The Study Of Flow And Sedimentary Characteristics During Spraying Process Of Large-load Plant Protection Unmanned Helicopter

Large-load unmanned helicopter spraying was a new technology in the field of agricultural plant protection.It had the advantages of high efficiency,wide application range,low operation cost and less environmental pollution.It is necessary to further improve the quality of unmanned helicopter spray spraying for the optimization of the spray parameters of unmanned helicopter spray,and to study the flow and sedimentation characteristics of the unmanned helicopter spray process.Therefore,this research is supported by the agricultural science and technology innovation fund project of Jiangsu Province(CX(15)1038).The experimental study,simulation and parameter optimization of flow and sedimentary characteristics during spraying process of large-load plant protection unmanned helicopter were carried out.The main results of this paper were as follows:1.Based on the FR-200 unmanned helicopter flight platform,the parameters of the unmanned helicopter were analyzed,the selection and design of each component of the spray system of unmanned helicopter were completed.2.Based on the FR-200 unmanned helicopter spray system,The atomization characteristics of flat fan nozzles were measured,the influence of different spray pressures on the particle size spectrum,flow rate and spray angle and the influence of different spray distance distribution uniformity on the spray quantity were obtained,which provided the basis for the nozzle,spray pressure,system size spectrum and nozzles distance selection.3.Based on the FR-200 unmanned helicopter flight platform,the simulation and experimental study on the hovering wind field of unmanned helicopter were carried out using Ansys Fluent simulation software,the position of the spray rod was determined,which provided a scientific basis for the study of the distribution of the unmanned helicopter.The hot wire anemometer was used to measure the vertical velocity distribution of canopy height at different flight height and different flight speed were studied and the effects of different flight parameters on the wind field of plant canopy were analyzed.4.Based on the structure of FR-200 plant protection unmanned helicopter,using the Ansys Fluent software,the discrete phase model(DPM),SST k-? turbulence model and SIMPLE algorithm for large scale plant protection unmanned helicopter multi-phase flow spray were studied in dynamic simulation,The test scheme and evaluation index for simulation optimization were designed.According to the results of the simulation analysis,the flight speed,the spray rod relative position and the spraying angle influence on the anti-drift coefficient,established function between flight speed and relative position of spray rod and spraying angle and anti-drift rate,and through the test of simulation studies in conclusion.According to the field test,the relationship between the unmanned helicopter flight parameters and characteristics of spray deposition had been studied,affecting law of flight speed and flight parameter distribution uniformity of sediment concentration and deposition,establish the function relationship between flight speed and flight altitude and sediment concentration and deposition uniformity,which can guidance for practical agricultural spraying operations.