Transactions of the Japan Society of Mechanical Engineers
Online ISSN : 2185-9485
Print ISSN : 0029-0270
ISSN-L : 0029-0270
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Volume 24, Issue 137
Displaying 1-14 of 14 articles from this issue
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  • On the Theory of Drag of Bluff Bodies
    Isao IMAI
    1958 Volume 24 Issue 137 Pages 1-2
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.1
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  • Studies on the Sealing Action of the Viscous Fluid : 5th Reports, Experiments using some greases as sealing substance
    Tuyoshi ASANUMA, Norihiro SAWA
    1958 Volume 24 Issue 137 Pages 3-8
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.3
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    In the previous reports, it has been shown that the pump lift or the sealing pressure is proportional to the viscosity of the working fluid. we have carried out therefore some experiments using greases of higher viscosity than liquid oils. A summary of the results is as follows ; a) The sealing pressure for the grease is proportional to the angular velocity (w) andthe coefficient of sealing performance (S) as shown in the previous peports for oils. b) Using some greases, the sealing pressure is about from 30 to 70 times of that for oils. c) The filling state of greases in grooves of rotating shaft is considerably varied with the kind of greases, so that we must select the suitable depth of groove. d) To keep the viscosity of the sealing substance at a higher value, it is extremely important to cool the sealing apparatus.
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  • Study of Three-Dimensional Internal Flow Distribution in Centrifugal Impeller
    Kunio FUJIE
    1958 Volume 24 Issue 137 Pages 9-15
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.9
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    The Flow distribution throughout the passage of the rotating impeller has been studied in detail about two types of the impellers, one is with radial-straight blades and the other is with logarithmic-spiral blades, and the results are presented in the form of relative velocity and direction of flow. In the former case, it is measured by changing numbers of rotation and flow factor, and is compared with the results of two-dimensional potentional theory which has been published. From this results, it is underatood that the flow in the impeller cannot be conjectured by the theories. The real flow at the experiment, especially when flow factor is large, it flows through the impeller with nearly the same angle with the entrance flow angle, and the region of the slowest velocity occurrs at the blade negative side. In the latter case, the flow is comparatively along the blades. The velocity distributions and direction of flow indicate that secondary flows in the boundary layer tend to shift the low-energy air toward the blade negative surface within the passage. There is a counter effect at the casing surfade apparently caused by leakage through the blade to casing clearance space. This results a vortex flow in the passage.
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  • A Study of Flow Properties of Paper Stock Suspension
    Shoju ITAYA, Toshio TAKENAKA, Sadao SANJO, Yoshinao MATSUOKA, Shigemi ...
    1958 Volume 24 Issue 137 Pages 16-21
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.16
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    The authors examined the effects of plug stoppage of high consistency pulp suspensions by the flow tests of nozzles using groundwood pulp suspensions which have comparatively stable flow properties, and observed that the suspensions of consistency more than 6% indicate flow patterns of brittle solid. Moreover, we measured the pipe friction losses up to high consistency of about 6%, using brass pipes with diameters 23.3, 36.6 and 48.8 mm, and galvanized gas pipes with diameters 1", 1 1/2" and 2". As the results of plotting the pipe friction coefficients vs. a new dimensionless number : N=8 (ρυ2)/(τω) (N is flow number, ρ : density, υ : mean velocity in pipe and τω : shear stress at pipe wall) which corresponds to Reynolds number in the case of water, the experimental values coincided well on the line of λ=64/N (λ being the coefficients of pipe friction losses). At last, the authors gave the calculation formulas of pipe friction losses which are more accurate than previous ones.
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  • Experimental Research on Disc Valve : The 4th Report
    Iwao OKI, Kosaku KAWAKAMI
    1958 Volume 24 Issue 137 Pages 21-27
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.21
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    The characteristics of flat-seated valves provided with guide cylinders as used in some types of safety valve are treated in this paper. Discharging water through a valve (39 mm in diam.) under a constant head of about 2 meters, either into the air, or into the vessel filled with water, we measured the discharge and lifting force for each valve lift, thus observing the performance of the guide cylinder. In the next place, to eliminate the effect of the cylinder edge, we kept the guide cylinder always a little higher than the valve, while the water was issued into the air. Under these conditions we measured the discharge and the lifting force as well as the angle of jet for each of the flat-seated valves of nine kinds, widely differing in diameter ratios. The relations between the quantities thus obtained were made clear by the use of the momentum equation.
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  • On Unusual Characteristic in Gear Pump
    Tsuneo ICHIKAWA
    1958 Volume 24 Issue 137 Pages 28-33
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.28
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    In some gear pumps the delivery quantity increases with the delivery pressure within a certain range of delivery pressure. Such unusual characteristic is undesirable especially when the gear pump is used to deliver the liquid at a constant volume rate. This paper shows that the unusual characteristic is due to the eccentricity of gears.
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  • On Vibration of an Ideal Fluid contained in an Annular Region bounded by two Eccentric Circular Cylinders : Case of Finite Amplitude
    Fumiki KITO
    1958 Volume 24 Issue 137 Pages 33-37
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.33
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    An infinitely long cylindrical wall d2 of circular cross section is assumed to exist. Inside which, another cylindrical wall d1, also of infinite length, is assumed to exist, their axes being parallel to each other. The axes of these two cylindrical walls need not necessarily coincide. The annular space lying between these two walls d1 and d2 is assumed to be filled up with an ideal fluid (non-viscous, incompressible). When the inner cylindrical wall d1 makes a transverse vibration, while the outer cylindrical wall d2 remain fixed, particles of the fluid will also make a vibratory motion. In this report, theoretical calculation is made of the vibratory hydraulic pressure thus set up in the fluid, for a case in which the amplitude A of vibration is of finite value, not necessarily confining to the case of very small amplitude.
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  • On Vibrations of the Draft Tube of Water Turbines (4th Report) : Calculation and Experiment of Forces
    Mitsukiyo MURAKAMI
    1958 Volume 24 Issue 137 Pages 38-43
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.38
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    Intensity of the vibration due to the whirling water flowing through the draft tube of water turbines will depend not only upon form and length of the tube but also upon the dimension of discharge end of the tube. The mode of vibration seems to be considerably different in accordance with form of the tube. Measuring intensity and frequency of this vibration under various conditions and also calcurating these theoretically, the author estimated the vibrating force and frequency which will be observed in the draft tube of water turbines.
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  • On Vibrations of the Draft Tube of Water Turbines (5th Report) : Calculation of Frequencies
    Mitsukiyo MURAKAMI
    1958 Volume 24 Issue 137 Pages 43-48
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.43
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    When the turbine runs on a part load, the water leaving the turbine runner will whirl more or less. Not only the frequency of vibration of the whirling water in the draft tube and the tube itself but also the intensity and the size of vortex core of the whirling water is calculated. This frequency, under particular conditions, coincides with the approximate frequency of draft tube surges given by an empirical formula found on extensive data.
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  • On Vibrations of the Draft Tube of Water Turbines (6th Report) : Characteristics of Vibration for various Tubes
    Mitsukiyo MURAKAMI
    1958 Volume 24 Issue 137 Pages 49-54
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.49
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    The draft tube of water turbines should preferably be straight, but recently the tube is often turned so as to discharge horizontally in order to save excessive cost of excavation. If the draft tube be turned in such a manner, the chracteristics of its vibration may be different from that of the straight tube. In this paper the character of vibration for various forms of the draft tube and the whirling water flowing through it has been investigated and also deviced the means of reducing the vibration.
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  • Effects of the Introduction of Air on Vibrations of the Draft Tube of Water Turbines (I) : Experimental Study
    Mitsukiyo MURAKAMI
    1958 Volume 24 Issue 137 Pages 55-61
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.55
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    When water turbines run on a part load, the whirling water inside the draft tube and the tube itself will vibrate terribly under certain circumstances. Generally to prevent these vibrations, some quantity of air has been introduced into the draft tube at the point just below the turbine runner. But if the introduction of air should not be done properly, it will destroy suction head of the tube or increase the vibration. In this paper the relation between the vibration and the quantity of air introduced into the draft tube to reduce the vibration is investigated experimentally.
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  • Experiments on the Pressure Drop in the Hydrocyclone
    Toshiharu FUJIMOTO
    1958 Volume 24 Issue 137 Pages 61-66
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.61
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    The pressure drop in the hydrocyclone is an important item together with its performances, because the pump, which is used for the hydrocyclone, must be selected according to the pressure drop, and the necessary energy depends upon the pressure drop and the liquid quantity. The author has measured the pressure difference between the inlet and the overflow pipe under the various operating conditions. The influences of the following factors upon the pressure drop were investigated : (1) Feed inlet velocity vi, (2) Diameters of vortex finder Do, underflow nozzle Du and cylindrical portion D, (3) Dimension of inlet nozzle √(bh), (4) Height of cyclone H, (5) Inserted length of vortex finder S, (6) Types of feedins, (7) Pulp density of feed slurries δf. From the above experimental results, author has shown that the pressure drop through the cyclone may be represented by the formulae (4·2).
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  • The Performance of Hydrocyclone as a Thickener
    Toshiharu FUJIMOTO
    1958 Volume 24 Issue 137 Pages 67-73
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.67
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    On the hypothesis that the thickening characteristics of hydrocyclone will depend upon the dimension of the unit and operating conditions, performance tests were carried out using experimental unit. This paper gives the results of the work, including some suggestions with respect to the thickening ratio δu/δf, i.e. the underflow density δu divided by the feed density δf. The influences of the following factors upon the thickening ratio δu/δf were investigated : (1) Diameters of vortex finder Do, underflow nozzle Du and cylindrical portion D, (2) Feed inlet velocity vi, (3) Dimension of inlet nozzle √(bh), (4) Height of cyclone H, (5) Inserted length of vortex finder S, (6) Types of feeding pipe, (7) Pulp density δf and particle size d of feed slurries. In addition to the above results, the author has shown the following two experimental formulas : (1) Flow ratio Gu/Go, i.e. the underflow quantity Gu divided by the overflow quantity Go, may be expressed as equation (4·5), (2) Thickening ratio δu/δf may be expressed as equation (5·8).
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  • The Performance of Hydrocyclone as a Classifier
    Toshiharu FUJIMOTO
    1958 Volume 24 Issue 137 Pages 74-79
    Published: January 25, 1958
    Released on J-STAGE: March 28, 2008
    DOIhttps://doi.org/10.1299/kikai1938.24.74
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    In view of the fact that a hydrocyclone is essentially a classifier, performance tests were carried out using an experimental unit. To evaluate the results of classification the method of Tromp's distribution curve is applied in relation to the particle size. This paper gives the results of the work, including some suggestions with respect to the cut size dT, i.e. dT is a 50% particle size in the above distribution curve. The influences of the following factors upon the cut size dT were investigated : (1) Feed inlet velocity vi, (2) Diameters of vortex finder Do, underflow nozzle Du and cylindrical portion D, (3) Dimension of inlet nozzle √(bh), (4) Height of cyclone H, (5) Inserted length of vortex finder S, (6) Pulp density δf and specific gravity s of feed slurries. In addition to the above results, the author has shown the following theoretical formula : cut size dT may be expressed as equation (4·2).
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