Researches On Aerodynamic Characteristics Of Rigid Coaxial Rotor Of High-speed Helicopter Based On CFD Method

The numerical computation of aerodynamic characteristics for the rigid coaxial rotor of high-speedhelicopter is a highly challenging and meaningful subject in the field of helicopter aerodynamics. ACFD method suitable for simulating the flowfield of coaxial rotor based on structuredmoving-embedded grids has been established firstly, and then it is employed to the investigations onblade aerodynamic configuration design and aerodynamic characteristics of the rigid coaxial rotor ofhigh-speed helicopter. The major research in the paper is as follows:As the background and premise of research, the object and significance as well as current situationat home and abroad of the research are introduced in Chapter1, and the disadvantages and difficultiesin the current research methods are pointed out, on this basis, the research approach used in the paperis proposed.Aiming at the structural and flowfield features of coaxial rotor, in Chapter2, a structuredmoving-embedded grid generation method suitable for numerical simulation of the flowfield ofcoaxial rotor is established based on the moving-embedded grid technology and the blade body-fittedgrid generation method.In Chapter3, a new CFD method and code suitable for simulating the flowfield of coaxial rotor inhover and forward flight is developed based on the structured moving-embedded grid system, andsome numerical examples with test data are used for validation. Euler equations are taken as thegoverning equations and the finite volume method is used to process spatial discretization. Toimprove simulation precision, both the low dissipation Roe scheme and MUSCL scheme areemployed to calculate inviscous flux. Meanwhile, the dual-time stepping method is used forsimulating the unsteady phenomenon in the flowfield of coaxial rotor.In Chapter4, a deep analysis of the blade aerodynamic configuration of the high-speed helicopterX2has been made, on this basis, the research on blade aerodynamic configuration design ofhigh-speed helicopter is conducted by using the present grid generation method and CFD method, andsome useful design rules are obtained.In Chapter5, the aerodynamic characteristics of the rigid coaxial rotor of the X2in hover andforward flight at high advance ratio are calculated and analyzed with the grid generation method andCFD method established in this paper, besides, the influence of parameter variations on theaerodynamic characteristics of the X2rotor is investigated emphatically, and some meaningfulconclusions are drawn.