论文部分内容阅读
利用数字图像技术和激光层析技术 ,提出了利用大尺度涡团结构和湍流间歇性来揭示火焰脱火和熄灭现象的新思路 .通过对射流浓度场的空间相关性分析发现 ,在射流内部存在着大尺度浓度涡团 ,这些涡团结构在不同的射流高度上的分布和尺度均有自相似性 .建立了等温射流混合的简化模型 ,利用标量浓度场和涡旋动量场来描述由大尺度涡团的运动所造成的射流边界的间歇性 .利用这一模型对射流边界的卷吸、燃料与氧化剂的混合 ,以及这种作用对扩散火焰点火条件的影响进行了解释 .对模型与试验中获得的临界熄火现象进行了对比 ,结果令人满意 .
Using the digital image technology and the laser tomography technology, a new idea of utilizing the large-scale eddy structure and intermittent turbulence to reveal the phenomenon of flame de-ignition and extinguishing is put forward. By analyzing the spatial correlation of the jet concentration field, A large-scale concentration of vortex clusters, which have self-similar distributions and scales at different jet heights, and a simplified model of isothermal jets mixing is established. The scalar concentration field and vortex momentum field are used to describe the large- The intermittence of jet boundary caused by the movement of vortex clusters is explained by using this model to simulate the entrainment of jet boundaries, the mixing of fuel and oxidant, and the effect of this action on the ignition conditions of diffusion flame.For the model and experiment The obtained critical quenching phenomenon was compared with satisfactory results.