适用于稳态蒸发和燃烧的定频率单液滴发生器的研究

A Fixed-Frequency,Single-Droplet Piezoelectric Generator for Research in Steady-State Droplet Evaporation and Combustion

对于持续稳态的单液滴蒸发和燃烧中的机理研究,受限于已有实验条件开展相对较少。本文引入了一种基于压电原理的固定频率单液滴发生装置,概述了液滴发生器的工作原理,实现了结构尺寸设计和信号单元设计。采用该液滴发生器研究了不同电压、频率和喷口直径等条件下的液滴发生特性,发现了不同条件下液滴的发生具有单液滴、伴随液滴、连续液柱和不产生等四种模式,而无量纲的We数控制了这些不同的模式行为,提出了产生稳定单液滴的准则是1<We<5。

In contrast to droplet group combustion, the studies on a single droplet evapora- tion/combustion in the quasi-thermal flow reactor are relatively scarce, because of the linfitation of a well-designed reliable droplet generator. In this paper, a novel single droplet generator based on piezoelectric ceramics is self-developed, in which the fixed frequency can be flexibly adjusted. The structure design and control system of the droplet generator are complete. The droplet generation characteristics under various voltage, frequency and nozzle diameter are studied. The four distinct patterns, steady single droplet, satellite droplets, continuous jet and non-injection, are discovered and drawn into a phase diagram. The non-dimensional We number determines these patterns and forms the criteria of droplet generation, in which the steady single droplet occurs at 1〈 We 〈5.