UWSS) to evaluate the unsteady wave propagation characteristics of materials in the uniaxial strain state. Stress-strain curves for PC are determined by applying of the UWSS to the plate impact experiment under the loading-reloading condition. It is clarified that the Hugoniot stress-strain curve must be thought to be distinguished from characteristics including loading-history such as loading-reloading.

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In this paper, safety bursting rupture discs are good examples for the very thin plates of metallic materials. Test specimen was made from actual bursting rupture discs. Experiments were conducted with specimen by six materials (aluminum, copper, nickel, monel, inconel, stainless steel). In these results, fatigue life and relations the burst pressure or excess cyclic pressure on the number of cyclic pressure were examined experimentally.

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In order to examine the impact behavior of mercury that is one of the important elements with a high intensity neutron spallation facility, the falling and colliding profiles of a mercury droplet were recorded by an image converter camera. The impact force was also measured using an input bar with strain gages. The profile change of the mercury droplet from the longitudinal ellipsoid to the transverse one was observed during the falling. The impact force of mercury was in proportion to the impact velocities and the square root of the potential energies as a sphere of metal. The difference between the impact duration times that were recorded by the camera and measured by the strain gages was three orders of magnitude.

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The torsional rigidity of spot-welded box section beams in the automobile body structure has been investigated. To analyze it, the warping torsion theory of spot-welded beams was used and adapted to the box beam composed of two open section beams with different thickness sheets. The torsional rigidity of box beams with different thickness was compared with one of beam with same thickness. And then the new approximate formula for local warping of spot-welded parts was deduced.

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A practically suitable and sensitive technique for quantitative nondestructive evaluation of small cracks is presented here. The technique is based on a back wall echo of the shear wave propagating in the solid containing the cracks. In contrast to the normal and angular incidence of longitudinal wave, the effect of the oblique shear wave on the ultrasonic response due to a crack is investigated. The testing is performed to predict an optimum angle of evaluation which provides the superiority of the method compared to the well-known usual techniques.

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Photoacoustic(PA) imaging of the simulated subsurface defect has been demonstrated. Subsurface defect is fabricated accurately on aluminum plate with end mill. The defect depth range from 0.8 to 1.2mm with an increment of 0.2mm. The diameter of the defect is 1.0, 2.0 and 3.0mm. The PA images processed by a computer for subsurface defect were shown with color graphics. The PA image obtained clearly showed the location and the size of the subsurface defect. The photoacoustic method is useful for detection of the subsurface defect.

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This paper describes the novel technique for evaluating the mechanical properties of ion-implanted surface layer. Some constants (Young modulus(E), yield stress (σ_y), work hardening coefficient (A) and work hardening exponent (n)) in the constitutive equation assumed as the power law curve were determined by the indentation test with indenters having different tip angles. The technique is combined with a finite element method. The indentation test with a spherical indeter and its simulation analyses were performed to examine accuracy of the constitutive equation determined by the technique. Furthermore, the influences of shape of indenter on the evaluation of mechanical properties and thickness of ion-implanted surface layer were discussed.

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