柴油机喷油嘴变截面喷孔内壁粗糙度影响研究  

Influence of Wall Roughness of Variable Section Injection Hole in Diesel Engine Nozzle

作　　者：张辉 韩振南[1] ZHANG Hui;HAN Zhen-nan(College of Mechanical Engineering,Taiyuan University of Technology,Shanxi Taiyuan 030024,China)

机构地区：[1]太原理工大学机械工程学院,山西太原030024

出　　处：《机械设计与制造》2020年第10期153-156,161,共5页Machinery Design & Manufacture

摘　　要：柴油机喷油嘴变截面喷孔内部流动和出口变化对燃油喷射雾化有直接影响。通过FLUENT软件数值仿真研究了变截面喷孔内壁粗糙度对孔内流动和喷孔出口的影响。研究结果:喷孔粗糙壁面对空穴有抑制作用,倒锥型喷孔几何结构促进空化的影响大于粗糙壁面的抑制作用,双曲线型喷孔粗糙壁面对空穴影响极小;粗糙壁面对变截面喷孔内湍流强度的增强远大于几何结构对湍流的影响;喷孔内壁面增设粗糙度正锥型喷孔、双曲线型喷孔质量流量显著降低,等径喷孔会抑制超空化进而增加质量流量,倒锥型喷孔对出口质量流量影响很小;增设喷孔内壁面粗糙度会使得等径喷孔、倒锥型喷孔、双曲线型喷孔的出口平均速度得到显著下降,椭圆型喷孔增设粗糙度出口速度降低很少,并且增加粗糙度几乎不会影响出口速度。The change of the internal flow and outlet of variable cross-section injection holes of diesel injectors has a direct impact on fuel injection atomization.FLUENT software numerical simulation was used to study the influence of the roughness of the inner wall of the variable section nozzle on the flow in the hole and the outlet of the nozzle.Research result:The rough wall of the spray hole has an inhibitory effect on the cavity,the effect of the inverted cone-shaped nozzle geometry to promote cavitation is greater than that of the rough wall surface,the hyperbolic spray hole rough wall has minimal effect on the cavitation;The enhancement of the turbulent intensity in the rough-walled nozzle with variable cross-section is much greater than the influence of the geometrical structure on the turbulence;The increase of the roughness of the cone-shaped nozzle and the hyperbolic nozzle in the inner wall of the nozzle hole significantly reduces the mass flow rate,equal diameter orifices suppress supercavitation and increase mass flow,inverted cone nozzles have little effect on the outlet mass flow;The increase of the roughness of the inner surface of the nozzle hole will cause the average speed of the outlet of the equal-diameter nozzle,inverted cone nozzle,and hyperbolic nozzle to decrease significantly.Elliptic nozzles increase the roughness,the outlet speed is reduced very little,and increasing the roughness hardly affects the exit speed.

关 键 词：柴油机 喷油嘴 粗糙度 空化 质量流量 

分 类 号：TH16[机械工程—机械制造及自动化] TK421.5[动力工程及工程热物理—动力机械及工程]