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Naomichi HIRAYAMA
1987 年 30 巻 269 号 p.
1699-1706
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
Recent research on the flow through turbine blade rows covers the following regions : (i) theoretical analyses of inviscid and viscous compressible flow through cascades or turbine stage, (ii) experimental investigations of the cascades and turbine stages, (iii) secondary flow, (iv) unsteady flow, (v) design methods, (vi) wet steam flow, and (vii) special turbines. In this review, research carried out over the past five years was dealt with. As regards the development in computing methods of internal flow, a time-marching method of viscous compressible transonic flow through a stage and an inviscid unsteady flow calculation was explained. As for secondary flow, theoretical analysis has been improved significantly as of late. However, more information on the turbulence structure of blade boundary layers and on the mixing process in the downstream of blade rows and the effect of leading edge vortices are necessary. Unsteady flow in a blade row due to the wake of the upstream blade row can be well described, but the more important unsteady flows in the low pressure stages, caused by non-uniform flow at low flow rate conditions or due to the fluctuation of the shock wave location, remain unsolved.
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Kazumi HIRANO, Hideo KOBAYASHI, Hajime NAKAZAWA, Akio HAYASHI
1987 年 30 巻 269 号 p.
1707-1713
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
The ultrasonic isoscanning technique using shear waves is employed to monitor the surface fatigue crack growth under a constant stress intensity factor range. It is shown that this technique has the potential to become an effective tool for the evaluation of quantitative surface fatigue crack growth characteristics. Not only can the three-dimensional crack profile be continuously measured with fairly high accuracy during fatigue crack growth testing, but this study indicates that the crack tip closure can be detected at the maximum depth point and near the surface. The surface regions under plane-stress conditions are closed for a greater portion of the fatigue load cycle than the maximum depth point under a predominantly plane-strain condition. The plane-strain crack tip opening load is smaller than the plane stress crack tip opening load.
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Takashi FUJIMOTO, Seinosuke SUMI
1987 年 30 巻 269 号 p.
1714-1723
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
The post-buckling behavior of centrally cracked rectangular plates subjected to a uniaxial tension is analyzed by the finite element method, taking into account both geometrical and material nonlinearities. The finite element formulation is based on the total Lagrangian coordinate system and the flow theory of plasticity. The effects of an initial imperfection on buckling deformation are studied in some detail. Post-buckling behavior is discussed in relation to undesirable effects on the fracture of cracked plates. The results of elastic analyses show that the magnitude of the stress intensity factor increases after buckling. The results of elastic-plastic analyses and experiments show that the residual strength of cracked plates is reduced by the interaction between buckling deformation and plastic deformation at the end of cracks.
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Seiichiro KITAOKA, Kazuhiko OHSHIMA
1987 年 30 巻 269 号 p.
1724-1731
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
By observing slip lines in a copper foil with grown grain structure, the method of measuring cyclic stresses acting on machine elements is studied. The features and distinction of this method in comparison with the copper electroplating method or the method using a recrystallized foil are examined. This method is superior to the method using a recrystallized foil from the standpoint of ease of measurement, and its strain sensitivity is much higher than that of the electroplating method. As an application of this method, the stress concentration factors in various types of circular shafts with a flat part under cyclic torsion are obtained, with the results showing good agreement with those obtained previously.
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Shigeo SAKURAI, Saburo USAMI, Hiroshi MIYATA
1987 年 30 巻 269 号 p.
1732-1740
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
Microcrack initiation and growth behavior were observed on the surface of nondegraded and degraded CrMoV cast steels under various strain wave shape loadings at high temperature. The degraded steel was taken from the inside of a main steam valve casing after 140 000 hours of service. No signigicant difference in crack growth behavior was observed under low cycle fatigue for either steel. However, the crack growth rate in the degraded steel was higher than that in the nondegraded one under creep-fatigue resulting from slow/fast straining. This was caused mainly by grown and coarsened grain boundary carbides. A residual life assessment method, based on microcrack growth and the statistical properties of microcrack length distribution, closely predicts the experimental results.
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Ryuichi OHTANI, Takayuki KITAMURA
1987 年 30 巻 269 号 p.
1741-1749
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
A stochastic model and a method of numerical simulation of the propagation of a microstructurally-short crack along grain boundaries in monotonic creep were proposed. In the model, a distribution of crack propagation rate at each grain boundary was expressed by means of random variables representing grain boundary length and crack propagation rates at and between two adjacent grain boundary triple points. The cumulative probability of crack length was calculated using a Monte Carlo method to clarify the effect of some factors such as the grain boundary length, the initial crack length, the upper and the lower bounds of crack propagation rates, and the waveform of the crack propagation rate between two adjacent triple points. The lower bound of the crack propagation rate an the initial crack length affected strongly the cumulative probability. The probability of the length of randomly distributed cracks for continuous crack initiation during creep was also simulated on the basis of the model, and it was confirmed to coincide with the experimental results.
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Eiji HASEGAWA, Fumio NAGASHIMA, Hiroshi TAKASHIMA
1987 年 30 巻 269 号 p.
1750-1756
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
The instability of an interface between two immiscible fluids under an externally vertical oscillation is investigated by using a linear perturbation theory. Two incompressible viscous fluids under the action of gravity are assumed to be bounded by the upper and lower solid walls which are oscillated vertically. The neutral stability curves are found in the plane consisting of the angular frequency and the amplitude of the external oscillation. A critical amplitude of the external oscillation, below which any instability does not arise, is found from the neutral stability curve. The effects of the Reynolds number, the thickness ratio and the viscosity ratio on the critical amplitude are examined. The results obtained theoretically are confirmed experimentally by using two liquid layers consisting of a light oil and aqueous glycerine.
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Katsuya FUNATSU, Yuji TOMITA, Noriyuki SHIRAKURA
1987 年 30 巻 269 号 p.
1757-1761
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
In the pneumatic transport of PVC powder whose mean diameter and material density are 134 μm and 1 330 kg/m
3, respectively, the solid velocity is measured by the "activable" tracers method, whereby tracers can be activated when required, in a vertical line 100.0 mm in inside diameter and 24 m in length, when the air velocity is changed from 16.5 m/s to 28.9 m/s and the solid-loading ratio between 48.8 and 82.5. The used nuclide was
56Mn or
82Br. The pipe friction factor for the solid phase was also obtained for the same conditions. The present method is applicable to measurements at high solid-loading ratios.
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Yujiro HAYASHI, Akira TAKIMOTO, Chorunamu KONG, Seiji KAWAHARA
1987 年 30 巻 269 号 p.
1762-1767
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
In order to pursue the high performance of thermal energy storage, a combined type of latent-and sensible-heat thermal energy storage (TES) system is proposed, and its performance is investigated experimentally and theoretically. The theoretical treatment is made taking in account the recirculating flow in the capsule. In comparison with the theoretical answers and the experimental results given by preceding report, the optimum design of TES is determined in relation to the operating conditions and Phase Change Material (PCM).
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Akira INOUE, Masanori ARITOMI, Minoru TAKAHASHI, Yosihito NARITA, Tosh ...
1987 年 30 巻 269 号 p.
1768-1775
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
Pressure drop and heat transfer coefficient of helium-lithium annular-mist flow in a rectangular duct were investigated experimentally under a transverse magnetic field at system pressure of 0.2 MPa. A ratio of MHD pressure drop to that of non-magnetic field increases with magnetic flux density and a mass flow rate ratio of lithium to helium in low helium velocity region. However, as increasing the helium velocity, the increment of MHD pressure drop with the magnetic flux density is much reduced and then becomes almost zero. At this condition, the MHD pressure drop of the annular-mist flow becomes much smaller than that of lithium single phase flow with the same lithium mass flow at the high magnetic flux density. Heat transfer coefficient ratio of the helium-lithium annular-mist flow to helium single phase in the non-magnetic field is well correlated by a ratio of the mass flow rate of lithium to helium. The heat transfer coefficient in the magnetic field increases with the magnetic flux density and then terminates at a certain value depending on the mass flow rate ratio and the helium velocity. These characteristics of the MHD pressure drop and the heat transfer in the magnetic field suggest that the helium-lithium annular-mist flow is effectively applicable to cooling of the high heat flux wall in a strong magnetic field like a first wall of a magnetic confinement fusion reactors.
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Tadashi YAMAMOTO, Yoshio TANAKA
1987 年 30 巻 269 号 p.
1776-1782
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
The purpose of this study is to investigate the heat-transfer rate, etc, for sodium heat pipes having three kinds of mesh screen layers. The heat pipes were fabricated from SUS 316 L stainless steel tubing of 1.5 mm wall thickness with 25 mm in outer diameter and 1 000 mm in length. A 50-mesh screen was used for the wick. A total of 2, 4 and 6 screen layers were used. The heat-transfer rates of the heat pipes were obtained experimentally in the temperature range from 500 to 700°C and the results agreed fairly well with the calculated results of the heat-transfer rates obtained by using the formula for the effective thermal conductivity on the series model.
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Hiroshi MAEKAWA, Mutsuo KOBAYASHI, Kazuo YASHIRO
1987 年 30 巻 269 号 p.
1783-1789
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
A temperature-sensitive hot wire under constant-temperature operation is analyzed to predict its frequency response to temperature fluctuations of the fluid. Effects of the finite Wollaston length, the over-heat ratio and the transconductance of the amplifier are taken into account, and a precise expression for the transfer function is derived. Various probes with different geometries are dynamically calibrated using the newly developed procedure, in which a linear temperature distribution or a thermal wake just behind parallel line sources is utilized to generate the prescribed temperature fluctuations over a wider frequency rage. Good agreement is obtained between the predicted and experimental results on the gain of the sensitivity. The gain increases slightly as the over-heat ratio increases, and is least affected by the transconductance. Owing to the moderate thermal inertia of the Wollaston portion, the attenuation in the gain sometimes appears in the range of energy-containing eddies.
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Takao INAMURA, Nobuki NAGAI, Hideto INAGAKI
1987 年 30 巻 269 号 p.
1790-1796
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
A study has been carried out for the purpose of clarifying spray performances of highly concentrated coal-water mixtures (CWM) and obtaining a guide for the design of practical twin-fluid atomizers. Disintegration mechanisms and spray characteristics were investigated on the simple twin-fluid atomization of CWM, and compared with those of single-phase liquids. Furthermore, these disintegration model. In the disintegration of a CWM jet by high-speed air, atomization phenomena are similar to those of low-viscosity liquids. Spray is generated basically by the tearing-off of irregularly shaped small drops from the jet surface and by the splitting-up of the unstably fluctuating jet into spherical drops. With the increase of air velocity, Sauter's mean diameter of spray decreases steeply, but its manner depends on the disintegration mechanism.
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Katsuhisa FUJITA, Tomohiro ITO, Norio KOHNO
1987 年 30 巻 269 号 p.
1797-1804
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
In this paper, the vibrational phenomena of circular cylinders in both uniform cross-flow and gap cross-flow were studied, and the similarities and the differences between them were clarified experimentally. The experiments were performed by utilizing the same simplified test apparatus employed in the previous report, besides expanding the flow band width of the cross-flow which was exerted on the circular cylinders from the extremely narrow width to the uniform flow width. As a result, it was found that the critical flow velocity for both the vortex shedding vibration and the fluid elastic vibration was almost constant, independent of the flow band width, when evaluated by the equivalent velocity which was calculated by applying the continuity condition and the momentum flux theory for the cross-flow jetted from a narrow gap.
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Koichi SUGIMOTO, ATSUKO HARA, Shiyuki SAKAUE
1987 年 30 巻 269 号 p.
1805-1811
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
The computer algorithm for generating all the possible structural patterns of mechanisms with a given number of degrees of freedom, number of general constraints and number of loops has developed. First, loop patterns composed of links with three or more kinematic pairs, which represent shapes of loops, are determined, and the kinematic graphs are obtained by allocating binary links to some edges of each loop pattern. The number of cases to be considered when allocating binary links to the edges decreases by grouping the edges of loop patterns with the same characteristics and, consequently, the computational time is well reduced.
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Satoshi ODA, Takao KOIDE, Junichi YOKOYAMA
1987 年 30 巻 269 号 p.
1812-1818
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
This paper presents a study on the dynamic behavior of WN gears. Tooth bearings of various WN and involute gears for various center distances were examined experimentally. The circumferential, radial, and axial vibration accelerations, sound pressure, and tooth root sresses of WN and involute gears were measured under different running conditions by using a gear testing machine of a power absorbing type. The dynamic behavior of WN gears was compared with that of involute gears, and the effect of center distance on the dynamic behavior of WN and involute gears was clarified to a considerable extent.
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Masami HARADA, Ryutaro MIYAJI, Yukio ANADA
1987 年 30 巻 269 号 p.
1819-1825
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
The paper is concerned with the characteristics of hydrostatic thrust bearings operating in the turbulent regime. Using the calculated results of the three-dimensional turbulent mean velocity between a rotating disk and a fixed wall, as already proposed, the pressure distribution, the load capacity and the oil flow rate of the hydrostatic thrust bearing with a circular recess are presented. Comparing the calculated results with the experimental ones, it has been found that the characteristics of the above bearing are little influenced by the transition to turbulence of the lubricant flow in the recess, but the transition in the land produces an extreme change in the bearing characteristics such as the load capacity and the lubricant flow rate.
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Akira ISHIBASHI, Shigeru HOYASHITA
1987 年 30 巻 269 号 p.
1826-1832
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
Rollers made from 0.45% carbon steel with hardnesses in the range of 190 to 500 HB were used as test pieces. The rollers were rotated under rolling with sliding conditions. The sum of the initial surface hardnesses of the rollers was made greater than the theoretical oil film thickness, in most cases. Not a single pit occurred on the 190 HB rollers at a Hertzian pressure of 1.30 GPa (132.7 kgf/mm
2) when the hardness differences were less than 40 HB units. However, pits occurred at the same Hertzian pressure before 1.5×10
6 revolutions on the slower rollers (follower) with hardnesses of 220, 250 and 300 HB when these rollers were rotated with the faster rollers of higher hardness, giving hardness differences greater than 10 HB units. By measuring the duration of full EHL conditions, the friction coefficients, etc., it was clearly shown that the reason why an unexpectedly small hardness difference can cause pitting failure is attributed to the insufficient running-in which occurs when the hardness difference is greater than a certain limit.
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Katsumi YAMAGUCHI, Kiyoshi ISOGIMI, Eiji SHAMOTO, Junichi KOJIMA
1987 年 30 巻 269 号 p.
1833-1839
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
Many kinds of recently developed materials are very hard and brittle, and it is very difficult and expensive to process them. Thus, it is necessary to develop an easier and more economical method to process these materials. As an example, punching holes in sheet glass was studied. Because punching holes in sheet glass by ordinary methods is impossible, we present a method for punching holes in sheet glass under static high pressure. This research confirmed that it is possible to punch holes in sheet glass, and clarified the conditions needed to obtain good holes without defects.
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Tadayoshi SHIOYAMA, Hiroshi KISE
1987 年 30 巻 269 号 p.
1840-1845
発行日: 1987/11/16
公開日: 2008/02/15
ジャーナル
フリー
This paper deals with an automated manufacturing system which consists of identical machines located along a loop type of conveyor with a loading-unloading station. The system is described by a Markov chain model and the production rate is analytically derived. The relations between the production rate and the arrival rate of parts and the average processing time of the machine are studied by numerical results. Furthermore, the optimal control problem of dispatching parts into the system is formulated as a Markov decision process. Some properties of the optimal control are considered, and the production rate under the optimal control is compared with that under non-control.
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