Study on Mechanism of Vortex Bursting

涡爆破机理研究

• 批准号: 11650221
• 负责人: TATSUYA Hasegawa
• 金额: $ 2.24万
• 依托单位: Nagoya Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650221/
• 关键词: Vortex; Premixed flame; Bursting; Hydrogen fuel; Turbulent flows; ボルテックス; 火炎伝播

Flame development along a straight vortex is experimentally studied to elucidate the effects of the maximum circumferential velocity and the density ratio of the flame and to compare with theories and numerical simulations. A pair of straight vortices is produced in nitrogen-diluted stoichiometric hydrogen-oxygen mixtures with density ratios of the flame ranging from 5.1 to 8.0 by a piston. The velocity field measured by the particle image velocimetry (PIV) shows that the vortex tube has a mean maximum circumferential velocity ranging from 18.0 m/s to 35.8 m/s and has a mean core diameter ranging from 5 mm to 6 mm. One of the vortices is ignited at the core by a focused laser light of 193 nm in order not to disturb the flow field. It is found that the flame propagates along the axis of the straight vortex with a speed much higher than that in the radial direction as well as that in the quiescent mixture. The axial propagation velocity increases in time and becomes nearly constant when … More the half-axial length of the flame becomes larger than the core diameter of the vortex tube. The axial propagation velocity at the steady state is roughly proportional to the maximum circumferential velocity and to the density ratio minus unity. The axial propagation velocity at the initial stage increases with the square root of the half-axial length of the flame as well as the maximum circumferential velocity and the density ratio minus unity. Numerical simulation of the same configuration as the experiment proves that the baroclinic effect produces azimuthal vorticity at the early stage of propagation, and that convection and stretch effects dominate the production at the later stage and as a result they provoke the flame to propagate along the vortex. Above results are presented at the IUTAM Symposium on Geometry and Statistics of Turbulence (1999), the First International Conference on Computational Fluid Dynamics (2000), the Third International Symposium on Scale Modeling, (2000), and the Thirty-Eighth Symposium (National) on Combustion (2000). Less

通过实验研究了火焰沿直涡方向的发展，阐明了最大周向速度和火焰密度比对火焰发展的影响，并与理论和数值模拟结果进行了比较。在氮气稀释的化学计量比氢氧混合气中，活塞在火焰密度比为5.1~8.0的范围内产生一对直涡。用粒子图像测速仪(PIV)测量的速度场表明，涡管的平均最大周向速度为18.0m/S~35.8m/S，平均核心直径为5~6 mm。其中一个旋涡被193 nm的聚焦激光点燃，以避免对流场的干扰。结果表明，火焰沿直涡轴线的传播速度远大于径向和静止混合气中的传播速度。轴向传播速度随时间增加，当…时，轴向传播速度趋于恒定火焰的半轴长度大于涡流管的中心直径。稳态时的轴向传播速度大致与最大周向速度成正比，与密度比减去1成正比。初始阶段的轴向传播速度随火焰半轴长度的平方根、最大周向速度和密度比减1的增大而增大。与实验相同构型的数值模拟证明，斜压效应在传播初期产生方位向涡度，对流和拉伸效应主导后期的产生，从而促使火焰沿涡旋传播。上述结果已在IUTAM湍流几何和统计专题讨论会(1999年)、第一届国际计算流体力学会议(2000年)、第三届国际尺度建模专题讨论会(2000年)和第三十八届(全国)燃烧专题讨论会(2000年)上公布。较少

项目成果

T.Hasegawa, S.Nishiki and R.Nakamichi: "Numerical Study on Flame Propagation along a Vortex Tube"Proceedings of the First International Conference on Computational Fluid Dynamics, Springer-Verlag. (in printing). (2001)

T.Hasekawa、S.Nishiki 和 R.Nakamichi：“沿涡流管火焰传播的数值研究”第一届国际计算流体动力学会议论文集，Springer-Verlag。

中道良介,錦慎之助,長谷川達也: "直線渦に沿う火炎伝播の数値計算"第38回燃焼シンポジウム講演論文集. 35-36 (2000)

Ryosuke Nakamichi、Shinnosuke Nishiki、Tatsuya Hasekawa：“沿直线涡流火焰传播的数值计算”第 38 届燃烧研讨会论文集 35-36 (2000)。

T.Hasegawa, S.Nishiki and S.Michikami: "Mechanism of Flame Propagation along a Vortex Tube"IUTAM Symposium on Geometry and Statistics of Turbulence, Kluwer Academic Publishers. 235-240 (2001)

T.Hasekawa、S.Nishiki 和 S.Michikami：“沿着涡管的火焰传播机制”IUTAM 湍流几何与统计研讨会，Kluwer 学术出版社。

R.Nakamichi, S.Nishiki and T.Hasegawa: "Numerical Simulation of Flame Propagation along a Straight Vortex"Proceedings of the Thirty-Eighth Symposium (National) on Combustion. 35-36 (2000)

R.Nakamichi、S.Nishiki 和 T.Hasekawa：“沿直线涡旋火焰传播的数值模拟”第三十八届燃烧研讨会（全国）论文集。