This paper presents a parallel LES technique for viscous incompressible flow based on the finite-element method using tetrahedral elements. A new algorithm based on the SIMPLER method is proposed, in which the BTD technique is inrtoduced to ensure the stability of computation and the Crank-Nicholson method is used as a time integration scheme to improve the accuracy. The Smagorinsky model is applied to approximate the Reynolds stress term. Two types of parallelization techniques are applied in the present scheme. One is mesh partitioning by the finite elements to carry out the element-based calculations. The other is row-based domain decomposition of the global matrix to solve the linear equations. Estimates of parallel computing performance show good scalability on the Hitachi SR 2201. The code was verified by simulating the turbulent wake of a circular cylinder at Re=10, 000 and was applied to predict the pressure-loss of the airflow for the cooling of a turbine generator. Numerical results show good agreement with the experimental results and the computational results using the hexahedral finite-elements.

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A three-dimensional Navier-Stokes code with a standard κ-ε two-equation turbulence model in boundary-fitted coordinate system has been developed for a screw-type centrifugal pump. The approach of logarithmic wall function is employed to treat near-wall regions. The interaction between the impeller and the volute casing is remamkable in this pump type. In the present study, to catch up the interaction effect between the two flow fields, we have calculated the flow fields in a volute casing as well as in an impeller simultaneously by exchanging the calculated data between them at every iteration step. Two kinds of data exchange methods as the boundary condition in grids overlapped between impeller and volute casing are discussed. The simulation results show that only the calculation considering the effect of the volute casing can be predicted reasonably well. The measured pressure distributions and visualizes flow patterns are also compared.

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This paper deals with viscoelastic flows due to a rotating disc enclosed in a cylindrical casing with variable axial clearances. The characterization for the behaviour of viscoelastic flows due to a rotating disc has been obtained by an experimental study using flow visualization technique and the numerical simulation using several models for constitutive equations. The patterns of secondary flow for the region of competition between the elastic force and the inertial force are a radially arranged double-cell structure (Type DC 1) for small aspect ratio H/R and an axially arranged double-cell structure (Type DC 2) for large H/R.Increasing Re₀, the Type DC 2 becomes a radially arranged double-cell structure (Type DC 1^′) which is different from the Type DC 1. The Type DC 2 was reproduced qualitatively by numerical simulation with Giesekus model and PTT model, but were not reproduced by numerical simulation with upper convected Maxwell model and power-law model. Furthermore, the profiles of tangential velocity component V_θ and radial velocity component V_r obtained by the numerical simulation with Giesekus model and PTT model for small H/R were in agreement with those measured by using particle tracking velocimetry (PTV).

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Flow of viscoelastic fluid is commonly analyzed by using constitutive equations. In this paper, bead-spring-damper macro model is proposed as an alternative to analyze viscoelastic flow. The tetrahedral structure of beads, springs and dampers models a gathering of interwined polymer chains. Behavior of the bead-spring-damper structure is computed under start-up flow, stop flow and oscillatory flow conditions. Stress overshoot, stress relaxation, dynamic viscosity and dynamic modulus are investigated. The results show that the effect of elasticity appears strongly in the unsteady flow, and that the bead-spring-damper macro model can express characteristics of viscoelastic fluid consistently.

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The present study is conducted to provide various fundamental data for torch and reactor designs, furthermore optimum operating conditions of plasma particle processing. A plasma jet is described by an Eulerian approach and each injected particle is described by a Lagrangian approach respectively, taking into account the compressibility, variable transport properties and plasma particle interactions coupled with Maxwell's equations. The effects of an applied radio-frequency electromagnetic field, nozzle angles, particle sizes, operating pressures, particle injection velocities and the injection locations on particle characteristics are clarified by numerical simulation as a parametric study. It is concluded that the particle trajectory and the particle velocity are influenced effectively by operating pressures and nozzle angles. Furthermore, the particle temperature can be controlled strongly by applying a radio-frequency electromagnetic field to the nozzle.

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The authors propose a novel numerical method to study dynamic behaviour of free surfaces. This method, which is based on a discrete singularity method with a Green function for the Laplace equation as a singularity, enables us to simulate three-dimensional complex-boundary problems more easily and efficiently. In the present research, to confirm the effectivity of this method and to estimate errors, the authors computed free-liquid sloshing with various modes in a cylindrical container which was forced to oscillate vertically. Results were compared with theoretical values and showed good agreement. Besides, both a finite-amplitude and surface-tension effects were taken into account.

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With an aim of suppressing the rotating cavitation by cutting back the leading edge alternately, 4-bladed inducers with uneven blade length were designed. Unsteady cavitations were observed through inlet pressure measurements and high-speed video pictures, covering a wide range of flow rate and cavitation number. It was found that, with the alternate cutting back of leading edge, the range of alternate blade cavitation was extended, and the region of rotating cavitation was diminished. However, the cavitation surge occurred instead of the rotating cavitation. In addition, two types of alternate blade cavitation were found as predicted theoretically. One of them is with longer cavities on longer blades, and the other is with longer cavities on shorter blades. Hysteresis in the alternate blade cavitation pattern was observed depending on the increase or decrease of cavitation number at low flow rate.

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With an aim of suppressing the rotating cavitation by cutting back the leading edge alternately, 4-bladed inducers with uneven blade length were designed. Effects of the uneven blade length on unsteady cavitation were examined. It was observed that the range of the alternate blade cavitation and asymmetric cavitation were extended by increasing the amount of alternate cutting back. As the result, on 4-bladed inducer with strong uneven blade length, the rotating cavitation and cavitation surge were almost suppressed for a wide range of flow rate and cavitation number, while the suction performance was deteriorated. However, we should note that the asymmetric cavitation that occurs more easily in uneven blade inducer may cause the synchronous shaft vibration, and unevenness causes the blade stress uneven.

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For a single blade with a tip clearance, tip leakage cavitations were observed experimentally for various cavitation numbers and angles of attack. In addition, to simulate the tip leakage vortex cavitation, a simple calculation of 2-D unsteady flow based on the slender body approximation was conducted with taking into account the effects of cavity growth. It was found that the calculation results showed qualitative agreement with experimental results for the cavity trajectory and radius of the tip leakage vortex cavitation. The effects of the angle of attack, cavitation number, blade loading, and tip clearance were simulated fairly well. Present calculation is expected to estimate the unsteady characteristics of the tip leakage vortex cavitation, which contributes substantially to the cavitation instability, such as the cavitation surge and rotating cavitation.

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Mechanism of self-excited shock oscillation in two-dimensional transonic diffuser flow is investigated experimentally. The diffuser used in this work is composed of the flat top wall and the curved bottom wall. Time-sequence of shock location is recorded by the high speed CCD camera combined with schlieren system, together with simultaneous measurements of static pressure fluctuations along the top wall. The pressure fluctuations at many locations on the side wall are also measured simultaneously. As a result, it is found that disturbances which induce shock oscillation are propagating upstream from downstream portion of the shock wave where the boundary layer behaves unsteadily and the most violently. Furthermore, vortices generated by the shock oscillation are observed to be convected downstream. The shock oscillation is explained to be sustained by the upstream-propagating disturbances and the downstream-convected vortices.

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Concerning the self-excited shock oscillation in a transonic diffuser flow, the response of a normal shock wave to a "white" pressure disturbance, that is, a small pressure disturbance having the same power spectral density over every frequency, is analyzed by solving the equation representing shock displacement due to the disturbance. According to the present analysis, the spectral density distribution and peak frequency of the shock oscillation depend on Mach number just upstream of the shock wave and a non-dimensional parameter determined from the diffuser geometry at the time-mean shock location. The shock displacement power spectral density distributions obtained by the analysis agree very well with those measured in our experiment. A non-dimensional relationship between the peak frequency of the shock oscillation and diffuser geometry at the shock location, Eq. (18), is obtained, and this equation agrees well with the present and previous experimental results.

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The equilibrium composition and spectral absorption coefficient of SiC ablation layer plasmas have been calculated for temperature of 5000 to 7000 K, layer thickness of 0 to 7.5mm, and pressure of 0.1 to 1.0 MPa. The radiations included were molecular bands, atomic lines, and continuum processes. The absorption coefficient thus calculated was applied to a simplified model of the ablation layer for Jupiter entry probe. It was found that the molecular carbon bands were very effective in reducing the high-temperature radiative flux from a stagnation shock layer at low ablation-layer temperature, and the photoionization process in atomic elements (carbon, silicon) at high ablation-layer temperature.

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Particle-in-cell simulation is carried out for the expansion of a multi-charged dense plasma for X-ray laser systems. All Coulomb collisions among charged particles are taken into consideration. The rapid cooling of the multi-charged plasma, which is essential for X-ray lasing, is accomplished when this plasma is surrounded by a cold ambient plasma. The mechanism of this cooling is clarified by the simulation. The expansion spreads, accompanying with the expanding dense wave front. Existence of a double layer of electric charge at the wave front is confirmed.

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An experimental investigation of fluid flows in a model of gas-turbine rotor disk rim seal has been carried out. The effects of outward throughflow and rotor speed were examined on the distributions of static pressure as well as velocity inside the rim seal when a mainstream was made nonaxisymmetric by stationary vanes. Measurements were made at the mainflow axial Reynolds number of 8.0×10⁴. As a radially outward flow is forced to be generated on the rotor by centrifugal force, a radially inward flow due to a mainstream ingestion is originated on the stator of the rim seal when the throughflow rate is decreased beyond the critical value. Once the ingestion occurs locally, the static pressure is increased remarkably just behind the stationary vanes resulting in the circumferentially non-uniform distribution. But the ingestion is suppressed with the increasing throughflow rate and the static pressure distribution tends to be uniform. The critical throughflow rate was found to be about 0.8 times of the outward flow rate caused by a free disk.

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A measuremnt technique of thermodynamic variables with high sensitivity is strongly demanded for analyses of highly rarefied gas flows, gas-surface interaction, and so on. REMPI (Resonantly Enhanced Multiphoton Ionization) is a powerful optical tool because of its high sensitivity even in highly rarefied gas flows and ability to measure nonequilibrium among internal (translational, vibrational, and rotational) energy. In this paper, the MEMPI system is constructed and the REMPI spectra are measured at the center line of a free molecular flow. The fundamental properties of REMPI signal are also described. A method of Boltzmann plot using the spectral lines of different branches is proposed, determining electronic transition dipole moments in Honl-London factors.

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Viscosity of magnetic fluid changes when an interaction angle between magnetic field and flow vorticity changes. The test shows that viscosity becomes maximum when they cross perpendicularly and becomes minimum when they are parallel. These phenomena were studied theoretically by M. I. Shliomis and W. F. Hall. This paper describes an analysis of the relation between viscosity and the interaction angle from test results and the comparison between that and the theory.

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Flow measurements were made at the mid-passage of a shrouded centrifugal impeller, by using a hot-wire anemometer rotated with the same speed as that of the impeller. The measurements were made for a flow rate corresponding to nearly zero incidence angle and two other flows with reduced and increased flow rates. The measurements show that, as the flow rate is reduced, the regions of a low velocity and a dissipation enlarge from the shroud-side to the hub-side near the suction surface and the values of Reynolds normal stresses tend to decrease. The Reynolds shear stressess qualitatively follow the eddy viscosity concept. However, the values of the shear stressess, that can not discuss by only this concept, also appear in the regions influenced by the secondary flow toward suction surface. Near the suction surface, the effects of the flow rate on the shear stresses are remarkable in the cross-component between the passagewise and blade-spanwise directions, but are little in two other cross-components.

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A numerical analysis has been performed for fully developed turbulent flow and heat transfer in a rectangular duct with smooth and rough walls by using algebraic Reynolds stress and turbulent heat flux models. The wall functions and the universal law of the wall, which are used as the boundary conditions of turbulent energy and dissipation, apply in the present analysis instead of taking shape of roughness element into account. Therefore, the roughness enters through the log law relating the velocity at the first grid point away from the wall with the friction velocity. In this numerical analysis, two kinds of turbulent heat flux models, i. e. Lumley-Launder model and Jones-Musonge model, are examined to compare the contour distributions of turbulent heat fluxes in three dimensions which have been measured in detail. In numerical analysis, convection and diffusion terms for the transport equation of turbulent heat flux are modelled as an algebraic turbulent heat flux model. From the comparison calculated results with the experimental data, it is found that two models can predict the mean temparature distributions which are distorted near the smooth wall located opposite to rough wall side. On top of that, Lumley-Launder model is able to better realize mean temperature near smooth and rough walls than Jones-Musonge model. As for comparison of the turbulent heat flux, calculated results suggest that two models predict characteristic features while two models have tendency to overestimate the experimental values.

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Heat transfer in a rib-roughened duct was numerically simulated by using the second order finite difference method in coordinates fitted to transverse or angled ribs. Turbulent and laminar cases of which Reynolds number was 350 and 50, respectively, were computed for rib angles of 60 deg and 90 deg. For the turbulent case, the large eddy simulation was adopted with a Lagrangian dynamic subgrid-scale model. The present turbulent results clearly showed the locally high heat transfer coefficient at following locations : midpoint between ribs, in front of the rib on the rib-roughened walls, and around the rib on the side walls. The comparison between the laminar and turbulent results showed clear differences in heat transfer distribution because the higher momentum fluid of the turbulent case was more disturbed by the ribs as compared to the laminar case.

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Low Reynolds number forced convection heat transfer of air flow through micro-scale meshes was investigated experimentally using a resistance-thermometry method. Two test meshes with wire diameter 25 μm and 35 μm were employed. The test meshes were placed in a vacuum chamber in order to examine the effect of Knudsen number, Kn, as well as Reynolds number, Re, on Nusselt number, Nu. The range of Re was from 0.02 to 5, and Kn was varied independently of Re up to 0.02. The results indicated that Nu dependence on Re is quite different from that in conventional Re range (Re>1) : Nu increased in proportion to the nth power of Re, where the value of n was higher than unity at first but it decreased gradually with an increase in Re, reaching asymptotically the conventional value of 0.5 of laminar forced convection. It was also confirmed that no substantial effect of Knudsen number appeared as far as the value of Kn was less than 0.02.

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Coherent structures near the wall (y⁺<60)in a turbulent channel flow were educed by a conditional sampling technique from the DNS data for two kinds of temperature fields : (a) the uniform heat flux assigned on the two walls (UHF) and (b) the constant spanwise mean temperature gradient imposed on the working fluid (STG). Attention was paid for roles of the quasi-streamwise vortex in heat transfer mechanisms. Flow and temperature fields around the quasi-streamwise vortex have basically two-dimensional structure. In the case of UHF, temperature fluctuation is high at right-and left-sides of the vortex core where the rotating flow motion due to the vortex has a wallnormal component. In STG, large value of the temperature fluctuation was observed at the top-and bottom-sides of the vortical structure where flow in the spanwise direction is conspicuous. In both cases, gradients of the time-mean temperature and the temperature fluctuation in the same direction have opposite signs since excessive temperature is transported by the vortical flow motion in the azimuthal direction with respect to the vortex axis. Therefore, temperature distribution for UHF and that for STG have azimuthally phase difference of about 90 degree, and they are almost similar in shape. Destruction (correlation between pressure and temperature gradient) of wall-normal turbulent heat flux and that of spanwise component are based on similar mechanisms. They are caused by the rotating motion of the vortex by which, near the center axis of the vortex, pressure fluctuation takes negative value and the gradient of temperature fluctuation becomes inverted for that of the mean temperature.

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We have studied the enhancement of heat transfer by vortex generators. Experimental test was done on rectangular-type vortex generators which were mounted on a parallel-plate heater. Heat transfer coefficient of the heater surface and the pressure drop in the duct were measured. These measurements indicated that a rectangular-vortex generator (called double-inclined winglet) with the inclination angle of the vortex generator surface to the heater surface (β) at 60 degrees and the attack angle to the flow direction (γ) at 45 degrees maximizes local Nusselt number of the heater surface. It was also found that the double-inclined winglet has an optimal arrangement in the winglet array, longitudinal pitch and transverse pitch, that maximizes the ratio [Colburn's heat transfer modulus j_H]/ [friction factor f]. Numerical calculation result showed that the double-inclined winglet was superior to the conventional rectangular vortex generator in heat transfer.

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A numerical experiment has been conducted to determine the interfacial convective heat transfer coefficient in the two-energy equation model of porous media, which is needed when the assumption of the local thermal equilibrium between the fluid and solid phases is not valid. The similarity of the fully developed temperature profile allows one to perform a numerical experiment using only a single structural unit, for determining the fully-developed heat transfer coefficient without any empiricism. A universal correlation for the Nusselt number, which agrees very well with the experimental data, has been established using the results obtained for a wide range of porosity, Prandtl and Reynolds numbers.

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Critical heat flux (CHF) has been measured on rectangular heated surfaces 40 and 80 mm in length and 20 mm in width during saturated forced boiling with a plane jet. The experiments were carried out at jet velocities of 3 to 15 m/s and system pressures of 0.1 to 0.4 MPa. The experimental result shows that there is no difference in occurrence of the CHF between upward-and downwardfacing heated surfaces. It is found that no existing correlation can predict the CHF over a wide range of p_l/p_g from p_l/p_g=6.6 to 1 603. A revised correlation is proposed to give the CHF over the range of p_l/p_g.

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This paper presents the heat transfer performance of a Flexible Looped Heat Pipe (FLHP) using R 134 a as a working fluid. In our evaluation system, an evaporator and a condenser are connected by long flexible tubes with diameter of 3 mm, and the total piping length of this loop heat pipe system is approximately 7500 mm. We selected porous teflon with effective pore diameter of 2γ_cw=1.2μm to overcome high gravitational heads. Elevation of the evaporator above the condenser (△H=He-Hc) were changed in 3 conditions ((1) Top heat mode (△H=+1m), (2)Horizontal mode (△H=0), (3)Bottom heat mode ((△H=-1m) considering the terrestrial application and the influence of gravity on the FLHP performance was investigated. FLHP provided high thermal transport capacities over long distances through small cross-sectional flexible tubes comparing with conventional heat pipes.

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We have developed a new compact boiling refrigerant type panel cooler. It is a kind of closed two-phase loop thermosyphon constructed with heat exchanger cores for automobile air conditioning system. We confirmed higher performance of the natural refrigerant circulation type and tried to optimize the size of the refrigerant path in the boiling core by observing the internal refrigerant flow and successfully achieved much higher cooling performance.

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Turbulent transition mechanisms and local heat transfer characteristics of the natural convective flows over upward-facing, inclined plates were investigated experimentally. The experiments were performed in the range of modified local Rayleigh numbers from 10⁴ to 8×10¹4 and of inclination angles θ from 0 to 90°. The flow fields over the plate and the surface temperatures of the plate were visualized with dye and liquid crystal thermometry. The results showed that longitudinal vortices play a main role on the turbulent transition over the plates of θ<72°. These vortices appear first in the laminar boundary layer, then, detach from the plate and, finally, become distorted. It is found that the heat transfer is enhanced markedly by the detachment and the distortion of these vortices. The local heat transfer coefficients were measured in the laminar, transitional, and turbulent regions. The results show that the coefficients, in particular, in the turbulent region become identical and independent of inclination angles.

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This paper describes quantitative 3-D measurement method for flow field of a rotating Rayleigh-Benard convection in a cylindrical cell heated below and cooled above. A correlation method for 2-D measurement is well advanced to a spatio-temporal correlation method. Erroneous vectors, often appeared in the correlation method, is successfully removed using Hopfield network. As a result, calculated 3-D velocity vector distribution well corresponds to the temperature distribution.

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This paper is concerned with the double diffusive convention due to the melting of a horizontal ice plate into a calcium chloride aqueous solution inside a square cavity. It appears a mass diffusion layer adjacent to the melting front in which the low density melt water accumulates. On the other hand, a three-dimensional natural convection appears under the mass diffusion layer, which becomes gradually weak during the melting process. The melting front temperature suddenly decreases just after the melting starts, however, the temperature gently decreases during the melting process. The present three-dimensional numerical results predicts well the transient temperature decrease in the ice plate and at the liquid bottom, the mean melting mass and the mean melting Nusselt number.

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To elucidate an effect of fixed separation points on the wake oscillation and surface character in the suppression of the Karman vortex street due to positive buoyancy, a wake with positive buoyancy from a heated elliptic cylinder submerged in an upward air mainstream is calculated by numerical analysis. Numerical results agree well with the previous result for the isothermal wake, and show that separation points are exactly fixed with time and do not move by buoyancy. The critical Richardson number Ri_c is much larger than that in a circular cylinder wake. This means that the wake vorticity is larger and harder to disappear than that in the circular cylinder wake. With an increase of the Richardson number, the local Nusselt number and wall shear stress vary with time between separation points, and the mean Nusselt number decreases near Ri_c, which dose not occur in a circular cylinder wake.

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This paper has dealt with the heat storage characteristics of fine microcapsules packed with latent heat storage material in the water layer. The heat storage operation to the latent microcapsules was carried out using hot air bubbles by direct contact heat exchange. The microcapsule consists of n-paraffin as a core latent-heat storage material and melamine resin as a coating substance. The relation of the completion time of latent-heat storage to some parameters was examined experimentally. The non-dimensional correlation equations for the completion time of latent-heat storage process had were derived in terms of the ratio of water layer height to diameter of microcapsule, Reynolds number for air flow, Stefan number and modified Stefan number for absolute humidity of flowing air.

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The two-phase flow nozzle is very important equipment in the total-flow system applied to the geothermal and the waste heat recovery power plants. As the flow in this nozzle is high-speed mist flow, we need to know the compressible fluid dynamical characteristics of the flow. In this paper, high-speed two-phase flow in one-dimensional convergent-divergent nozzle is basically researched by the theoretical consideration where the phase change is ignored. It is shown that although the Mach number is less than unity, the flow rate scarcely change by the back pressure of nozzle and the shock waves appear in the divergent section of the nozzle. These shock waves occurred in subsonic flow by the relaxation phenomenon are classified into two types. One is the disperse shock wave which appears in near equilibrium two-phase mist flow. The other is shock waves like pseudo-shock wave in near frozen flow.

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Cooling performance of an aluminum electrolytic capacitor, whose element is pressed on the inner bottom surface of the capacitor housing in order to decrease thermal contact resistance between the element and the housing, was improved. It was found that a thermally conductive elastomer decreases this contact resistance. The elastomer with the thickness ranging from 0.5 to 1.5 mm was inserted between the bottom surface of the capacitor element and the plain metal surface. Experimental measurements show that the contact resistance with the 0.5 mm-thickness elastomer is smaller than that without an elastomer. A simple analysis was also developed for predicting the thermal contact resistance with different elastomer thicknesses, and these predicted resistances agree reasonably well with the experimental measurements.

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The characteristics of a plate burner and a heat exchanger are experimentally investigated in this paper. The present burner consists of a stack of ceramic filaments catalyzed with Pd, which is featured by low concentrations of NO_x and CO. Furthermore, the burner surface emits light and thermal radiation in a high activity region of catalyst. Therefore, the thermal efficiency, that is, heat input to the heat exchanger with regard to combustion load, is expected to increase. In this study the combustion characteristics of this burner and the efficiency of the heat exchanger have been examined to see the efficiency of the system. Two major results were obtained; one is that the thermal efficiency has been improved by about 5%, and the other is that unburned combustion gas after the heat exchanger was reduced because combustion starts on the burner surface. Thus it is confirmed that the catalytic burner is useful for energy saving and downsizing of a combustor.

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The comparison between the single and the twin probes methods was achieved to measure ion current in propane-air premixed combustion flame. When using the single probe method, it was inevitable that there was much error in the measure of combustion flame, since leak current conducted to an insulation tube which an electrostatic wire passed through. Noise in the measuring circuit also exerted serious influence because of the feeble ion current. To prevent such effect, this study proposes the twin probes method, using two measuring probes which had some different protrusion lengths each other. And this method gave its simpler usage without the above problems. It was also found that the maximum ion current at half height of each flame was appropriate for evaluating the total condition of combustion flame.

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An experimental study has been carried out to obtain the detailed information needed for the deep understanding of the combustion process of an emulsified fuel droplet under microgravity. The experiments were conducted by using the drop shaft of JAMIC (Japan Microgravity Center) at Hokkaido. Photographic observation and temperature measurement were made of the emulsified fuel droplet burning in quiescent gaseous environment at the atmospheric pressure. The primary attention was toward the transport processes in the liquid phase and the time histories of liquid temperature and the amount of water in the liquid phase during the period of time prior to the microexplosion. The results showed that the agglomeration and separation of the water and the base fuel layers occurred with the lapse of time. The increase in the temperature of the emulsified fuel resulted in the formation of a single water droplet enveloped by a shell of base fuel prior to the microexplosion. After the phase separation, selective evaporation of the base fuel would occur and the volume of base fuel decreased while the water volume did not change. The effects of the water volume on the onset rate of microexplosion were also revealed.

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Functionally graded materials (FGM) chamber with perfect PSZ/NiCr FGM cross-sectional profile was evaluated in the high altitude envirement to obtain the engine real performance and also to identify the safty combustion from obtained chamber thermal data. After the performance acquisition test, the fabricated FGM chamber was cyclically tested in the sea level environment to study the effect of FGM coating on thrust chamber life. The thrust chamber used in this test series was employed the reversed process of composing perfect FGM profile to provide an improved ceramic-metal bond between the sprayed FGM layer and electro-formed FGM layer. A total of 50 firing tests including the long durability test were performed. The high performance of the engine was verified in the high altitude performance test. At cylindrical section of the chamber, the thermal barrier coating composed of pure PSZ layer remained intact.

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The relationship between temperature and entropy, and its T-S diagram are presented for a displacer-type Stirling engine operating on a closed reversible cycle. A practical engine has spaces of high and low temperatures, so the temperature and entropy of the working gas are not uniform throughout the engine. In this study the relationship between pressure and volume of working space is obtained using the Schmidt cycle model. Next, the mean temperature of working gas is obtained by integrating the temperatures of high and low temperature spaces. The mean entropy is calculated in the same method as for the mean temperature estimation, using the pressure obtained from the Schmidt cycle model. The validity of the method is confirmed by the agreement of the works on P-V and T-S diagrams. The heat storage in the regenerator is then correlated with the thermal efficiency.

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Detailed composition of exhaust emission from various gaseous fuels and gasoline was obtained including unregulated species by using an FTIR analyser, and dependency of the composition mainly on equivalence ratio was compared paying emphasis on relation between NO_x and unburned species. The results show that NO emission is increased when liquified petroleum gas and propane were used compared with the other gaseous fuels, and that NO₂ concentration becomes comparable with NO when the charge mixture comes close to its lean limit. Trends of NO_x and unburned hydrocarbon emissions are quantitatively similar for the gas fuels and gasoline, however, there are some differences on constituents in the unburned species.

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Reduction of exhaust gas emissions and CO₂ from gasoline engine vehicles which dominate the automotive market are important to solve problems of the air pollution in major cities and the global warming. Attempts are made to investigate the maximum potential of the gasoline engine for reduction of bothitems focusing on the technology of variable valve timing (VTEC) engine with three way catalyst system. 8% improvement of fuel economy by the application of VTEC to the small displacement (1.21) and high speed engine compared with the same performance vehicle with 2.01 engine. For another application of VTEC, high-swirl combustion by inlet-one-valve-deactivated mechanism of VTEC at low engine speed can reduces HC during cold start and contributes to achieves ULEV standard. The fuel economy of this ULEV improved 4% compared with LEV equipped with the conventional engine. And the performance of VTEC engine for ULEV increased 11kW (15Ps) and 9.8 Nm (1 kgm) compared with the conventional engine.

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