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Study on Themo-Fluiddynamic Coupling involved in Supercritical Droplet Combusion and Vaporization/Combustion Characteristics Prediction

Research Project

Project/Area Number 07650234
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Thermal engineering
Research InstitutionNagoya University

Principal Investigator

UMEMURA Akira  Nagoya University, Graduate School of Engineering, Professor, 工学研究科, 教授 (60134152)

Co-Investigator(Kenkyū-buntansha) JIA Wei  Yamagata University, School of Engineering, Lecturer, 工学部, 講師 (10235799)
Project Period (FY) 1995 – 1997
Project Status Completed (Fiscal Year 1997)
Budget Amount *help
¥1,900,000 (Direct Cost: ¥1,900,000)
Fiscal Year 1997: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1996: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 1995: ¥700,000 (Direct Cost: ¥700,000)
KeywordsSupercriticcality / Droplet Vaporization / Liquid Jet Flow / Thermo-Hydrodynamic Coupling / Phase Change / Flow Instability / Supercompressibility / Atomization / 液体ジェット / 混合 / 超臨界圧 / 噴霧燃焼 / 蒸発特性 / モデリング / 連続的相変化 / 流体力学的カプリング / 超臨界圧力 / 蒸発様態領域図 / 計算スキーム開発 / 表面張力 / 形状変化
Research Abstract

The effects of thrmo-fluidynamic coupling phenomena which take place near the critical mixing surface of liquid fuel have been examined for droplet vaporization and liquid fuel jet flow.
(1) Our previous study on supercritical droplet vaporization has been extended to reveal new features which intrinsically appear in such a gasification regime that the droplet experiences a transition to continuous phase change, showing that (a) The gasification lifetime becomes very short and comparable to the temperature relaxation time of the droplet. (b) The heating of droplet is indespensable for the transition. (c) The fuel diffusivity is greatly increased by the loss of phase equilibrium constraint. (d) A moving droplet without surface deforms to enlarge its surface area, thus enhancing vaporization and mixing rates. (e) Sprays confined in a chamber may experience an acoustically resonant vaporization mode.
(2) The atomization, vaporization and mixing characteristics of a liquid fuel issued into an inert gas whose pressure and temperature exceed the critical values of the fuel have been examined by means of linear stability analysis and TVD simulation. Main findings are ; (a) The reduction of surface tension at elevated pressures requires the formation of thinner liquid fragments, for which Rayleigh instability effectively works to atomize liquid. (b) The inviscid analysis conducted for the linear stability of shear flow in vicinity of the jet surface shows that the maximum growth rate rapidly increases to a saturated value due to density variation and vanishing surface tension as the critical mixing condition is approached. (c) Since the sound speed takes a small value near critical conditions, the effect of compressibility (supercompressibility) must be taken into account for the numerical simulation of supercritical fluid flow- a new flow regime in which both Reynolds number and Mach number may take large values.

Report

(4 results)
  • 1997 Annual Research Report   Final Research Report Summary
  • 1996 Annual Research Report
  • 1995 Annual Research Report
  • Research Products

    (25 results)

All Other

All Publications (25 results)

  • [Publications] Umemura, A.& Jia, W.: "Gasification and Combustion of a Moving Droplet Undergoing Continuous Phase Change in Supercritical Ambience" Modeling in Combustion Science,D.J.Buckmaster & T.Takeno Eds.,Springer-Verlag. 237-248 (1995)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A.& Shimada, Y.: "Characteristics of Supercritical Droplet Gasification" Twenty-sixth Symposium (International) on Combustion,The Combustion Institute,Pittsburgh,PA. 1621-1628 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Jia, W.& Umemura, A.: "Computation on Gasification and Combusiton of a Moving Droplet in Supercritical Ambiences" Transport Phenomena in Combustion,S.H.Chan Ed.,Taylor & Francs,Bristol,PA. 838-849 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Jia, W.& Umemura, A.: "Computation on Head-On Collision of Two Identical Droplets with Constant Surface Tension Coefficiences" Trans.Japan Soc.Aeron.Space Sci,. 39. 401-415 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A., Wakashima, Y., Yokoi, A.& Takihana, Y.: "Linear Stability Analysis of a liquid Fuel Jet Issued into Supercritical Environment" Proc.First Asia-Pacific Conference on Combustion,Osaka. 432-435 (1997)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A., Miura, K.& Takada, K.: "Suppression of Embedded Shocks in Supersonic Free-Shear-Layer Structures" Shock Waves. 6・3. 167-175 (1996)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A.& Jia, W.: "Gasification and Combustion of a Moving Droplet Undergoing Continuous Phase Change in Supercritical Ambience" Modeling in Combustion Scinece, D.J.Buckmaster & T.Takeno Eds., Lecture Notes in Physics, Springer-Verlag, Berlin. 237-248 (1995)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A.& Shimada, Y.: "Characteristics of Supercritical Droplet Gasification" Twenty-sixth Symposium (international) on Combustion, The Combustion Institute, Pittsburgh, PA. 1621-1628 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Jia, W.& Umemura, A.: "Computation on Gasification and Combustion of a Moving Droplet in Supercritical Ambiences" Transport Phenomena in Combustion, S.H.Chan Ed., Taylor & Francs, Bristol, PA. 838-849 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Jia, W.& Umemura, A.: "Computation on Head-On Collision of Two Identical Droplets with Constant Surface Tension Coefficiences" Trans.Japan Soc.Aeron.Space Sci.39. 401-415 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A., Wakashima, Y., Yokoi, A.&Takihana, Y.: "Linear Stability Analysis of a liquid Fuel Jet Issued into Supercritical Environment" Proc.First Asia-Pacific Conference on Combustion Osaka. 432-435 (1997)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] Umemura, A., Miura, K.& K.Takada, K.: "Suppression of Embedded Shocks in Supersonic Free-Shear-Layr Structures" Shock Waves. 6-3. 167-175 (1996)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1997 Final Research Report Summary
  • [Publications] 島田洋介・梅村章: "超臨界雰囲気中の燃料液滴の気化特性" 日本機械学会論文集 B編. 63・606. 668-674 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] W. Jia&A. Umemura: "Computation on Head-On Collision of Two Identical Droplets with Constant Surface Tension Coefficiences" Transactions of the Japan Society for Aeronautical and Space Sciences. 39・126. 401-415 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] A.Umemura, Y.Wakashima,A. Yokoi & Y.Takihana: "Linear Stability Analysis of a Liquid Fuel Jet Issued into Supercritical Environment" Proceedings of The First Asia-Pacific Conference on Combustion. 432-435 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] 梅村章・瀧花洋一: "定断面流路内超音速二重剪断層流れの不安定性" 日本航空宇宙学会誌. 45・525. 564-574 (1997)

    • Related Report
      1997 Annual Research Report
  • [Publications] A.Umemura: "Supercritical Droplet Gasification and Combustion" In Mechanics and Combusion of Droplets and Sprays,N.Chigier & H.H.Chiu eds.,Begell House,New York. 351-363 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] W.Jia and A.Umemura: "Computation on Gasification and Combustion of a Moving Droplet in Supercritical Ambiences" In Transport Phenomena in Combustion,S.H.Chan Ed.,Taylor & Francs,Bristol. 838-849 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 島田・梅村: "超臨界雰囲気中の燃料液滴の気化特性" 日本機会学会論文集 B編. 63-606. 668-674 (1997)

    • Related Report
      1996 Annual Research Report
  • [Publications] A.Umemura and Y.Shimada: "Characteristics of Supercritical Droplet Gasification" Twenty-sixth Symposium (International) on Combusion,The Combustion Institute,Pittsburgh. (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] W.Jia & A.Umemura: "Computation on Head-On Collision of Two Identical Droplets with Constant Surface Tension Coefficients" Transactions of the Japan Society for Aeronautical and Space Sciences. 39-126. 401-415 (1997)

    • Related Report
      1996 Annual Research Report
  • [Publications] A.Umemura,K.Miura and K.Takada: "Suppression of Embedded Shocks in Supersonic Free-Shear-Layer structures" Shock Waves. 6-3. 167-175 (1996)

    • Related Report
      1996 Annual Research Report
  • [Publications] 梅村,三浦: "二次元圧縮性せん断層の大規模構造" 日本機械学会論文集(B編). 61. 2973-2980 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] A.Umemura & W.Jia: "Gasification and Combustion of a Moving Droplet Undergoing Continuous Phase change in Supercritical Ambience" In Modeling in Combustion Science,D.J.Buckmaster & T.Takeno Eds.,Springer-Verlag,Germany. 237-248 (1995)

    • Related Report
      1995 Annual Research Report
  • [Publications] A.Umemura: "Supercritical Droplet Gasification and Combustion" In Mechanics and Combustion of Droples and Sprays,N.Chigier & H.H.Chiu Eds.,Begell House,NY. (1996)

    • Related Report
      1995 Annual Research Report

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Published: 1995-04-01   Modified: 2016-04-21  

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