Experimental And Numerical Simulation Research On Axial Flow And Air-assisted Electrostatic Spraying

Over the past years, the advantages of axial flow and air assisted electrostatic spraying have been recognized and accepted by people in the field of plant pests chemical protection and disinfection in large-size common place. Based on some problems of traditional spray ,such as short spraying distance, big droplets' diameter, uneven mass distribution, low untilization of pesticide and badly environment polluton etc, axial flow and air assisted electrostatic spraying are studied systematically in this thesis.1 Analyzed the basic principle of electro-spray with different electrode and different charging method on theory , and constructed a mathematic model for ring electrode and polarized by contacted needle electrode to calculate electric potential of room. Based on analyzing the properties of forces on the charged droplets in the sprays, droplets' equation of motion are solved .2. Constructed charged two-phase turbulent jet flow model, in which the interaction between electric field and flow field, the inter-phase action between droplets and gas and droplets' energy are considered.3. Has carried on the shaping, the design to the spray nozzle, and examined its atomization performance through the experimental method,finally indicated: The revolution injecting spray nozzle atomization performance obviously surpasses the commonly used membrane injecting spraynozzle, its atomization produces droplet body mean diameter 17.638μm.4. Through the experimental study on the electrostatic field and flow field ,and the result of studieds indicate: The electrostatic field obviously improved the atomization effect. Along with charging voltage elevating, droplet charge-mass rate increase,and droplets diameter decrease obviously,and the droplet quality distribution uniformity and the deposition performance all obviously enhance. Disinfection experiment on optimized equipment indicate,disinfection ability of electrostatic spray far higher than that of no charged spray, when spray 60 seconds, efficency of disinfection could exceed 90%. The gas phase flow field influence on the atomization mainly in the transportation to the droplet and in the atomization uniformity,. The method of air assisted can obviously enhance the spray distance, enhance the uniformity of gas phase, and enhances the uniformity of atomization. At the same time, the droplet diameter measurement result indicated that, the wind delivers to the droplet secend atomization function is not obvious.5. Established the deposition performance empirical formula of axial flow and air assisted electrostatic spraying through massive experiments. 6. Adopted Reynolds time averaged N-S equations and RNG k-εmodel to calculate air flow field, and DPM model to calculate droplets' movement, and made a comparation between computational results and experimental results, the results show that this model could predict the charged two phase turbulent flow in some degree.