Analysis On Flowfield And Flight Characteristics Of Heavyhelicopter With Slung Load Based Upon CFD Method

Analysis on the flowfield and flight characteristics for heavy-lift helicopter slung-load flightis a research subject with great significance in the field of helicopter technology. Firstly, Based onthe momentum-source model, a numerical method which can be used to simulate the interactionflowfiled of rotor/fuselage/slung-load object is established, meanwhile, a flight dynamic model isalso developed to model the slung-load flight. On the basis of the above method, therotor/fuselage/slung-load object interference flowfiled and flight characteristics are investigated,the main work is as follows:As background of present research, the objectives of the thesis are briefly introduced, andthen the research status of flowfield and flight characteristics analysis of heavy-lift helicopterslung-load flight is overviewed, shortcomings in current research are also pointed out, finally, theresearch method and content employed in this paper are presented.In Chapter2, a CAD model for the heavy-lift helicopter slung-load flight is presented, and byadding the rotor and tail rotor momentum-source term, comparing the characteristics of differenttype of CFD grid, an unstructured grid generation method is given, which is suitable for thesimulation of the helicopter slung-load flight.In the third chapter, on the basis of the grid and Euler equation, and by adding the rotor (tailrotor) momentum-source term, A new CFD method and a code are developed, which can be usedto simulate the flowfiled of heavy-lift helicopter slung-load flight. Meanwhile, the flowfiled of2Dairfoil and3D Robin fuselage are choosed as numerical examples, and the result shows theeffectiveness of the proposed method.Based on the aforementioned method, a flight dynamic model is established for heavy-lifthelicopter slung-load flight. Then, In order to validate the developed method, the method isadopted to simulate the UH-60and Z-11helicopters with/without slung-load object respectively,trim calculation is also carried out on the sample heavy-lift helicopter, and some meaningfulconclusions are concluded.Combining with the flowfield solving method developed, a hanging flight dynamics model isestablished for heavy helicopters in the fourth chapter. On this basis, the UH-60and Z-11helicopters are chosen as numerical examples respectively, so as to validate helicopter flightdynamics model with/without hanging objects considered. Through the heavy helicopter trim sample calculations, some meaningful conclusions are obtained.In the fifth chapter, based on the established flowfield simulation method, calculations arecarried out for the rotor/fuselage/slung-load object interaction flowfield of CH-53E heavy-lifthelicopter at different flight speed with/without slung-load, and the effects of such parameters asweight, frontal area of slung-load object, etc. on the interaction flowfield are emphaticallyinvestigated.In Chapter6, based on the small-perturbation assumption, by the linearization of thehelicopter flight-dynamics equation, the central difference method is used to obtain theaerodynamic derivatives for stability and control. Then the control and stability characteristics of aheavy-lift helicopter in slung-load flight regime are investigated and analyzed, the parameterinfluence study is also performed, and some results are obtained, which are of practicalsignificance to the helicopter control and manipulation in slung-load flight.Finally, in the sixth chapter of the thesis, the work that has been done is summarized, andnext step research plan are proposed.