柴油喷雾初始阶段喷孔内流及油束破碎特性  

Nozzle internal flow and primary breakup characteristics of diesel spray during initial stage

作　　者：王字满 戴晓宇 李佳峰 吴晗[1] 李雁飞 WANG Ziman;DAI Xiaoyu;LEE Chia-fon;WU Han;LI Yanfei(School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China;State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China)

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]汽车安全与节能国家重点实验室,清华大学,北京100084

出　　处：《汽车安全与节能学报》2019年第2期241-248,共8页Journal of Automotive Safety and Energy

基　　金：汽车安全与节能国家重点实验室开放基金(KF1820);国家自然科学基金(51806012);北京市自然科学基金资助项目(3192032)

摘　　要：喷孔内部流动对内燃机燃油雾化、燃烧及排放有显著影响。采用高速显微成像技术,捕捉了气-液演变过程,研究了透明单孔柴油喷油器在初始阶段的喷孔内流及油束初次破碎特性;采用数值模拟方法,解析了气泡与油膜耦合作用过程,剖析其速度场,阐明了不同条件下油束形态的形成机理及破碎过程。研究发现:残余液体燃料体积、物性、压力冲击波强度及气泡之间的相互作用决定了油束形态特性。低喷油压力下,气泡存储能量少,形成薄蘑菇头状油束。在高压条件下,气泡存储能量多,有效促进油束的雾化并形成鼓状油束。Nozzle internal flow significantly affects the spray breakup, combustion and emissions of an internal combustion engine. The characteristics of internal flows in a nozzle and the corresponding diesel spray primary breakup during the initial stage were investigated through a single transparent nozzle by using a high-speed microscopic technique to capture the interaction process between gas-bubbles and liquid films. Numerical simulation was used to analyze the coupling process between the bubbles and thin fuel films with probing the velocity field and clarify the formation mechanism of the spray formation and its breakup process. The results show that the residual liquid fuel volume, the fuel properties, the strength of pressure shock wave, and the interaction between gas-bubbles dominate the spray morphology. Under low injection pressure, the gas-bubbles store less energy, and lead to the formation of mushroom-shaped spray. When injection pressure is high, the gas-bubbles save more energy, effectively promote spray atomization, and form a drum-shaped spray.

关 键 词：内燃机 节能减排 燃油燃烧 喷雾形态 气泡 初次破碎 喷雾 

分 类 号：TK421.4[动力工程及工程热物理—动力机械及工程]