不同海拔条件下柴油机撞壁喷雾燃烧特性的可视化研究  

Visualization of Combustion Characteristics of Diesel Spray Wall Impingements at Different Altitudes

作　　者：王成官[1] 楼狄明[1] 谭丕强[1] 房亮[1] WANG Chengguan;LOU Diming;TAN Piqiang;FANG Liang(School of Automotive Studies,Tongji University,Shanghai 201804,China)

机构地区：[1]同济大学汽车学院,上海201804

出　　处：《内燃机工程》2020年第3期9-17,共9页Chinese Internal Combustion Engine Engineering

基　　金：国防重大基础研究项目(613252)。

摘　　要：使用定容燃烧弹模拟一款重型柴油机在海拔0 m、3000 m和4500 m条件下运行时缸内的热力学状态,利用多种成像技术实现了撞壁燃烧过程的可视化,研究了不同海拔对撞壁喷雾燃烧的高温着火、火焰传播和碳烟生成特性的影响。结果表明,海拔从0 m升高到4500 m,撞壁着火延迟从0.55 ms延长到0.88 ms,撞壁着火距离从20.38 mm增大到26.87 mm,高海拔对撞壁着火过程有明显的抑制效果;撞壁火焰呈现圆盘状火焰形态,火焰发展进入稳定阶段后,由于前锋区域的涡流强度增大,撞壁火焰铺展高度、撞壁火焰铺展宽度和撞壁火焰面积都随海拔升高而增大,但在火焰发展初期,由于撞壁平板的冷却作用,撞壁火焰尺寸在海拔升高到4500 m时减小;空间积分火焰亮度和时间积分火焰亮度均随海拔升高而增大,海拔升高到4500 m时碳烟生成速率和氧化速率均增大。A constant-volume combustion bomb was used to simulate the thermodynamic states of a heavy-duty diesel engine when operating at altitudes of 0 m,3000 m and 4500 m,respectively.Based on the use of multiple imaging technologies to visualize the spray wall impingement combustion process,the effect of different altitudes on high temperature ignition,flame propagation,and soot formation characteristics of spray wall impingement combustion were studied.Results showed that as altitude increased from 0 m to 4500 m,the ignition delay during the spray wall impingements extended from 0.55 ms to 0.88 ms,and the ignition distance increased from 20.38 mm to 26.87 mm,indicating that high altitude had a significant suppression effect on ignition process.At this time,the burning flame assumed a disk-like shape.When the flame development entered a quasi-steady stage,the height,width and area of flame expansion rose with altitudes due to the increase of vortex intensity in flame front area.However,at the early stage of flame development,the flame size began to decrease after altitude reaches 4500 m due to the cooling effect of spray impinged surface.In addition,the space-integrated flame luminosity and time-integrated luminosity rose with increased altitude,and both of soot formation and oxidation rate would increase accordingly when altitude rises to 4500 m.

关 键 词：柴油机 海拔 定容燃烧弹 喷雾撞壁 燃烧 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]