二甲醚发动机实现预混等压燃烧模式的计算与分析

Calculation and analysis of realizing premixed isobaric combustion mode on the DME engine

探索了二甲醚(DME)发动机的一种新型的预混等压燃烧模式,即掺混LPG燃料实现发动机的等压燃烧.基于STAR-CD平台,对某二甲醚发动机内掺混液化石油气(LPG)燃料后的缸内喷雾与燃烧过程进行了计算与分析.计算结果表明:与纯二甲醚发动机相比,掺混LPG燃料后其滞燃期延长、燃烧持续期缩短、着火点延后;同时燃烧压力与温度有所升高,放热率峰值增大,燃烧控制在上止点附近,基本实现了发动机等压燃烧模式.为进一步提高二甲醚发动机的效率提供了重要参考.

A new kind of premixed isobaric combustion mode that mixes LPG fuel to realize isobaric combustion of a dimethyl ether engine has been explored. Based on STAR - CD platform, the calculation and analysis of the fuel spray and combustion process in cylinder of certain dimethyl ether engine after mixing liquefied petroleum gas （LPG） has been finished. The calculation results show that compared with the pure DME engine, after mix- ing LPG fuel, there are a longer combusting delay period, a shorter burning duration, and a delay in ignition. At the same time, the pressure and temperature of combustion rise somewhat. The peak of the heat release rate in- creases, and the combustion has been controlled nearby TDC, which show that the isobaric combustion mode of the engine has been realized basically. This measure provides a significant reference to further enhance the effi- ciency of DME engine.