燃烧室形状对醇醚燃料发动机燃烧和排放影响的数值模拟

Effects of Combustion Chamber Geometry on the Combustion and Emissions of Alcohol Ether Fuel Engine

为了研究燃烧室形状对醇醚燃料发动机燃烧和排放特性的影响,在压缩比不变的条件下,设计了5种不同形状的燃烧室,运用AVL_Fire软件对具有不同形状燃烧室发动机的燃烧过程进行了模拟计算。结果表明,缩口燃烧室E内气流运动最强烈,缸内平均压力较高,NO和soot排放很低;直口燃烧室A的缸内压力最低,噪声小,NO和soot排放较低;敞口燃烧室B的NO排放最高,soot排放较低。尖底凸台对气流的导流效果比圆底、平底凸台要好,更利于挤流的形成和发展。缩口燃烧室内的挤流强度比直口、敞口燃烧室强烈。

To study the effects of combustion chamber shape on the combustion and emission characteristics of alcohol ether fuel engine,under the condition of the same compression ratio,five kinds of combustion chambers with different shapes were designed. Then using AVL_Fire,it simulates the specific combustion process of the engines with different chamber shapes.Results show that,the reentrant chamber E has higher air motion intensity,higher average pressure and lower NO and soot emissions. Straight chamber A has the lowest in-cylinder pressure,smaller noise and lower NO and soot emissions. While the open chamber B has the highest NO emission,but low soot emission. The diversion effect of sharp convexity on the airflow is better than that of the round bottom and the flat bottom,which is helpful to the formation and development of extrusion flow.The strength of the squish flow in the reentrant combustion chamber is stronger than that of the straight and open one.