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Analysis of Finite Amplitude Wave Motion in Acoustic Compressor using a Duct with Varying Cross-Section.

Research Project

Project/Area Number 09650178
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Fluid engineering
Research InstitutionSAITAMA UNIVERSITY

Principal Investigator

KAWAHASHI Masaaki  Saitama University, Faculty of Engineering, Professor, 工学部, 教授 (70008853)

Project Period (FY) 1997 – 1998
Project Status Completed (Fiscal Year 1998)
Budget Amount *help
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 1998: ¥900,000 (Direct Cost: ¥900,000)
Fiscal Year 1997: ¥2,400,000 (Direct Cost: ¥2,400,000)
KeywordsAcoustic Standing Wave / Finite Amplitude Wave / Acoustic Compressor
Research Abstract

First, the results of numerical analysis are described. On finite amplitude wave motion of the air column in a closed tube with cross sectional area contraction for the acoustic compressor which is driven by a piston oscillating sinusoidally, the numerical analysis based on explicit Mac-Cormack method with second order accuracy in time and fourth order accuracy in space was applied, and the detailed analysis within cross section reduction ratio 1 - 100 was carried out. Especially, boundary condition based on valve operating condition considering the acoustic compressor real operation in exhaust and intake processes was newly set in this analysis. And also in the wall friction term, not only steady term based on the instantaneous flow velocity but unsteady friction term was considered. From the analytical result, following fact clarified. Though the compression ratio at the closed end of the tube increases with the increase in the cross section reduction ratio, under cross section reduc … More tion ratio of 16, the propagating shock wave is appeared, and it suppresses the increasing rate in compression ratio with increase of the piston amplitude. The shockless resonance is obtained in the wide range of the piston amplitude, when the cross section reduction ratio increases, and the compression ratio also increases. But the effect of the cross section reduction ratio is not remarkable over 50. In the numerical analysis introduced boundary condition based on actual motion of valves, the instability of wave phenomenon appeared. It shows that improvement of further boundary condition is required.
Next, the experimental verification result is described. In this experiment, an axisymmetric acoustic tube (cross section reduction ratio 100) in which cross section is exponentially reduced and a tube in which cross section is constant cross section were used. The air column in these tubes was excited using the piston driven by the electromagnetic accelerator in die resonance point vicinity. And the wave motions were measured. By raising the rigidity of the whole system, the improvement in the measurement accuracy was attempted it. In addition, the accuracy of the piston displacement measurement was improved by the introduction of high-precise displacement gage. The results obtained show that the pressure fluctuation in the tube with constant cross section was closely coincident with calculated result in the amplitude and in the wave form at the closed end of the tube. However, the experimental results for the tube with cross section reduction was not coincident with the calculated results, and it shows that the improvement of numerical analysis in the case with large reduction ratio of cross section is required. Less

Report

(3 results)
  • 1998 Annual Research Report   Final Research Report Summary
  • 1997 Annual Research Report
  • Research Products

    (15 results)

All Other

All Publications (15 results)

  • [Publications] M.Kawahashi, K.Kondo and H.Hirahara: "Large Amplitude Oscillation of Air Column in a Closed Duct with Varying Cross-Sectional Area" Proceedings of 4th KSME/JSME Fluid Engineering Conference. 405-408 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Kawahashi, K.Nishino and H.Hirahara: "Visualization and Measurement of Thermal Convection Flow in a Closed Duct Combined with Acoustic Standing Wave" Proceedings of 4th KSME/JSME Fluid Engineering Conference. 501-504 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] 川橋正昭: "振動流の流体力学的基礎" 伝熱研究. 5・3. 23-30 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] 近藤孝、川橋正昭、平原裕行: "断面縮小管内気柱の共振現象" 可視化情報. 17・Suppl. 2. 35-38 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Kawahashi, T.Kondo and H.Hirahara: "Large Amplitude Oscillation of Air Column in a Closed Duct with Varying Cross-Sectional Area" Proc.4th KSME/JSME Fluid Engng.Conf.405-408 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Kawahashi, K.Nishino and H.Hirahara: "Visualization and Measurement of Thermal Convection Flow in a Closed Duct Combined with Acoustic Standing Wave" Proc.4th KSME/JSME Fluid Engng.Conf.501-504 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Kawahashi: "Fluid Dynamic Basis of Oscillatory Flow(in Japanese)" Research on Heat Transfer. 5-3. 23-30 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] T.Kondo, M.Kawahashi and H.Hirahara: "Resonant Oscillation of Air Column in a Duct with Area Contraction.(in Japanese)" J.Visual.Soci.Japan.17-Suppl.2. 35-38 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1998 Final Research Report Summary
  • [Publications] M.Kawahashi,K.Kondo and H.Hirahara: "Large Amplitude Oscillation of Air Column in a Closed Duct with Varving Cross-Sectional Area" Proceedings of 4th KSME/JSME Fluid Engineering Conference. 405-408 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] M.Kawahashi,K.Nishino and H.Hirahara: "Visualization and Measurement of Thermal Convection Flow in a Closed Duct Combined with Acoustic Standing Wave" Proceedings of 4th KSME/JSME Fluid Engineering Conference. 501-504 (1998)

    • Related Report
      1998 Annual Research Report
  • [Publications] 川橋正昭: "振動流の流体力学的基礎" 伝熱研究. 5・3. 23-30 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] 近藤孝、川橋正昭、平原裕行: "断面縮小管内気柱の共振現象" 可視化情報. 17・Suppl,2. 35-38 (1997)

    • Related Report
      1998 Annual Research Report
  • [Publications] 近藤、川橋、平原: "断面縮小管内気柱の共振現象" 可視化情報. 17・Suppl.2. 35-38 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] M.Kawahashi, T.Kondo & H.Hirahara: "Large Amplitude Oscillation of Air Column in a Duct with Varying CrossーSectional Area" FEC4. (発表予定).

    • Related Report
      1997 Annual Research Report
  • [Publications] M.Kawahashi, K.Nishino & H.Hirahara: "Visualization and Measurement of Thermal Convection Flow in a Closed Duct excited by Acoustic Standing Wave." FEC4. (発表予定).

    • Related Report
      1997 Annual Research Report

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Published: 1997-04-01   Modified: 2016-04-21  

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