气泡雾化喷嘴水平喷射特性的研究

A STUDY ON HORIZONTAL EJECTION CHARACTERISTICS OF EFFERVESCENT ATOMIZERS

研究了一种喷嘴的雾化与流场特性。在喷嘴上游以一定方式将空气或其它种类的气体注入液体中形成两相流动，用水在常温、常压下进行试验。研究了水平喷射时，喷嘴的气体注入方式、气孔大小、锥形收敛段的结构尺寸及气液比对喷嘴雾化和流场特性的影响。试验结果表明，气泡雾化喷嘴水平喷射与竖直向下喷射存在明显的差别，喷射方向不同，喷嘴内的两相流动不同，因而雾化特性不同，收敛段的结构对雾化特性也有影响。该喷嘴的显著特点是在小气液比下可获得较好的雾化效果。

The atomizing and flow field characteristics of a novel type of injector have been investigated.Essentially,the injector is a plain-orifice atomizer with injecting air or gas into the liquid upstream of the final discharge orifice.Measurements of mean drop size and drop-size distribution and velocity characteristics of the spray are obtained with the aid of Particle Dynamic Analyzer (PDA).The liquid employed is water and all tests are carried out at normal atmospheric pressure and temperature.The injecting pressures of water range from 1 5×10 5 to 5 5×10 5 Pa,and air/liquid mass ratios from 0 to 0 12.Investigations are focused on the influence of gas-ejecting methods and the convergent angles on atomization performance of horizontally ejecting effervescent atomizer.The results show that atomization quality changes obviously at horizontally and downwards injecting of the atomizer.Different two-phase flow patterns lead to various atomization effects.