Investigation On The Electrostatic Atomization Characteristics Of Nano-fluids

With the development of electronic products,integration degree of chip become better and better,heat dissipation of the chip on micron scale is a challenging task.Efficient thermal conductive thin film materials for chip cooling provides a new method to resolve the problem.Electrostatic spray deposition,one of the thin film preparation method,have unique advantages and get the attention of the researchers.Nano-fluids as raw materials,because of its specific physical properties,the electrostatic atomization characteristics is different from ordinary fluid.Electrostatic atomization characteristics of nano-fluids have a certain guiding role to improve the electrostatic spray deposition,and improve the quality of thin film material.Based on this,the atomization characteristics of nano-fluids and pneumatic breakage characteristic has carried on the experimental research in this paper,the main work is as follows:Based on microscopic high-speed camera technology a visualization research on the characteristics of electrostatic spray of nano-fluids has been reported.Using nano-fluids in different mass concentration as experiment medium,the microscopic morphology of eletrosprays has been captured to discuss the effect of surface tension,flow rate and conductivity on the evolution of electrostatic atomization of nano-fluids.Experimental results show that with the increase of mass concentration of nano-fluids,the atomization range of cone-jet mode gradually becomes narrow,critical electric field intensity gradually increases when atomization range transition to cone-jet mode,and the increase of conductivity make nano-fluids are more likely to transition the multi-jet mode.The increase of flow rate causes instability of atomization,higher electric field intensity are required to achieve the same atomization effect.Nano-fluids atomization mode transition diagram provide some guidance for the preparation of micro/nano film materials.Deposition distribution characteristics of nano-fluids is the key to affect the thin film preparation use electrostatic spray deposition.Therefore,based on the pattern change rule of electrostatic atomization on nano-fluids,droplet deposition distribution characteristic on different atomization mode has carried on the experimental study.The experimental results show that with the increase of voltage,droplet diameter trend to decrease exponentially in dripping mode;Droplet diameter cone-jet mode linearly decrease;Multi-jet mode droplet diameter is complicate.With the flux reduce,droplet size become smaller unconspicuous,droplet size distribution widely and have a rising proportion of droplet size.This study concerns the effects of breakup properties of charged nano-fluids droplet by aerodynamic force.The experimental results show that as the mass fraction of nano-particles increasing,the grow up and breakup time of bag is decreasing during the bag breakup process of charged nano-fluids droplet.The ethanol droplets which carry more electrostatic charges have a similar breakup time and morphology with the graphite-ethanol nano-fluids droplets during the breakup process,it indicates that nano-particles can promote the bag breakup process of charged nano-fluids droplet under the action of aerodynamic force.