Optical and Numerical Analyses of Vortex-Flame Interaction Using Simultaneous and Two-Directional High-Speed Schlieren Photography and Discrete Vortex Method

使用同步和双向高速纹影摄影和离散涡旋方法对涡旋火焰相互作用进行光学和数值分析

基本信息

批准号：
16560182
负责人：
OHIWA Norio
金额：
$ 2.37万
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：
2004
资助国家：
日本
起止时间：
2004 至 2005
项目状态：
已结题

项目摘要

The behavior of the propagating flame after the spark ignition in the plane propane-air premixed shear layer is first observed in this paper by combining the following two devised techniques; the acoustic excitation of the plane shear layer and the simultaneous and two-directional schlieren system. To obtain characteristic flame appearances due to the vortex-flame interaction in the plane premixed shear layer, another special idea of assigning two extreme points of ignition is introduced; one at the center of an organized eddy where the vortex motion plays an important role, and the other at the midpoint between two adjacent organized eddies where the rolling-up motion prevails. The two-dimensional change of flame outlines after the midpoint ignition is also simulated by superposing the flame movement with a constant burning velocity followed by thermal expansion on the two-dimensional vortex flow field described by the discrete vortex method. The results obtained are summarized as fol … More lows.(1) It is found that two types of the enhancement mechanisms of flame propagation exist among the organized eddies in the plane shear flow; one is the vortex bursting due to the vortex motion, the other is the vortex boosting due to the rolling-up motion, and exert quantitatively almost the same influences on the flame propagation enhancement process. Also found is that the vortex boosting which is one of the two configurations of vortex-flame interactions can be qualitatively captured by the proposed discrete vortex method.(2) The simulated lateral flame propagation velocities agree relatively well with the axial and lateral flame propagation velocities experimentally obtained from the simultaneous and two-directional high-speed schlieren images, although neglect of the combined effects of the baroclinic torque, the three dimensionality of vortex-flame interaction and the flame curvature leads to slight overestimation of the flame propagation velocity. This result verifies that the proposed two-dimensional discrete vortex method combined with Huygens' Principle is useful for qualitatively estimating and modeling the flame propagation velocity in the plane premixed shear layer, in spite of many assumptions introduced to simplify the numerical simulation.(3) The enhancement effects of flame propagation in the plane premixed shear layer are composed of the physical one due to the vortex-flame interactions and the chemical one through the laminar burning velocity. For both configurations of the vortex-flame interactions, the flame propagation velocity V_f with vortex interaction in the plane premixed shear layer is given by the vortex tangential velocity v_θ plus the propagation speed of the undisturbed flame (ρ_u/ρ_b)S_L, and expressed by the following simple linear equation.V_f=v_θ+(ρ_u/ρ_b)S_L Less

在本文中首先结合以下两种设计的技术，首先观察到平面丙烷 - 空气预混合剪切层的火花点火后传播火焰的行为；平面剪切层以及最简单和两方向的Schlieren系统的声学兴奋。为了获得由于平面预混合剪切层的涡旋形式相互作用而引起的特征火焰外观，引入了另一个特殊的想法，即引入了两个极端的点火点；在有组织的涡流的中心，涡流运动起着重要作用，另一个在两个相邻的有组织的涡流中的中点占据了冠军。在中点点火之后，火焰大纲的二维变化也通过超级燃料运动以恒定的燃烧速度进行模拟，然后在二维涡流流场上由离散涡流方法描述的二维涡流流场进行热膨胀。所获得的结果总结为fol…更多的低点。（1）发现在平面剪切流中有组织的涡流中存在两种类型的火焰传播的增强机制。一个是由于涡旋运动而引起的涡旋爆发，另一个是由于滚动运动引起的涡旋增强，并且对火焰传播增强过程的施加几乎相同的影响。 Also found is that the vortex boosting which is one of the two configurations of vortex-flame interactions can be Normally captured by the proposed discrete vortex method.(2) The simulated lateral flame propagation velocities agree respectively well with the axial and lateral flame propagation velocities experimentally obtained from the simple and two-directional high-speed schlieren images, although neglect of the combined effects of the斜压扭矩，涡旋 - 弗拉姆相互作用的三个维度和火焰曲率导致火焰传播速度略微高估。该结果验证了提出的二维离散涡度方法与Huygens的原理相结合，可用于在飞机上预估算和建模的定性估算和建模火焰的传播速度预处理剪切层中的火焰传播速度，尽管引入了许多假设，尽管它简化了数值模拟，但在造成了数值的效果。通过层流燃烧速度，涡旋形式相互作用和化学效果。对于Vortex-Flame交互的两种配置，在平面预混合剪切层中具有Vortex相互作用的火焰传播速度V_F由Vortex切向速度V_θ加上，加上不受干扰的火焰的传播速度（ρ_U/ρ_B）S_L，并表达等式v_f =v_θ+（ρ_U/ρ_b）s_l少