JSME International Journal Series B Fluids and Thermal Engineering
Online ISSN : 1347-5371
Print ISSN : 1340-8054
ISSN-L : 1340-8054
Volume 36 , Issue 4
Showing 1-28 articles out of 28 articles from the selected issue
  • Kei Miyazaki, Mohamed Shemy Ahmed, Risaburo Oba
    1993 Volume 36 Issue 4 Pages 511-516
    Published: November 15, 1993
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    In this paper, the term "hard erosion" refers to erosion which is faster than ordinary erosion by a factor of two or more. Here, we carefully observe cavitation aspects of several types and the corresponding eroded surfaces in typically accelerating vibratory erosion tests on a typical erosion-resistant material of 304 stainless steel by means of high-speed and SEM photography, under a specified condition of uniform cavitation nuclei size distributions. Hard erosion clearly results from very high shock pressures accompanied not by microjet bubbles or bubble clusters, but by collapsing massive bubbles. The massive bubbles very rapidly develop within the low-pressure region where the Hooper vortex is predominant around the test specimen, and then collapse, resulting in marked shock waves by which almost all of the tiny bubbles are destroyed.
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  • Mohamed Shemy Ahmed, Kazuo Hokkirigawa, Kinya Kikuchi, Jiro Higuchi, R ...
    1993 Volume 36 Issue 4 Pages 517-523
    Published: November 15, 1993
    Released: February 18, 2008
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    Scanning electron microscopic investigations of particles produced by cavitation erosion and fracture surfaces for 304 stainless steel, revealed that the dominant mode of cavitation erosion is fatigue failure. In addition, the surface roughness facilitates the separation of particles, especially the longitudinal ones. The gathered particles can be classified into three types according to their shapes, namely the longitudinal, the triangular and the mixed quadrangle hexagon. The spherical particles, which were reported in a previous study on cavitation erosion, are not observed in this work.
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  • Hitoshi Soyama, Tsutomu Narasaka, Risaburo Oba, Ryoichiro Oshima, Johs ...
    1993 Volume 36 Issue 4 Pages 524-531
    Published: November 15, 1993
    Released: February 18, 2008
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    As a first step to finding thin, low-drag foils in cascades applicable to Kaplan turbines of high specific speed, we systematically investigate the subcavitation performance and the cavitation aspects, especially those of the leading-edge separation bubble related to the drag, for two foils whose shapes are very similar, except for two percent of the total area near the leading edge contained by a chord, with somewhat modified edges, for various cavitation numbers and incidences. A marked change in drag results from a very small modification in the edge, and it is closely related to the stochastical appearance of the leading-edge separation bubble visualized through the attached cavitation.
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  • Ken-Ichi Funazaki, Toshikatsu Meguro, Shigemichi Yamawaki
    1993 Volume 36 Issue 4 Pages 532-539
    Published: November 15, 1993
    Released: February 18, 2008
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    Detailed studies are conducted to investigate the effects of the incident wakes generated by rotating circular cylinders on the characteristics of the transitional boundary layer developing on a flat plate. In this report, the primary concern is to measure the time-averaged heat transfer distribution along the flat plate under several conditions of wake characteristics and cylinder speeds. The obtained data are then utilized in the development of a simple but accurate model for an intermittency factor of the transitional boundary layer subjected to the incoming wakes. Two transition models, the Mayle-Dullenkopf model and a geometrical intermittency factor model, i. e., a modified Pfeil model, are employed for comparison with the measured heat transfer data, and it is found that the latter model, which only considers evolution of the turbulent spot in the space-time domain, yields a better prediction.
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  • Kazuyasu Matsuo, Heuy-Dong Kim
    1993 Volume 36 Issue 4 Pages 540-552
    Published: November 15, 1993
    Released: February 18, 2008
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    When interaction between a normal shock wave and a turbulent boundary layer occurs on the curved surfaces of transonic or supersonic airfoils, the static pressure in the vicinity of the boundary layer edge immediately downstream of the shock wave decreases along the stream lines. This phenomenon, the so-called post-shock expansion, has been studied by many researchers since it has a significant effect on the airfoil performance. Normal shock/turbulent boundary layer interaction may also be found in such confined flows as supersonic inlets or diffusers. The present study describes an experimental investigation of the post-shock expansion in supersonic diffuser flows. The Mach number immediately upstream of the shock wave is varied from 1.10 to 1.85 and the Reynolds number, based upon the boundary layer thickness of the approaching flows, is 1.3-2.5 x 104. Measurement methods include schlieren optical observations, surface oil tracers, static pressures, and pitot pressures in the boundary layer. The effect of the approaching flow Mach number on the post-shock expansion phenomenon is presented.
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  • M.A.I. El-Shaarawi, M.E. El-Refaie, M.M. Kemry, S.A. El-Bedeawi
    1993 Volume 36 Issue 4 Pages 553-559
    Published: November 15, 1993
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    A non-iterative finite-difference scheme has been developed to solve the boundary layer equations governing the laminar flow engendered by the rotation of a sphere about its diameter in a stagnant fluid. Advantages of the developed numerical scheme are simplicity, low required computer core storage, and less computational time. No points of zero meridional velocity gradient normal to the wall (separation points) could be detected in the domain of solution (from the pole to the equator). The obtained numerical results for the meridional, azimuthal and radial velocity components and for the torque are presented and compared with the results of other investigators.
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  • Ichiro Sakamoto, Fumio Higashino, Rolf Holl
    1993 Volume 36 Issue 4 Pages 560-566
    Published: November 15, 1993
    Released: February 18, 2008
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    In the present work, a numerical scheme for the unsteady motion of shock waves in gases is developed based on Whitham's theory of geometrical shock dynamics (GSD) . To investigate the effect of the initial shock strength on the shock reflection and diffraction on a wall, the two-dimensional focusing of cylindrical blast waves reflected from a concave elliptic wall is analyzed under various initial conditions. The results are compared with finite difference simulations based on the piecewise linear method (PLM) as well as with previous experimental results. It is found that geometrical shock dynamics is a practical and economical method to analyze the shock focusing process of the blast waves produced by exploding wires. Pressure changes along the major axis of the ellipse show good agreement when the present computations are compared with experimental results as well as with PLM simulations.
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  • Yoshimi Nishihara
    1993 Volume 36 Issue 4 Pages 567-576
    Published: November 15, 1993
    Released: February 18, 2008
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    Using the lumped-parameter Greitzer model, most compressor surging behavior (for classic or deep surge) can be estimated. However, this model is too simple, since, in general, the rotor flow passage length is longer for high-pressure compressors than that for low-pressure ones, and modern high-pressure compressors have a strong axial pressure gradient distribution in the flow passage. Dealing with the above, this paper aims to suggest a multielement model to which a Greitzer model is applied for each element, and explain relationships between the surging behavior and compressor flow field time constant, by comparing the results from the Greitzer model and the experiments of the aircraft gas turbine with a relatively high-pressure compressor.
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  • Makoto Oki, Toshifumi Iwasawa, Masumitsu Suehiro, Tomomi Umeda, Yasuki ...
    1993 Volume 36 Issue 4 Pages 577-583
    Published: November 15, 1993
    Released: February 18, 2008
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    Backward-facing step flow, which has many applications in engineering, was calculated by directly solving the Navier-Stokes equation, using the third-order accurate upwind finite-difference scheme. First of all, the influence of mesh size on the numerical results was studied by comparison with the exprimental results, and the appropriate mesh sizes were determined. Next, the calculated results with three different step ratios were compared with the experimental results by hot-wire anemometer and flow visualization. These results showed good agreement. The vortex development in the recirculation zone behind the step was clarified by the calculated results and the experimental results.
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  • Hiroyuki Hashimoto, Kenji Amagai
    1993 Volume 36 Issue 4 Pages 584-591
    Published: November 15, 1993
    Released: February 18, 2008
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    The conservation equations of mass, momentum and energy for a molten liquid flow of two chemical constituents with their solidified particles were derived by means of the averaging method. The drift flux model equations for the fine particles were also derived under a locally homogeneous approximation. The present model suggests that the energy equation should have energy transport terms corresponding to the heat conduction, the migration of particles and the diffusion of chemical constituents. As representative examples, these energy transports were evaluated quantitatively for binary molten salt and liquid alloy under the assumption of a locally thermal equilibrium. The results show that the energy conservation equation for solidified particles and melt flow should include an energy transport term due to particle migration.
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  • Hideyuki Ohba, Shigeaki Kuroda
    1993 Volume 36 Issue 4 Pages 592-597
    Published: November 15, 1993
    Released: February 18, 2008
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    Flows around a rotating square cylinder in a uniform flow are analyzed numerically. Body-fitted grid generation with moving boundaries is used to obtain the numerical solution of the incompressible Navier-Stokes equations. The time-dependent curvilinear coordinate system which coincides with a contour of the moving boundary is transformed into a fixed rectangular coordinate system in a calculational plane. The results of this method are compared with those of previous experiments, and their validity is confirmed. The changes in the stream lines, pressure distributions, CD and CL as the cylinder rotates are analyzed. The periodical flow can be simulated when the Karman vortex shedding and the rotation of the square cylinder are synchronized .
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  • Byeong Shin Rog, Toshiaki Ikohagi, Hisaaki Daiguji
    1993 Volume 36 Issue 4 Pages 598-606
    Published: November 15, 1993
    Released: February 18, 2008
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    A finite-difference method based on the SMAC (Simplified Marker and Cell) scheme for analyzing two-dimensional unsteady incompressible viscous flows is developed. The fundamental equations are the incompressible Navier-Stokes equations of contravariant velocities and the elliptic pressure equation in general curvilinear coordinates. With application of the Crank-Nicholson scheme, unsteady flow is calculated iteratively by the Newton method at each time step, and the elliptic pressure equation is solved by the Tschebyscheff SLOR method with alternating the computational directions. Therefore, the elliptic character of incompressible flow is well described. The present implicit scheme is stable under the proper boundary conditions, since spurious error and numerical instabilities can be suppressed by employing the staggered grid and upstream differences such as the modified QUICK scheme. Numerical results for two-dimensional flows through a decelerating cascade at high Reynolds numbers are shown. Some computed results of the surface pressure coefficient are in satisfactory agreement with the experimental data.
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  • Byeong Shin Rog, Toshiaki Ikohagi, Hisaaki Daiguji
    1993 Volume 36 Issue 4 Pages 607-611
    Published: November 15, 1993
    Released: February 18, 2008
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    An implicit time-marching finite-difference method, which has been developed previously to solve the incompressible Navier-Stokes equations of contravariant velocities in curvilinear coordinates, is extended to a turbulent flow scheme employing a suitable low Reynolds number κ-ε model. The present method has second-order accuracy in time with application of the Crank-Nicholson scheme, and utilizes the QUICK (Quadratic Upstream Interpolation for Convective Kinematics) upwind-difference scheme in space. The elliptic equation of pressure is solved by means of the Tschebyscheff SLOR (Successive Line Over Relaxation) method with alteration of the computational directions. The present implicit turbulent flow scheme is stable under the proper boundary conditions, since spurious error and numerical instabilities can be suppressed by employing a staggered grid. Numerical calculations are performed for turbulent flows through a two-dimensional cascade. Computed results of the cascade turbulent boundary layers and the wake profiles are shown. The calculated surface pressure distribution is in good agreement with the experimental data.
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  • Masaaki Okubo, Hiroatu Endo, Shuzo Oshima, Yukio Ishibashi, Ryuichiro ...
    1993 Volume 36 Issue 4 Pages 612-619
    Published: November 15, 1993
    Released: February 18, 2008
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    A new method is developed, using a semiconductor laser and optical fiber, to measure the local velocity of magnetic fluid flow. In this method, the local flow velocity is obtained by measuring the time taken for a tracer particle to pass between two sets of optical fiber probes. After this method is calibrated with a rotational flow in a rotating channel, it is applied to magnetic fluid flows in an open channel under the influence of a traveling magnetic field which is produced with a stator of a single-sided linear induction motor. As a result, it is clarified that the flows are mainly induced opposite to the traveling direction of the magnetic field and the magnitude of induced velocity is almost proportional to the frequency of the magnetic field, increasing especially near the free surface. The velocity distributions are quite different from those of nonmagnetic fluid flow in an open channel.
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  • Hong-Hui Shi, Kazuyoshi Takayama, Osamu Onodera
    1993 Volume 36 Issue 4 Pages 620-627
    Published: November 15, 1993
    Released: February 18, 2008
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    Pulsed liquid jets with speeds ranging from 100 m/s to 1000 m/s were produced using a gas gun. Kerosene, water and alcohol were injected into ambient air by the impact of a projectile driven by the gas gun operated with high-pressure helium. Jet speed was measured by output signals generated when the jet cut two laser beams at the exit of the gas gun. Double exposure holography interferometry visualized the shock wave generated in front of a supersonic jet as well as the moving jet shape. Interesting phenomena associated with jet motion and the impact of the jet on the solid surface were observed. Jet generation time and evolution of the jet shape was measured. The effect of the nozzle size on the jet speed was studied. Experimental findings indicate that the formation of a precursor jet and a bifurcated jet largely depends on the liquid-air surface tension.
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  • Takaaki Mochizuki, Yasuhiko Mori H., Nobufuji Kaji
    1993 Volume 36 Issue 4 Pages 628-635
    Published: November 15, 1993
    Released: February 18, 2008
    JOURNALS FREE ACCESS
    This paper is concerned with mutual interactions between liquid drops translating in an immiscible, dielectric liquid medium confined by a pair of tilted parallel-plate electrodes, across which a steady electric field is being applied. Each drop exhibits a bouncing motion between the electrodes, exchanging a net charge on it on each impact with either electrode. The performance of a liquid-liquid contactor utilizing such bouncing motions of drops, if provided, will be limited by a need for averting mutual coalescence of neighboring drops charged oppositely to each other from time to time. Thus, the critical conditions for drop coalescence have been defined experimentally, and the motions of paired drops exerting mutual interactions have been analyzed theoretically to predict the critical conditions for coalescence.
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  • Dong-Ho Rie, Takao Kashiwagi
    1993 Volume 36 Issue 4 Pages 636-643
    Published: November 15, 1993
    Released: February 18, 2008
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    The purpose of this study is to obtain basic knowledge of the heat and mass transfer processes as affected by interfacial disturbance induced by addition of surfactants. We apply a nonflowing bulk absorption model and assume that interfacial disturbance occurs randomly. Four governing equations-for continuity, laminar momentum, energy, and diffusion-are solved numerically to obtain the unsteady temperature and concentration distribution during vapor absorption with interfacial disturbance for various aspect ratios δ(D/L = thickness of absorbent solution/length of model cell) and random numbers of interfacial disturbance points. In this study, surface tension between the surfactant ( n-octanol) and absorbent solutions (H2O/LiBr) is considered to be constant during the vapor absorption (i. e., independent of concentration changes in the absorbent solution). The influence on the occurrence of random interfacial disturbance is quantified in terms of mean Sherwood number and Nusselt number for severalδ(=0.1, 0.3, 0.5, 1) and with variations in the number of random disturbance points (1 to 5) where disturbance randomly occurs on the model cell surface. As a result of these calculations, the absorption enhancement ratio (amount of vapor absorption with surfactant addition/amount of vapor absorption without surfactant addition) is obtained by comparison between surfactant-added and nonadded conditions, for the same calculation parameterδ.
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  • Ryoji Ishiguro, Hiroto Sakashita, Ken-ichiro Sugiyama, Yoji Takamura
    1993 Volume 36 Issue 4 Pages 644-650
    Published: November 15, 1993
    Released: February 18, 2008
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    For the purpose of obtaining essential information on scaling in heat exchangers, microscopic observations were made for CaCO3 deposition from a flowing solution onto initially clean heat transfer surfaces. The growth rates of CaCO3 crystals were measured by changing the Reynolds number and supersaturation degree of the bulk solution, materials and temperature of the heat transfer surface. The growth rate was found to be relatively well correlated with the supersaturation degree of the solution adjacent to the surface, deduced from the equilibrium relationships between the species in the calcium carbonate solution. The nucleation rate was also estimated by measuring the change of the cumulative number density of deposited crystals against time. The crystals were formed on the surface at a constant nucleation rate over time, but the factors which dominate the nucleation rate could not be determined.
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  • Shigenao Maruyama
    1993 Volume 36 Issue 4 Pages 651-656
    Published: November 15, 1993
    Released: February 18, 2008
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    The possibility of radiation heat transfer control by a combined model of an active thermal insulation system and a radiative converter was investigated. A semitransparent porous layer was placed between a high-temperature region and a low-temperature region, and gas was injected through the layer in the positive and negative directions. The mechanism of heat transfer is completely different for the positive and negative mass flux. By varying the mass flux of air between - 0.1 and 0 kg (m2s)-1, dimensionless radiative flux at the back face can be controlled between 2 X 10-4 and 0.1. In this region, the porous layer behaves as the active thermal insulation system, and the mechanism of radiation heat transfer control is similar to that of a triode.
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  • Marie Oshima, Richard Thome J.
    1993 Volume 36 Issue 4 Pages 657-664
    Published: November 15, 1993
    Released: February 18, 2008
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    A computer program has been developed for simulating quench propagation and associated transient thermal and electric behavior of superconducting coils. The quench propagation has been analyzed using a logical coordinate system in order to transform a three-dimensional problem into a one-dimensional problem. In a logical coordinate system, superconducting coils are assumed to consist of long wires which are divided into elements of finite length. The capability of the present method was examined by analyzing the quench propagation in the solenoid coil system with epoxy-bonded NbTi superconductors, and the analysis results were compared with the experimental data. The comparison indicated good correlation of the computed quench time with the experimental data.
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  • Zhen-Yi Qian, Atsuo Nishimura, Haruki Sato, Koichi Watanabe
    1993 Volume 36 Issue 4 Pages 665-670
    Published: November 15, 1993
    Released: February 18, 2008
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    The compressibility factors of difluoromethane (HFC-32) in the gaseous phase have been determined by means of the Burnett method, and the vapor pressures have also been measured using the same apparatus. The cell constant of the Burnett apparatus has been calibrated by measuring the thermodynamic properties of gaseous helium. Using the cell constant, we measured 95 compressibility factors at temperatures from 290 to 370K, and pressures from 0.15 to 6.6 MPa. These experimental compressibility factors for temperatures from 290 to 370 K have been discussed along each isotherm by applying the virial-type equation having second, third and fourth virial terms. We have also measured 9 vapor pressures at temperatures from 280 to 350 K. On the basis of the present vapor-pressure measurements, the critical pressure of HFC-32 has been determined so as to correspond to the critical temperature directly measured in our laboratory. The present data were also used to develop the vapor-pressure correlation which are effective for temperatures from the normal-boiling-point temperature to the critical temperature. The present data are represented within a deviation of ± 0.035% ( ±0.6 kPa) by the derived vapor-pressure correlation. The uncertainty of temperature measurements was estimated to be better than ±10 mK and that of pressure measurements was estimated to be better than ±0.8 kPa. Experimental uncertainty for the compressibility factor was evaluated as not lower than ± 0.2%. The purity of the HFC-32 sample used was higher than 99.98 wt%.
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  • Kouichi Kamiuto
    1993 Volume 36 Issue 4 Pages 671-676
    Published: November 15, 1993
    Released: February 18, 2008
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    An analytical procedure is proposed to simultaneously determine the size distribution and optical dispersion parameters of soot from multispectral transmittance data for a luminous flame. Blokh's distribution and a gamma distribution are assumed as particle size laws, but only Blokh's distribution is successfully utilized throughout the study. The dispersion model of three bound and one free electrons developed by the author is adopted to describe the complex refractive index of soot. Of the dispersion parameters, only the effective free electron number density is treated as an adjustable parameter for each soot and the remaining parameters are fixed at adequate values. The proposed method is applied to Lee-Yu-Tien's data of spectral extinction coefficients of small-pool diffusion flames of six fuels. It was found that the most probable radius of in situ soot particles is less than 0.1 μm for luminous flames examined here and that the relationship between the effective free electron number density and the fuel H/C ratio is well represented by an expression derived from our previous formula.
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  • Hiroshi Yamasaki, Mitsuhiro Tsue, Toshikazu Kadota
    1993 Volume 36 Issue 4 Pages 677-681
    Published: November 15, 1993
    Released: February 18, 2008
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    An experimental study has been carried out to investigate the onset of micro-explosion of emulsified fuel. Silicone oil and water emulsions contained in Pyrex glass capillaries were immersed in an oil bath after degasification. The waiting time for the onset of microexplosion was measured at atmospheric pressure in the temperature range of 423 K to 463 K. The results showed that the waiting time at constant temperature correlated with the Weibull distribution and that the shape parameter was unity. It was also found that the mean waiting time for the onset of microexplosion decreased exponentially with increasing liquid temperature. An empirical equation was proposed for the mean waiting time as a function of superheating of water emulsified. The probability density function of the onset of microexplosion during the unsteady heating period was predicted on the basis of this equation.
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  • Junichi Furukawa, Kaoru Maruta, Tomohiro Nakamura, Tsutomu Gomi, Toshi ...
    1993 Volume 36 Issue 4 Pages 682-687
    Published: November 15, 1993
    Released: February 18, 2008
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    It is well known that the characteristics of an ion current recorded by an electrostatic probe depend not only on the ion density distribution near the reaction zone but also on the flame configuration and movement. Therefore, it is expected that the configuration of turbulent premixed flames can be examined by analyzing the ion current record obtained in a turbulent flame brush. In the present study, an attempt has been made to elucidate the dependence of the characteristics of ion currents on the curvature and movement of flame. It is shown that even though the local flame curvature is constant, the ion current changes its profile significantly with changes in the flame movement. As the angle between the flame front and the probe axis increases, the maximum ion current decreases and the half value period increases. As the distance from the center of flame curvature to the midpoint of a probe sensor increases, the half value period increases.
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  • Kazunari Kuwahara, Hiromitsu Ando
    1993 Volume 36 Issue 4 Pages 688-696
    Published: November 15, 1993
    Released: February 18, 2008
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    The Laser sheet particle track velocimetry procedure was improved by employing a two-color light source. Velocity vectors resolving the directional ambiguity could be obtained with high spatial resolution. The forward-scattering LDV adopting a high-power light source and large diameter / low density tracer particles revealed a potential for cycle-resolved turbulence analysis with high temporal resolution. Adopting these procedures, flow field in the pentroof combustion chamber of a two-intake-valve engine was analyzed. It was clarified that at the early and middle stages of the compression stroke, both tumble and swirl maintain distinctive vortex structures and at the late stage of the compression stroke, tumble and swirl are converted into many small eddies of relatively large scale. Experimental results demonstrated that because these eddies are distributed uniformly throughout the combustion chamber and the scale conversion proceeds, maintaining the equilibrium relationship, it is reasonable to treat these eddies as turbulence.
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  • Jesus-Ignacio Prieto, Roberto Diaz
    1993 Volume 36 Issue 4 Pages 697-710
    Published: November 15, 1993
    Released: February 18, 2008
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    Dimensional analysis has been employed to review the isothermal or quasi-static simulation of kinematic Stirling engines and to study the influence of the engine and drive mechanism types, and other parameters, on the thermodynamic engine cycle. The use of isothermal simulation with decoupled losses to obtain reliable predictions at practical levels of rpm is experimentally justified. The method seems to be an adequate tool to study a large number of configurations, which the engineer needs at the initial design stage. At the same time it provides a intuitive knowledge of and similarity criteria for the thermodynamic engine performance.
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  • Seong Soo Kim, Sung Soo Kim
    1993 Volume 36 Issue 4 Pages 711-722
    Published: November 15, 1993
    Released: February 18, 2008
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    The effects of swirl on early flame development and late combustion characteristic were investigated using a high-speed single-shot visualized SI engine. LDV measurements were performed to obtain a better understanding of the flow field in this combustion chamber. Spark plugs were located at half-radius (R/2) and center of bore. High-speed Schlieren photographs at 20 000 frames/sec were taken to visualize the detailed formation and development of the flame kernel with cylinder pressure measurements. This study showed that high swirl favorably affected combustion-related performances in terms of the maximum cylinder pressure and flame growth rate regardless of spark position. However, at R/2 ignition the low swirl showed desirable effects at low engine speed, and degraded performance as engine speed increased than without swirl. There were distinct signs of slow-down in flame growth during the period when the flame front expanded from 2.5 mm in diameter until it reached 5.0 mm apparently due to the presence of ground electrode. There seemed to be a heat-transfer effect on the flame expansion speed which was evidenced in the high swirl case by the slowdown of the late flame front presumably caused by relatively large heat loss from burned gas to wall compared with low- or no-swirl cases.
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  • Jeong Eui Yun, Sung Soo Kim
    1993 Volume 36 Issue 4 Pages 723-729
    Published: November 15, 1993
    Released: February 18, 2008
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    In order to improve engine performance and reliability, it is important to measure the friction force between the piston-ring assembly and cylinder wall, and to understand the friction characteristics. A new device was developed in this study for piston friction force measurement. Compared with existing floating liner systems this device requires less installation space and alleviated the system noise problem induced by piston thrust and slap impulse forces. This system was used for friction force measurement to determine the functional relationship between friction force and variables such as engine speed, oil viscosity and engine load. The friction force characteristics were established from the analysis of the experimental data.
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