Transactions of the Japan Society of Mechanical Engineers Series B

Unsteady Responses of Aerofoil- and Hycrofoil-Cascade to Sinusoidal Gust

Tetsuo NISHIYAMA

1985 Volume 51 Issue 471 Pages 3429-3437
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3429

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Study of a Bounded Jet Flow Considering the Initial Turbulence : 2nd Report, In the Case of Relatively Large Nozzle Aspect Ratio

Masahiro NAKASHIMA, Tsutomu NOZAKI, Keiji HATTA

1985 Volume 51 Issue 471 Pages 3438-3446
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3438

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Flow Around a Valve Plate Installed in a Duct and its Fluid Force : 3rd Report, Determination of Side Gap Leakage Effects

Junichi KUROKAWA, Akira TAKAGI

1985 Volume 51 Issue 471 Pages 3447-3452
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3447

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Fully-Three-Dimensional Flow Field Analysis through Turbine Stages Comparison between Computation and Experiments

Atsuhide SUZUKI, Tadashi KOBAYASHI, Tatsuo ARAKI, Yasuo OKAMOTO

1985 Volume 51 Issue 471 Pages 3453-3460
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3453

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Effects of Swirl Generator's Charactor on Swirl Velocity in Pipe

Osami KITO, Yoshifumi SUZUKI

1985 Volume 51 Issue 471 Pages 3461-3470
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3461

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Investigation of Film Flow of a Conducting Fluid in a Transverse Magnetic Field : 1st Report, Film Flow in a Nonuniform Magnetic Field

Shuzo OSHIMA, Ryuichiro YAMANE, Yoshihiro MOCHIMARU, Kouzo SUDO

1985 Volume 51 Issue 471 Pages 3471-3479
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3471

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Investigation of Film Flow of a Conducting Fluid in a Transverse Magnetic Field : 2nd Report, Rivulet in a Nonuniform Magnetic Field

Shuzo OSHIMA, Ryuichiro YAMANE, Yoshihiro MOCHIMARU, Kouzo SUDO

1985 Volume 51 Issue 471 Pages 3480-3487
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3480

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Vortex Breakdown Phenomena in a Circular Pipe : 4th Report, Mechanism of Axisymmetric Bubble Type Breakdown

Yoshikazu SUEMATSU, Tadaya ITO, Toshiyuki HAYASE

1985 Volume 51 Issue 471 Pages 3488-3496
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3488

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Experimental Study on a Diagonal-Flow Pump : Energy Losses Caused by Mixed-Flow Impeller

Shigenori MATSUNAGF, Mitsuo UNO, Tsugio HIDA, Hiroshi TSUKAMOTO

1985 Volume 51 Issue 471 Pages 3497-3505
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3497

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Behavior of Solid Particles in a Radial-Flow Pump Impeller

Kiyoshi MINEMURA, Mitsukiyo MURAKAMI, Shigeru SAWADA

1985 Volume 51 Issue 471 Pages 3506-3515
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3506

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Study on a Savonius-Type Wind Turbine : 2nd Report, Effects of Guide Vanes

Takenori OGAWA, Kazuyuki TAHARA, Norio SUZUKI

1985 Volume 51 Issue 471 Pages 3516-3522
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3516

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Study on a Savonius-Type Wind Turbine : 3rd Report, Effects of a Deflecting Plate and Rotor End Plates

Takenori OGAWA, Haruo YOSHIDA

1985 Volume 51 Issue 471 Pages 3523-3529
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3523

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Studies on the Flow Patterns around the Horizontal Shaft Wind Turbines and the Characteristics : Comparison between Optimum Twisted Blades Rotor and No Twisted Blades One

Yukimaru SHIMIZU, Syunsuke NAKAMURA

1985 Volume 51 Issue 471 Pages 3530-3538
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3530

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Transient Boiling Heat Transfer in a Narrow Channel : 3rd Report, Fluctuation Phenomena in the Channel Due to Bubble Growth and Collapse

Kunito OKUYAMA, Shigebumi AOKI, Yoshiyuki KOZAWA, Akira INOUE

1985 Volume 51 Issue 471 Pages 3539-3547
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3539

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Heat Transfer in Nucleate Boiling outside Horizontal Tube Bundles : 1st Report, Experimental Investigation on Tube Bundle Effect

Yasunobu FUJITA, Kaneyasu NISHIKAWA, Haruhiko OHTA, Sumitomo HIDAKA, K ...

1985 Volume 51 Issue 471 Pages 3548-3558
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3548

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Occurrence Threshold of Pressure Oscillations Induced by Steam Condensation into Pool Water

Izuo AYA, Hideki NARIAI

1985 Volume 51 Issue 471 Pages 3559-3566
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3559

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A Study of the Melting Process in Ice-Air Composite Materials : In Presence of Heat Loss from Body End

Kazuo AOKI, Masaru HATTORI, Sakae CHIBA

1985 Volume 51 Issue 471 Pages 3567-3573
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3567

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A Computer Simulation of the Fluid Motion and Heat Transfer of a High Viscosity Fluid in a Rectangular Tank of a Ship with Rolling Motion

Shinsuke AKAGI, Kanji UCHIDA, Hideaki KONDO

1985 Volume 51 Issue 471 Pages 3574-3581
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3574

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Laminar Free Convection with Variable Fluid Properties in Vertical Ducts Having Uniform Wall Temperature

Toshio AIHARA, Shigenao MARUYAMA, Jun-Seop CHOI

1985 Volume 51 Issue 471 Pages 3582-3588
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3582

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Study on Liquid Atomization by Ultrasonic : Case of Low Frequency Ultrasonic

Chikashi CHIBA

1985 Volume 51 Issue 471 Pages 3589-3598
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3589

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An Experimental Study of Spray Flow Field Formed by Liquid/Gas Coaxial Injector Elements : Application for the Combustion Performance Prediction Model of LO₂/LH₂ Rocket Cumbustors

Nobuyuki YATSUYANAGI

1985 Volume 51 Issue 471 Pages 3599-3607
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3599

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Behavior of a Refractory-Lined Distributed-Injection Type Cyclone Furnace

Yukio MIZUTANI, Kohji TOKUDA

1985 Volume 51 Issue 471 Pages 3608-3614
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3608

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A Study on the Drop Formation by Ceramic Piezoelectrical Transducer

Hideyuki HONOKI, Masayuki YAGI, Naochika TOKUOKA, G.Takeshi SATO

1985 Volume 51 Issue 471 Pages 3615-3622
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3615

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Analysis of Combustion Induced Noise of Engine by Single Explosion Excitation : 1st Report, Combustion Noise Characteristics of Stationary Engine

Naoya KOJIMA, Minoru TSUBAKI, Motokazu FUKUDA

1985 Volume 51 Issue 471 Pages 3623-3630
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3623

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Heat Loss into Combustion Chamber Wall of 4-Stroke Gasoline Engine : 2nd Report, Heat Loss into Cylinder Head, Intake and Exhaust Valves

Yoshiteru ENOMOTO, Shoichi FURUHAMA

1985 Volume 51 Issue 471 Pages 3631-3640
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3631

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NO_x Formation in a Precombustion Cbamber Diesel Engine : Combustion Gas Anabysis by High Speed Gas Sampling

Yasuhiro DAISHO, Takeshi SAITO

1985 Volume 51 Issue 471 Pages 3641-3647
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3641

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Experimental Study on Transient Jet Implinging on a Wall : Impinging upon a Flat Plate Vertically

Seiichirou KARITA, Hideaki TANABE, Norimasa IIDA, G.Takeshi SATO

1985 Volume 51 Issue 471 Pages 3648-3654
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3648

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Hydrodynamic Forces on Cylinders Oscillating Sinusoidally in Water

Shusuke HARA, Toshiki SUZUKI

1985 Volume 51 Issue 471 Pages 3655-3658
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3655

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The forces generated by water-cylinder interaction have been investigated experimentally. Two kinds of cylinder models of 75 mm and 100 mm diameter were used. The cylinder with two end-plates was oscillated horizontally in standing water by mechanical oscillating machinery. The force was measured by means of a quartz force transducer. Period parameters ranging from 0.2 to 1.3 and Reynolds numbers from 2180 to 57440 were covered in the investigation. The results have shown that the wave forms of the forces are found to depend on a period parameter, the force amplitudes are determined only by inertia force and the inertia force coefficient takes a constant value of 0.94.

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Transient Fluid Force on a Rapidly Rotating Circular Cylinder in a Uniform Flow

Shigenori MATSUNAGA, Michihiro NISHI, Hiroshi TSUKAMOTO, Takashi YOSHI ...

1985 Volume 51 Issue 471 Pages 3659-3664
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3659

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Experiments were conducted to study the transient characteristics of the fluid force produced on a circular cylinder, which started to rotate rapidly about its axis in a uniform flow. Since the force was influenced by the strength and position of the shedding vortex special care was taken to select the initial condition of rotation which is represented by the lift coefficient and its derivative. The time histories of lift obtained from pressure measurements were compared with corresponding quasi-steady ones. As a result of this study, it is made clear that the initial condition affects the transient lift, and that there is a relationship between the transient characteristics of lift and the quasi-steady ones.

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Break-Line Mode Valve Operation in Large Oil Hydraulic Systems

Sumio ARAI

1985 Volume 51 Issue 471 Pages 3665-3670
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3665

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Oil column separation in the return line of a large oil hydraulic system is studied analytically, and the relation between the valve operation of the break-line mode and the rejoinder surge pressure is investigated. The valve operation of the break-line mode, which has a lower operating speed near the closing point, shortens the valve closing time without increasing the rejoinder surge pressure following the oil column separation. There is a region of the dimensionless valve opening corresponding to the break point of the valve operation, in which the rejoinder surge pressure is lowered. The critical value of this region depends upon the dimensionless parameters which describe the return line. The result obtained in this study is available for the design of the breakline mode valve operation which shortens the valve closing time.

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An Implicit Time-Marching Scheme for Transonic Flows

Hisaaki DAIGUJI, Motoshi KUZUHARA

1985 Volume 51 Issue 471 Pages 3671-3674
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3671

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An implicit time-marching finite-difference scheme is developed for computing the steady two-dimensional inviscid transonic flows with arbitrary shaped boundaries. Most existing implicit time-marching schemes, including the Beam-Warming scheme, are unconditionally stable according to Neumann's stability criterion, but actually cannot take a sufficiently large Courant number, because the diagonally dominant condition of thee coefficient matrix is destroyed. In the present scheme, in order to remove this restriction of the Courant number, the Robert-Weiss convective-difference scheme is applied in place of the Crank-Nicholson scheme in the Beam-Warming delta-form approximate factorization algorithm. As a numerical example, the shocked flows through a nozzle are calculated, and the results are compared with the one-dimensional theory.

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Numerical Analysis of Two-Dimensional Compressible Turbulent Flows in a Turbine Stage

Yoshio SHIKANO, Masahiro IKEGAWA

1985 Volume 51 Issue 471 Pages 3675-3679
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3675

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A numerical technique for the analysis of two-dimensional compressible turbulent flows in a turbine stage is presented. A steady interaction between nozzle and bucket flows is assumed. To calculate the flows in arbitrarily shaped geometries, a control volume method combined with a body-fitted curvilinear coordinate system is used to obtain spatially discretized governing equations. For time integration, a damping surface technique is employed to ensure the stability of computation and to reduce computing time. In the present analysis, a two-equation turbulence model is introduced to estimate the turbulence effect. In order to assure the effectiveness of the present method, a computation is carried out for the two-dimensional section in a turbine stage, and the numerical results are compared with the experimental data. It is shown that the present method gives encouraging results for two-dimensional flow prediction in a turbine stage.

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An Analysis of the Flow on the Bucket of a Pelton Wheel : 2nd Report

Yoshiyuki NAKASE, Junichiro FUKUTOMI, Takashi WATANABE, Yoshio YAMAMOT ...

1985 Volume 51 Issue 471 Pages 3680-3684
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3680

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In this report, a method of analyzing steady, thmee-dimensional flow on the bucket of a Pelton wheel is presented. In the first report, it was assumed that the thickness of the flow on a bucket was very thin, and the effects of pressure on the bucket were neglected. but in this report, the pressure changes based on the thickness of the flow on the bucket are properly considered.

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Determination of Vortex Shedding Frequency and Drag for Karman Vortex Street : 1st Report, Vortex Shedding Frequency

Kensaku IMAICHI, Eiichi TADA

1985 Volume 51 Issue 471 Pages 3685-3688
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3685

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The present paper deals with a theoretical research on the problem of staggered vortex streets formed behind a cylinder in a stream. Assuming that the boundary layer vorticity is perfectly conserved as the shear flow in the wake and the concentrated point vortices, and recorgnizing the justice of Karman's stability criterion, the Strouhal number can be computed as a function of the base pressure coefficient. The calculated results are in very good agreement with the experimental ones for the full Reynolds number range. It is also possible to find the intensity of the circulation of the point vortices of vortex streets over a wide range of Reynolds numbers.

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Determination of Vortex Shedding Frequency and Drag for Karman Vortex Street : 2nd Report, Drag and Lift

Kensaku IMAICHI, Eiichi TADA

1985 Volume 51 Issue 471 Pages 3689-3692
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3689

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The second report paper deals with a drag and a lift on problem of starggered vortex streets formed behind a cylinder in a stream. Assuming that the boundary layer vorticity is perfectly conserved as the shear flow in the wake and the concentrated point vortices, and recorgnizing the justice of Karman's stability criterion, the drag and the lift on the cylinder can be computed as functions of the base pressure coefficient. The calculated results are in very agreement with the experimental ones for the Reynolds number.

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Time-mean Flow around Downstream Circular Cylinder in Staggered Arrangement : Effect of Oscillating Upstream Cylinder

Masaru MORIYA, Hiroshi SAKAMOTO

1985 Volume 51 Issue 471 Pages 3693-3698
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3693

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Two circular cylinders in staggered arrangement can be found very often in the engineering applications. In this paper, the effects of forced oscillation of the upstream cylinder on the time-mean flow around the downstream cylinder in staggered arrangement studied experimentally are presented. The upstream cylinder was forced to oscillate transversely to the main flow direction at the natural vortex shedding frequency of the downstream cylinder. Even for the small amplitude of oscillation, the time-mean flow around the downstream cylinder was greatly affected in some particular arrangements. The instrumental measurements were mainly made with static surface pressure, and the visual investigations were made on the surface oil flow pattern.

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Measurement of Turbulence by Laser Homodyne Technique

Makoto IKEGAMI, Masahiro SHIOJI, Dao-yuan WEI

1985 Volume 51 Issue 471 Pages 3699-3705
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3699

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A method of measuring turbulence by means of the laser homodyne technique without relying upon time-sequential data, which ordinary methods use in obtaining information on turbulence, is proposed. The principle of this method is to detect relative fluid motions of turbulence by receiving a beat of light scattered from each pair of tracer particles. A photoelectron correlation method has been used to process the photomuliplier signal to yield statistical average of the light beat over the pairs in the measuring volume. A set of autocorrelograms that are gained for different dimensions of the measuring volume leads to a relation between fluctuation velocity and the dimension, which is fitted to theoretical one to yield turbulence intensity and integral scale. A verification of the proposed method has been made by comparing the results with hot-wire anemometer results. A disscusion is made of several factors that affect the accuracy.

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Study on Control of Radial Attaching Jet Flow : 2nd Report, Effects of Control Flow on Pressure Distributions

Toshio TANAKA, Eiichi TANAKA, Satoru NAGAYA

1985 Volume 51 Issue 471 Pages 3706-3711
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3706

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This paper presents the results of an experimental study on the reattachment of a radial turbulent jet flow discharged from a cylindrical nozzle on an adjacent offset disc plate. Static pressure distributions along the disc surface and across the jet flow were measured with a disc type pressure hole, and the effects of step height and control flow rate (suction and blowing) on them were investigated. Length and average negative pressure in the recirculating flow region, and the position of reattachment to the wall surface were examined. An oil film flow visualizing technique was also applied to determination of the flow pattern, and the results were compared with those obtained from the pressure distributions.

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A Study of Movement of a Sphere in Air Flow Through Horizontal Pipe

Fujio YAMAMOTO

1985 Volume 51 Issue 471 Pages 3712-3719
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3712

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The present study was carried to produce some basic data for the numerical investigation of pneumatic convection of solid particles. In the equation of motion for a spinning sphere, a force F^^&roarr;_v due to the velocity gradient of air flow through pipe was newly proposed, in addition to the forces of gravitation, drag, and lift. The force F^^&roarr;_v acts so as to move the sphere to the pipe center line. In the preliminary experiment, the drag coefficient C_d of the test sphere, whose diameter was 3mm, rebound coefficient e and friction coefficient μ_d for collision between the sphere and pipe wall were measured. Their values were substituted into the corresponding terms of the equation of motion. The equation of motion was numerically solved by use of the Runge-Kutta-Gill method. The values of lift coefficient C_L and coefficient G_s for F^^&roarr;_v were decided by making comparison between the computed and the experimental results of the trajectory of sphere. As a result, C_d=0.6, C_S=0.1, C_L=(1.6-2.0) d_pω/| W^^&roarr;'| and μ_d=0.12-0.20 were obtained for Reynolds number R_{e, p}=2000-6000.

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Production of Uniform-Size Droplets by a Rectangular Nozzle : 2nd Report : Effect of Liquid Properties on a Producible Range

Takao KARASAWA, Seiichi SHIGA, Toshio KURABAYASHI

1985 Volume 51 Issue 471 Pages 3720-3725
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3720

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A simple method for producing uniform-size droplets has been proposed. A thin rectangular nozzle can generate a chain-type jet and, under some conditions, the jet disintegrates into droplets of high uniformity. The previous paper reported on the mechanism of uniform-droplet formation, and showed that the imposition of sound vibration to the jet can remarkably stabilize the phenomenon and extend the producible range. In the present paper, experiments are carried out using suger and ethanol solutions to reveal the effect of liquid properties, such as viscosity and surface tension, on the producible range of uniform-droplet. The results showed that both the increased viscosity and the isreased surface tention have a tendency to extend the producible range, though far increased viscosity has a negative effect. The producible range lies over Weber Number W_e=203000 and stability number S_b=0.0030.08.

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On The Various Boundary Layer Approximations of the Flow on a Rotating Cylinder in an Axial Flow

Ikuo NAKAMURA, Takashi WATANABE, Kinichi KATO

1985 Volume 51 Issue 471 Pages 3726-3731
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3726

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In the Navier-Stokes equations, the effects of rotation and transverse curvature on the flow on a rotating circular cylinder in an axial flow are estimated in terms of the Blasius variables, the Mangler-Falkner-Skan variables and the Seban-Bond variables. Three systems of boundary equations are obtained. The equations in terms of the Seban-Bond variables represent the radius effect more appropriately then the others. These equations are integrated for a prescribed external adverse pressure gradient and the difference in approximation is investigated. In each case, when the cylinder is rotating, the calculation proceeds beyond a separation point and terminates at a point where an internal singularity appears. The flow pattern, predicted by each of the equations, varies with the angular velocity of the cylinder in the same process. when the boundary layer grows, the higher order effect of the radius becomes significant.

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A Study of Separation and Reattachment of a Turbulent Flow Behind a Backward-Facing Step : 2nd Report, Effects of Free Stream Turbulence and Step Geometry

Kaoru ISOMOTO, Shinji HONAMI

1985 Volume 51 Issue 471 Pages 3732-3736
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3732

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The behavior of a separating shear layer and its reattachment is clarified experimentally when free stream turbulence is provided for six separate cases in a backward-facing step flow. The reattachment point was determined by a thermal tuft probe. A hot-wire anemometer was used for measurements of mean velocity and turbulence. Reynolds number based on step height was 3.2×10⁴, turbulence level ranging from 0.25 to 7.4%. The turbulence level upstream of the step is the higher, the shorter reattachment length is obtained, while no effect of step geometry on reattachment is observed.

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A Study on Radially Curved Mixed-Flow Vaneless Diffusers : Diffusers Having a Constant Radius of Curvature at a Radially Curved Section

Yoshiki NIIZEKI, Toshimichi SAKAI

1985 Volume 51 Issue 471 Pages 3737-3742
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3737

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The flow pattern and performance of radially curved mixed-flow vaneless diffusers having constant radius of curvature at the diffuser meridional plane were examined. The correlation between the inlet flow angle and the radius of curvature of the radially curved test section was clarified. A favorable inner flow and higher diffuser performance were obtained in the case of diffusers having a small pressure gradient normal to the diffuser walls near the inlet portion.

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Blade Force Measurement and Flow Visualization of Savonius Rotors

Tadashi SAWADA, Masahide NAKAMURA, Shin KAMADA

1985 Volume 51 Issue 471 Pages 3743-3747
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3743

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For the purpose of clarifying the mechanism of rotation of Savonius rotors, ones which have two semicylindrical blades are studied experimentally. The force acting on a blade is measured in a water two tank for both cases where a rotor is at rest and rotated. The flow around a rotor is observed by using aluminum powder floating on the water surface. Although the Savonius rotor is classified into a resistance type, the lift produces the torque in a pretty wide range of angle relative to the flow.

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An Analysis of Unsteady Flow Induced by Interaction Between a Centrifugal Impeller and a Vaned Diffuser : 1st Report, Measurement of Pressure Fluctuations in Pump Impellers

Toshiki IINO, Kenichi KASAI

1985 Volume 51 Issue 471 Pages 3748-3753
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3748

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The pressure fluctuations were measured in the impellers of centrifugal pumps with vaned diffusers. Frequency analysis shows that N (rotor speed)×Z_d (number of diffuser blades) component and its harmonics are dominant in the fluctuations. The amplitudes of the NZ_d component have their minimum value when the flow coefficient is close to the value for shockless entry into the diffuser vanes. The phase angles of the NZ_d component at most measuring points are determined only by the circumferential position of the measuring points when the flow coefficient is small. The maximum amplitude of the NZ_d component throughout the experiments was 4% of the dynamic pressure defined by the peripheral velocity of the impellers.

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A Study on Performance of Centrifugal Pumps Driven in Two-Phase Flow : 2nd Report, Prediction of Pump Head

Hideo FUJIE

1985 Volume 51 Issue 471 Pages 3754-3759
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3754

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A method to predict the head of centrifugal pumps driven in two-phase flow is proposed. With the method, pressure changes in and after the impeller are estimated considering the phase separation in the impeller; that is: (1) The pressure change in the impeller is calculated from integration of the pressure gradient term (dP/ds) in momentum conservation equations of both phases in the impeller. The friction loss coefficients used in the equations are so selected that the calculated hydraulic torques using the equations with the selected coefficients agree with experimental data; (2) The pressure change after the impeller exit is estimated considering velocity difference between the phases induced by the centrifugal force in the impeller as well as losses attributable to two-phase flow. For rated conditions, the calculated results show pretty good agreement with experimental data and the proposed prediction method seems useful. However, for a condition of 45% rotation speed with rated flow rate, the agreement is not good enough and some improvements in the method may be needed.

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An Investigation of Heat Transfer to Gas Turbine Cooling-Blade Surfaces

Masakazu OBATA, Joji YAMAGA, Hiroshi TANIGUCHI

1985 Volume 51 Issue 471 Pages 3760-3765
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3760

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Velocity distributions and local heat transfer coefficients obtained experimentally are presented for various Mach numbers and blade Reynolds numbers for the two surfaces of a typical gas turbine cooling-blade having considerably large leading- and trailing-edge radii. Confirmation of the theoretical velocity distribution, applicability of the cylinder formulae to the heat transfer coefficient at the leading-edge, and determination of boundary-layer transition criteria and length are considered in the light of the areodynamic, heat transfer, and lamp-black experimental values. It is found that the local and the mean heat transfer coefficients can be predicted well by presently available calculation methods using the theoretical velocity distribution and the transition criteria determined in this way.

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Natural Convection Heat Transfer in an Inclined Air Layer Packed with Spherical Particles

Hideo INABA, Takeyuki FUKUDA, Masahiro SUGAWARA

1985 Volume 51 Issue 471 Pages 3766-3771
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3766

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Experiments of natural convection heat transfer in an inclined air layer with spherical particles under isothermal heating and cooling conditions were carried out for the ranges of inclination angles (θ=0180°), aspect-ratios (H/W=2.57.9), modified Prandtl numbers (P*_r=1.145), ratios of diameter of spherical particles to width of the porous layer (d/W=0.040.516) and modified Rayleigh numbers (R*_a=2.2×101.03×10³). According to the inclination angle, the convection heat transfer in the porous layer varied because of the change of the convection flow type. In addition, useful correlations of non-dimensional convection heat transfer were derived in the relations Nusselt number N_u=f[P*_r, d/W, R*_a cos(θ-60°)] for θ=015°, and N_u=f[P*_r, H/W, R*_a (θ-60°)] for θ=0120°.

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Natural Convective Heat Transfer on a Vertical Plate with Discontinuous Surface-Heating : Effect of the Heat Conduction of a Plate

Koki KISHINAMI, Hakaru SAITO

1985 Volume 51 Issue 471 Pages 3772-3776
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3772

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Natural convective heat transfer along vertical plates with discontinuous heating elements has been studied by numerical computation and experiments. It has been found that the heat transfer on the surface of a plate and the temperature distribution of unheated elements change depending upon the ratio of the thermal conductivity of convective fluid and that of the unheated element material, the ratio of thickness and length of unheated elements, and the length and surface temperature of the heating elements. The heat transfer data are also found to be correlated by using a parameter S=B··R_λ/G^1/4_rL, presented in this paper through vectorial dimensional analysis, and the observation of convective behavior visualized by a Mach-Zehnder interferometer and computational results. An empirical formula has been presented to predict heat transfer coefficients of discontinuously heated plates based on the new parameter S.

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Pipe Fracture by Freezing in Curved Water Pipes : 1st Report, Freezing Behavior of 180° Curved Pipes

Shigeyoshi OIWAKE, Hideo INABA

1985 Volume 51 Issue 471 Pages 3777-3781
Published: November 25, 1985
Released on J-STAGE: March 28, 2008

DOIhttps://doi.org/10.1299/kikaib.51.3777

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The formation of the ice growth that occurs in 180° curved pipes containing water flow was investigated. The experiments were carried out under various experimental conditions in a range of pipe with an inside diameter of d=16.5mm21mm, Reynolds numbers (based on pipe i.d.) R_e=2906653, and temperature ratios of the freezing parameter, T*(=T_f-T_w)/(T_∞-T_f), T_f=0°C, T_f=cooling pipe temperature, T_∞=temperature of flowing water)=1.5211. From visual observations of ice formation and measurements of the pressure drop between the inlet and outlet of a curved pipe, it was understood that the flow condition and temperature ratio T* played an important role in the formation of ice in the curved pipe. The transient behaviors of ice formation, according to time proceeding, were expressed in the relationship between nondimensional friction resistance f and Reynolds number for various temperature ratios T*. Moreover, the critical condition of perfect ice blockage in the curved pipe was obtained with experimental correlation equations in terms of T* and R_e.

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