Imaging and Numerical Simulation of Unsteady Spray

非定常喷雾的成像与数值模拟

• 批准号: 18560213
• 负责人: FUJIMOTO Hajime
• 金额: $ 2.42万
• 依托单位: Doshisha University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2006
• 资助国家: 日本
• 起止时间: 2006 至 2007
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-18560213/
• 关键词: Unsteady spray; Refraction type telescope; Numerical simulation; DDM; LES; LIC; Sauter mean diameter; Hairpin type vortex; 非蒸発噴霧; Large Eddy Simulation; 渦構造

An unsteady spray is composed of ten millions of droplets. Their minute behavior affects the combustion process of the spray. Consequently, it is very useful for understanding the process to capture their spatial distribution. However, the spatial resolution of photographs taken by CCD camera is very low and it is difficult to recognize the individual droplet when the whole spray is taken on a photograph and only the local information is captured by the enlarged photography. The unsteady spray itself has the three dimensional structure, nevertheless, there is very little research to find this kind of structure. This project proposed the new technique of the super enlarged photography and calculated the two and three dimensional structures of an unsteady spray by the numerical simulation.The system of the super enlarged photography was composed of the lens system like a telescope of refraction type and a laser with low coherency and a large sized film (8[m] x 10[in]). It was able to cat … More ch the droplets information out of the region near the spray axis where the droplets density is too much through this optics and to obtain the two dimensional structure of the unsteady spray applying PIV technique to a photograph. Before about 35 years ago the head investigator found the droplets information in the range of about only 2[mm] from the spray envelope which was taken on a 35[mm] film by use of enlarging photography with a telescope.The numerical simulation was carried out by applying DDM for droplets and LES for the gaseous turbulence under the reference of KIVA code. It was capable of simulating the two dimensional structure of the spray by increase in the number of numerical mesh, by decrease in the numerical viscosity through the application of CIP technique and by optimization of breakup model And it is possible to calculate the two dimensional structure of vortex by LIC and the three dimensional structure of vortex by velocity gradient tensor.The main conclusions are as follows :1. It is able to capture the droplets information in the range from about 3[mm] from the spray axis to the spray envelope by use of new optics proposed.2. The Sauter mean diameter of droplets is ranged about from 10[μm] to 20[μm]. It decreases as the injection pressure increases.3. The droplets with small and medium size follow the movement of vortex with large scale generates at the spray tip region and those with large size appear at the outside of the vortex. The two dimensional arrangement of vortices is alternately and the three dimensional one is the multiplex of the vortices like hairpin. Less

一个不稳定的喷雾是由一千万个液滴组成的。它们的微小行为影响喷雾的燃烧过程。因此，它是非常有用的理解的过程中捕捉它们的空间分布。然而，CCD摄像机拍摄的照片的空间分辨率很低，并且当将整个喷雾拍摄在照片上时难以识别单个液滴，并且通过放大的照片仅捕获局部信息。非定常喷雾本身具有三维结构，但目前对这种结构的研究还很少。本项目提出了一种新的超放大摄影技术，并通过数值模拟计算了非稳态喷雾的二维和三维结构，超放大摄影系统由折射式望远镜、低相干激光器等透镜系统和大尺寸胶片（8[m] × 10[in]）组成。它能够捕捉 ...更多信息 通过该光学系统将液滴信息从喷雾轴线附近液滴密度过大的区域提取出来，并将PIV技术应用于照片中，得到非稳态喷雾的二维结构。大约在35年前，研究者在35 mm胶片上用望远镜放大摄影，在距喷雾包层仅2 mm的范围内发现了液滴信息，并参照KIVA程序，对液滴采用DDM，对气相湍流采用LES进行了数值模拟。通过增加数值网格数、采用CIP技术降低数值粘度、优化破碎模型等方法，可以模拟喷雾的二维结构，并可以用LIC计算二维旋涡结构，用速度梯度张量计算三维旋涡结构。该系统采用新的光学系统，能够在从喷雾轴线到喷雾包络线约3[mm]的范围内捕获液滴信息.液滴的Sauter平均直径范围约为10[μm]至20[μm]。随着注射压力的增加，其值减小.中小尺寸的液滴跟随涡流运动，大尺寸的液滴出现在喷嘴尖端区域，大尺寸的液滴出现在涡流的外侧。二维涡系呈交替排列，三维涡系呈发夹状复合排列。少

项目成果

Large Eddy Simulation of Diesel Spray Combustion with Eddy-Dissipation Model and CIP Method

涡耗散模型和CIP方法对柴油机喷雾燃烧的大涡模拟

• 发表时间: 2007
• 期刊: Paper of Society of Automotive Engineers International No.2007-01-0247
• 作者: Hori;T.;Senda;J.;Fujimoto;H.;et al.
• 通讯作者: et al.

Large Eddy Simulation of Diesel Spray Structure in Constant Volume Vessel by Use of KIVALES

利用KVALES对定容容器内柴油喷雾结构进行大涡模拟

• 发表时间: 2006
• 期刊: Proc. Int. Conference on Liquid Atomization and Spray Systems No.204
• 作者: Hori;T.;Senda;J.;Fujimoto;H.et al.
• 通讯作者: H.et al.

Large Eddy Simulation of Diesel Spray Structure in Constant Volume

定容柴油喷雾结构的大涡模拟

• 发表时间: 2006
• 期刊: 10th Int.Conference on Liquid Atomization and Spray Systems(CD-ROM) B-3-06-204
• 作者: Hori;T.;Senda;J.;Fujimoyo;H.;他1名
• 通讯作者: 他1名

Novel Photographic Imaging Method for Diesel Spray Structure with New Lens and Lens and Large Sized Film System

新型镜头和镜头及大尺寸胶片系统柴油喷雾结构摄影成像新方法

• 发表时间: 2006
• 期刊: 10th Int.Conference on Liquid Atomization and Spray Systems(CD-ROM) F1-02-119
• 作者: Nakagawa;H.;Senda;J.;H.;Fujimoto;H.;他3名
• 通讯作者: 他3名

Large Eddy Simu Lationによるディゼル噴霧の解析(第1報計算格子幅が非蒸発解析に与える影響)

使用大涡模拟分析柴油喷雾（第一份报告：计算网格宽度对非蒸发分析的影响）

• 发表时间: 2007
• 期刊: 日本機会学会論文集B編 73券
• 作者: 堀;千田;藤本;他1名
• 通讯作者: 他1名