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Simulation models for unsteady dispersed multiphase flows

Research Project

Project/Area Number 08650208
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Fluid engineering
Research InstitutionEhime University

Principal Investigator

AYUKAWA Kyozo  Ehime University, President, 学長 (30036230)

Co-Investigator(Kenkyū-buntansha) KAWAHARA Genta  Ehime University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (50214672)
OCHI Junji  Ehime University, Faculty of Engineering, Professor, 工学部, 教授 (00036245)
Project Period (FY) 1996 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1997: ¥700,000 (Direct Cost: ¥700,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
KeywordsMultiphase Flow / Bubbly Flow / Numerical Simulation / Gravitational Field / Bubbly Plume / 非定常 / 分散性
Research Abstract

The early-time evolution of two-dimensional flows induced by rising small bubbles, which are released at short intervals on the bottom of an open vessel, has been examined by using a new numerical method. In the present method, the variation of the relative liquid velocity along bubble trajectories is approximately represented to be piecewise linear, and the short-time motion of discrete bubbles is described in terms of the exact solution to the full Basset-Boussinesq-Oseen (B-B-O) equation for constant fluid acceleration. Bubbly fluid is then assumed to be a continuum, the mass desity and the viscosity of which fluctuate in space and time via intermittent existence of moving bubbles, and the velocity and pressure of the bubbly fluid is obtained from numerical integration of the Navier-Stokes and continuity equations. The numerical method to be proposed in this study has the following significant advantages : The use of the exact solution to the B-B-O equation reduces both computer mem … More ory and CPU time necessary to numerically analyze the motion of a large number of bubbles. The use of the full B-B-O equation makes it possible to take into account the historical effects on bubble behavior, which are represented by the so-called Basset term and often neglected without any consensus for the difficulty in its numerical treatment. We applied this method to numerical simulations of the transient bubbly flow in a two-dimensional vessel of a square cross-section under the effect of the gravity. The validity of this method has been confirmed by comparing the numerical results with the experimental ones. In this application, we have shown that the whole flow becomes highly asymmertric and plume exhibits unstable meandering, when relatively small bubbles are released with their arrangement being symmetric with respect to the vessel centerline. In addition, it is observed that the flow recovers its symmetry and the plume is stabilized if we introduce relatively large bubbles into the unstable above flow by adding the large ones to the symmetric arrangement of the small ones. Less

Report

(3 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • Research Products

    (8 results)

All Other

All Publications (8 results)

  • [Publications] 森永 栄二、鮎川 恭三、越智 順治、河原 源太: "気泡群周りの流れの数値シミュレーション" 日本機械学会論文集(B編). 63・609. 1489-1495 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 森永 栄二、鮎川 恭三、越智 順治、河原 源太: "気泡流の初期挙動に関する数値シミュレーション" 混相流. 11・3. 250-257 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] E.Morinaga, K.Ayukawa, J.Ochi, G.Kawahara: "Numerical simulation of the flow around clusters of bubbles" Transactions of the Japan Society of Mechanical Engineers B. 63-609. 1489-1495 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] E.Morinaga, K.Ayukawa, J.Ochi, G.Kawahara: "Numerical simulation for initial behavior of bubbly flow" Japanese Journal of Multiphase Flow. 11-3. 250-257 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 森永 栄二、鮎川 恭三 越智 順治、河原 源太: "気泡群周りの流れの数値シミュレーション" 日本機械学会論文集(B編). 63・609. 1489-1495 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 森永 栄二、鮎川 恭三 越智 順治、河原 源太: "気泡流の初期挙動に関する数値シミュレーション" 混相流. 11・3. 250-257 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 森永栄二,鮎川恭三,越智順治,河原源太: "静止液体中を上昇する気泡群のゆらぎの数値シミュレーション" 液体工学部門講演会 講演論文集. NO.96-9. 315-316 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 森永栄二,鮎川恭三,越智順治,河原源太: "気泡群周りの流れの数値シミュレーション-連続的に放出する場合-" 混相流シンポジウム'96(第15回)講演論文集. 193-196 (1996)

    • Related Report
      1996 Annual Research Report

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Published: 1996-04-01   Modified: 2016-04-21  

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