The Effect Of Aerodynamic Parameters On Endurance Time Of Agricultural Electric Flying Wing

With the rapid development of agricultural low altitude remote sensing technology,in our country's agricultural production,as agricultural information monitoring and data collection tools,the UAV plays more and more important role.The electric flying wing UAV due to its advantages of high efficiency,simple structure and layout of the flight,it is widely used in the field of low altitude remote sensing in agriculture,provide a more stable platform for the modernization of agricultural information collection.In order to get the best overall parameters of flying wing UAV and improve the cruise operation time,this paper mainly use the method of CFD numerical simulation and flight test verification to analysis the electric wing aerodynamic characteristics influences with the sweep angle and aspect ratio change.The main contents and conclusions are as follows:(1)This paper selects the flying wing UAV which widely used in aerial remote sensing as the research object.According to the flight operation requirements of the agricultural flying wing UAV,determined the range of parameters for the aspect ratio and the sweep angle under the flying wing UAV cruise operation.Designe 25 kinds of flying wing UAV with these two parameters.Using Catia complete two-dimensional airfoil and modeling of UAV 3D parameterized modeling.(2)Through the calculation of aerodynamic characteristics of N60 airfoil,proving that the aerodynamic characteristics of UAV can be simulated accurately by Fluent through the selection of appropriate turbulence model and the calculation of the relevant conditions.In addition,the simulation parameters of the UAV are established by the principle of aerodynamic similarity.(3)In this paper,the aerodynamic characteristics of agricultural electric flying wing UAV airfoil are analyzed by numerical simulation,it is found that when the flight speed is12 m / s and the cruising altitude is 100 m,the angle of attack of the lift drag ratio is 8°.Since the corresponding angle of attack of the airfoil maximum lift-drag ratio indicates the aircraft cruise the best angle of attack,the research of flying wing UAV's best cruise attack angle of 8°under the same flight operation condition.(4)The aerodynamic characteristics in cruise mode of 25 different aerodynamic parameters of flying wing UAV were calculated by Fluent.Found that within the scope of thisstudy,when the aspect ratio was consistent,with the increase of the sweep,the lift drag ratio of UAV increases at firsr and then gets decreased,and the lift drag ratio reached the maximum value of UAV when the sweep angle is 30 degrees.When the sweep angle was consistent,the research of flying wing UAV's lift drag ratio increases as the aspect ratio increases.(5)Combined with the influence factors of electric UAV flight time,found that when the power system efficiency and UAV weight consistent,the UAV which one has the sweep angle of 30 degrees and the aspect ratio of 3,it's flight efficiency and operating life time is best in the 25 sets of different pneumatic parameters UAVs.(6)In this paper,the power system and the control system of UAV are re-selected according to the operation parameters of agricultural electric cruise flying wing UAV,and made two test prototype(the original layout UAV and the optimization ones).And we carried out the flight test of two test prototypes under the same power and weight.The test results show that the agricultural electric flying wing UAVUAV which one has the sweep angle of30 degrees and the aspect ratio of 3,it's endurance time and flight efficiency is superior to the original layout UAV.This illustrates that we can use the method of numerical simulation get the best overall parameters of flying wing to improve cruise operation time of the agricultural electric wing UAV.