EFFECT OF NOZZLE HOLE SIZE COUPLING WITH EXHAUST GAS RE-CIRCULATION ON THE ENGINE EMISSION PERFOMANCE BASED ON KH-ACT SPRAY MODEL

摘要

To research an effective measure of reducing the Soot and NOx in engine at the same time, different nozzle hole diameters coupled with exhaust gas recirculation (EGR) were adopted in this study based on KH-ACT spray breakup model, which takes the aerodynamic-induced ,cavitation-induced and turbulence-induced breakup into account. The SAGE detailed chemistry combustion and the new atomization model used in the simulation have been verified with the experiment data from a YN4100QBZL engine. Different diesel nozzles was adopted in the study combined with different EGR rates ranging from 0% to 40%. The simulation results show that the NOx emission could be reduced effectively for both small(0.1mm) and large(0.15mm) diesel nozzle when increasing EGR ratio. The soot emission increases for the small nozzle hole size as the EGR increasing. However, when it comes to the large diesel nozzle, the emission increases slightly first and decrease quickly when the EGR rate above 20%.