Results 201 to 210 of about 4,154,170 (239)
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Air Flow in Fan-Discharge Ducts
Journal of Fluids Engineering, 1934Abstract This paper is concerned with an examination of possible causes of the discrepancies which are sometimes found between pitot-tube measurements and nozzle measurements of the volume of air flowing in a fan-discharge duct. Among the conclusions reached are the following: (1) Air pulsations may cause a small error; (2) Incorrect ...
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Acoustic Isolation of Fans in Ducts
Proceedings of the Institution of Mechanical Engineers, 1966A method of reducing the sound power radiated downstream from axial flow fans is described and investigated. The normal parallel duct fan housing is replaced by a contoured arrangement. With one type of contour and the use of porous absorbent material the reduction in the downstream overall sound power level is 5 dB, that is, the total sound power is ...
A. W. Roberts, R. E. Luxton
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Noise radiation from ducted fans with realistic duct-rotor coupling
The Journal of the Acoustical Society of America, 1992The problem of noise radiation from inlet and exhaust of ducted fans is important because of anticipated stringent noise standards. The aerodynamic and duct propagation problems of these engines have been solved. What is needed is the coupling of rotor aerodynamics and duct propagation using realistic physical and geometrical models on today’s high ...
F. Farassat, P. L. Spence
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Impact of Bypass Duct Bifurcations on Fan Noise
Journal of Propulsion and Power, 2012The present work is concerned with the impact of bifurcations, i.e., extensions of the pylon inside the bypass duct, on fan tonal noise radiated by civil turbofan engines. The investigation is carried out on a typical configuration composed of a rotor–stator stage, a row of struts, and one upper and one lower bifurcation.
Holewa, Axel +2 more
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Unsteady flowfield simulation of ducted prop-fan configurations
30th Aerospace Sciences Meeting and Exhibit, 1992A technique for the simulation of unsteady flows in and around complex rotating machinery is presented. Additional domain decomposition mechanisms are introduced which extend the range of applicability of software developed for the time-accurate simulation of rotating machinery flowfields.
J. Mark Janus +2 more
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Experimental/Numerical Study of Ducted-Fan Noise: Effect of Duct Inlet Shape
AIAA Journal, 2018The paper presents an investigation of flow and noise produced by the generic fan of an environmental control system installed in a circular duct, with a focus on the evaluation of the effect of me...
Shur, M. +7 more
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Bypass duct fan noise reduction assembly
The Journal of the Acoustical Society of America, 2003A gas turbine engine fan assembly includes fan blades spaced axially from stator vanes inside an annular bypass duct. A plurality of perforated baffle plates are installed in the annular bypass duct downstream of the stator vanes. The perforated baffle plates extend in a generally axial direction and are unevenly, circumferentially spaced apart from ...
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Fan Angular Momentum Analysis for Ducted Fan UAVs During Conceptual Design
50th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition, 2012This paper outlines some of the effects of fan angular momentum on ducted fan UAVs. All aircraft will be affected by their propeller’s angular momentum, however, ducted fan vehicles are particularly susceptible due to the relative sizes of the fan and the airframe.
Brandon Stiltner, Osgar Ohanian
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Numerical investigations of ducted fan aerodynamic performance with tip-jet
Aerospace Science and Technology, 2018Tip-jet technology has the potential value for application in vertical take-off and landing or short take-off and landing concept aircraft. The main objective of this work is to present a rapid prototyping method to model the power of the tip-jet during ...
Jie Chen +3 more
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Composite observer-based robust model predictive control technique for ducted fan aerial vehicles
Nonlinear dynamics, 2022Tayyab Manzoor +2 more
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