Aerodynamic Characteristics and Test Optimum Design of Ducted Coaxial Rotors in Forward Flight

The aerodynamic characteristics of ducted coaxial rotors in forward flight were numerically simulated with Fluent. The curves indicating the lift, drag and pitching moment of ducted coaxial rotors with the change of the forward tilt angle, <em<H/R</em< and airflow velocity were obtained respectively. 25 groups of tests were designed by orthogonal test to study the three main factors that influence the lift, which include forward tilt angle <em<α</em<, different rotor distances <em<H</em< and airflow velocity <em<v</em< with total lift <em<F</em<<sub<L</sub< as the test index. The test results were calculated by range analysis, which show that the rank of influence degree on the total lift of ducted coaxial rotors with the above factors changing in common use range is: different rotor distances, forward tilt angle, airflow velocity. Finally, optimal scheme is selected according to the test results.