A 186F diesel engine running at altitudes of 10 m,1 000 m and 1 670 m is numerically studied.By analyzing the parameters of spray penetration distance,oil droplet vaporization rate,in-cylinder velocity field,temperature field and oil film quality at different altitudes,the combustion characteristics and emission characteristics under the same power condition are com-pared.The results show that with the increase of altitude,the fuel spray penetration distance increases,the apparent reverse extru-sion movement is delayed,the ignition delay period becomes longer,a large amount of combustible mixture is formed at the end of the jet beam,the premixed combustion is intense,the maximum average temperature in the cylinder increases,and the NOx emis-sion increases.At high altitude,there is oil film accumulation in the pits of the combustion chamber,and the vortex movement in the cylinder is far away from the pits,where the combustion of the mixture deteriorates,the post-combustion phenomenon is obvi-ous,the exhaust temperature rises,soot and CO emissions increase,and the thermal efficiency decreases.
关键词
高海拔/燃烧特性/排放特性
Key words
high altitude/combustion characteristics/emission characteristics
维普
万方数据