单孔和多孔喷雾近场形态的可视化研究  

Visualization Research on Near-Field Morphology of Single-and Multi-Hole Spray

作　　者：卢鑫辉 张周 李钦伟 马骁[1] 沈义涛 帅石金[1] Lu Xinhui;Zhang Zhou;Li Qinwei;Ma Xiao;Shen Yitao;Shuai Shijin(State Key Laboratory of Automotive Safety and Energy,Tsinghua University,Beijing 100084,China;Automotive Engineering Department,Harbin Institute of Technology(Weihai),Weihai 264209,China;School of Electromechanical and Engineering,Yantai University,Yantai 264005,China)

机构地区：[1]清华大学汽车安全与节能国家重点实验室,北京100084 [2]哈尔滨工业大学汽车工程学院,山东威海264209 [3]烟台大学机电汽车工程学院,山东烟台264005

出　　处：《内燃机学报》2020年第5期401-408,共8页Transactions of Csice

基　　金：国家自然科学基金资助项目(51506111,51636003).

摘　　要：基于高速摄影数据,参考存在空气阻力时的斜抛运动轨迹方程对喷雾近场轮廓进行曲线拟合,对比了不同工况下多孔喷雾轮廓与同一位置单孔喷雾轮廓在近场相对位置关系.结果表明:对于常温、常压下的非闪沸正庚烷喷雾,多孔喷雾轮廓在单孔喷雾轮廓内侧;随着过热度的增加,多孔喷雾轮廓表现出向外扩展的趋势,过热度达到1附近时向外扩展程度达到最大;继续增大过热度时,多孔喷雾轮廓开始反向收缩.在极高的过热度下,多孔喷雾轮廓在单孔喷雾轮廓内侧.为解释试验现象,提出了多孔喷雾中心压力场类型模式图,并分析了压力场类型随过热度变化的演变模式.在多孔喷雾各油束中心区域,存在射流诱导低压区、挤压高压区和膨胀诱导低压区等若干类型的压力场.不同过热度下各类压力场大小、位置和强弱的变化是多孔喷雾轮廓与单孔喷雾在近场相对位置差异的主要原因.Through high speed photography,referring to the equation of the oblique trajectory of motion with air resistance,the curve of the near-field profile of the spray was fitted and the difference between multi-and singlehole spray profile at the same position in the near field under different conditions was compared.The experimental results show that for non-flashing n-heptane spray at normal temperature and pressure,the multi-hole spray profile is inside the single-hole spray profile.As the degree of superheat increases,the multi-hole spray profile exhibits a tendency to expand outward,and when the degree of superheat reaches around 1,the expansion reaches its maximum value.When the degree of superheat continues to increase,the multi-hole spray profile begins to contract in the opposite direction.At very high superheat,the multi-hole spray profile is inside the single orifice spray profile.In order to explain the experimental phenomenon,the pressure field type pattern of the multi-hole spray center was proposed and its evolution mode was discussed.In the central region of each oil bundle of the multi-hole spray,there are several types of pressure field including jet induced low pressure zone,squeezed high pressure zone and expansion induced low pressure zone.The variation of the type,size,position and strength of pressure fields under different degrees of superheat is the main reason for the difference between the multi-hole spray profile and the single-hole spray in the near field.

关 键 词：闪急沸腾 高速摄影 曲线拟合 

分 类 号：TK411.2[动力工程及工程热物理—动力机械及工程]