Conference Paper 実験によるパラメータチューニングを必要としない新しい乱流噴霧ハイブリッドLES コードの開発

新城, 淳史  ,  梅村, 章  ,  Shinjo, Junji  ,  Umemura, Akira

Conventional spray simulation codes, including commercial codes, require parameter tuning using experimental data due to the fact that the models included are not closed since they are not necessarily based on a thorough understanding of related physical mechanisms such as liquid atomization. This makes the predictability of simulation low, which has been a critical issue for decades. Our previous findings on liquid atomization mechanisms through detailed spray/droplet simulations, microgravity experiments of liquid jet pinch-off, theoretical considerations, etc. have paved the way to overcome this issue, and we have proposed a hybrid spray LES (large-eddy simulation) code with a novel turbulent atomization model. The turbulent atomization model features that the main atomization modes are driven by turbulent resonance or Rayleigh-Taylor (RT) instability, and the LES-resolved liquid surface information, such as turbulent Weber number and turbulent Bond number, determines the mode and timing of atomization. Several test cases for Diesel fuel injection are conducted to examine the validity of the model, and the obtained results indicate that the present code quite accurately reproduce the global characteristics such as the initial liquid behavior, spray spreading angle and droplet distribution. In addition, more detailed information on the atomization mode, the effect of flow Reynolds number, detailed flow structures, etc. is obtained and gives insight on the spray development mechanisms. For the first time, the present code has enabled a spray simulation free of parameter tuning and expected to improve the predictability of spray simulation both in academic studies and industrial applications.
会議情報: 第49回流体力学講演会/第35回航空宇宙数値シミュレーション技術シンポジウム (2017年6月28日-43日. 国際オリンピック記念青少年総合センター), 渋谷区, 東京
形態: カラー図版あり
Meeting Information: 49th Fluid Dynamics Conference /the 35th Aerospace Numerical Simulation Symposium (June 28-30, 2017. National Olympics Memorial Youth Center), Shibuya-ku, Tokyo, Japan
Physical characteristics: Original contains color illustrations

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