| In recent years,the environmental pollution caused by chemical pesticides has attracted attention from all walks of life,and it has become a research hotspot to replace toxic chemical pesticides to kill crop pests and diseases.The influence of different structural parameters on the physical characteristics of the DBD discharge process was simulated by one-dimensional simulation.Based on the simulation results,the DBD discharge device was designed and manufactured,and the influence of the peak voltage and frequency on the discharge characteristics and the performance of generating gaseous free radicals was studied and analyzed.On this basis,a gas-liquid mixing system was constructed,and the effects of different conditions on the synthesis of strong oxidizing free radical solutions were studied and analyzed.Crop diseases and insect pests could be killed by synthetic green,efficient,and residue-free strong oxidizing free radical solutions,and some chemical pesticides coud be replaced by this solutions,which solves the problem of environmental pollution caused by some chemical environmental pesticides from the source.The main conclusions are as follows:（1）A simplified one-dimensional model of DBD discharge was constructed to simulate and the results show that the relative permittivity was positively related to the electron number density and the average electron energy,and was inversely proportional to the electron temperature inside the discharge gap.The discharge gap was inversely proportional to the average electron energy,and inversely proportional to the total electron number density and electron temperature.DBD discharge performance was better at 0.5mm discharge gap than 0.3mm and 0.7mm discharge gap;The peak voltage was positively correlated with the electron number density,and the temperature of the electrons at the end of the high-voltage electrode inside the gap also increases with the increase of the peak voltage.（2）The DBD discharge device was designed and manufactured,and its discharge characteristics and spectral characteristics,as well as the discharge performance of the device were studied and analyzed using instruments such as oscilloscope and spectrometer.The results show that the higher the peak voltage,the higher the concentration of gaseous free radicals produced by DBD,and the maximum gaseous free radicals can be up to 73g/m3;the larger the input gas flow rate,the gaseous state produced by the DBD discharge device The lower the concentration of free radicals;As the peak voltage increases,the output efficiency of the power supply gradually increases and then drops sharply,and reaches a peak value of96.67%when the peak voltage was 4.4k V.The energy efficiency of ozone generation was increased sharply with the increase of the peak voltage,and reaches a peak value of 562.75g/k Wh was reached at about 3.2k V,and then gradually decreased.The energy efficiency of ozone was not significantly affected by the discharge frequency.（3）A gas-liquid mixing system was constructed,and the effects of different gas-liquid mixing methods,as well as different gas-liquid ratios and p H values on the gas-liquid mixing effect were tested and analyzed.The results show that the maximum concentration of TRO produced by the system was 1.52g/m3by using the diap Hragm pump self-priming air inlet and the micro-nano bubble release device,at a flow rate of 0.1L/min.Compared with the other two air inlets,the micro-nano bubble device has a smaller flow The free radical gas input into the system can make the TRO concentration reach a larger value,and the attenuation rate within 5 minutes was not much different,but due to the water pressure loss,the mixing flow rate inside the system was small;the p H value has a greater impact on the gas-liquid mixing effect.When the p H value of citric acid is adjusted to 4,the gas-liquid mixing effect of the system was the best;when the p H value of hydrochloric acid was adjusted to 3,the gas-liquid mixing effect is the best.（4）Free radical detection was carried out on the solution produced by the gas-liquid mixing system,and the results showed that·O2+,·OH,O3,·O2and other free radicals were produced in the gas-liquid mixing system,and the content of these free radicals varies with the gas-liquid ratio Increase and increase.（5）Taking wheat powdery mildew as the test object,a spray test of strong oxidizing free radical solution on actual crops was carried out.The results showed that the oxidizing free radical solution prepared by the gas-liquid mixing system has a certain ability to kill crop diseases and insect pests. |
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