引导射流改善冲击面压力脉动特征的mPOD分析  

mPOD Analysis on Improving Fluctuation Characteristicsof Impinging Pressure with a Guiding Jet

作　　者：胡傲 宋兴州 高咏辉 吴辉 韩淼鑫 游永华 HU Ao;SONG Xingzhou;GAO Yonghui;WU Hui;HAN Miaoxin;YOU Yonghua(Wuhan Branch of Baowu Water Technology Co.Ltd.,Wuhan 430080,China;State Key Lab.of Refractories and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China)

机构地区：[1]宝武水务科技有限公司武汉分公司,武汉430080 [2]武汉科技大学耐火材料与冶金国家重点实验室,武汉430081

出　　处：《科技和产业》2024年第24期316-324,共9页Science Technology and Industry

摘　　要：为了解决气刀射流冲击面压力脉动诱导带钢镀层表面起伏的问题,在有引导射流和无引导射流两种工况下分别对狭缝冲击射流进行LES仿真,对比研究两者涡结构演变情况,同时提取它们的冲击面压力场快照,进行多尺度本征正交分解(mPOD),在谱纯净基础上研究两种射流脉动功率密度谱,并对比分析主能量谱下的空间模态和相干结构。涡结构分析显示,引导射流促进了喷嘴出口两侧涡旋合并,增大了流场中主导涡旋,进而扩大了旋涡冲击壁面的空间尺度。模态和相干分析则表明,引导射流显著降低了冲击面压力脉动频率,并大幅提高了前5个模态能量份额,压力脉动具有明显低秩特性。这些发现可用于深入理解热镀锌擦拭过程和改善镀层质量。In order to solve the undulation defects on the coating of galvanization strips,caused by pressure pulsation of turbulent jet of air knife,LES simulation was conducted on the slit impinging jet under the conditions with and without a guiding jet,respectively.The evolutions of vortex structures of two impinging jets were compared with the numerical fields.Meanwhile,a series of snapshots of impinging pressure fields were extracted for mode analysis via multi-scale Proper Orthogonal Decomposition(mPOD),where the fluctuation power density spectra were studied based on spectral purity,and the spatial modes and coherent structures at the dominant energy spectra were extracted and compared for the two types of jets.Vortex structure analysis shows that the guiding jet promotes the merging of vortices on both sides of nozzle outlet and increases the dominant vortex scale in the flow field.This leads to an increase in the spatial scale of vortex impinging on the wall.Modal and coherent analyses indicate that the guiding jet significantly reduces the fluctuation frequency of impinging pressure on the surface and increase the energy share of the first five modes,resulting in that pressure fluctuation exhibits a significantly low rank characteristic.These findings can help the understanding of wiping process in hot-dip galvanization and improve coating quality.

关 键 词：mPOD 模态分析 引导射流 狭缝冲击射流 大涡模拟 相干结构 

分 类 号：TF03[冶金工程—冶金物理化学]