4、进气末期射流速度减小对缸内流动结构的影响迅速减弱。进气射流的破碎和缸内涡心变动是导致进气阶段缸内湍动能增大的原因之一。关键词：增压柴油机，大涡模拟，进气流动，进气射流IABSTRACTThe intake process of diesel enginesstrongly depends onthe geometry of intake ports, valve rodsand complex operation conditions, which result inbackflowand flow separation at the valve gap. Afterwards, itmayw
5、orsenthe charge performance and combustionefficiency.Therefore, there isan urgent need to understand the flow characteristics nearthe intake valves. In this work, large eddy simulations (LES) of a four-stroke single-cylinder supercharged diesel engine wereperformed.The main conclusions are:Firstly,
6、the flow around the intake valve wasinvestigated.The resultsshowthat: (1) backflow is the mainreason for the non-uniform distribution of thevelocity aroundthe intake valve curtain underhigh valve lifts. Specifically, under a lowvalve lift, the velocitydistributes around the intake valve curtain unif
7、ormly. Asthe liftincreases, the backflow was gradually enhanced, resulting in non-uniform distribution of velocity around the valve curtain. For different geometries of intake ports, backflow was only
