CAJ | 학술논문

通过将柴油机尾气引入两级稀释取样系统,模拟柴油机排气在近排气管大气环境中稀释变化特性,以期揭示大气稀释作用下柴油机排气尾流中核模态颗粒的形成和变化机制。实验发现：改变初级稀释通道内混合气温度（PDT）、湿度（PDH）、混合气停留时间（PRT）和稀释比例（PDR）等稀释参数会显著影响稀释混合气中核模态粒子（Dp〈50 nm）的数浓度和粒径分布,表明核模态粒子主要由排气稀释过程中气-粒转化作用产生的二次颗粒构成;随PDT的降低以及PDH、PRT的增加,排气尾流中核模态粒子数浓度显著增加,颗粒粒径向大粒子方向迁移;核模态粒子的数浓度随PDR增加呈先增加后减小趋势,采用气溶胶动力学变化理论对测试结果进行了讨论。
통과장시유궤미기인입량급희석취양계통,모의시유궤배기재근배기관대기배경중희석변화특성,이기게시대기희석작용하시유궤배기미류중핵모태과립적형성화변화궤제。실험발현：개변초급희석통도내혼합기온도（PDT）、습도（PDH）、혼합기정류시간（PRT）화희석비례（PDR）등희석삼수회현저영향희석혼합기중핵모태입자（Dp〈50 nm）적수농도화립경분포,표명핵모태입자주요유배기희석과정중기-립전화작용산생적이차과립구성;수PDT적강저이급PDH、PRT적증가,배기미류중핵모태입자수농도현저증가,과립립경향대입자방향천이;핵모태입자적수농도수PDR증가정선증가후감소추세,채용기용효동역학변화이론대측시결과진행료토론。
The dilution and change characteristics of diesel engine exhaust near tailpipe atmospheric environment were investigated based on two-stage diluter experiments.The purpose is to find the evolution characteristics of nucleation mode particles in the exhaust plume of diesel engines.It is shown that the changes of primary dilution parameters,such as primary dilution mixture gas temperature（PDT）,primary dilution mixture air humidity（PDH）,primary dilution ratio（PDR）,and primary residence time（PRT）,significantly affect the size distribution of nucleation mode particles（Dp50 nm） in the exhaust plume of diesel engines,further indicating that the nucleation mode particles are composed mainly of secondary particles based on gas-to-particle conversion during exhaust dilution and cooling.The decrease of PDT or the increase of PDH and PRT can significantly increase the number concentration of nucleation mode particles in the exhaust plume of diesel engines.With increasing PDR,the number concentration of nucleation mode particles exhibits a rise-decay trend,and after a peak point it steadily decreases.The measurement results were explained based on the aerosol dynamic theory.