基于一维、三维耦合仿真的歧管式催化转化器结构优化

利用BOOST和FIRE软件建立了某发动机进排气系统的热力学模型和三维排气歧管CFD模型,通过实验进行了仿真分析的初始标定和边界条件数据融合,并采用一维和三维耦合方法分析了低速和高速工况下排气歧管的压力损失和瞬态流场分布。根据评价试验结果显示:优化后的结构显著提高了各管内部流场的流畅性和排气一致性,在一定程度上降低了背压,缩短了起燃时间,提高了发动机的最大转矩。

Structure optimization for manifold catalytic converter based on 1D-3D coupled simulations

In this paper,BOOST and FIRE software were respectively used to establish thermodynamic model of an engine’s intake,an exhaust system and internal CFD steady-state model of the exhaust manifold.Then initial calibration and boundary condition fusion were conducted through experimental data.The pressure loss and transient flow field distribution of the exhaust manifold in low and high-speed conditions were analyzed by one-dimensional(1D)and three-dimensional(3D)coupling methods.According to the evaluation test results,the optimized structure has significantly improved internal flow field fluency and the exhaust uniformity of each manifold,reduced back pressure,shortened ignition time,and improved the maximum torque of the engine to a certain extent.