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Studies on the optimum Shapes of Cross-Section and Arrangement of Fin Rows of a Heat Exchanger

Research Project

Project/Area Number 01550140
Research Category

Grant-in-Aid for General Scientific Research (C)

Allocation TypeSingle-year Grants
Research Field Fluid engineering
Research InstitutionKanazawa University

Principal Investigator

OKAJIMA Atsushi  Kanazawa University, Faculty of Technology, Professor, 工学部, 教授 (80013689)

Co-Investigator(Kenkyū-buntansha) KIWATA Takahiro  Kanazawa University, Faculty of Technology, Research Associate, 工学部, 助手 (40225107)
UENO Hisanori  Kanazawa University, Faculty of Technology, Associate Profssor, 工学部, 助教授 (80019752)
長久 太郎  金沢大学, 工学部, 助教授 (20019706)
Project Period (FY) 1989 – 1991
Project Status Completed (Fiscal Year 1991)
Budget Amount *help
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1991: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1990: ¥1,200,000 (Direct Cost: ¥1,200,000)
Fiscal Year 1989: ¥700,000 (Direct Cost: ¥700,000)
KeywordsHeat exchanger / Shape and arrangement of fins / Experiment in a wind tunnel / Numerical simulation / Biased flow / Heat transfer / Rectangular cylinder row / Thermal field
Research Abstract

A row of uniformly spaced bluff bodies with a rectangular cross-section placed perpendicularly to an approaching flow like the fin rows of a heat exchanger produces unsteady and non-uniform flow across the row, which consists In separated flow region with an unsteady cell structure. The present study consists of experiments In a wind tunnel and numerical simulations of flow by a finite difference method. Firstly, a simultaneous measurements of pressures around the circumference of a fin row and velocity distribution of a wake In a wind tunnel allow the evaluation of instantaneous drag and lift forces In each mode of two and more flow patterns which appear by unsteadiness of a biased flow formed In the gaps, and In the biased flow, we find good correspondence of pressure distributions and lift and drag forces to wake velocity profiles. It Is concluded that the biased flow is metastable and can switch Intermittently In gaps, and that the nonuniformity of gap and wake flows is significant … More in the range of the gap ratio S/H below a critical value. We find also that the uniformity of a wake velocity Is the best at the critical gap for elongated rectangular cylinders, B/H=3, 5 In rows. Next, we have developed the computer-code for computation of flows around rectangular cylinders, to gain a better Insight into the detailed characteristics of the fluld- and thermo-dynamics of bluff bodies. By a finite volume method, both laninar flow and thermal fields around bluff bodies with a rectangular cross section of various B/H ratios and an aerofoil seption haie been computed on body-fitted curvilinear coordinates at a Reynolds number of(1, 4, 7)x1O^3, and we can successfully simulate some Interesting flow and thermal phenomena whereby a flow pattern critically, changes when the B/H ratio Is about 2.5 and 6 ; that Is, a fully separated flow, an alternately reattached one and a stationarily reattached one. It is also clarified that Nusselt number distribution well corresponds with a motion of flow about the body, such as the size of a vortex-formation region and a notion of vortices shed downstream over the side walls. The present computational code Is certified to be suitable as the computed results show a good agreement with the measured results, and the computed results clearly show the effects of a shape of the bluff body on aero- and thermo-dynamic characteristics. The results reveal an interactions between a wake and separation bubbles, also. Furthermore, turbulent flows around rectangular bodies also have been computed by a standard k-epsilon turbulence model. There are, however, some discrepancies between the results from the k-epsilon, turbulence model and experiments for unsteady phenomena. We have reported the results of experiments and numerical simulations on the optimum shapes of cross-section and arrangement of a row of fins, In six papers. Less

Report

(4 results)
  • 1991 Annual Research Report   Final Research Report Summary
  • 1990 Annual Research Report
  • 1989 Annual Research Report
  • Research Products

    (21 results)

All Other

All Publications (21 results)

  • [Publications] Okajima A.,Kondoh Y.,Ueno H.: "Numerical Simulation of Flow and Thermal Fields around Rectangular Cylinders" Proc.2nd KSME-JSME Fluids Eng.Conf.2. 287-292 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Okajima A.: "Numerical Simulation of Flow Around Rectangular Cylinders" J.Wind Eng.and Industrial Aerodynamics. 33. 171-180 (1990)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Okajima A.: "Change of Flow about an Elongated Rectangular Cylinder in a Range of Reynolds Numbers of 200 to 0.7×10^4" Proceeding of the First ASME-JSME Fluids Engineering Conference. FED-112. 107-113 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Okajima A.,Ueno H.,Sakai H.: "Numerical Simulation of Laminar and Turbulent Flows Around Rectangular Cylinders" Proceeding of IV-ICCBE'91 Conference. 180-180 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 小林 秀樹,岡島 厚,矢部 隆二: "角柱列を通過する非定常不均一流れ" 日本機械学会・流体工学部門講演会講演論文集. No.910ー50. 48-50 (1991)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 岡島 厚,上野 久儀,木綿 隆弘,恵上 浩一: "並列2角柱の空力静特性におよぼす迎え角の影響" 土木学会・構造工学論文集. 38AーII. 857-864 (1992)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Atsushi OKAJIMA, Yasuhiro KONDOH, Hisanori UENO: "Numerical Simulation of Flow and Thermal Fields around Rectangular Cylinders" Proc. the 2nd KSME-JSME Fluids Eng. Conf.2. 287-292 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Atsushi OKAJIMA: "Numerical Simulation of Flow Around Rectangular Cylinders" J. Wind Eng. & Indust. Aerodyn.33. 171-180 (1990)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Atsushi OKAJIMA: "Change of Flow about an Elongated Rectangular CYlinder in a Range of Reynolds Numbers of 200 to 0.7X10^4" Proc. the lst ASME-JSME Fluids Eng. Conf. FED-112. 107-113 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Atsushi OKAJIMA, Hisanori UENO, Haruhisa SAKAI: "Numerical Simulation of Laminar and Turbulent Flow Around Rectangular Cylinders" Ppoc. Iv-ICCBE'91 Conf.180-180 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Hideki KOBAYASHI, Atsushi OKAJIMA, Ryuji YABE: "Study on Unsteady and Non-uniform Flow Through Rectangular Cylinder Arrays" Proc. Fluids Eng. Conf. '91. No. 910-50. 48-50 (1991)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] Atsushi OKAJIMA, Hisanori UENO, Takahiro KIWATA, Kohichi EGAMI: "Effect of Angle of Attack on Aerostatic Characteristics of Two Rectangular Cylinders Arranged Side-by-Side" J. Struct. Eng.38A-2. 857-864 (1992)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1991 Final Research Report Summary
  • [Publications] 岡島 厚,坂井 晴久: "直接法とkーεモデルによる矩形柱まわりの流れの数値シミュレ-ション" 日本風工学会誌. 47. 79-80 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Okajima A.: "Change of Flow about an Elongated Rectangular Cylinder in a Range of Reynolds Numbers of 200 to 0.7×10^4" Proceeding of the First ASMEーJSME Fluids Engineering Conference. FEDーVol.112. 107-113 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] Okajima A.,Ueno H.,Sakai H.: "Numerical Simulation of Laminar and Turbulent Flows Around Rectangular Cylinders" Proceeding of IVーICCBE '91 Conference. 180-180 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 小林 秀樹,岡島 厚,矢部 隆二: "角柱列を通過する非定不均一流れ" 日本機械学会・流体工学部門講演論会講演論文集. No.910ー50. 48-50 (1991)

    • Related Report
      1991 Annual Research Report
  • [Publications] 岡島 厚,上野 久儀,木綿 隆弘,恵上 浩一: "並列2角柱の空力静特性におよぼす迎え角の影響" 土木学会・構造工学論文集. 38AーII. 857-864 (1992)

    • Related Report
      1991 Annual Research Report
  • [Publications] 岡島 厚: "角柱まわりの層流流れ場と温度場の数値計算" 日本機械学会第67期通常総会講演会講演論文集(B). 135-137 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] A.Okajima,Y.Kondoh,H.Ueno: "Numerical Simulation of Flow and Thermal Fluids around Rectangular Cylinders" Proceedings of the Second KSMEーJSME Fluids Engineering Conference. 2. 287-292 (1990)

    • Related Report
      1990 Annual Research Report
  • [Publications] 岡島厚: "長方形断面柱まわりの流れと温度場の数値シミュレ-ション" 第3回数値流体力学シンポジウム講演論文集. 395-398 (1989)

    • Related Report
      1989 Annual Research Report
  • [Publications] 岡島厚: "角柱まわりの層流れ場と温度場の数値計算" 日本機械学会第67期通常総会講演会講演論文集(B). 135-137 (1990)

    • Related Report
      1989 Annual Research Report

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Published: 1989-04-01   Modified: 2016-04-21  

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