Transactions of the Japan Society of Mechanical Engineers
Online ISSN : 2185-9485
Print ISSN : 0029-0270
ISSN-L : 0029-0270
Volume 19, Issue 81
Displaying 1-20 of 20 articles from this issue
  • Yoshimasa FURUYA
    1953 Volume 19 Issue 81 Pages 1-6
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In order to study the effect of the thickness of the layer and the pressure gradient on the velocity distribution curve, the experiments are carried out in the boundary layer along the smooth wall in a diverging channel of rectangular section. In order to make the layer thicker, for example, a corrugated plate is laid on the wall up-stream the measuring wall. These experiments cover a range of Reynolds number Uδ/ν from 2×104∼1·3×105 and a range of thickness of layer δ from 6 mm to 60 mm. The effect of the non-dimensional pressure gradient Γ on the velocity curve appears a little later, but if the pressure gradient dp/dx/ρ/2U2<2m-1, the shape of the non-dimentional velocity distribution has a single family of curves within the discrepancy not exceeding 2∼3%. When the pressure gradient becomes greater, the velocity curve near the wall varies and cannot be fixed by one form parameter.
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  • Yukio TOMITA
    1953 Volume 19 Issue 81 Pages 7-9
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In this paper the author obtained the velocity distribution in turbulent flow between parallel planes and in pipes basing on the idea of energy that the dissipation of energy in turbulent flow is minimum. It was shown, moreover, that the minimum theory of energy is equivalent to the transport theory of momentum.
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  • Naotsugu MASUGI
    1953 Volume 19 Issue 81 Pages 10-15
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In this report, compressible gas flow passing a long and straight simple nozzle is analysed, considering the influence of the laminor boundary layer at the wall, and its theoretical calculation with air is reported. According to its results, the state of flow is determined by the nozzle-characteristic-number shown here : and as the function of which, the distribution of the boundary layer's thickness and mainstream's pressure etc. are calculated. Especially, this report differs from the others in the important points that, when the nozzle charact. -number is more than 0.03, the throat of mainstream is calculated to be at about 80% of the nozzle length, and behind which the main stream becomes super-sonic, inspite of parallel-nozzle or pipe.
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  • Jurio TSUCHIYA
    1953 Volume 19 Issue 81 Pages 16-20
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In this paper, the experimental results of the circular wing lattice used with a wind tunnel are described. The wing lattices were formed with 12 and 24 aerofoils, thickness 11%, and setting angle of each wing was 0, ±15, ±30, ±45, ±60, ±75 degrees and under the above condition, the author measured the pressure distribution of the aerofoil along the span and the direction of the stream which flowed from the guide vane. The normal force coefficient, the moment coefficient at the leading edge of the aerofoil, the center of pressure and the moment around the revolution axis which induced the hydrodynamical force were calculated from the pressure distribution. The circulation around each vane, which was calculated from the velocity distribution were compared with one which was calculated from the direction of the surfaces of the aerofoil at the trailing edge, and the inner circulation of the wing lattice, which was calculated from the pressure distribution was compared with one which was calculated from the direction of the stream.
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  • Atsushi MIYADZU
    1953 Volume 19 Issue 81 Pages 20-25
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    (1) To study the flow of viscous fluid trapped between the teeth of a gear pump, the differential equation determining the pressure of flow pressed-out (or drawn-in) by the boundary walls has been derived on the basis of Navier-Stokes' equations (Fig.1). The inside pressure rises or falls respectively at the opening, as the sectional area of the flow is decreasing or increasing. The pressure distribution along the flow is parabolic, with maximum (or minimum) value at the innermost section. (2) The differential equation determining the pressure in the layer of laminar flow pressed-out (or drawn-in) by two adjacent plane or curved walls has been derived. To obtain a general view of the nature of flow, the solution has been worked out for the circular planes. The rise or fall of the inside pressure is proportional to the coefficient of viscosity and time rate of discharge, and is inversely proportional to the 3rd power of the thickness of fluid layer.
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  • Atsushi / MIYADZU, [in Japanese]
    1953 Volume 19 Issue 81 Pages 25-32
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    As a development of the equation obtained in the 1st Report, the pressed-out (or drawn-in) flow through a channel of rectangular cross-section (Fig.1) has been studied to see the effect of trapping flow in a gear pump on the pump power and discharge. (1) Work done for trapping flow is composed of two parts, one being that to overcome friction, which is rather small, in order of 1/20 of the total friction loss of power, and the other that to overcome the pressure at the opening. (2) The dividing wall, in the relief groove, between the delivery and suction sides has the optimum thickness for the increase of discharge, depending upon the resistance of the groove. Fig.8. shows the volumetric efficiency, which is defined as ην=ΔV/V, where ΔV=volume of fluid delivered to the pressure side and V=volume of fluid pressed out by the trapping action.
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  • Atsushi MIYADZU
    1953 Volume 19 Issue 81 Pages 32-37
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    This paper supplements to the 1st Report (1) the discussion of the pressure distribution over the fluid layer, and (2) the illustrative treatments for the layer of non-uniform thickness. (1) The pressure distribution over the section of layer is parabolic, in assumption that the fluid velocity in the direction normal to the wall is proportional to the distance from the fixed wall. (2) When the walls are drawn apart, the pressure on them is lower than that in mid-layer, and when pressed close, it is higher. (3) The assumption of uniform pressure within the layer does not satisfy the continuity for any point, but can do only for any section, that is no other than the basic equation obtained in the 1st report. (4) The pressure rise or fall on the bounding wall is noticable when the thickness of the layer is not uniform with narrow opening.
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  • Atsushi MIYADZU
    1953 Volume 19 Issue 81 Pages 37-40
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    As an application of the basic equation in the 1st Report, the radial flow of a viscous fluid has been treated, with special reference to the flow between two circular discs, one of which is connected to the circular pipe at the central part. Since the dynamic terms involoing the square of the velocity have been neglected, the conclusions are contrasted to those for the flow of a perfect fluid. (1) The pressure inside becomes higher or lower than that outside, according as the flow is radially outward or inward, and it is more noticable in inner part. (2) If the plate rotates and the centrifugal pressure is induced, the mean pressure inside becomes lower than that outside, even when the flow is radially outward, the critical condition for which has feen decided.
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  • Syoju ITAYA, Toshio TAKENAKA
    1953 Volume 19 Issue 81 Pages 41-43
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    According to our viewpoint that the submerged weirs will be a submerged orifice, we gave a formula of coefficient of discharge of submerged sharp-creasted weirs. The result was compared with those obtained by many methods, i.e., "du Buat", "Wisconsin", "Fteley & Stearns", "Francis", "Herschel" and "Bazin".
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  • Ichiro TODOROKI, Shichiro HATANO, Kazuaki SHIRAMOTO
    1953 Volume 19 Issue 81 Pages 43-47
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    We made three different types of Pitot spheres with five pressure holes in order to research the characteristics of the Pitot tube. The results of our experiment are as follows : 1. For the hook-formed stem the effect on the characteristics by the stem is smaller than straight one, so that the former is better. 2. The Pitot sphere with α=40° is superior to that with α=30°. (α is the angle between the hole on the meridian and the equatorial plane).
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  • Masato HIROTSU
    1953 Volume 19 Issue 81 Pages 47-50
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    The author formerly presented an efficiency calculation formula of water turbines. But, the formula involved somewhat complicated calculation. So a new simple formula for the case of propeller and Kaplan water turbine was deduced to avoid this complication. The theoretical difference between former and latter formulas lies in the calculation of wake energy. In the former, wake energy was estimated by inlet velocity to runner, and The latter case by outlet velocity. The assumption to deduce the former formula for Kaplan turbine was also investigated in detail, because there was no actual basis to justify this assuption. By investigation of actual example, it was found that the former assumption is closely equivalent to assume the incidence angle of aerofoil element at the representative radius is constant in the case of Kaplan turbine.
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  • Taijiro KASAI, Takefumi IKUI, Yuji SATO
    1953 Volume 19 Issue 81 Pages 50-55
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    An experimental investigation is carried out on the characteristics of a gear pump to clarify the effects of side clearance and fluid viscosity. The gear of pump on test is of corrected involute type, 7 teeth, pressure angle 14° 30', module 4, pitch circle dia. 28 mm, external dia. 37.9 mm, teeth thickness 21.88 mm, theoretical displacement 17.14 cc/rev, tip clearance 0.05 mm, and side clearances are varied from 0.2 to 0.5 mm. Viscosities of the fluids are varied in the range 150∼5000 Redwood-seconds. It is shown that the effects of side clearance δ and viscosity ν can be expressed quite briefly using non-dimentional parameter Φ=H/n f(ν, δ), where H and n denote the manometric head and number of revolutions of the pump respectively, and f (ν, δ) is a function of ν and δ, which are characteristic to pumps.
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  • Tomokazu ASANO, Shuro MACHIDA
    1953 Volume 19 Issue 81 Pages 55-61
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In this report, the influences of the mixing-chamber dimensions on the efficiency were investigated. The most desirable dimensions for the mixing-chamber to give the maximum efficiency were obtained. That is : To give the maximum efficiency for the parallel-wall circular-section type ; (a) the length of the mixing-chamber L must be L÷8 D, where D is the internal diameter of the mixing-chamber. (b) the ratio of the sectional area of the nozzle and that of the mixing-chamber must be an/A÷0.15. (c) the coefficient of resistance of the driven-side must be A2/a÷0.93.
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  • Takefumi IKUI, Toshihiko UEDA
    1953 Volume 19 Issue 81 Pages 61-66
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    In the axial fan, the flow pattern for the two dimensional flow in which the fluid flows in concentric cylindrical surface is free vortex. For free-vortex type axial-flow fan, we introduce an expression of circulation, lift and drag coefficient, blade efficiency for impeller and guide vane and show that the Howell's expression of lift is essentially identical with ours. Also we show the expression for manometric efficiency of blade element, whole impeller and guide vane and contra-rotating axial fan and overall manometric efficiency of complete fan including ducts. We can obtain at once the efficiency by these expression.
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  • Takefumi IKUI, Toshihiko UEDA
    1953 Volume 19 Issue 81 Pages 66-71
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    It is important to know in which section the stall of impeller and guide vane occurs at first. It seems that the stall is closely connected with the distribution of lift on the blade. Though at the root solidity is small, large lift coefficient is frequently required, we also introduce the expression for stall condition at the root and prepare certain diagrams convenient for application to design. By using the diagrams we can easily know whether the flow and pressure coefficient at the design point are safe or not for stall. And we introduce a method of assuming the pressure-and efficiency-discharge characteristic curve, especially at once predicting stall point and show examples.
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  • Takefumi IKUI, Toshihiko UEDA
    1953 Volume 19 Issue 81 Pages 71-78
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    The condition that the axial flow fan is to be operated at maximum efficiency is to make the overall manometric efficiency maximum taking also the loss of pipe line which is connected the fan into consideration. We show a disign to obtain the maximum manometric efficiency, in two cases where the diameter of impeller is determined freely or given, when the discharge, r.p.m., no. of stages and pressure are known or discharge and r.p.m. are given. We also described the design to make power of non-pressure fan for ventilating minimum and prepar diagrams of φt, ψt, and ηMb useful for design of axial fan with guide vane (axial inlet flow and axial outlet flow) and fans with guide vanes ahead of and past the impeller when neglecting the pipe resistance. We can obtain the values of size and efficiency of fans for given data at once.
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  • Koichi IINOYA
    1953 Volume 19 Issue 81 Pages 78-83
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    The small eccentricity between a pitot tube and the center of air flow gives a large apparent error to the radial flow component. The flow distributions in an exit pipe are measured with a spherical pitot tube. Air flows in the suction type and at different quantities, and its circumferential as well as axial flow distributions, and the pressure distributions on cylinder wall are measured. Pressure drops of a cyclone occur by changing the total length, exit diameters and air quantities. These experimental results serve for foundamentals of the cyclone theory.
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  • Koichi IINOYA
    1953 Volume 19 Issue 81 Pages 83-89
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    Applying Stokes' law to the settling velocity of a dust particle, we noticed the balanced diameter of a particle and its max. value on the wall. Using Rosin's formula for the size distribution of dusts and being assumed partial collection efficiency against the dust diameter, we got many approximate formulae for the total collection efficiency, of which 1 st approximation (the critical particle diameter theory) is sufficient for the practical use. To confirm this theory the effects of inlet velocity, cyclone size, exit diameter, kind of dusts, cylinder wall length, inlet area, cylinder diameter and cone angle were measured, and we found that it coinsides with the results on the whole, although the absolute value of the collection efficiency will not be obtained only by this theory.
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  • Koichi IINOYA
    1953 Volume 19 Issue 81 Pages 90-95
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    Pressure drop of the cyclone is its important characteristic, and here the pressure drop is defined as the inlet static pressure Pi, when the exit pipe opens to atmosphere. From many experiments of flow patterns in the cyclone, theoretical formulae of pressure drop are obtained, and an approximate formula is also given. Many experiments on pressure drop are done and discussed, and thereby the theory is verified. This theory makes it easy to design a cyclone and to estimate its characteristics.
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  • Tadaya ITO
    1953 Volume 19 Issue 81 Pages 96-99
    Published: May 30, 1953
    Released on J-STAGE: March 28, 2008
    JOURNAL FREE ACCESS
    Accuracy of the theoretical formulas, which furnish the natural frequencies of air columns in the pipes having a discontinuous cross section, is tested by the experiment. A pressure-sensitive diaphragm having a high natural frequency was used to receive the pressure variation of air columns. And a record was obtained on a bromide paper by an optical method. For the periodic analysis, the N. Bernstein's method was used. And the experimental values of natural frequencies were in good agreement with the theoretical ones.
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