Aerodynamic Analysis And Test Research On Rotor System Of Agricultural Unmanned Rotorcraft

To ensure the safety of grain production is an important basis for the sustainable development of agriculture in China, also is a strong guarantee for the prosperity of a country. As years of plant diseases and insect pests occur frequently, the yield and quality of crops have been seriously affected. To be able to timely and effective spraying pesticides is prevention and control of plant diseases and elimination of pests damage important measures in place, so plant protection work is an important part of agricultural production.Agricultural plant protection mode of traditional operation labor intensity big, high cost, low rates of resource utilization, and often occurs in operation personnel poisoning incident, has not adapted to the modern agricultural development model. The UAV aerial plant protection operation low flight altitude, drug less drift, strong flexibility, now more and more by the government and the people of all ages. The unmanned rotorcraft through the relative current rotation, produce large lift force, has large carrying capacity and good low altitude,low cost, simple structure, convenient manipulation, low failure rate, the security features of higher, the unmanned rotorcraft can adapt to the requirements of agricultural aviation plant protection operation. Study on aerodynamic characteristics of rotor engine rotor system is of great significance for the development of the unmanned rotorcraft late development and its application on agriculture.Based on the introduction of rotorcraft research background and characteristics of the rotor system, on the pre theoretical analysis and rotation, the pre rotor flow numerical simulation using computational fluid dynamics method, and pre research of rotation and rotation test on the rotor, the main work content as follows:(1)Analysis of rotor system working mechanism from the two aspects of kinematics and dynamics of autorotating rotor, establish mathematical model, analyzed the effect of transferring properties of the rotor aerodynamic parameters and working condition changes in the pre rotation.(2)The grid division on rotor 3D model by using GAMBIT software, import the CFD software FLUENT, the standard k?? turbulence model was adopted, to select the SIMPLE algorithm, the numerical simulation of flow field around the rotor pre distribution analysis when the situation. The results show that: on the surface of rotor under the pressure difference increases with the pitch angle and the anteversion angle increased first and then dropped, as the speed increases gradually increasing trend.(3)In order to pitch, anteversion angle, speed as experiment factors, pre lift, power consumption of the test of single factor and multi factor experimental index. The results showed that: the effect of various factors on the experiment index is significant, optimize out the factors best combination, that is: the pitch angle of 8 degrees, the front angle of 3.5 degrees, speed 390 r/min cases.(4)The rotation of the rotor test, fitting out mathematical model of each factor and the test index, size relations, the influence factors analysis of interaction of two test indicators are: wind speed > the pitch angle > after the chamfer. Optimization analysis of various factors, the optimal portfolio: pitch angle 9.5 degrees, after chamfering 7.5 degrees, wind speed 8m/s,and the use of test verified the reliability.To sum up, through the theoretical analysis and numerical simulation of helicopter rotor system, finally the verification test, reveals the aerodynamic characteristics of rotor system, provides the reference for the development and control of subsequent unmanned rotorcraft.