Research On Atomization Characteristics And Effect Of Droplet Charging Of Electrostatic Spraying With Corona Plasma

As agricultural chemical pesticide brings more and more serious environmental pollution and has even worse influence on human health. Some problems with pesticide spraying exist in agriculture. Corona plasma electrostatic spraying is a new technology developed with ultra-low volume spraying technology. Over the past few decades, the advantages of electrostatic spraying have been recognized and accepted by people in the field of plant protection. This paper firstly presents an overview of the development of electrostatic spraying technology and study on atomization and deposition distribution in home and abroad. In addition, the process of the droplet atomization and characteristics of deposition were discussed in detail and deduced the calculating formula about the critical electric filed intension from basic theoretic formula.Aimed at the problem of the droplets sampling, a sampler of droplets was designed. In order to solve the defects in normal measurement of spray angle. A new method based on MATLAB digital image processing was put forward in this paper and analyses the spray angle under different voltage and pressure. This new method can not only avoid the unknown interference in spray field, but also reduce error in manual measurement for spray angle. The experiment result shows that this method is both simple and feasible for using. The measurement result is more objective, more reliable than normal methods.At end of this paper the plant-simulating test is done in lab and used colorimetric-weighing counting on the glass methods to measure the deposition and deposit density under the charged and uncharged. The atomization quality and droplet cover distribution charge performances and its affecting factors were studied by carrying out performance experiment and statistic analysis. Result of the studies indicates:(1) The mechanism of corona charge could be explained by the model of equivalent circuit of corona charge exactly.(2) The atomization process of charged droplets was divided into four zones by their function and effectiveness: jetting zone; charge zone; striation zone; atomizationzone. The critical charge of charged droplets breakage is Q₀ = 8πεσR³; the criticalfield is ??;the critical charge-mass tation is.(3) The NMD,VMD and D decreases with the increase of the voltage, the spray droplet size of uncharged droplet is 101．8μm. The size decreases to 64μm when thevoltage increases to 23kV. The experimental results show that the droplet diameter decrease with increasing charging voltage and liquid pressure, and increase with decreasing flow rate. With the increase of the voltage, the spray angle increases gradually, and the liquid pressure has no influence to the spray angle.(4) The spray distribution of horizontal spray and 30 elevation angle of nozzle have a skewed distribution and its peak is 40-60cm distance from the nozzle. The spray distribution shows saddle shape when the nozzle was vertical installed.(5) With the increase of the voltage, the deposit quantity and the deposition density increase gradually. The deposit quantity and the deposition density enhance over 10% and 50%.For this box, increases the voltage of the electrode will improve deposits and penetrations of droplets, rise of the uniformity of the droplets and the droplets table is narrower, the droplet diameter is smaller, deposit amount and the atomization quality can meet the need of electrostatic spraying.The improvement function of the droplet cover rate on the front and reverse side of the imitation leaf were obvious. The moving of the droplet has certain trend nature, the droplet coverage rate of each position of the target is improved a lot, the piercing through of the droplet is strengthened to some extent, so it should kill worm better.