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Valve Vibration Induced Intake Air Flow Dynamics Analysis Using Near Valve Particle Image Velocimetry
参考中译:利用近气门粒子图像测速仪分析气门振动引起的进气气流动力学


          

刊名：Journal of engineering for gas turbines and power: Transactions of the ASME
作者：Shi, Fenghao（University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University）
Liu, Mengqi（University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University）
Hung, David L. S.（University of Michigan-Shanghai Jiao Tong University Joint Institute, Shanghai Jiao Tong University）
Li, Xuesong（School of Mechanical Engineering, Shanghai Jiao Tong University）
Xu, Min（School of Mechanical Engineering, Shanghai Jiao Tong University）
刊号：720B0002
ISSN：0742-4795
出版年：2022
年卷期：2022, vol.144, no.9
页码：091004
总页数：10
分类号：TK
关键词：Flow (Dynamics)；Valves；Air flow
参考中译：流动(动力学)；阀门；气流
语种：eng
文摘：The transient dynamics of air flow running through the moving intake valve gaps in combustion cylinders is crucial to the performance of spark-ignition direct-injection engines. However, research on the air flow behavior in the vicinity of valve exits is still limited. In this work, transient air flow characteristics of a custom-designed dual-valve system under the operating conditions of a fixed valve lift and a vibrating valve lift at two frequencies are experimentally investigated. The velocity vector field measured using planar particle image velocimetry (PIV) is first analyzed in time domain based on temporal mean and root-mean-square (RMS) values. Comparison of temporal mean flow fields reveals the difference in flow pattern while RMS represents the variation of intake air jet velocity along the inlet path of the vibration-affected jet. Instantaneous snapshots provide direct analysis of the valve vibration-induced intake air jet behavior. Furthermore, investigation in frequency domain extends insights into the dominant spectral components of flow structures. Fast Fourier transform (FFT) applied to every vector on the velocity field yields a vibration frequency affected zone (VFAZ), indicating the regions where the effect of valve vibration is significant. By employing dynamic mode decomposition (DMD) method, the spatio-temporal PIV results are decomposed into modes with specific frequencies. Reconstructed flow field using modes with the valve operating frequency visually unveils a cyclic vortex structure near the valve exit. In summary, this study elucidates the mechanism of near-valve intake air flow impingement and interaction behavior induced by the valve vibrating motion.
参考中译：缸内气流运动的动态特性对火花点火直喷式发动机的性能有重要影响。然而，对阀门出口附近空气流动行为的研究还很有限。本文对自行设计的双阀系统在固定气门升程和振动气门升程两种频率下的瞬时气流特性进行了实验研究。基于时间均值和均方根(RMS)对平面粒子图像测速仪(PIV)测量的速度矢量场进行了时间域分析。时间平均流场的比较揭示了流型的差异，而均方根则代表了进气射流速度沿受振动影响的射流入口路径的变化。瞬时快照可直接分析气门振动引起的进气喷射行为。此外，在频域的研究扩展了对流动结构的主要频谱分量的洞察。对速度场上的每个矢量进行快速傅立叶变换(FFT)，得到一个振动频率影响区(VFAZ)，指示阀门振动影响显著的区域。通过使用动态模式分解(DMD)方法，将时空PIV结果分解成特定频率的模式。利用气门工作频率的模式重建的流场直观地揭示了气门出口附近的循环涡流结构。综上所述，本研究阐明了气门附近进气气流撞击的机理以及气门振动引起的气门相互作用行为。



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