中文摘要：

为了区分火花塞点火式缸内直喷（SIDI）发动机喷雾和环境气体两相流场,将优化后的高速双色PIV（Particle Image Velocimetry）技术应用于多孔直喷喷油器的喷雾和环境气体速度的测试.此双色P IV 系统由一个特殊的示踪和滤波系统组成,可同时对燃油喷雾及其环境气体的速度场进行测量.本研究采用该双色P IV 方法研究不同环境压力和燃油温度的条件下,喷嘴孔数及其布置情况对燃油喷雾和环境气体的相互作用的影响.在此研究中,对3 个汽油直喷喷嘴做了详细的研究,包括1 个6 孔喷嘴,1 个3 孔喷嘴及1 个2 孔喷嘴.研究结果表明,随着燃油温度的提高或者环境气体压力的降低,喷雾雾化增强,燃油颗粒粒径减小,导致喷雾油束变宽,喷雾与环境气体接触面积变大,喷雾和环境气体的两相流场的作用变强.不同孔数和布置的喷油器在冷态及闪沸条件下油束间干扰作用的强度不同,导致喷雾传递给环境气体的动能不同.较强的油束间的干扰作用加强了燃油喷雾与环境气体之间的动量交换过程,进而增强了环境气体的动能.

英文摘要：

In order to investigate the two-phase flow fields of fuel spray and ambient air of spark ignition direct injection (SI-DI) engine ,the optimized high speed two-color particle image velocimetry ( PIV) technology was applied to the velocity meas-urement of fuel spray and ambient air .PIV system consisting of special trace and filter system could measure the velocity of fuel spray and ambient air simultaneously .Effects of nozzle hole number and distribution on interaction between fuel spray and am-bient air under different ambient pressures and fuel temperatures were studied based on three direct-injection injectors including one 6-hole injector ,one 3-hole injector and one 2-hole injector .The results showed that the interaction between fuel spray and ambient air strengthened due to the better spray ,the smaller fuel particle size and their produced wider spray beam and larger contact area with the increase of fuel temperature or the decrease of ambient pressure .Different interference intensity between spray beams for multi-hole injectors under normal and flash boiling conditions led to different kinetic energy transfer from fuel spray to ambient air .The momentum exchange between fuel spray and ambient air was enhanced by the stronger interference effect between beams ,and thus the kinetic energy of ambient air increased .