单液滴破碎空间尺寸分布特性的实验研究

Experimental Study for Dimensional Distribution Characteristics of Particles Swarm of Single Droplet Breakage

关键词:  均匀气流  单液滴  颗粒群分布  雾化均匀性

Key words:  Uniform airflow  Single droplet  Particle swarm distribution  Atomization uniformity

摘要:

为了研究液滴破碎后颗粒云空间尺寸分布的机理特性，通过试验方法并建立相应的均匀性指标数学模型，分析了不同We数对液滴破碎后颗粒群空间分布均匀性的影响。结果表明:(1)液滴袋状破碎后颗粒分布类似于袋形的蜂窝结构，并以类似爆破的形式向后方外围扩散分离。(2)多模式破碎后颗粒群为类似于“树”形结构的颗粒分布，前端有分布密集、粒径较小的聚集团，后方分布着大范围的颗粒群。(3)剪切破碎后颗粒群为类似“桶”形的颗粒分布，外围分布着大量颗粒，而内部分布较为复杂。(4)在We数为10～70时，颗粒群的离散率在整体上是呈现先升高后下降再升高的趋势。当We数为30和60时，两个方向上的离散率存在较大差异，而三种不同的破碎模式中，剪切破碎均匀性表现最好。

Abstract:

In order to research the mechanism characteristics of particles dimensional distribution of single droplet breakage，an experimental method and the mathematical model of uniformity index are employed to analyze the effects of different We parameters on uniformity of particles dimensional distribution. Results indicate that:(1)Particles distribution of droplet baggy breakup is similar to the pouched honeycomb structure，with the similar form of blasting to diffuse and separate to the rear;(2)Particles distribution of droplet multi-mode breakup is similar to a tree structure. The front has an aggregation with compact-smaller particles，and the rear distributes with a wide range of particles group;(3)Particles distribution of droplet sheet-thinning breakup is similar to the bucket structure. The periphery distributes with a large number of particles，but the internal distribution is complex;(4)Within the scope of the We count for 10～70，the discrete rate of particles distribution show that trend is fall after the first rise，and then increases. But there are large difference between the discrete rates of two directions when We count for 30 or 60，and the uniformity of sheet-thinning breakup is among the best in three kinds of broken patterns.