Numerical Simulation And Wind Tunnel Test Of Airfoil Icing Of A Fixed-wing UAV

In recent years,unmanned aerial vehicle(UAV)has many advantages in replacing traditional manual operation and some special fields.The scale of UAV industry is growing rapidly,but icing has seriously affected the flight safety of UAV.Icing will lead to aerodynamic deterioration,center of gravity change,abnormal sensor data and other hazards of UAV,which may lead to crash in severe cases.Because small and medium-sized UAVs generally have no anti/de-icing system,small load and slow speed,the UAV icing is different from manned aircraft,and the icing hazard is more serious.Taking common unmanned aircraft wings as the research object,the typical icing conditions of unmanned aircraft are deeply analyzed by means of CFD numerical simulation and experiment.Finally,the icing of a fixedwing unmanned aircraft is studied.The main research contents and conclusions are as follows:(1)The research status of aircraft icing at home and abroad is expounded,and the icing mechanism,hazards,anti/de-icing methods and research methods are analyzed.(2)Calibrate the important icing parameters of the small backflow icing wind tunnel,conduct wind tunnel tests with symmetrical airfoil NACA0012 and asymmetric airfoil Clark Y test models,introduce typical icing characteristics,and analyze the error between numerical simulation and experimental ice shape.The results show that the ice shape obtained by numerical simulation has small error and good agreement,which proves that the numerical simulation method is feasible.(3)The icing calculation of airfoils with different inflow velocities,droplet diameters,liquid water content,angle of attack,airfoil chord length and icing time is carried out,and the impact characteristics of water droplets under different working conditions are obtained.Through quantitative analysis of the obtained ice shape,the influences of different factors on icing characteristics are summarized.(4)The numerical simulation results of a fixed-wing UAV show that the nose,the leading edge of the wing,the leading edge of the tail and the windward side of the camera are the areas where the water droplets hit more,and the peak value of the wing collection coefficient increases and the icing becomes more and more serious.The variation law of icing quality in different working conditions is analyzed.Through the analysis of liquid water content distribution in UAV cross section,the installation height range of icing detector is determined.After icing,the lift coefficient increases,the drag coefficient decreases,the lift coefficient decreases by12.12% at the maximum,and the drag coefficient varies from 8.91% to 13.10%,which seriously deteriorates the aerodynamic characteristics.In this paper,the icing characteristics of UAV are deeply analyzed by numerical simulation,and the correctness of numerical simulation method is verified by wind tunnel test,which can provide technical reference for UAV anti/deicing design and safe flight.