基于正交试验的内混式空气雾化喷嘴结构参数优化

Structural parameters optimization of internal mixing air atomizing nozzle based on orthogonal experiment

为掌握结构参数对内混式空气雾化喷嘴雾化特性和降尘效率的影响规律,从而获得经济合理的喷嘴结构参数,采用自行设计开发的喷雾降尘试验平台,应用正交设计方法,开展了不同结构参数组合下的喷嘴雾化特性及降尘效率试验。试验结果表明:随着液体帽注水孔直径的增大,喷嘴水流量不断增加,而气流量不断减小;喷嘴气流量随液体帽注气孔数量增加而增大,喷嘴水流量受液体帽注气孔数量的影响较小。当逐渐增大注水孔直径时,索太尔平均粒径(Dsm)不断增大;Dsm随着注气孔数量的增加呈现出先减小后增大的变化规律,当注气孔数为4时达到最小值,雾化效果最好;空气帽出口直径为2.0 mm和2.5 mm时,喷嘴雾滴粒径较小。全尘和呼吸性粉尘降尘效率均随着液体帽注水孔直径和注气孔数量的增加呈现先增大后减小的变化规律,并分别在注水孔直径为1.5 mm和注气孔数量为4时获得最佳的降尘效果;随着空气帽出口直径的增大,全尘和呼吸性粉尘降尘效率均有所提高,但空气帽出口直径大于2.0 mm后,降尘效率增幅较小。综合考虑喷嘴雾化特性参数和降尘效率,对于喷嘴空气帽,其出口直径应选择2.0 mm;对于喷嘴液体帽,注水孔直径为1.5 mm和注气孔数量为4时较为合理,能够获得最高的降尘效率。工业应用现场采用以上结构参数组合的喷嘴较为合理,该种结构参数组合的喷嘴在耗气量和耗水量较低时,能获得较小的雾滴粒径和较高的降尘效率。

In order to grasp the influence of structural parameters of internal mixing air atomizing nozzles on the atomization characteristics and dust reduction efficiency,so as to obtain economical and reasonable nozzle structure parameters,the self-designed and developed spray dust reduction experimental platform and the orthogonal design method was used to carry out experiment on nozzle atomization characteristics and dust reduction efficiency under the combination of structural parameters.The experimental results shown that,with the diameter of the liquid cap injection hole increased,the nozzle water flow rate increased,while the air flow rate decreased continuously.Nozzle air flow increased with the number of liquid cap injection hole,whereas nozzle water flow was less affected by the number of liquid cap injection hole.When the diameter of the water injection hole gradually increased,the Sauter Mean Diameter(SMD)increased continuously.SMD with the increase of the number of air injection holes shown a change law of first decrease and then increase,and the minimum value was reached when the number of air injection holes was 4,where the atomization effect was the best.When the air cap outlet diameter was 2.0 mm and 2.5 mm,the nozzle droplet size was smaller.With the increase of the diameter of the water injection holes and the number of air injection holes of the liquid cap,the dust reduction efficiency of total dust and respirable dust both first increased and then decreased,and the best effect of the dust reduction was obtained in the diameter of water injection holes of 1.5 mm and the number of air injection holes of 4,respectively.With the diameter of the air cap outlet increased,the dust reduction efficiency of both total dust and respirable dust increased,but the increase of the dust reduction efficiency was smaller when the diameter of the air cap outlet was greater than 2.0 mm.Comprehensively considering the nozzle atomization characteristics and dust reduction efficiency,for the nozzle air cap,the outlet diameter should be 2.0 mm,for the nozzle liquid cap,it was reasonable to use a water injection hole diameter of 1.5 mm and the number of air injection holes to be 4,which can obtain the highest dust reduction efficiency.It is more reasonable to use the nozzles with the combination of above structure parameters for industrial applications,which can obtain smaller droplet size and higher dust reduction efficiency with lower air and water consumption.