柴油机喷雾近场结构及非稳定性研究与初次雾化模型再构

项目名称： 柴油机喷雾近场结构及非稳定性研究与初次雾化模型再构

项目编号： No.51276084

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 能源与动力工程

项目作者： 王谦

作者单位： 江苏大学

项目金额： 80万元

中文摘要： 柴油机燃油喷射雾化特性对其燃烧和排放性能至关重要，特别是近喷嘴区域的初次雾化对喷雾的发展起决定性作用，而目前对初次雾化机理的认识仍很缺乏，精确的初次雾化模型有待建立。在前期对全场喷雾特性和喷孔内部流动的研究基础上，本项目提出开展柴油机近场喷雾结构和液核表面非稳定性研究，针对时空小尺度喷雾近场区域采用X射线同轴相衬成像新技术结合长距显微高速摄影捕获喷雾液核区表面波形态和破碎图像，采用Tomo-PIV联合PLIF技术测试近场液核区速度场和浓度场，获取湍流、空穴和气流共同作用下的喷雾近场区域的内部精细结构和剪切层非稳定性特征；同时，运用两相流理论详细数值模拟湍流和空穴作用下，燃油射流在喷雾近场区域与气流相互作用后的液核区表面非稳定波变化特点和破碎形态。在此基础上，进一步揭示燃油喷射初次雾化机理，构建基于K-H非稳定性理论的精确初次雾化模型，为准确预测柴油机喷雾特性奠定基础。

中文关键词： 柴油机；近场喷雾；表面波；空穴；喷雾模型

英文摘要： The fuel spray characteristics is known important to the combustion and emission process in diesel engines and the primary breakup near the nozzle exit directly affect the subsequent spray development. But at present, the knowledge of mechanisms of primary breakup is not clear and the accurate primary breakup models need to be setup. Based on the previous fundamental researches on full-field spray characteristics and nozzle internal flow, the spray configuration near the nozzle orifice exit and surface instability of fuel liquid core will be investigated in this program. Focus on the near nozzle region in which the temporal and spatial scale is quite small, the synchrotron-based ultrafast phase-contrast X-ray and high-speed microscopic imaging techniques will be utilized to capture the surface perturbation and breakup process of liquid jet core. Tomo-PIV combined with PLIF will be implemented to measure the spray droplet velocity and concentration of near-nozzle field. And eventually the precise inner structure and shear layer instability characteristics of this region induced by turbulence, cavitation and ambient air flow will be acquired. Meanwhile, detailed simulation based on the two- phase flow theory will be performed to analyze the change of liquid jet core surface perturbation and breakup process of fuel

英文关键词： Diesel engine；Near-filed spray；Surface-wave；Cavitation；Spray model