48,107 research outputs found

    A Computer Program for the Prediction of Ducted Fan Performance

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    Manual for computer program for predicting performance of ducted fan

    Evaluation of a ducted-fan power plant designed for high output and good cruise fuel economy

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    Theoretical analysis of performance of a ducted-fan power plant designed both for high-output, high-altitude operation at low supersonic Mach numbers and for good fuel economy at lower fight speeds is presented. Performance of ducted fan is compared with performance (with and without tail-pipe burner) of two hypothetical turbojet engines. At maximum power, the ducted fan has propulsive thrust per unit of frontal area between thrusts obtained by turbojet engines with and without tail-pipe burners. At cruise, the ducted fan obtains lowest thrust specific fuel consumption. For equal maximum thrusts, the ducted fan obtains cruising flight duration and range appreciably greater than turbojet engines

    Theoretical Study of Ducted Fan Performance

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    Existing computer program improved capability for predicting performance of ducted fan in uniform axial flo

    Ducted fan propulsion system study for ONAerospace eVTOL

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    In recent years, the relentless advance of climate change forces society to adapt to more sustainable modes of transportation. In a not so distant future, urban transport is envisioned to expand to the skies with new innovative electric Vertical Take-Off and Landing (eVTOL) aircraft. Although this idea seems very futuristic, the concept of an electric aircraft might not be as far away as previously thought. ONAerospace aims to take part in this future by designing its own eVTOL aircraft. This project focuses on the ongoing propulsion system design. On its first iteration the project introduced ducted fan propulsion, electric motors and bateries. This second iteration delves into ducted fan performance in order to give a more accurate design of the aircraft¿s propulsive units, and better predict its performance capabilities. Two propulsion configurations have been studied separately: a takeoff and hovering configuration, which uses two ducted fans before the wings and one coaxial ducted fan embedded inside the aircraft¿s tail; and a cruise configuration which uses just the two front engines. The propulsive units are designed to be adaptive ducted fan. This means that, each ducted fan can morph and adapt to optimize its performance to any given condition. Ducted fan performance has been predicted using two theoretical analyses: momentum theory, and blade element theory. These methods have been used to size the propulsive units in order to ensure that the thrust requirements are met. Also, the power required in each configuration and flight phase has been computed. Finally, experimental data on the effects of varying different design parameters was reviewed with the objective to give a more detailed design of each ducted fan

    Design and analysis of a ducted fan UAV

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    The ducted fan unmanned aerial vehicle (UAV) can operate in vertical flight and horizontal flight. A new tilt-body ducted fan UAV with wings, which is capable of high-speed forward flight in wing-borne mode, is designed. Two fixed wings can provide sufficient lift of the ducted fan UAV in the high-speed wing-borne flight. The fixed geometry duct design reflects a compromise between low and high speed performance requirements of it. Computational fluid dynamics (CFD) and wind tunnel testing are used to study its aerodynamic characteristics in various modes. Momentum source items are utilized to replace two counter-rotating propellers in the numerical simulation. The results illustrate that the ducted fan MAV designed can hover, take off and land vertically. Furthermore, it has the ability to fly slowly in helicopter mode and fly rapidly in wing-borne mode and has excellent aerodynamic characteristics throughout the whole flight envelope

    SOUND SPECTRUM MEASUREMENTS IN DUCTED AXIAL FAN UNDER STABLE CONDITION AT FREQUENCY RANGE 6000 TO 6600 HZ

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    Performance of axial fan is found to reduce drastically when instability is encountered during its operation. Performance of an axial fan is severely impaired by many factors mostly related to system instabilities due to rotating stall and surge phenomenon experienced during its operation. The present work involves measuring the sound spectrum measurements in ducted axial fan under stable condition at frequency range from 6000 to 6600 Hz. Objective of the experiment is to measure the frequency domain signal and study the sound Characteristics in ducted axial fan by using spectrum analyser. Different types of FFT signals have been measured under stable condition for the frequency range of 6000 Hz to 6600 Hz with respect to rotor speed and different graphs are plotted for ducted axial fan

    Investigation of the Tip Clearance Effect in a Counter-rotating Ducted Fan for VTOL UAV

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    The tip clearance effect on counter-rotating ducted fan of VTOL UAV in hovering condition, was investigate using computational analysis. The numerical results of baseline model are validated by wind tunnel test in hovering and forward conditions. It is observed that if tip clearance of one rotor in the counter-rotating ducted fan increase then the thrust coefficient of another rotor increases. In Addition to this, when the tip clearance of the rear rotor increases, the thrust of the ducted fan is improved due to increasing of average total pressure at exit plane.This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(No. 2009-009072)

    Aggressive maneuvering of a thrust vectored flying wing: A receding horizon approach

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    This paper deals with the control of a thrust vectored flying wing known as the ducted fan, developed at California Institute of Technology. The experiment was developed to serve as a testbed for nonlinear control design. In an earlier paper, the authors reported simulation results based on a simplified (no aerodynamics involved) planar model of the ducted fan around hover position. In this paper we report on the modeling and simulation of the ducted fan in forward flight, where aerodynamic forces and moments can no longer be ignored. A receding horizon scheme is developed to generate trajectories for the forward flight model. Using a more simplified version of the model, some aggressive trajectories are generated. These trajectories are then used as a reference in the receding horizon scheme, and morphed into the trajectories of the full model. Simulation results depict the capabilities of the ducted fan as well as this methodology in performing aggressive maneuvers

    Propulsion airframe integration

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    Wind tunnel simulation tests are reported that utilize a 20 inch powered nacelle for airframe integration studies. Considered are: effects of boattail positioning, nacelle size, aft fuselage drag, over-the-wing half span model installation, and turboprop and ducted fan configurations
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