微喷嘴射流截面能量密度和信息熵

Energy Density and Information Entropy of Micro-nozzle Jet Section

静电消除器微喷嘴出气量的多少和空气速度,直接决定其一次电离出的正负离子数量和运送离子的能力,从而决定了其除静电的能力。因为微喷嘴出气口间隙只有几十微米,因此用粒子图像测速法研究其工作流场,存在着很大堵塞的风险。在此通过数值仿真方法对微喷嘴工作流场进行了分析,利用射流截面能量密度和信息熵对微喷嘴的射流截面进行了能量均匀性的定量分析研究,并发现微喷嘴出气间隙对空气动能密度分布和信息熵影响明显;小间隙喷嘴更聚能,但能量损失也更大,为后续进一步设计和优化微喷嘴性能提供了可靠的定量评估指标。

The air amount and the air velocity of the static eliminator micro-nozzle determine its ability to remove static electricity.Because the two factors directly determine the number of positive and negative ions which are ionized at one time.The gap between the outlets of the micro-nozzles is only a few tens of micrometers.And there is a great risk of blockage to use the particle image velocimetry(PIV)method to study its working flow field.Here the working flow field of the micro-nozzle is analyzed by numerical simulation method.The energy density and the information entropy are adopted to assess the energy uniformity of the micro-nozzle jet cross-section.During the research,it was found that the air gap of the micro-nozzles has a significant effect on the air kinetic energy density distribution and information entropy.The nozzles with small gaps are more concentrated,but the energy loss is also greater.This study provides a reliable quantitative evaluation index for the further design and optimization of micro-nozzle performance.