多缸柴油机进气歧管的仿真计算与试验研究

Simulation calculation and experimental research on intake manifold of multi-cylinder diesel engine

对于多缸直喷柴油机,进气歧管的结构对空气流通性能和各缸进气均匀性影响很大,进而影响到整机性能。文章利用AVL FIRE软件对原机进气歧管进行了三维CFD稳态计算,获得了进气歧管的流通性能数据和最大进气不均匀度。通过带进气歧管的缸盖稳流试验,验证了该进气歧管的进气均匀性较差。仿真流场结果表明,该歧管入口段与容积腔过渡处结构不合理,阻碍了气流运动,据此指导设计部门对进气歧管结构进行改进。计算结果表明,改进后的进气歧管相比于原机进气歧管流通能力和最大进气不均匀度均得到有效改善。

As for multi-cylinder diesel engine ,the structure of intake manifold has a great effect on the performance of air flow and intake evenness of each cylinder ,thus influencing the engine performance . The 3D computational fluid dynamics（CFD） steady calculation is performed on the intake manifold of original engine by using AVL FIRE software .The flow performance data and maximum intake un-evenness degree are obtained .The steady experiment of cylinder head with intake manifold confirms that the intake manifold’s evenness is poor .The results of flow field simulation show that the struc-ture of transition part between inlet and volume cavity is unreasonable ,which is not beneficial for air flow .The intake manifold is improved based on the obtained results .The calculation results of im-proved intake manifold show that the air flow ability and maximum intake unevenness degree are both improved compared with those of the original engine intake manifold .