Analysis On Aerodynamic Interactions Of The Compound High-Speed Helicopter Rotor/Fuselage Based On CFD

The analysis on rigid coaxial rotor-fuselage interference of the compound high-speed helicopteris a challenging subject in the field of helicopter aerodynamics. The rigid, coaxial rotor-fuselageinteraction have been investigated in this thesis, the corresponding code and model based on the CFDare also developed. The rotor airfoil on large advancing ratio, rigid coaxial rotor aerodynamiccharacteristics, rotor-fuselage interaction flow field and hub drag at high speed are computed. Themajor contributions of the author’s research work are as follows:As the premise and background of present work, the objectives of the research are firstlydescribed. The research and development in the field of high-speed helicopter coaxial rotoraerodynamic characteristics and rotor-fuselage aerodynamic interaction are briefly introduced, thedifficulties in the current research are also pointed out and the great significance of compoundhigh-speed helicopter rotor-fuselage interaction and hub drag-reduction research are proposed. Inaddition, the methods used in the present research are briefly brought forward.In Chapter2, a computational model for airfoil aerodynamic characteristics analysis at highspeed and reverse-flow condition is established, which is based on full turbulence CFD method tosolve N-S equations and a simulation is carried out through several airfoil used at the compound,high-speed helicopter rotor. Meanwhile, a comparison of aerodynamic characteristics between doubleended and conventional airfoils are also conducted.In Chapter3, a numerical method and related program, based on momentum theory and Eulerequations, for predicting coaxial rotor-fuselage interaction in hover and large advancing ratios hasbeen developed. By this method, several cases such as fuselage pressure distributions, coaxial rotorsinduced velocities and rotor aerodynamic characteristic at large advancing ratio are performed. Thegood agreements of the computational result with available measured data demonstrate the validationof the method.By applying the developed coaxial rotor-fuselage interaction prediction method, in Chapter4, theresearches on aerodynamic characteristics of rigid coaxial rotor are performed with comparison to thesingle rotor. In order to predict the hub drag precisely, a CFD code is used to analysis the helicopterdrag at different forward flight speed and angles of pitch. An effective hub drag-reduce method is putforward based on above.In Chapter5, the deep researches on interactional flow field variation of rigid coaxial rotor-fuselage interaction in hover and different advancing ratios are performed at first. On the basis,the influence of changing design parameters on the rotor-fuselage interaction characteristics isanalyzed. And some meaningful conclusions are drawn.