含水乙醇/生物柴油燃烧与排放分析

Effect of Water Content on Biodiesel/Ethanol Combustion and Emissions

乙醇与生物柴油混合可以降低柴油机颗粒物排放.乙醇燃料吸水性较强,含有一定水分的燃料对柴油机的燃烧与排放会产生一定的影响.通过采集186F柴油机燃用乙醇/生物柴油燃料的示功图,建立了186F柴油机燃用含水乙醇/生物柴油的燃烧与排放模型.在186F标定工况进行了不同含水率的乙醇对柴油机燃用乙醇/生物柴油燃烧与排放特性影响的仿真研究.分析了乙醇含水率为0,10%,15%,20%时,气缸压力、平均指示压力、缸内平均温度、滞燃期、燃烧持续期、燃烧中心、指示比能耗、NO与Soot排放的变化规律.结果表明:随着乙醇含水率的增加,燃烧过程的缸内最大爆发压力、缸内平均温度、平均指示压力等均呈下降的趋势,指示比能耗略有增加,NO与Soot质量浓度降低,Soot直径减小.含水乙醇的掺混比为20%、乙醇含水率由0增加到20%时,缸内最大爆发压力由7.75 MPa降低为7.08 MPa,指示比能耗由11.39 kJ·kW^-1·h^-1增加到11.64 kJ·kW^-1·h^-1.相比于无水乙醇,NO和Soot质量浓度均有大幅度降低,NO降低约14.4%~27.1%,Soot降低约28.1%~73.6%.

Mixing ethanol with biodiesel can reduce diesel particulate emissions.Ethanol fuel has strong water absorption,and fuel containing certain water content will have a certain influence on the combustion and emission of the diesel engine.The combustion and emission model of the 186F diesel engine with water-containing ethanol/biodiesel was established by collecting the indicator map of the 186F diesel engine burning ethanol/biodiesel fuel.In the 186F calibration condition,the simulation study on the effects of ethanol with different water content on the combustion and emission characteristics of diesel fuel ethanol/biodiesel is carried out.The law of change in cylinder pressure,average indicated pressure,average cylinder temperature,retardation period,combustion duration,combustion center,indicating specific energy consumption,NO and Soot emissions are analyzed when the water content of ethanol is 0%,10%,15%,and 20%respectively.The results show that with the increase of water content of ethanol,the maximum burst pressure,average temperature in the cylinder and average indicated pressure of the combustion process are decreasing,indicating a slight increase in specific energy consumption and a decrease in the mass concentration of NO and Soot.The Soot diameter is reduced.When the blending ratio of aqueous ethanol is 20%and the water content of ethanol is increased from 0%to 20%,the maximum burst pressure in the cylinder is reduced from 7.75 MPa to 7.08 MPa,indicating that the specific energy consumption is increased from11.39 kJ·kW-1·h^-1 to 11.64 kJ·kW-1·h^-1.NO and Soot mass concentrations are significantly reduced compared to absolute ethanol,NO approximately decreased from 14.4%to 27.1%,and Soot approximately decreased from 28.1%to 73.6%.