基于数值模拟的柴油机后处理系统阻力研究

Study on Resistance of Diesel After-treatment System Based on Numerical Simulation

将柴油机用肇流式过滤体（Diesel Particulate Filter，DPF）简化为单通道流动管道的集合，根据准稳态流动的压力损失方程和传热方程建菠了DPF的一维流动模型；将柴油机工作过程模型与DPF流动模型集成，建宦了后处理系统的排气阻力模拟计算模型，通过台架试验验证，证明误差在3％以内。计算结果表明：柴油机在低负荷时，系统排气阻力与负荷近似呈线性关系；在高负荷时，二者近似呈二次曲线关系。计算给出柴油机全工况排气阻力MAP图，可用于标定DPF再生控制器。

According to the mathematic and physical equations on channel flow, wall thermal, which are based on Quasi-steady and embedded in computation fluid dynamics software, the CFD model is established to simulate a one-dimension flow of DPF（Diesel Particulate Filter）. The BJ493ZQ3 diesel model is also established, then the integrated model connected with the end of engine vent-pipe is formulated, and the resistant force of the whole exhaust system is calculated with error less than 3%. Based on the same rotate speed, both numerical and experimental study indicate that there exists a linear correlation between resistance and load in the case of light load but a conic approximate correlation in the case of heavy load. The practical resistance MAP over a full operating condition range is presented, by which a regeneration controller is calibrated.