可控热氛围中喷雾的雾化特性和粒径分布

Atomization and Droplet Size Distribution of Diesel Sprays Issuing into a Hot Vitiated CoFlow

摘要:

基于可控热氛围燃烧器提供的均匀温度场，使用高速摄像机和激光衍射粒度仪对300~673 K协流温度范围内的柴油喷雾进行测量.结果表明，随协流温度升高，相同时间内的喷雾贯穿距减小，喷雾锥角先增大后减小.在300 K协流下，索特平均直径处于10~20 μm之间，随轴向高度升高而略有增加，大尺寸液滴的直径在离开喷孔20~40 mm过程中下降了17%.各粒径参数随径向距离的增大而减小.粒径一致性随着轴向和径向距离的增加而提高.在协流温度从300 K上升至673 K的过程中，索特平均直径从15 μm上升到24 μm，粒径一致性提高，蒸发使得小尺寸液滴大量消失.

Abstract:

The information of diesel spray in a stable hot coflow (300—673 K) is recorded with a highspeed camera and a laser diffraction instrument. The results show that as the coflow temperature increases, the spray penetration decreases and a peak spray angle appears. When the coflow temperature is equal to 300 K, the Sauter mean diameter of the droplets is between 10 μm and 20 μm and slightly increases along the axis. Dv90 decreases by 17% from 20 mm to 40 mm in the axial distance. The size distribution parameters decrease along the radius. The uniformity of the droplet sizes becomes better as the axial/radial distance increases. The Sauter mean diameter increases from 15 μm to 24 μm and the uniformity increases as the coflow temperature increases from 300 K to 673 K, owing to the fast evaporation of small droplets.