气泡雾化喷嘴水平喷射的雾化特性研究

研究了水平喷射、端面注气方式的气泡雾化喷嘴结构及工作参数对雾化及流场特性的影响.试验全部在常温常压下进行,液体采用水,雾化气为压缩空气.用2D PDA测量了液雾的平均直径尺寸分布和速度分布.液体喷射压力变化范围200~600 kPa,气液比变化范围4%~10%左右.试验研究了端面注气方式下,注气孔孔径及数目、混合管长度、液体流动状态及工作参数对雾化特性的影响.结果表明,水平喷射的气泡喷嘴,注气孔的尺寸及数目均对雾化特性产生影响;混合段存在一最佳值范围,在此范围内,喷嘴可获得高的雾化质量;液体旋转流动对雾化特性无显著影响,但可影响两相流动中气泡的分布.

Influence of Gas Injector Geometry on Atomization Performance of Horizontally Injecting Effervescent Atomizers

The atomizing performance of effervescent atomizers are examined with special emphasis on the influence of gas\|injector geometry on spray characteristics.A particle dynamic analyzer (2D\|PDA) is used to measure mean drop size,drop\|size distribution and velocity distribution.All tests are carried out at normal atmospheric pressure and temperature.Water injection pressures are varied from 0.20 to 0.60 MPa and air/liquid ratios from 0.04 to 0.12 by mass.Three different gas injectors are used,one having 4 holes,each of 2.2 mm diameters and the others 20 holes of 0.7 and 1.0 diameters.They are used in conjunction with three mixing tubes of different lengths.The results obtained show that the changes in the number and size of the gas injection holes have significant influence on atomization qualities of horizontally ejecting effervescent atomizers.Moreover,there is an optimum length of the mixing tube leading to higher atomization quality.However,when swirling the liquid,atomization quality appears to be slightly improved.