进气中CO_2浓度对预混合燃烧和排放影响的试验和模拟研究

EXPERIMENTAL AND NUMERICAL STUDY OF THE EFFECTS OF CO_2 CONCENTRATION IN THE FRESH CHARGE ON COMBUSTION AND EMISSIONS

本文研究了进气中CO2浓度对燃烧和排放特性的影响.研究表明在所有的预混合燃料比下,当CO2浓度增加时,NOx排放随之大幅减少,烟度排放有小的变化。利用KIVA3V和湍流与化学反应交互的燃烧模型对柴油机预混合燃烧进行了模拟研究,对缸内OH浓度的模拟计算表明,随着CO2浓度的增加,着火前期OH生成浓度明显向后推移,这表明燃料的氧化速率随CO2浓度的增加变慢,从而延长了着火滞燃期。进气中CO2浓度变大时,燃烧温度降低,有利于降低NOx的排放。

This paper presents a study of premixed combustion in a CI engine. The effects of CO2 concentration in the intake gas on the engine combustion and emissions were investigated. The results illustrate that NOx emission is reduced substantially and smoke emission increase slightly with increases of CO2 concentration. The turbulence chemistry interaction model in KIVA3V was used to simulate the combustion. The results show that the OH concentration before ignition and NOx emission are reduced when the CO2 concentration increases.