入口颗粒物浓度对EGR冷却器颗粒物沉积过程的影响

Effect of Inlet Particulate Concentration on the Deposition Process in EGR Cooler

废气再循环(exhaust gas recirculation,EGR)冷却器积碳会使冷却器换热效率恶化,影响发动机性能。基于EGR冷却器颗粒物沉积试验平台,研究了不同浓度的颗粒物在EGR冷却器内物理沉积过程,分析了颗粒物浓度对EGR冷却器内HC冷凝量、不同粒径范围颗粒物减少率以及颗粒物中数粒径的影响。结果表明:颗粒物浓度越高,气态碳氢(Hydrocarbon,HC)的冷凝量越多;气态HC体积分数相同,颗粒物浓度增加,HC冷凝成核对粒径小于30 nm(D_p<30 nm)的颗粒物浓度的影响增强;颗粒物浓度越高,颗粒物撞击凝结对颗粒物沉积过程的影响越大。

Particulate deposition in EGR(exhaust gas recirculation)cooler will deteriorate the heat transfer efficiency of cooler,which affects engine performance.Based on the particulate deposition test platform of EGR cooler,this paper studied the physical deposition process of particles with different concentrations in EGR cooler,and analyzed the effects of particle concentration on the HC condensation,particle reduction rate in different particle size range and median particle diameter in EGR cooler.The results show that the higher the particle concentration,the higher the condensate of gaseous HC.With the same gaseous hydrocarbon volume fraction,the concentration of particles is increased,and the influence of HC condensation on the concentration of particles with D_p<30 nm is enhanced.The higher the particle concentration,the greater the impact of coagulation of particulate on the particle deposition process.