基于AVLFIRE的柴油机试验台架排气系统内部流场的数值分析

Numerical Simulation of the Flow Field in the Exhaust System of Diesel Engine Test Bench Based on AVL FIRE

针对小型柴油机试验台架排气管接头拆装麻烦、流通特性不好、影响测量准确度等的问题,提出采用滑板式排气管接头代替原装的排气管接头,建立了GD190柴油机试验台架排气系统的计算流体动力学(CFD)模型,应用AVL FIRE软件进行仿真分析和对比试验,数值模拟结果表明,滑板式排气管接头具有良好的流通特性和较大排气的质量流量,但流场中存在气体流动不顺畅,也有明显的涡流存在,对其结构尺寸进一步优化,保证试验台架测试的准确度。

A computational fluid dynamic（CFD）model of the GD190 diesel engine was constructed for the heavy exhaust back pressure and the exhaust pipe redness of the small diesel engine test bench. Using the software of AVL FIRE to respectively analysis the flow characteristics inside the exhaust system connected by three kinds of exhaust pipe joint. Using flow characteristics and flow mass in the outlet to measure the quality of exhaust system.Numerical simulation results show that the sign of the ball joint is best,but the gas flow in the flow field is not smooth for that there are marked roll currents. It is necessary to optimize the structure size to ensure the measurement accuracy of the test bench.