天然气柴油双燃料发动机内部燃料混合模拟研究

摘要

基于AVL FIRE软件,模拟了缸内直喷引燃天然气和柴油喷射混合过程,对湍流模型进行了校核和验证,分析了不同喷孔高度、喷孔倾斜角及喷孔交角下柴油和天然气射流的混合情况.研究表明:k-ε湍流模型更适用于天然气/柴油双燃料的模拟;喷孔高度、倾斜角及交角越大,索特平均值经(SMD)越小,其中喷孔交角大的获得的雾化效果最好;喷孔之间的相对位置决定了油气射流之间能量传递,从而影响了油气贯穿距及雾化效果.%Based on the AVL FIRE code, the simulation of injection and mixture of natural gas and diesel fuel in a natural gas engine with pilot injection was carried out to study its combustion and emission performance.The related turbulent model was verified by the bed test and then the characteristic parameters, such as orifice position, inclined angle and gas-diesel over-lapping angle were analyzed.Results show that the k-ε turbulent model is more suitable for simulating the dual fuel injection, and the larger the injection height, inclination angle and over-lapping angle, the smaller SMD.In particular, using a large over-lapping angle can obtain the best atomization effect.The relative nozzle position will decide the energy transfer between the fuel and gas jets, thus influencing the penetration distance of fuel and gas and the atomization effect.