JAPANESE JOURNAL OF MULTIPHASE FLOW
Online ISSN : 1881-5790
Print ISSN : 0914-2843
ISSN-L : 0914-2843
Search
Advanced search
OR
Browse
Search
Volume 11, Issue 1
Displaying 1-12 of 12 articles from this issue
Show all abstracts
    • |<
    • <
    • 1
    • >
    • >|
  • Rheology and Turbulence Control Effect of Rod-like Micelles Formed by Surfactants
    Hiromoto USUI
    1997 Volume 11 Issue 1 Pages 3-6
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.3
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The addition of cationic surfactants with suitable counter ion causes a remarkable drag reduction in a turbulent pipe flow. This drag-reducing technique is one of the candidates for pumping power reduction in a district heating and cooling system. Since the scale of micelles formed by surfactant additives is very small, the dynamics of rod-like micelles in a turbulent flow field can not be detected at the present stage. Also, the theoretical prediction of the movement of a rod-like micelle as a two phase turbulent flow is very difficult. The configuration of rod-like micelles and the viscoelasticity caused by the rod-like micelles are reviewed. Recent approaches to the theoretical prediction of surfactant drag reduction mechanism are also reviewed. These information reveals out the present status of drag reduction phenomenon from the stand point of multiphase flow.
    View full abstract
    Download PDF (2598K)
  • Liquid Rocket Engine
    Kenji KISHIMOTO
    1997 Volume 11 Issue 1 Pages 7-10
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.7
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Liquid propellant rocket engine is introduced, and discussed about the technology status. As a relation with Multiphase technology, a new rocket engine development approach is introduced.
    View full abstract
    Download PDF (8022K)
  • Geothermal Energy Development and Multiphase Flows
    Shigeo KIMURA
    1997 Volume 11 Issue 1 Pages 11-14
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.11
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Multiphase flows that arise in geothermal energy development have been briefly reviewed. A particular emphasis is placed on gas-liquid two-phase flows in geothermal production well. A liquid phase geothermal fluid is normally fed at the bottom of the well. However, as the fluid rises in the wellbore, it loses the pressure and eventually starts boiling; a steam-water two-phase flow results. A one-dimensional formulation of the two-phase flow for wellbore simulation is described in some detail, where the steam-water relative velocity is taken into account through empirical correlations. The presence of dissolved NaCl and noncondensable gas (CO2) is. one characteristic of geothermal fluid. The present status of two-phase flow simulators for production wellbore is also described. It is suggested that the empirical correlations to differentiate flow regimes and to evaluate the frictional pressure losses along the well, especially for large diameter pipe flows, are essential in accurate prediction of the wellbore two-phase flows.
    View full abstract
    Download PDF (484K)
  • Numerical Simulation of Particulate Flows in Pharmaceutical Apparatus
    Yoshitsugu MUGURUMA
    1997 Volume 11 Issue 1 Pages 15-18
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.15
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Numerical simulation of the particulate flows has become possible by using discrete element method (DEM) with high performance computers. Calculations of particle motion in three kinds of pharmaceutical apparatus done by the author are reviewed. A centrifugal tumbling granulater, a rotating vessel type mixer and a screw feeder are dealt with. The present simulations predict well the realistic particulate flows. Pharmaceutical industries manufacture products which affect human life. Therefore it is necessary to make the process validation which guarantees the security of life and the effect of a medicine. It is important to know the behavior of particles in detail in order to control the quality 01 pharmaceuticals. The numerical simulation makes it possible to know the detailed information such as the three dimensional particle behavior, the interaction between particles and the effect of condition of equipment. These information is helpful in deepening out understanding powder processes.
    View full abstract
    Download PDF (3564K)
  • Ships and Multiphase Flow
    Yoshiaki KODAMA
    1997 Volume 11 Issue 1 Pages 19-22
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.19
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Flows around ships have various kinds of multiphase flows because ships move at the interface between air and water. The first example is free-surface waves generated by an advancing ship. The phenomenon can be simulated using CFD based on NS solvers, and the comuted wave pattern and the wavemaking resistance agree well with measurements. The second example is wave impact generated at the bow of a ship running in waves. In this example, the flow becomes a multiphase flow type with foams or bubbles. The third example is propeller cavitation, which is an evaporation process at normal temperature. On a full-scale propeller, the cavitation consists of bubbles, which cause erosion in the collapsing stage. The last example is microbubbles for the reduction of frictional drag, the major part of ship's drag. The microbubbles are quite effective in the reduction, but further study is needed for its practical use.
    View full abstract
    Download PDF (3786K)
  • Interlacing Process of Multiple Filament Yarns
    Yoshiyuki IEMOTO
    1997 Volume 11 Issue 1 Pages 23-29
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.23
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    The processing mechanism, structure and property of multiple filament interlaced yarns with alternate tangling and opening parts are described on the basis of experimental data. The most important factor in the interlacing process is an air flow in a yarn duct of an interlacer. The high speed turbulent air jetting into the yarn duct from an air jet nozzle opens multiple filaments of running yarns separately and changes their relative positions. An opening part is formed at the position subjected to the air jet directly and tangling parts are formed at its both ends. The tangling parts keep their forms by the friction among filaments although the tangling part formed before the air jet nozzle is directly subjected to the air jet. Filaments in the tangling parts contact with each another and the number of tangles depends on the processing conditions of the working air pressure and feed ratio.
    View full abstract
    Download PDF (3986K)
  • Fundamental Problems of Emulsion Characteristics in Particle-Gas Fluidized Beds
    Hisashi KONO
    1997 Volume 11 Issue 1 Pages 30-36
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.30
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    A review on the classical two phase flow theory is carried out in this paper, based on the updated theories and experimental works of the 1990s. Recent developments of the emulsion phase characterization methods using powder rheology in fine powder fluidized beds are introduced and reviewed. Particularly, the physical meaning and significance of incipient bubbling points are interpreted in terms of the fracture model. The significance of flow characteristic functions of aerated fine powders, obtained theoretically and experimentally, is explained.
    View full abstract
    Download PDF (2996K)
  • Study on Direct Mixing Type Axial Flow Cyclone Heat Exchanger between Gas and Particles
    1st Report: Proposal and Gas-Particle Separation Performance
    Takehiko YOKOMINE, Akihiko SHIMIZU, Tatsurou NAGAFUCHI, Mitsuhiro NAKA ...
    1997 Volume 11 Issue 1 Pages 37-45
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.37
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    A direct mixing type axial flow cyclone heat exchanger between gas and high temperature particles is proposed which serves as particle separator as well. The proposal was motivated by the concept of high temperature nuclear energy conversion system for which dense gassolid suspension flow is considered as primary coolant. However, it may also be used as a general heat recovery device from various high temperature powdery waste material from conventional industry. In this heat exchanger, the particles, after being mixed directly with gas, transfer their heat to the gas in the form of quasi-counter-flow and are effectively re-separated by centrifugal force due to swirling motion of the gas. The mock-up of the heat exchanger was designed and constructed and its reseparation performance was examined both experimentally and numerically, which is the key to realize such innovative energy conversion systems.
    View full abstract
    Download PDF (7715K)
  • Experimental Investigation of Bubble Formation from a Nozzle and an Orifice
    1st report, Frequency of Bubble Formation for Upward Gas Injection
    Manabu IGUCHI, Tomoyuki CHIHARA
    1997 Volume 11 Issue 1 Pages 46-55
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.46
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Gas was injected into a bath vertically upward through a nozzle, an orifice, or a lance nozzle. The frequency of bubble formation at the exit of these injection devices was determined by counting the number of bubbles per second from visual images recorded using a high-speed video camera. The measurements were carried out under the condition that the effect of the gas chamber volume on the bubble formation was negligible. An empirical correlation of the bubble frequency was proposed as a function of gas flow rate, inner diameter of the nozzles and orifices, and the physical properties of gas and liquid. This correlation could estimate measured values of the frequency of bubble formation even for a high gas flow rate within a scatter of ±30% regardless of the injection devices.
    View full abstract
    Download PDF (1049K)
  • Critical Heat Flux under Flow Oscillation in a Natural Circulation Loop of Liquid Nitrogen
    Hisashi UMEKAWA, Mamoru OZAWA, Naoki ISHIDA
    1997 Volume 11 Issue 1 Pages 56-65
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.56
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    In a natural circulation loop, flow instability, such as density wave oscillation, occurs under a certain operating condition, while the influence of flow oscillation on the heat transfer is not well understood so far. Experiment was conducted by using a natural circulation loop of liquid nitrogen with test tubes of dimensions of 3.0mm/5.0mm I.D., and 900mm heated length. It was indicated that the heat transfer correlation of Schrock-Grossman was in good agreement with experimental results in the saturated boiling region even under oscillatory flow condition, and that the correlation of Roko was in good agreement with the experimental results of post-dryout heat transfer even under oscillatory flow condition. On the other hand, the CHF was well predicted using the lumped-parameter model, taking account of the circulation rate, oscillation frequency and amplitude of mass flux in the natural circulation loop.
    View full abstract
    Download PDF (1217K)
  • Comments on the Technical Terms for Cavitation and Bubble Dynamics
    Hiroyuki TAKAHIRA
    1997 Volume 11 Issue 1 Pages 66-69
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.66
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    [in Japanese]
    View full abstract
    Download PDF (504K)
  • Development of a Void Distribution Measurement Method in Two-Phase Flow by Electrical Impedance CT
    Isao SUMIDA, Hideaki HAYASHI, Kazuya TANAKA
    1997 Volume 11 Issue 1 Pages 70-73
    Published: March 15, 1997
    Released on J-STAGE: February 22, 2011
    DOIhttps://doi.org/10.3811/jjmf.11.70
    JOURNAL FREE ACCESS
    Show abstractHide abstract
    Though impedance CT (Computed Tomography) has been developed for medical applications at first, it is attractive to apply to the measurement of time-averaged void distribution in two-phase flow, because the device is simple and easy to handle. In the impedance CT, the image of void distribution is reconstructed from current signals of electrodes set up in outer boundary of the measurement area. Therefore the point of the development is how to solve the reverse-problem.This paper describes a method based on the neural-network theory to solve this reverse-problem and its verification by comparing with experimental data.
    View full abstract
    Download PDF (1155K)
    • |<
    • <
    • 1
    • >
    • >|
feedback
 Top