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Microscopic Clarification of a Non-Steady Non-Evaporating and Evaporating Spray and 3-D Numerical Simulation of a Burning Non-Steady Spray

非稳态非蒸发和蒸发喷雾的微观澄清以及燃烧非稳态喷雾的 3D 数值模拟

基本信息

批准号：
20360105
负责人：
FUJIMOTO Hajime
金额：
$ 12.48万
依托单位：
Doshisha University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2008
资助国家：
日本
起止时间：
2008 至 2010
项目状态：
已结题

项目摘要

The fundamental data of droplet size in a non-steady spray was captured on a film with large size through a speckle killer and a telescopic lens system with super high spatial resolution. The main conclusions are 1) it is able to measure droplet size with the accuracy of 5 [μm] which is just the minimum in the world not only at the spray envelope but also at near the spray axis, 2) it is capable to visualize the vortex structure with large scale in a spray, 3) the large droplets exist at the vortex envelope and the small ones do inside the vortex and 4) it is possible to measure the velocity of droplets by photographing them with double exposure through the same system. The laser holography was applied to measure droplets size as 3D information. However, there is the problem of the selection of filter to obtain the reconstruction image. This is the next step of the selection of a suitable filter.The results of 3-D numerical calculation based on KIVA code where the technique of Large Eddy Simulation (LES) was built in with suitable model of the break-up and that of burning show that 1) it is possible to express the vortex structure with large scale appeared in a non-steady spray, 2) it is capable of presenting the time history of mixture fraction, temperature and rate of heat release, and 3) on the time history of rate of heat release it is able to representing the period of premixed burning, however,, it must be improve the prediction of the period of diffusion burning.

通过散斑抑制器和具有超高空间分辨率的伸缩透镜系统，在大尺寸胶片上获得了非稳态喷雾中液滴尺寸的基本数据。主要结论是：1)测量液滴尺寸的精度为5[μm]，这是世界上最小的，不仅在喷雾包络处，而且在喷雾轴线附近；2)它能够显示喷雾中大尺度的涡旋结构；3)大液滴存在于涡包，小液滴存在于涡旋内部；4)通过同一系统进行两次曝光，可以测量液滴的速度。将激光全息技术应用于液滴尺寸的三维测量。然而，在获取重建图像时，存在着滤波片的选择问题。基于KIVA程序的三维数值计算结果表明：1)可以表示非定常喷雾中出现的大尺度的旋涡结构；2)可以表示混合物分数、温度和放热率的时程；3)放热率的时程能够表示预混燃烧的阶段，但是，对于非定常喷雾，大涡模拟(LES)技术是可能的。必须改进对扩散燃烧周期的预测。