Development of a rotor model for the numerical simulation of helicopter exterior flow-fields

 

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dc.contributor.advisor Meyer, CJ en_ZA
dc.contributor.advisor Von Backström, TW en_ZA
dc.contributor.author Hotchkiss, Paul en_ZA
dc.date.accessioned 2014-08-30T05:59:56Z
dc.date.available 2014-08-30T05:59:56Z
dc.date.issued 2004 en_ZA
dc.identifier.citation Hotchkiss, P. 2004. Development of a rotor model for the numerical simulation of helicopter exterior flow-fields. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/6774
dc.description Includes bibliographical references (leaves 84-85). en_ZA
dc.description.abstract A numerical methodology is developed to model the effect of a rotor on the surrounding flow-field. The model calculates the time-averaged aerodynamic forces exerted on the air by the fan blades within the blade-swept region, and permits the user to specify blade properties such as cross-sectional profile and orientation at a particular radial and azimuthal location. The calculated forces are included as source terms within the Reynolds-averaged Navier-Stokes equations for an incompressible fluid, which are solved by the commercial CFD solver, FLUENT. The effects of turbulence are incorporated through the use of Launder and Spalding's k-g turbulence model. This method is selected as being the most efficient use of the resources available, giving the economic advantages of a steady simulation, while allowing radial and azimuthal variations of rotor characteristics. In order to validate the accuracy of the numerical model for both aligned and non-aligned inflow conditions, results are compared with experimental data reported for an axial flow fan. Agreement between experimental and numerical results is excellent to good. Fan static pressure rise is closely predicted by the numerical solution, while fan power consumption and fan static efficiency are under and over-predicted respectively. This error may be attributed to frictional losses not accounted for in the numerical model. These include physical rotational instabilities, leading to increased mechanical losses, and tip effects due to the clearance between the fan blade tips and the fan casing. Trends are nevertheless consistently predicted by the numerical model for inflow angles up to 45°, and for the range of blade pitch settings used. The adverse effect of off-axis inflow on the fan static pressure rise is numerically predicted, while fan power consumption is found to remain independent of inflow angle, as had been experimentally observed. The rotor model is finally integrated with the fuselage of the CIRSTEL (Combined Infra-Red Suppression and Tail rotor Elimination) prototype in an analysis of the helicopter exterior flow-field. No experimental data for this configuration was available for validation purposes. However, the model is used in the simulation of several common helicopter flight conditions. Results are presented graphically, and generally indicate good agreement with physically observed phenomena. en_ZA
dc.subject.other Mechanical Engineering en_ZA
dc.title Development of a rotor model for the numerical simulation of helicopter exterior flow-fields en_ZA
dc.type Thesis / Dissertation en_ZA
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering & the Built Environment en_ZA
dc.publisher.department Department of Mechanical Engineering en_ZA
uct.type.filetype Text
uct.type.filetype Image


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