小缸径直喷柴油机喷雾与燃烧三维数值模拟

应用CFD软件对一台小缸径增压中冷柴油机进行了喷雾燃烧数值模拟,得到了详细的喷雾发展形态、燃油浓度分布和燃烧过程温度场、有害排放物分布等重要信息,为燃烧室结构优化设计和与油嘴匹配奠定基础。计算结果表明,计算示功图与实测值吻合较好;喷油阶段,油束存在碰壁现象,燃烧室凹坑底部燃油浓度较高;随着活塞下行,锥台与凹坑连接处空气运动较弱,燃油浓度较高,同时NOx与Soot生成与混合气浓度、空气运动、温度有密切联系。

Three-dimension Numerical Simulation of Spray and Combustion of D.I. Diesel Engine with Small Cylinder Bore

CFD software is applied for simulation of spray and combustion of a small cylinder D.I.diesel with turbocharging and intercooling.The important information such as spraying evolution,space distribution,temperature field and harmful emission distribution in detail gets by numerical simulation laid the foundation for optimum design of combustion and matching with the injector.It's found the simulated indicator diagram tallies well with the experimental one;In the progress of injection,fuel spray impingement on chamber happened and the fuel concentration at the bottom of the chamber is higher;as the movement of the piston,the air flow at the connecting area of the taper convexity and concave pit is worse and also the fuel concentration at this area is high.The formation of NOx and soot is closed related with the mixture concentration,air flow,temperature and so on.