进口边界条件对两级增压级间管路内部旋流畸变的影响

Influence of Inlet Boundary Condition on Internal Swirl Distortion of Two-Stage Turbocharger Interstage Pipeline

柴油机两级增压系统高、低压压气机级间复杂连接管路导致高压压气机进口发生旋流畸变并进而影响系统匹配,通过级间管路畸变流动特征研究,为级间管路设计提供参考依据。采用三维数值仿真方法,对比研究了均匀法向进气和低压压气机蜗壳出口流场两类进口边界条件对级间管路内部流动的影响,发现采用低压压气机蜗壳出口流动特征作为进口边界条件,级间管路出口平面的旋流强度SI大幅高于均匀法向进气情况,级间管路总压损失相差16%,下游高压压气机效率绝对值相差达到2个百分点。管路折转是影响级间管路内部旋流强度变化的主要原因,在工程方案设计中需要结合低压压气机蜗壳出口气流特征考虑级间管路折弯位置、折转半径等参数的设计与优化。

The complicated interstage connection pipeline between the high and low pressure compressor in the two-stage turbocharging system of diesel engine leads to the swirl distortion at the inlet of high-pressure compressor,which affects the system matching.The distorted flow characteristics were studied to provide a design reference for the interstage pipeline design.The effects of uniform normal intake and low-pressure compressor volute outlet flow field on the flow field of interstage pipeline were comparatively studied by using the 3 D numerical simulation method.It was found that the swirl intensity of interstage pipeline outlet for the low-pressure compressor volute outlet flow field was significantly higher than that of uniform normal intake,the total pressure loss between them differed by 16%,and the downstream high-pressure compressor efficiency between them differed by 2%in absolute value.Pipeline bending was the main reason that affected the swirl intensity.Accordingly,the outlet flow characteristic of low-pressure compressor volute and the bending position and turning radius of interstage pipeline should be comprehensively considered in engineering design.