汽油机燃烧室内温度场测量的激光剪切干涉法

采用激光剪切干涉法测量了汽油机燃烧室内的温度场,并分析了剪切干涉法测温的基本原理,推导出利用干涉条纹图求解温度分布的关系式。在一台二冲程火花点火发动机上设置石英窗和信号同步系统,建立了适合高速摄影的激光剪切干涉测量装置。通过改变剪切干涉量,测取发动机燃烧室内干涉条纹图,从而获得缸内燃烧的二维温度场。结果表明,激光剪切干涉法抗振性强,光路简单可靠,可以进行高速摄像,是研究内燃机燃烧过程的有效方法。从温度场可以看出,燃烧过程中缸内大致可分为三个区,即已燃区、未燃区和燃烧区,具有不同的温度分布和温度梯度。燃烧区温度最高,温度梯度大;已燃区温度次之,梯度较小;未燃区温度最低,但梯度较大。

Laser Shearing-Interferometry for Measurement of Temperature Field in Combustion Chamber of Gasoline Engine

The temperature field in combustion chamber of gasoline engine was measured using laser shearing-interferometry. The basic principle was analyzed, and the equations between the interference wave figure and temperature distribution were deduced. The quartz window and signal synchronization system were set on a two-stroke spark ignition engine, and a set of shearing-interferometry and high speed photography experimental equipment which is suitable for studying combustion was established successfully. Changing the shearing-interferometry quantity, the two-dimensional temperature field of engine combustion chamber can be measured quantitatively by image processing. The results show that laser shearing-interferometry can resist vibration well. The optical route is simple and durable. It can also make high speed photography. It is an efficient way to research combustion process in engine. There are three zones in the combustion process in the cylinder concluded from the temperature field. They are burned zone, unburned zone and burning zone. The temperature distribution and the temperature gradient are different in each zone. The temperature is highest in the burning zone and the temperature gradient is big. The temperature is lower in the burned zone and the temperature gradient is smaller. The temperature is lowest in the burned zone but the temperature gradient is bigger.