背景温度和密度对柴油喷雾特性影响灵敏度分析  

Sensitivity analysis on the effect of background temperatures and densities on the diesel spray characteristics

作　　者：高浩卜[1] 李向荣[1] 薛继业[1] 白洪林[2] 何旭[1] 刘福水[1] 

机构地区：[1]北京理工大学机械与车辆学院,北京100081 [2]中国北方发动机研究所(天津),天津300400

出　　处：《哈尔滨工程大学学报》2016年第11期1553-1559,共7页Journal of Harbin Engineering University

基　　金：装备预研项目(104010204)

摘　　要：为优化发动机缸内喷油时刻背景温度和密度,以改善喷雾特性、提高功率,通过高速摄影直拍和纹影技术,利用自编图像处理程序进行数据处理,引入灵敏度概念,研究了背景温度和密度对柴油喷雾特性影响灵敏性。试验发现:在背景温度304~770 K,密度13~26 kg/m^3范围内,背景温度对气相体积百分比的灵敏度远大于密度对气相体积百分比的灵敏度,在770 K、26 kg/m^3时,大约是密度的10倍;而密度对喷雾平均空燃比的灵敏度略大于温度对喷雾平均空燃比的灵敏度,在770 K、26 kg/m^3时,大约是温度的1.18倍。将此规律应用于发动机某工况仿真计算,微调喷油初始时刻背景温度和密度(3.5%以内变动),功率可提高2.8%。In this paper, a direct imaging and schlieren technique of high-speed photography is applied to optimize the background temperature and density at the time of diesel spray inside an engine cylinder and consequently improve the spray characteristic and increase power. Accordingly, an in-house image processing program is used to process the data. The concept of sensitivity is then introduced. Furthermore, a sensitivity analysis is performed on the effect of the background temperatures and densities on the diesel spray characteristics. The background temperature sensitivity against the volume percentage of the gas phase is far more than the density sensitivity （i.e., approximately 10 times that of the density at 770 K and 26 kg/m^3 ） when the density and the temperature varied from 13 to 26 kg/m^3 and 304 to 770 K, respectively. Moreover, the density sensitivity against the average air-fuel ratio of the spray is slightly higher than the temperature sensitivity （i.e., approximately 1.18 times that of the temperature at 770 K and 26 kg/m^3） under the same condition. The power can be increased by 2.8% by applying the sensitivity law to an engine-simulating calculation at some behaviors when the background temperature and the density at the initial diesel spray moment are slightly adjusted, with a variation scope within 3.5%.

关 键 词：柴油喷雾特性 背景温度 背景密度 纹影 定容装置 灵敏度分析 

分 类 号：TK421.1[动力工程及工程热物理—动力机械及工程]