摘要
针对某型号柴油机开展了高海拔条件下柴油机壁面液膜燃烧机理的数值计算研究,详细分析了不同海拔高度下,柴油机附壁燃油量、液膜位置、液膜面积及液膜厚度分布特性、蒸发特性及燃烧放热特性等。结果表明,附壁燃油量与撞壁燃油量成正相关。就撞壁形态而言,绝大部分燃油铺展和粘附在燃烧室凹坑侧壁上,仅有极少量附着在壁上;附壁液膜位置由燃烧室凹坑侧壁中部向其上下方向扩展;在燃烧结束时,绝大部分附壁燃油仍未全部蒸发。海拔越高,撞壁燃油量越大,液膜面积及液膜厚度越大,液膜蒸发越慢,燃烧室内部分剩余未燃燃油及附壁液膜的燃烧持续时间越长,燃烧恶化越严重。
The numerical simulation of the combustion mechanism of wall film in a diesel engine under high altitude condition was studied. The characteristics of attached wall fuel quantity, wall film position, area and thickness,and wall film evaporation rate and combustion heat release were analyzed under different altitudes. Results show that： the attached wall fuel quantity has a positive relationship with the wall impingement fuel quantity. In terms of the shape of wall impingement, most of the wall impingement fuel spread and adhere on the wall, while only a very small amount of fuel can stick onto the wall. The position of the attached wall film extends from the middle to the up and down direction of sidewall of combustion chamber. A large amount of the attach-wall fuel still doesn＇t evaporate at the end of combustion process. With the altitude increasing, the amount of the hit-wall fuel becomes larger. The area and thickness of the wall film increases with the altitude. The rate of wall film evaporation becomes slower under higher altitude. There is longer combustion duration of the residue of the space fuel and the wall film in the third stage with the increase of altitude, leading to deterioration of combustion.
出处
《小型内燃机与车辆技术》
2017年第2期1-6,共6页
Small Internal Combustion Engine and Vehicle Technique
关键词
柴油机
壁面液膜
高海拔
燃烧
数值仿真
Diesel engine
Wall film
High altitude
Combustion
Numerical simulation
