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Hideaki NAKAYAMA, Yukio KANAYAMA, Tsuneshichi TANAKA
1983 Volume 26 Issue 219 Pages
1453-1460
Published: 1983
Released on J-STAGE: February 15, 2008
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A series of experiments are conducted to investigate the impact fatigue crack growth behavior of O.1%C aluminum killed carbon steel conforming to JIS. S10C. And results obtained are discussed from several viewpoints in comparison with those in non impact fatigue. It is clear that macroscopic crack growth rate, da/dN, in impact fatigue is higher than that in non impact fatigue especially in relatively low Kmax or low ΔK region. Through quantitative analysis of fracture surface morphology, it is revealed that the higher crack growth rate in impact fatigue is sustained by the larger amount of intergranular fracture mode which accelarates crack growth rate to some extent. Other characteristical aspects in impact fatigue crack growth behavior are also described in detail.
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Yohtaro MATSUO
1983 Volume 26 Issue 219 Pages
1461-1467
Published: 1983
Released on J-STAGE: February 15, 2008
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In the first paper, a new multiaxial distribution function having location parameters was formulated involving both effects of internal and surface cracks. Using this new distribution function, fracture probability ratios under biaxial tension and expected fracture loci under biaxial stresses are calculated, and the following results are obtained. (1) Fracture probability ratios increase as the principal stress ratio tends to unity. (2) Fracture probability ratios tend to zero as the stress level ratios tend to unity. (3) The expected fracture stress under uniaxial tension coincides with that under equi-biaxial tension as a shape parameter or a location parameter tends to unity ; namely, the expected fracture stress in any tensile stress state should coincide with each other.
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Takeji ABE, Uyu KAMATA
1983 Volume 26 Issue 219 Pages
1468-1474
Published: 1983
Released on J-STAGE: February 15, 2008
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Discussions are made on the possibility of expressing elastic deformation of an inhomogeneous material by dislocations distributed in a homogeneous elastic medium. A model of the inhomogeneous material is employed, which is composed of plane rectangular regions with different elastic constants. The model is analytically replaced by models with both discrete dislocations and continuum dislocations distributed in a rectangular network. Strain distribution in the dislocation models is compared with that in a rectangular inhomogeneous material, where constraint ratio is used as a parameter for expressing the mode of deformation. It is concluded that the elastic deformation of the inhomogeneous material is expressed approximately by the dislocations distributed in elastic homogeneous materials, so far as proper correspondence between the model of inhomogeneous material and dislocation model is chosen.
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Masataka TOKUDA, Yoshio OHASHI, Tsutomu IIDA
1983 Volume 26 Issue 219 Pages
1475-1480
Published: 1983
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The hypothesis of local determinability proposed by V.S. Lensky was experimentally confirmed to hold with high accuracy on a curved part of strain path. That is, a rate dθ/ds (θ is a difference between directions of stress and strain increment vectors, and s is a length of strain path) depends only on the current values of θ(s) and curvature K(s) of strain path. Experiments were performed along some strain paths with two circular parts in a two-dimensional space of strain, by applying combined loads of axial force and torque to thin-walled tubular specimens of initially isotropic brass. A simple stress-strain relation which reflects the curvature effect was formulated by using the hypothesis for a practically important set of strain paths with intermediate curvature.
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Toshikazu SHIBUYA, Takashi KOIZUMI, Toshimitsu TAKAGI
1983 Volume 26 Issue 219 Pages
1481-1487
Published: 1983
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In an elastic contact between two uneven surfaces, elastic bodies come in contact with each other smoothly along the inner and outer contact edges, and both edges shrink with the applied force. In the case of a small protrusion, we can approximate it as a parabolic one. So we analyze the three-dimensional elastic contact problem of an elastic layer pressed on a rigid base with a smooth parabolic protrusion and obtain the surface displacement and the contact stress, and make clear the influence of the thickness of the layer on these results.
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Kazuo TAKAKUDA, Takashi KOIZUMI, Toshikazu SHIBUYA
1983 Volume 26 Issue 219 Pages
1488-1494
Published: 1983
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The applications of the boundary integral equation methods (indirect methods) to static elasticity problems are investigated. We examine the existence and the uniqueness of solutions, and modify the integral equations to have unique solutions in cases of necessity. Detailed discussions are made on non-trivial homogeneous solutions of the integral equations for two-dimensional displacement boundary value problems.
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Hisaaki DAIGUJI
1983 Volume 26 Issue 219 Pages
1495-1501
Published: 1983
Released on J-STAGE: February 15, 2008
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A numerical method is developed for analysing a three-dimensional steady incompressible potential flow through an impeller in centrifugal turbomachines. The method is the same as the previous method which was developed for the axial flow turbomachines, except for some treatments in the downstream region. In order to clarify the validity and limitation of the method, a comparison with the existing experimental data and numerical results is made for radial flow compressor impellers. The calculated blade surface pressure distributions almost coincide with the quasi-3-D calculation by Krimerman and Adler, but are different partly from the quasi-3-D calculation using one meridional flow analysis. It is suggested from this comparison that the flow through an impeller with high efficiency near the design point can be predicted by this fully 3-D numerical method.
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Michinori MATSUSHITA, Teruaki AKAMAISU
1983 Volume 26 Issue 219 Pages
1502-1508
Published: 1983
Released on J-STAGE: February 15, 2008
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A two-moment one-parameter integral method is proposed which is generally applicable even to unsteady separated boundary layers over bodies of arbitrary shape in arbitrarily time-varying external flows. The governing equations of momentum and energy integrals are confirmed to be classified as a quasi-linear hyperbolic system and numerically solved by an up-wind differencing scheme. Then the method is applied to the laminar boundary layers over impulsively started circular and elliptic cylinders. The time-varying profiles of displacement thickness, shape factor and skin-friction coefficient are obtained. Especially, the loci on x-t diagram of the points of vanishing wall shear stress agree quite well with the known analytical or exact numerical solutions. The present method is found by no means inferior to exact numerical methods in accuracy and wide applicability, moreover it is excelently efficient in computer storage and computational time.
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Takahiko TANAHASHI, Tatsuo SAWADA, Tsuneyo ANDO, Motoichi IGA, Hiroyuk ...
1983 Volume 26 Issue 219 Pages
1509-1517
Published: 1983
Released on J-STAGE: February 15, 2008
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A new complete set of basic equations for magnetic suspensions is derived on the theory of micropolar fluids developed by Eringen and a solution to these basic equations is obtained analytically for a steady motion of magnetic suspensions in a circular pipe which is placed in a homogeneous magnetic field parallel to the flow direction. A phenomenological treatment is given for the specification of material constants of a micropolar fluid, which are vortex viscosity and spin viscosity. In order to clarify the dynamical flow characteristics in the presence of a magnetic field, six dimensionless parameters to show the magnetic effect, polar effect, wall surface effect and so on are introduced into the solution for the rotational Peclet number Per≪1 and Per≥1. Some discussions are presented on velocity profiles, distribution of microrotations and distribution of vorticities. In particular, the suspension is non-Newtonian even if a magnetic field does not exist.
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Sei-ichi IIDA, Shinichiro FURUKAWA
1983 Volume 26 Issue 219 Pages
1518-1525
Published: 1983
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A fast method to generate curvilinear coordinate systems with arbitrary line densities in the physical region is presented. There are no restrictions on the shape of the surrounding boundaries. Two numerical examples are given to show the validity of the method ; one is a rhomb as a typical shape of an inner boundary with many corners on its contour, and the other is a Karman-Trefftz airfoil as a typical case of a cusped body. In the latter case, in particular, an orthogonal curvilinear coordinate system can be obtained when a conformal mapping technique is used simultaneously. Moreover, it is expected that this grid generation procedure can be applied to a wide variety of other problems.
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Yutaka TANAKA, Michihiko MASUDA, Yuzuru SHIMAMOTO
1983 Volume 26 Issue 219 Pages
1526-1533
Published: 1983
Released on J-STAGE: February 15, 2008
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In this report, two-directional velocity measuring technique with pressure detecting probes is developed with the intention of obtaining in real time the velocity vector in the flow fields accompanying combustion. Preferable shape of pressure heads and dimensions of pressure conducting tube were decided, and electronically processing circuit which enables realtime measurement was devised. Examination was made on such the applicability of this method as the extent of velocity and flow direction, and evaluation was made on the errors which may arise in the measurement of flow with velocity gradient. Finally, this technique was applied to the simultaneous measurement of velocity vector, temperature and their correlation functions in a turbulent jet flame.
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Shigeaki MASUDA, Hide S. KOYAMA, Ichiro ARIGA
1983 Volume 26 Issue 219 Pages
1534-1541
Published: 1983
Released on J-STAGE: February 15, 2008
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A Reynolds stress closure model for rotating turbulent shear flows is developed. Special attention is paid to keeping the model constants independent of rotation. First, a general forms of the model of a Reynolds stress equation and a dissipation rate equation are derived, the only restrictions of which are high Reynolds number and incompressibility. The model equations are then applied to two-dimensional equilibrium boundary layers and the effects of Coriolis acceleration on turbulence structures are discussed. Comparisons with the experimental data and with previous results in other external force fields show that there exists a very close analogy among centrifugal buoyancy and Coriolis force fields. Finally, the model is applied to predict the two-dimensional boundary layers on rotating palane walls. Comparisons with existing data confirmed its capability of predicting mean- and turbulent quantites without employing any empirical relations in rotating fields.
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Kotohiko SEKOGUCHI, Kengo MORIKAWA, Kenji TAKAFIASHI, Masayuki TAKEISH ...
1983 Volume 26 Issue 219 Pages
1542-1548
Published: 1983
Released on J-STAGE: February 15, 2008
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Time-varying liquid hold-up was measured for air-water two-phase flow in a 26 mm vertical pipe by means of the constant-current method. The experimental data were collected in froth flow and the transition region between froth and annular flow, where the liquid lumps such as liquid slugs or disturbance waves appeared. A computer-aided-processing was proposed for the determination of flow parameters, i.e., the velocity, frequency, height or length of liquid lump, and the thicknesses of the base and minimum films. It was found that at superficial water velocities lower than 0.7 m/s the liquid lump velocity had a maximum and a minimum with an increasing air velocity ; whereas at higher liquid lump velocities it increased without presenting the maximum and the minimum. It was also suggested that the initiation or termination of froth-annular transition was closely related to the flow conditions under which the flow parameters drastically increased or decreased.
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Takenori OGAWA, Toyohiro TSUDA, Jo MASUTANI
1983 Volume 26 Issue 219 Pages
1549-1555
Published: 1983
Released on J-STAGE: February 15, 2008
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An analysis of a flow through the impeller of a centrifugal compressor which consists of inducer and radial vanes, is presented. The three-dimensional flow through the actual impeller is replaced by a two-dimensional inviscid subsonic flow model. The numerical calculation is carried out by the use of the singularity method. Influences of parameters, that is, Mach number of the rotational speed, impeller width ratio, dimension of the inducer etc. upon the impeller performance and upon the velocity distribution along the blade are investigated.
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Kazuyasu MATSUO, Shigetoshi KAWAGOE, Keisuke SONODA, Toshiaki SETOGUCH ...
1983 Volume 26 Issue 219 Pages
1556-1562
Published: 1983
Released on J-STAGE: February 15, 2008
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In the case of moist air or steam rapidly expanding in a Laval nozzle and condensation occurring in a supersonic section of the flow, if the heat released by the condensation exceeds a certain quantity, the flow becomes unstable and a periodic flow oscillation occurs. In the present paper, the flow oscillation has been examined experimentally in the case of rapid expansion of moist air, using a Ludwieg tube with a downstream diaphragm. As the result, the effects of the initial relative humidity of moist air and the configuration of the nozzle on the frequency of the periodic flow have been clarified. Furthermore, the relation between the incipient relative humidity in the supply condition at which the flow becomes unstable and the configuration of the nozzle has been presented.
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Terukazu OTA, Eiichi KANEKO
1983 Volume 26 Issue 219 Pages
1563-1566
Published: 1983
Released on J-STAGE: February 15, 2008
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Experiments were carried out for investigating an early state of development of a reattached turbulent flow which separated at the leading edge of a flat plate with finite thickness and blunt leading edge. Measured in detail were mean velocity profiles and boundary layer characteristics along with three components of turbulence and a turbulent shear stress. It is clear from the results that the mean flow properties develop relatively quickly and approach a nearly fully developed flow state at about 20 plate thicknesses downstream from the leading edge. The development of the turbulence characteristics is, on the other hand, extremely slow and a very long distance is needed for a fully developed flow situation to be reached, especially in the outer region of the boundary layer.
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Hiroshi MIZUNUMA, Hiroshi KATO
1983 Volume 26 Issue 219 Pages
1567-1574
Published: 1983
Released on J-STAGE: February 15, 2008
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Turbulent drag reduction in a mixed fiber-polymer system was observed both in a pipe flow and a flow on a rotating disk. Drag reducing rate in a mixed system was approximately the sum of each rate in separate system, though the effect of fiber additives is weakened a little by mixing with an increase in polymer concentration. In addition, we observed a phenomenon that transition to turbulence was delayed in a mixed system.
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Katsuine TABEI, Hiroyuki SHIRAI
1983 Volume 26 Issue 219 Pages
1575-1582
Published: 1983
Released on J-STAGE: February 15, 2008
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The basic conservation equations for ionization relaxation behind shock waves of rare gases are coupled with a steady state Boltzmann equation for electron energy distribution functions and are extended to include the effects of non-Maxwell(NMx) electrons and boundary layers in shock tubes. Numerical calculations are conducted for Xe and Ne with systematic combinations of shock Mach number, initial pressure(p
1) and shock tube diameter(D). It is found that NMx electrons really exist in the almost entire course of the relaxation and that the effects of NMx electrons and boundary layers appear in behaviors of macroscopic plasma parameters and ionization relaxation times. The present theoretical relaxation times are reasonably in good agreement with other experimental ones rearranged according to the magnitude of p
1D value.
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Naohiro IBOSHI, Atsushi YAMAGUCHI
1983 Volume 26 Issue 219 Pages
1583-1589
Published: 1983
Released on J-STAGE: February 15, 2008
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An experiment using a swash plate type axial piston pump was carried out in order to ascertain the availability of theoretical analysis. The pump was so designed that the behaviour of a slipper bearing could be continuously investigated for one cycle. The oil film thickness between the slipper land and the slipper plate was measured with three displacement transducers installed in the slipper land. The measurements were taken under constant load and normal operating conditions. As a result, the experimental values agreed relatively well with the theoretical ones.
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Atsushi ODA, Masahiko UEMATSU, Koichi WATANABE
1983 Volume 26 Issue 219 Pages
1590-1596
Published: 1983
Released on J-STAGE: February 15, 2008
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An equation of state for sulfur hexafluoride (SF
6) is proposed based on the available experimental data. Method and procedures for formulating the equation of state are reported. The proposed equation of state as a function of temperature and density is valid in the range of temperatures from the triple point of 222.35 K to 500 K and of pressures from the ideal gas state to 50 MPa which corresponds to the density variation from 0 to 2000 kg/m
3. The thermodynamic properties calculated by the proposed equation agree well with the available experimental data, which verifies the thermodynamic consistency of the proposed equation. According to the method applied here, it is possible to formulate an equation of state for fluids describing the most reliable thermodynamic state surface.
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Kenichi HASHIZUME
1983 Volume 26 Issue 219 Pages
1597-1602
Published: 1983
Released on J-STAGE: February 15, 2008
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An experiment on a refrigerant two-phase flow in a horizontal pipe was performed for flow pattern observation and void fraction measurement. Refrigerants used were R12 and R22, and the saturation pressure range was from 5.7 to 19.6 bar. From obtained data it was found that the flow pattern of the refrigerant two-phase flow can be presented on a revised Baker map, where the property correction factor on surface tension was modified. It was also found that the influence of the shut-off speed in void fraction measurement is negligible. Experimental data on void fraction agree well with Zivi, Thom and Baroczy correlation approximated by Butterworth.
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Kozo KATO, Michihiro SHIRAHA, Chikatoshi KURATA, Kenichi FUJII
1983 Volume 26 Issue 219 Pages
1603-1611
Published: 1983
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The influences of coal properties and combustion conditions on the unburned carbon content in flyash from the modern pulverized-coal-fired boiler were predicted numerically through a one-dimensional model, in which the profiles of temperature and air-fuel ratio in the furnace were predetermined. The main factors inestigated are the percentage of two stage combustion, furnace length, heat liberation rate in the furnace, exhaust gas recirculation and fuel properties. Predicted results give useful information to reduce unburned carbon in flyash.
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Kozo KATO, Michihiro SHIRAHA, Chikatoshi KURATA, Kenichi FUJII
1983 Volume 26 Issue 219 Pages
1612-1619
Published: 1983
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To discuss the validity of the prediction method described in our first report, five kinds of bituminous coals have been burned in two furnaces for a wide range of furnace temperatures and air-fuel equivalence ratios. Measured unburned carbon content in flyash is in good agreement with the predicted one in case of four coals and in the range of unburned carbon contents above 1%, verifying the validity of the prediction method.
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Katsumi KATAOKA, Yoshio HIRAKO
1983 Volume 26 Issue 219 Pages
1620-1627
Published: 1983
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The method of computation is proposed to estimate NO emission levels of spark ignition engines operating with not only homogeneous but also nonhomogeneous mixtures, because mixture states other than a homogeneous one may deliberately be used to improve pollutant emissions and engine performance. First proposed is a model valid for homogeneous mixtures, and then it is so modified as to be applicable to various nonhomogeneous mixtures such as a stratified charge. These models allow us to survey the relation between NO emissions and the variations of mixture states or operating conditions in SI engines.
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Hideyuki TSUNEMOTO, Hiromi ISHITANI, Tadashi MURAYAMA
1983 Volume 26 Issue 219 Pages
1628-1634
Published: 1983
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In this paper, a Two Stage Combustion EGR (TSCE) system which was effective in improving the cold starting characteristics was adopted to achieve NO
x reduction. By this system the mass emissions of NO and unburned hydrocarbon was cut to half without the sacrifice in fuel economy. To reduce the smoke density when TSCE was running, the compression ratio of the second stage cylinder was reduced. With this pressure reduction it is possible to use the TSCE system up to a load of 0.3 MPa BMEP, without negative effects.
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Akio NAGAMATSU, Akihiro NAKAO, Toshitaka IWAMOTO, Masaru NAGAIKE
1983 Volume 26 Issue 219 Pages
1635-1640
Published: 1983
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A new, convenient and accurate method is introduced for curve fitting of a frequency spectrum of a transfer function with light damping. Using this method, both the building block approach and the extracting block approach are tried to analyze the vibration of a simple model structure. Transfer functions necessary for these two approaches are obtained in the following two ways, namely in experiment by the harmonic exciting test and in numerical calculation by the reduced impedance method the authors proposed before. The above two approaches are performed under the following three combinations of transfer functions, namely, experiment : experiment, experiment : calculation and calculation : calculation. The analytical resuits agree well with the experimental ones in all cases. Combination of the above two approaches and the reduced impedance method makes it possible to foresee the vibration of mechanical structures only by calculation in design stage.
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Shinji HAYAMA, Keiji ARUGA, Tatsuo WATANABE
1983 Volume 26 Issue 219 Pages
1641-1648
Published: 1983
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An analytical solution to represent the nonlinear responses of sloshing in a rectangular tank is obtained, in which the perturbation method is used, under the assumption of potential flow for the liquid, and it is compared with experiments. As the result, the following are found. When the depth of liquid in the tank is deeper than a certain value which is determined by the ratio of depth and width of the tank, then the surface elevation shows nonlinear response curves with softening restoring force characteristics. When the depth becomes shallower than that value, it shows nonlinear response curves with hardening ones. In deeper cases, the analytical solution is in good agreement with experiments. In shallower ones, it represents the qualitative characteristics of actual nonlinear sloshing. In the lower forcing frequency range, it deviates from the experimental values, but the linear solution is in good agreement with them in this range.
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Junkichi INOUE, Atsuo SUEOKA, Shinichi NISHIWAKI
1983 Volume 26 Issue 219 Pages
1649-1653
Published: 1983
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This paper investigates new types of vibrating lift made by utilizing the principle of self-synchronization of mechanical vibrators. Two unbalanced vibrators whose axes are non-parallel and each driven by two motors, rotate at the same speed and have a definite phase angle as the result of the phenomena of self-synchronization. Accordingly, due to a screw vibration about the axis of the structure, products ride up the inclined way of a spiral trough. Two types of vibrating lift were set up and vibrations of the spiral trough were measured for various values of set parameters of the unbalanced rotors. In addition, the travelling speeds of products in the spiral trough were measured.
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Hiroyuki Kawamoto
1983 Volume 26 Issue 219 Pages
1654-1660
Published: 1983
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Radial stable stiffness of radial stable type magnetic bearing having more than one ring-shaped magnetic pole-piece has been analyzed by using the Schwarz-Christoffel transformation, and the results of calculations of stable stiffness have been indicated with the tooth-width, tooth-length, and groove-width used as nondimensional geometrical parameters, to examine the influence of each parameter. The influences of these geometrical parameters have been proved to be larger in the order of the groove-width, tooth-length and tooth-width.
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Naohisa TSUKAMOTO
1983 Volume 26 Issue 219 Pages
1661-1669
Published: 1983
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When the nylon gear is meshed with the steel gear, the data is short that the nylon gear would be used the driving gear or the follower. Nylon gear should be used as the follower, because as the follower is the reduction gear, the contact ratio is less at the follower. But as the materials of nylon is expensive than the materials of steel, the nylon gear request the predominancy. In this report, the abrasion, the state of tooth form variation and the life for the nylon gear of follower was examined. And about these things, the nylon gear of driving was compared and examined with the nylon gear of follower. Then the characteristic of the nylon gear of follower was distinct.
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Etsuji OHMURA, Yoshiharu NAMBA, Saburo MAKINOUCHI
1983 Volume 26 Issue 219 Pages
1670-1677
Published: 1983
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In this paper, a method of laser hardening is proposed, where CW CO
2 laser beam is used as a step functional heat input instead of a moving heat source. This method is applied to the plane surfaces of cylinders as an example. The hardening process is analyzed theoretically using the theory of heat conduction and considering the following four important subjects synthetically ; (1) temperature dependence of thermophysical properties, (2) absorptance for the laser beam, (3) heating rate dependence of Ac
3 transformation temperature, and (4) cooling rate. The hardened layers can be estimated by this analysis, and good agreement is obtained between the experimental and analytical results.
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