基于X射线成像技术的柴油喷嘴内流与喷雾的关联研究

项目名称： 基于X射线成像技术的柴油喷嘴内流与喷雾的关联研究

项目编号： No.51309149

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 水利工程

项目作者： 张旭升

作者单位： 上海海事大学

项目金额： 25万元

中文摘要： 为了满足日益严格的船舶柴油机尾气排放法规和减少温室气体排放，从柴油机机内控制的角度出发，必须进一步优化燃油喷雾和改善缸内燃烧过程。其中，详细掌握燃油的喷雾特性及其内在的破碎机理是进一步实现缸内燃烧控制优化的重要前提条件。燃油的一次破碎过程是衔接液核区和液滴形成（喷雾完全形成）的纽带。近些年来针对高压柴油近场喷雾（一次破碎）特性的研究发现，喷雾的形态和破碎过程与喷嘴的内部流动存在密切的联系。但是目前针对真实结构柴油喷嘴的内部流动研究极为有限，并且仍没有与喷雾特性直接联系起来。因此本项目拟采用X射线成像技术，利用高强度铝合金制造的柴油喷嘴前端，在实现较高喷射压力的前提下，对柴油喷嘴内部流动和外场喷雾同时测量，掌握喷嘴结构和针阀运动对内流和喷雾的影响规律，进一步揭示柴油喷雾一次破碎的机理，同时指导新的喷雾破碎模型开发，优化喷油器的结构设计，最终实现柴油机先进燃烧模式的可控最优喷雾特性。

中文关键词： 燃油喷雾；内部流动；喷嘴结构；空穴特性；相衬成像

英文摘要： In order to meet the more strict emission regulation of marine diesel engine and reduce the green-house emissions, it is necessary to improve the fuel spray and internal combustion process from the point of view of engine internal control. Moreover, the importance prerequisite of optimizing the internal combustion is to understand the spray characteristics and break-up mechanism. The primary break-up is the link between liquid core and formation of liquid droplets. Recent studies on the near-field spray（primary break-up） of diesel injection found that spray morphology and break-up process has close relationship with nozzle internal flow. However, the research on the internal flow of real diesel injector is limited and few direct correlation between internal flow and spray characteristics. In this project, X-ray imaging technology and high-strength Al alloy nozzle tip will be used to measure the spray and nozzle internal flow simultaneously at high injection pressure. The expected results will show the effect of nozzle structure and needle lift on the spray characteristics and find the primary break-up mechanism of diesel spray. In addition, new spray model and optimization of nozzle structure can be created. Finally, it is possible to obtain the controllable optimum spray characteristics matching the modern comb

英文关键词： fuel spray；internal flow；nozzle geometry；cavitation；phase-contrast imaging