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Volume 54, Issue 501
Displaying 1-27 of 27 articles from this issue
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Kazuyasu MATSUO, Toshiyuki AOKI1988 Volume 54 Issue 501 Pages 1027-1033
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSDownload PDF (889K) -
Shiro AKAIKE1988 Volume 54 Issue 501 Pages 1034-1041
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe mixing process of opposing jets by coaxial impingement in the mixing chamber of a reaction injection molding has not been clarified. This paper presents the results obtained from numerical experiments for the coaxial impingement of opposing laminar jets. The numerical solution of Navier-Stokes equations is obtained by a finite-difference approximation which is extended from the exisiting solution for a laminar jet. The effects of the jet Reynolds number, the velocity profile at the nozzle exit and the distance from the nozzle to the impingement surface on the flow after the impingement are shown, and their effects on the flow mixing of the two jets are discussed.View full abstractDownload PDF (859K) -
Masaru USAMI, Tetsuo FUJIMOTO, Seizo KATO1988 Volume 54 Issue 501 Pages 1042-1050
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSMass-flow reduction of rarefied gas through a two dimensional slit by roughness of a slit surface is investigated numerically. The direct simulation Monte-Carlo method is very effective in an analysis of rarefied gas flow but it costs a lot of CPU time, especially for the near-continuum regime. Recently, some super-computers with a vector processor are available and they enable high-speed calculation. It is necessary for using them in the best condition that a program is adequately vectorized. The programming technique called 'collection of data' is used very often, so that the simulation program eight times faster than conventional one is attained. In the transition regime, the effect of roughness of the slit surface on rarefied gas flow becomes clear. An experiment is carried out in order to confirm the effect.View full abstractDownload PDF (1136K) -
Yoichiro MATSUMOTO, Masao WATANABE1988 Volume 54 Issue 501 Pages 1051-1057
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe pressure response of a small air bubble in water is calculated numerically in an oscillatory pressure field. The following phenomena are taken into account in the calculation ; mist formation inside the bubble due to homogeneous condensation, diffusion between vapor and noncondensable gas inside the bubble and so on. The internal condition adapts itself easily to the oscillatory pressure field by the internal phenomena, which includes mist formation, evaporation and deposition onto the bubbler wall, so that the bubble tends to oscillate synchronously. The frequency response curves for bubbles are calculated. The curve is shifted towards low frequency, and the maximum bubble radius becomes large. When the pressure amplitude is increased, the periodic bubble oscillation bifurcates to non-periodic oscillation, which is a deterministic chaos.View full abstractDownload PDF (975K) -
Masahiro OTA, Naomichi HlRAYAMA1988 Volume 54 Issue 501 Pages 1058-1063
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSEffects of inlet gas density and pressure ratios on a discharge coefficient through a rectangular De Laval nozzle were studied. In the region of Reynolds number less than 2.0 and Knudsen number greater than 1.0, the discharge coefficient appeared to be nearly constant. The flow conductance of the nozzle was compared with free molecular flow theory. Flow characteristics with air or argon through the nozzle were measured and Mach number distributions on horizontal and vertical planes at the nozzle exit revealed. Furthermore, detached shock waves in front of a circular cylinder in a supersonic gas stream were visualized by a glow discharge technique. In this paper, shock detachment distances and pressure rises of the shock waves are compared with conventional data and theory.View full abstractDownload PDF (782K) -
Keizo WATANABE, Toru KAMOSHIDA, Hiroshi KATO1988 Volume 54 Issue 501 Pages 1064-1072
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe friction factor of fly ash slurries in a spiral tube with three-shaped groove tube walls has been analytically and experimentally obtained. It is made clear that the experimental data for the laminar flow range almost agree with the obtained analytical results for a pseudo-plastic fluid for which the rheological characterization of the slurries is determined by using the pressure loss data for the circular tube from the differential method. The drag reduction on the hydraulic transport of a solid has been obtained by using the fly ash slurries. Maximum drag reduction occurs at the spiral tube of p/D=6.98. The value of the drag reduction ratio is about 40%.View full abstractDownload PDF (946K) -
asanobu NAMBAM, Kazuhiko TOSHIMITU1988 Volume 54 Issue 501 Pages 1073-1080
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe improved double linearization theory is extended to three-dimensional subsonic cascades to study three-dimensional effects upon unsteady aerodynamic forces for vibrating blades with spanwisely nonuniform mean loadings. It is found that two kinds of unsteady spanwise aerodynamic forces arise due to nonzero mean loading. One is proportional to the blade inclination times steady pressure difference between upper and lower blade surfaces. Another is the aerodynamic force which acts on streamwise component of steady bound vorticies moving with blades relatively to the fluid. Numerical examples are presented, which illustrate the comparison between the present theory and the strip theory and some features of three-dimensional effects of nonuniform mean loadings on unsteady aerodynamic responses are made clear.View full abstractDownload PDF (914K) -
Takehiko NAGAYAMA, Chikamune MASUZAWA, Hiroshi SAKATA, Yoshito KIMURA1988 Volume 54 Issue 501 Pages 1081-1087
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe 3-D stacking effect on turbine stators was investigated by the fully three-dimensional computation and the experimental method. The Denton code was used to predict the turbine stage flows. The experiments were conducted by the wake traverse methods and the stator surface static pressure measurements using the single stage air turbine. The comprison of the computational results with the experimental results show good agreement between them. And also, those results show that the bowed stator has the significant potential to improve the aerodynamic performance.View full abstractDownload PDF (797K) -
Michihisa TSUTAHARA, Takeyoshi KIMURA1988 Volume 54 Issue 501 Pages 1088-1094
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe dynamic properties of a ship's propulsion mechanism using the Weis-Fogh mechanism are studied by the discrete vortex method. The wing in the channel is approximated by a finite number of bound vortices and vortices representing the separated flow are introduced from the leading edge and/or the trailing edge of the wing. The thrust, the drag, and the moment on the wing are calculated, including the forc due to the change of strength of the bound vortices. The propulsive efficiency is also obtained. These calculated values agree well with previously obtained experimental values. Flow patterns for some cases are shown and the negative thrust in the opening stage is also investigated.View full abstractDownload PDF (789K) -
Sumio SAITO1988 Volume 54 Issue 501 Pages 1095-1103
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe source of cavitation nose and its generation mechanism was investigated by measuring pressure fluctuation levels along the impeller casing under various cavitation conditions. The source of cavitation noise is located in an area between the leading edge and at about 30% of the chord length of the impeller blades. Discontinuous Layer between the tip clearance cavitation region and the main flow is one of the factors contributing to cavitation noise generation. The radiation of cavitation noise was also explained by measuring the casing vibration and the air-borne noise caused by cavitation.View full abstractDownload PDF (992K) -
Shigefumi NISHINO, G.Rohana CHANDRATILLEKE1988 Volume 54 Issue 501 Pages 1104-1109
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSEffects of surface inclination and roughness on saturated pool boiling curve were experimentally established for atmospheric liquid-helium. Based on the measured boiling curves, the following results were obtained. In nucleate boiling, heat transfer coefficients are increased as either the surface inclination or the roughness is increased. As for film boiling on vertical and inclined surfaces, the so-called two-phase boundary layer model underestimates heat transfer coefficients but it can correctly estimate the effects of surface superheat and surface inclination. This result indicates that a vapor film of laminar, smooth-interface is restricted to a small distance from the leading edge of the vapor film, but the nature of the vapor film remains laminar irrespective of the distance from the leading edge. Critical heat flux is not dependent on surface roughness and its dependency on surface inclination is predicted well by Vishnev's correlation. Finally, the minimum-heat-flux point temperature is not affected by surface roughness and inclination.View full abstractDownload PDF (802K) -
Shigenao MARUYAMA, Toshio AIHARA, Yoshiteru TANAKA, Keisuke KASAHARA1988 Volume 54 Issue 501 Pages 1110-1115
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSAn experiment was carried out on heat-transfer and pressure-loss characteristics of a low pressure-loss fluidized-bed heat exchanger with extremely shallow static bed-height of glass beads. The heat exchanger was composed of a staggered tube bank and a multi slit distributor designed specially to reduce the pressure loss. The effects of the shape of the distributor, the mean diameter and static bed-height of glass beads, and the numbers of row of the tube bank on the heat-transfer performance were examined. The heat-transfer and pressure-loss characteristics are compared with existing experimental data, considering the power requirement of blowers and the compactness of heat exchangers.View full abstractDownload PDF (724K) -
Shigeru KOYAMA, Tetsu FUJII, Kanei SHINZATO, Moriya TANAKA1988 Volume 54 Issue 501 Pages 1116-1122
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSForced convective heat transfer to fully developed laminar flow inside a tube which is uniformly heated along a finite length from the outer surface is numerically analysed as a conjugated problem. The four prescribable dimensionless parameters in this analysis are : heated length to inner diameter ratio L*, outer to inner diameter ratio Ro, wall to fluid conductivity ratio Λ, and Peclet number Pe. Effects of the parameters on the distributions of heat flux and wall temperature at the inner surface of the tube, the mixing-cup temperature of fluid and the local Nusselt number are graphically demonstrated. The region affected by axial heat conduction in the wall is discussed with respect to the heat flux distribution and the length of the region is expressed by a function of Λ, Ro and Pe.View full abstractDownload PDF (753K) -
Akio SAITO, Takahiro IMAMURA, Yoshio UTAKA, Akihiro SAITO1988 Volume 54 Issue 501 Pages 1123-1130
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSExperimental and analytical investigations were performed on a direct-contact melting process of a phase change material (PCM) which was contained in an inclined rectangular space surrounded by a heat-transfer surface and plate fins. The solid phase varied its shape, receiving the latent heat of fusion from the surrounding walls at the contacting spots, and moved within the rectangular space, changing the contacting mode. The numerical method to simulate such a direct-contact melting process was proposed. Experiments were also carried out to examine the numerical method, using N-octadecane as the PCM. The experimental and analytical results agreed quite well with each other. It was found from the analytical results that the inclination angle scarcely affected the average melting rate despite the serious effects on the contacting mode and the heat flux distribution over the walls.View full abstractDownload PDF (1067K) -
Takuya HATAKEYAMA, Yoshito MIYAHASHI, Masakazu OKUDA, Yuji NAGASAKA, A ...1988 Volume 54 Issue 501 Pages 1131-1137
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe thermal diffusivity of molten KCl has been measured in the temperature range up to 1000°C by the forced Rayleigh scattering method. Through the experimental assessment of appropriate dye materials for high temperature molten salts, the materials employed here were CoCl2 and NiCl2 for KCI and K2[PdCl6] for NaNO3 (check measurement at 333°C). In the case of very weak absorbing dye for molten salts, it was found that scattered light superimposed over the diffracted light of interest has to be taken into account to analyze the output voltage signals of a photomultiplier. The accuracy of the measurement is estimated to be ±7% for KCl colored with NiCl2. The present KCl results show one of the smallest values among other previous data and they are different by a factor of four. The present study demonstrates the promising applicability of this method to high temperature molten salts.View full abstractDownload PDF (905K) -
Toshiro MAKINO, Tetsuya NIWA, Tomohiko KASAI1988 Volume 54 Issue 501 Pages 1138-1144
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSAn idea relating to the surface scattering of electromagnetic radiation is presented as a theoretical basis for a study on thermal radiation characteristics of metals in the actual environments of industry. The interference and diffraction of electromagnetic waves are discussed for a film element, in which an absorbing film with three-dimensionally non-parallel interfaces is formed on a metallic substrate of an order of the wavelength of radiation. Boundary conditions at a two-medium interface are described generally for the infinitely wide system. The results are applied to a non-parallel film element model with a diffraction theory. Numerical computation is performed to demonstrate an inhomogeneous field realized by the element, which is one of the dominant factors of the scattering at real surfaces.View full abstractDownload PDF (855K) -
Shigeru HAYASHI, Hideshi YAMADA, Kazuo SHIMODAIRA, Takashi SAITOH, Sho ...1988 Volume 54 Issue 501 Pages 1145-1149
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSMeasurements of spontaneous ignition lag have been conducted using mixtures of atomized kerosene and air at pressures from 1 MPa to 4 MPa under weakly vitiated conditions (18-19 O2%). Equivalence ratios very from 0.3 to 0.6. The apparatus is comprised of a preburner, a multiventuri fuel injector, a premixing tube of 45.2 mm in diameter and 200 mm in length, and an afterburner. The results shows that ignition lag can be expressed in terms of inlet air temperature T and pressure P, by the equation τig=A exp(E/RT)/P The activation energy E is close to 92 kJ/mol, being a half of the value for prevaporized kerosene/ air mixtures.View full abstractDownload PDF (623K) -
Kazuo SAITO, Kunihisa EGUCHI, Ken KISHIMOTO, Toshihiko SAITO, Shoichi ...1988 Volume 54 Issue 501 Pages 1150-1156
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSEnsemble-averaged heat release rates and pressures in a combustion chamber have been measured to better understand the operating characteristics of a twin valveless pulse burner. An OH chemiluminescence intensity measurement system and pressure transducers were used as diagnostic tools. Based on the Rayleigh's criterion, the effects of changing the equivalence ratio and the mass flux on the combustion stabilities are discussed. Results show that the phase difference between heat release rate and pressure significantly affects the pulse combustion stability. In addition, the phase difference does not depend on the mass flux but on the equivalence ratio, this indicating that the fuel/ air mixing is a determining factor in the phase relationship. Also, it was found that the operating frequency increased with increasing mass flux, while it decreased with increasing equivalence ratio.View full abstractDownload PDF (877K) -
Masaaki MURAKAMI, Tetsurou OGUSHI, Goro YAMANAKA1988 Volume 54 Issue 501 Pages 1157-1162
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThis paper describes an experiment and the analysis of the heat transport capability of a flat shaped heat pipe with a thickness of a few millimeter. Two types of heat pipes are investigated. One is a triangular channel heat pipe made of a column of triangular tubes with small leg height. The other one is a flat plate heat pipe with rectangular vapor space and axial grooves along the inside wall. The liquid recession in the liquid channel and the liquid pressure drop at the condenser end due to the capillary pressure of the liquid slug (slugging effect) were taken into consideration in the prediction of the heat transport capability. The prediction agreed well with the experimental data. The flat plate heat pipe with axial rectangular grooves had larger heat transport capability than the triangular channel heat pipe for the small slugging effect and the larger cross sectional area for the liquid return.View full abstractDownload PDF (704K) -
Hidetoshi OHKUBO, Shigefumi NISHIO1988 Volume 54 Issue 501 Pages 1163-1169
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThis paper presents a feasibility study of glass tempering using mist cooling. First, transient tests of mist cooling were conducted to investigate the effects of the thermal properties of cooling surface. To do this, test plates were made of silver, nickel, stainless steel (SUS304), and fused quartz. The experimental conditions of mist flow were as follows : the air velocity was Va=20 m/s, the temperature of the water droplets Tl=21°C, and the volumetric-droplet-flow-rate D=0.0003-0.01m3/m2s. The experimental data show that both the plate temperature corresponding to the minimum heat flux (TM) and the heat transfer coefficients at wall temperatures above TM increase for decreasing thermal conductance of the surface material. Second, tempering tests of soda-lime glass plates of 2.95 and 3.90 mm thicknesses were conducted using mist cooling. The initial temperature of glass plates was about 690°C. The plates were cooled only from one side. Test results indicate that thin and low-cost tempered glass plates can be made by mist cooling without fracture.View full abstractDownload PDF (885K) -
Masatoshi DAIKOKU, Hideaki SUNANAGA, Nobuki NAGAI1988 Volume 54 Issue 501 Pages 1170-1178
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSAn atomization method was proposed for using the surface of a rotating body. The profile of the body was designed on the basis of Tanasawa's empirical equations for a rotating disk. Liquid disintegration on the surface was observed, and the behavior of the liquid film was investigated by measuring the disturbances and thicknesses of liquid film using the Pt-wire probes. At the condition of low flow rate, spiral waves are formed on the surface, and are broken up at the base periphery. Dropwise and filamentwise atomization on the surface of the body is realized in the wide range of flow rate and rotational speed without filmwise disintegration. The profile of the body for effective atomization should be designed to have a curved shape moderately increasing in diameter from the top, but without small radius of curvature.View full abstractDownload PDF (1210K) -
Toshimi TAKAGI, Takefumi KONDO, Masaharu KOMIYAMA, Yasuyuki SHlNTANl1988 Volume 54 Issue 501 Pages 1179-1182
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSContinuous and space-resolved measurements of concentration (mixture fraction) are made by detecting the fluorescence from the added iodine molecules induced by an argon ion laser. It is demonstrated that the combination of the laser-induced fluorescence detection and laser Doppler velocimeter (LDV) enables the cotinuous and simultaneous detection of concentration and velocity. Examples are shown of the measurements of the concentration fluctuation and its correlation with the velocity to get the turbulent mass trasnport in a turbulent jet.View full abstractDownload PDF (542K) -
Mitsushige NAKAYAMA, Takahisa ARAKI1988 Volume 54 Issue 501 Pages 1183-1188
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSIn order to visualize the internal structure of a spray cloud injected from a diesel nozzle, a computed tomography diagnostic technique was applied. A compact type of CT systems was developed, an Industrial Television Video Camera was used for the detector and a small computer was adopted for reconstruction of image data. A noninstrusive measurement technique was developed. At first, the algorithm for data reduction was discussed, followed by the effects of filter function on reconstruction data. The modified Sheff and Logan's filter function was recommended for the reconstruction of images such as diesel spray clouds.View full abstractDownload PDF (842K) -
Kenichi NIU, Tatsuro TSUKAMOTO, Yasusige UJIIE, Michikata KONO1988 Volume 54 Issue 501 Pages 1189-1193
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe formation process of flame kernels in the ignition process by electric sparks has been investigated by using a numerical simulation, which employs unsteady two-dimensional cylindrical co-ordinate systems. In the simulation, effects of the value of the diameter of spark electrodes and the width of the spark gap on the calculated results are mainly examined. The calculated results show that the hot gas kernel produced by a spark discharge takes an ellipsoidal form at first and then develops into a torus. Under some conditions, there exist two high-temperature regions, namely within the rings of torus and just between the spark electrodes. It is also found that a narrow groove is formed inside the torus. These configurations of the flame kernels agree well with those found by schlieren photographs of the practical flame kernels which are taken by a flash-schlieren photographic technic.View full abstractDownload PDF (789K) -
Yutaro WAKURI, Shinsuke ONO, Eiichi MURASE, Zhimin WANG1988 Volume 54 Issue 501 Pages 1194-1201
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSA new type of single compression machine has been developed to investigate basic aspects of the spray combustion phenomenon. The mechanism of a single compression is different from the usual rapid compression machines, i.e. a crank mechanism is used to make a steady reciprocating motion of the piston and a single compression state can be made without any mechanical impact. By the use of this single compression machine and a high pressure accumulated fuel injection system which was controlled electrically, combustion tests and photographic observations were carried out. From a series of tests, the influences of the surrounding air pressure, the temperature, the fuel injection pressure, and the swirl flow on the ignition delay are shown. Furthermore, the factors affecting the period of the initial stage of spray combustion are shown by introducing a new coefficient of heat release rate of spray combustion.View full abstractDownload PDF (1067K) -
Yasuhide TANI, Akinori SAITO, Masatoshi YAMADA1988 Volume 54 Issue 501 Pages 1202-1206
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSA single cylinder engine with the combustion chamber mounted on the piston was designed to allow visualization in the direction of the cylinder axis. By using this engine, the evaporating process of the fuel injected into the combustion chamber was observed. High speed Schlieren, shadowgraph, and back-illuminated movies were taken for detailed observation of the combustion chambers with a single hole injector and a swirl injector which have different injection characteristics. The one with a single hole injector shows strong collision of the spray with the bottom of the chamber and fast evaporation. Another with a swirl injector shows no trace of such collision and relatively slow evaporation.View full abstractDownload PDF (785K) -
Yoshiharu TSUJIKAWA1988 Volume 54 Issue 501 Pages 1207-1212
Published: May 25, 1988
Released on J-STAGE: March 28, 2008
JOURNAL FREE ACCESSThe characteristics of LACE, or a liquid air cycle engine, for hypersonic airbreathing propulsion is discussed. Both air and hydorgen are pumped up to a high pressure in the liquid phase; the liquid air and gaseous hydrogen from the heat exchanger (air condenser) are burned in a rocket chamber and are expanded in a normal propelling nozzle. With the speed range up to a Mach number of 10, LACE can be found to maintain its superiority over the rocket concering the specific impulse.View full abstractDownload PDF (687K)
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