Relevant bibliographies by topics / Ducted Rotor

Contents

  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Ducted Rotor'

Author: Grafiati
Published: 4 June 2021
Last updated: 10 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the lists of relevant articles, books, theses, conference reports, and other scholarly sources on the topic 'Ducted Rotor.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Journal articles on the topic "Ducted Rotor"

1

He, Xing Zhu, Shu Nan Liu, Yan Li Chen, Chun Xue Wang, and Song Yang. "Research on Hover Characteristics of Ducted Fan with Coaxial Rotors." Applied Mechanics and Materials 427-429 (September 2013): 216–20. http://dx.doi.org/10.4028/www.scientific.net/amm.427-429.216.

Full text
Abstract:
The method of handling respectively is used to refine the grid of ducted fan with coaxial rotors. Research the complex flow field of the ducted fan by numerical simulation to analyze its hover characteristics. The curve of the upper rotors lift, the lower rotors lift, the ducts lift with collective and the distance between rotors is got respectively. By comparing with the aerodynamic characteristics of ducted fan with a single rotor, results show that there is interference between the upper and lower rotors, the upper one interferes the lower one more heavily and interference is reduced with the increase of distance between the rotors; the duct of ducted fan with coaxial rotors can provide more lift than the one with a single rotor.
APA, Harvard, Vancouver, ISO, and other styles
2

Mishra*, Mr Vinay, and Dr H. K. Paliwal. "CFD Analysis of Torque and Power for Single Rotor, Dual Rotor, and Ducted Dual Rotor Wind Turbine." International Journal of Engineering and Advanced Technology 10, no. 4 (April 30, 2021): 215–17. http://dx.doi.org/10.35940/ijeat.d2500.0410421.

Full text
Abstract:
With the present advancement, a wind turbine needs a wind rotor with high torque and power. The present study aims to enhance the torque and power of wind turbine by employing the ducted dual rotor. In this regard, CFD analysis is performed to analyze the torque and power produced for horizontal axis single rotor bare wind turbine, dual rotor wind turbine, and convergent-divergent ducted type dual rotor wind turbine. The comparative study is conducted to enhance the power and torque for the aforementioned rotor type. The results highlight the maximum value of torque for a dual ducted wind turbine is 36.9% more than a dual rotor at 16 m/s of wind velocity and 92.2 % more than a single rotor at 16 m/s of wind velocity, and the maximum value of the power produced for a dual ducted wind turbine is 40.48% more than a dual rotor at 16 m/s of wind velocity and 139.66% more than a single rotor at 16 m/s of wind velocity. Therefore result suggested that a dual ducted wind turbine is better than a single rotor wind turbine.
APA, Harvard, Vancouver, ISO, and other styles
3

Roh, Nahyeon, Sejong Oh, and Donghun Park. "Aerodynamic Characteristics of Helicopter with Ducted Fan Tail Rotor in Hover under Low-Speed Crosswind." International Journal of Aerospace Engineering 2020 (October 27, 2020): 1–14. http://dx.doi.org/10.1155/2020/7059209.

Full text
Abstract:
The tail rotor of a helicopter operating under low-speed crosswind undergoes highly complex flow due to the interaction between the main rotor, fuselage, and tail rotor system. In this study, numerical simulations have been conducted on the complete configuration of a helicopter with a ducted fan tail rotor system (comprising a main rotor, ducted fan tail rotor, fuselage, and empennage) to analyze the wake interaction in hovering flight under various crosswind directions. The flow characteristics around the tail rotor, the tail rotor thrust, and the yawing moment of the helicopter are investigated and evaluated. The aerodynamic forces are compared with those of a helicopter with an open-type tail rotor. The results indicate that the aerodynamic performance of the ducted fan tail rotor is highly affected by the wakes of both the main rotor and port wing. Nevertheless, the helicopter with a ducted fan tail rotor is observed to be much more directionally stable under various crosswind directions, than that with an open-type tail rotor. This is because the rotor is protected by the fixed part of the tail rotor system in the former case.
APA, Harvard, Vancouver, ISO, and other styles
4

Oweis, Ghanem F., David Fry, Chris J. Chesnakas, Stuart D. Jessup, and Steven L. Ceccio. "Development of a Tip-Leakage Flow Part 2: Comparison Between the Ducted and Un-ducted Rotor." Journal of Fluids Engineering 128, no. 4 (March 2, 2006): 765–73. http://dx.doi.org/10.1115/1.2201619.

Full text
Abstract:
The vortical flow in the tip region of a three-bladed rotor was examined using particle imaging velocimetry (PIV). The vortex forming at the tip of the un-ducted propeller was compared to the tip-leakage vortex of the ducted rotor. The planar flow fields were used to identify regions of concentrated vorticity and determine instantaneous vortex properties, revealing the presence of a primary tip-leakage vortex surrounded by a number of secondary vortices. Comparison between the ducted and un-ducted rotor indicated that the presence of the duct reduced the relative strength of the primary tip vortex, making its strength a smaller fraction of the overall shed circulation near the tip. The weaker tip-leakage vortex then became closer in strength to the other secondary vortices in the tip-flow region. However, for the rotor tip geometry considered here, the radius of the primary vortex core did not vary substantially between the ducted and un-ducted cases. The variability of the flow was larger for the ducted case, in terms of the primary vortex position, its identified circulation, core size, and inferred core pressure. This variability was also observed in the scaled velocity fluctuations near the core of the vortex.
APA, Harvard, Vancouver, ISO, and other styles
5

Kim, Woo-Yul, Santhosh Senguttuvan, and Sung-Min Kim. "Effect of Rotor Spacing and Duct Diffusion Angle on the Aerodynamic Performances of a Counter-Rotating Ducted Fan in Hover Mode." Processes 8, no. 11 (October 23, 2020): 1338. http://dx.doi.org/10.3390/pr8111338.

Full text
Abstract:
The aerodynamic performance of a counter-rotating ducted fan in hover mode is numerically analyzed for different rotor spacings and duct diffusion angles. The design of the counter-rotating fan is inspired by a custom-designed single rotor ducted fan used in a previous study. The numerical model to predict the aerodynamic performance of the counter-rotating ducted fan is developed by adopting the frozen rotor approach for steady-state incompressible flow conditions. The relative angle between the front and the rear rotor is examined due to the usage of the frozen rotor model. The results show that the variation of thrust for the different relative angles is extremely low. The aerodynamic performances are evaluated by comparing the thrust, thrust coefficient, power coefficient, and figure of merit (FOM). The thrust, thrust coefficient, and FOM slightly increase with increasing rotor spacing up to 200 mm, regardless of the duct diffusion angle, and reduce on further increase in the rotor spacing. The duct diffusion angle of 0° generates about 9% higher thrust and increases the FOM by 6.7%, compared with the 6° duct diffusion angle. The duct diffusion angle is highly effective in improving the thrust and FOM of the counter-rotating ducted fan, rather than the rotor spacing.
APA, Harvard, Vancouver, ISO, and other styles
6

Misiorowski, Matthew P., Farhan S. Gandhi, and Assad A. Oberai. "Computational Analysis and Flow Physics of a Ducted Rotor in Edgewise Flight." Journal of the American Helicopter Society 64, no. 4 (October 1, 2019): 1–14. http://dx.doi.org/10.4050/jahs.64.042004.

Full text
Abstract:
This study examines the performance of the ducted rotor in hover and edgewise flight conditions. The flow over a threedimensional model of a ducted rotor was simulated using the Spalart–Allmaras Reynolds-averaged Navier–Stokes model implemented in a stabilized finite element method. A sliding mesh was used to conveniently account for the large-scale motion associated with rotor revolutions. The simulation results were analyzed to understand the flow physics and quantify the contributions of the rotor and various sections of the duct interior surfaces on the total aerodynamic forces (thrust, drag, and side force) and moments (pitching and rolling). In edgewise flight, freestream flow separates off the front of the duct inlet, causing a region of recirculating flow and upwash in the rotor plane. The upwash region biases rotor thrust production to the front of the disk. The swirl velocity further biases the region of flow separation over the inlet and upwash at the front of the rotor toward the retreating side of the disk. The shift of thrust production on the rotor and duct toward the front produces a strong nose-up pitching moment on the ducted rotor. The rear of the diffuser is a significant contributor to the total drag; this force includes a nose-down pitch moment, which partially negates the moment from the duct inlet. The rotor is the primary source of vertical vibratory forces as well as vibratory pitching and rolling moments. The small tip clearance of the rotor causes a local interaction between the blade tip and duct that is the dominant contributor to in-plane vibratory forces on the ducted rotor.
APA, Harvard, Vancouver, ISO, and other styles
7

Kanya, Benjamin, and Kenneth D. Visser. "Experimental validation of a ducted wind turbine design strategy." Wind Energy Science 3, no. 2 (December 18, 2018): 919–28. http://dx.doi.org/10.5194/wes-3-919-2018.

Full text
Abstract:
Abstract. A synergistic design strategy for ducted horizontal axis wind turbines (DWTs), utilizing the numerical solution of a ducted actuator disk system as the input condition for a modified blade element momentum method, is presented. Computational results of the ducted disk have shown that the incoming flow field for a DWT differs substantially from that of a conventional open rotor. The rotor plane velocity is increased in the ducted flow field, and, more importantly, the axial velocity component varies radially. An experimental full-scale 2.5 m rotor and duct were designed, using this numerical strategy, and tested at the University of Waterloo's wind turbine test facility. Experimental results indicated a very good correlation of the data with the numerical predictions, namely a doubling of the power output at a given velocity, suggesting that the numerical strategy can provide a means for a scalable design methodology.
APA, Harvard, Vancouver, ISO, and other styles
8

Bagheri-Sadeghi, Nojan, Brian T. Helenbrook, and Kenneth D. Visser. "Maximal power per device area of a ducted turbine." Wind Energy Science 6, no. 4 (July 29, 2021): 1031–41. http://dx.doi.org/10.5194/wes-6-1031-2021.

Full text
Abstract:
Abstract. The aerodynamic design of a ducted wind turbine for maximum total power coefficient was studied numerically using the axisymmetric Reynolds-averaged Navier–Stokes equations and an actuator disc model. The total power coefficient characterizes the rotor power per total device area rather than the rotor area. This is a useful metric to compare the performance of a ducted wind turbine with an open rotor and can be an important design objective in certain applications. The design variables included the duct length, the rotor thrust coefficient, the angle of attack of the duct cross section, the rotor gap, and the axial location of the rotor. The results indicated that there exists an upper limit for the total power coefficient of ducted wind turbines. Using an Eppler E423 airfoil as the duct cross section, an optimal total power coefficient of 0.70 was achieved at a duct length of about 15 % of the rotor diameter. The optimal thrust coefficient was approximately 0.9, independent of the duct length and in agreement with the axial momentum analysis. Similarly independent of duct length, the optimal normal rotor gap was found to be approximately the duct boundary layer thickness at the rotor. The optimal axial position of the rotor was near the rear of the duct but moved upstream with increasing duct length, while the optimal angle of attack of the duct cross section decreased.
APA, Harvard, Vancouver, ISO, and other styles
9

Jiang, Yuening, Hai Li, and Hongguang Jia. "Aerodynamics Optimization of a Ducted Coaxial Rotor in Forward Flight Using Orthogonal Test Design." Shock and Vibration 2018 (May 28, 2018): 1–9. http://dx.doi.org/10.1155/2018/2670439.

Full text
Abstract:
To investigate the aerodynamic complexities involved in the combination of freestream and propeller’s suction flow field of ducted coaxial rotors system in forward flight, an orthogonal L16(43) test design has been applied to optimize the design parameters including forward speed, pitch angle, and axial spacing between rotors. Multiblock grids and Multiple Frame of Reference (MFR) method are adopted for calculating aerodynamic performance of the system, hover characteristic was compared with experimental data obtained from the test stand, and the thrust performance is well predicted for various rotor spacing and a range of rpm. This solution approach is developed for the analytical prediction of forward flight and the simulation results indicated that the design parameters influenced lift, drag, and torque reduced in the order: wind speed > rotor spacing > pitch angle, wind speed > pitch angle, and rotor spacing > wind speed > pitch angle, respectively. The optimal rotor spacing and pitch angle were determined to maximize the aerodynamic performance considering high lift, low drag, and trimmed torque.
APA, Harvard, Vancouver, ISO, and other styles
10

Zhong, Guo, Jun Huang, and Mingxu Yi. "Design parameters improvement of helicopter ducted tail rotor." Aircraft Engineering and Aerospace Technology 90, no. 2 (March 5, 2018): 237–45. http://dx.doi.org/10.1108/aeat-01-2017-0033.

Full text
Abstract:
Purpose The purpose of this paper is to reduce the acoustic noise of helicopter ducted tail rotor. Design/methodology/approach To predict the noise accurately, a thin-body boundary element method (BEM)/Ffowcs Williams–Hawkings method is developed in this paper. It is a hybrid method combining the BEM with computational aeroacoustics and can be used efficiently to predict the propagation of sound wave in the duct. Findings Compared with the experimental results, the proposed method of acoustic noise is rather desirable. Practical implications Then several geometry parameters are modified to investigate the noise reduction of ducted tail rotor by using the numerical prediction method. Originality/value The aerodynamic and acoustic performance of different modification tasks is discussed. These results demonstrate the validity of design parameters modification of ducted tail rotor in acoustic noise reduction.
APA, Harvard, Vancouver, ISO, and other styles
More sources

Dissertations / Theses on the topic "Ducted Rotor"

1

Karamolegkos, Konstantinos. "Ducted Tail Rotor Perfomance Prediction Using CFD." Thesis, Cranfield University, 2014. http://dspace.lib.cranfield.ac.uk/handle/1826/9241.

Full text
Abstract:
Aviation industry has a crucial impact on society on the grounds that it offers wider social and economic benefits. The demand of transportation is increasing and it is expected that the worldwide fleet of aircraft and rotorcraft will increase accordingly. This growth will introduce an increased environmental impact which can be controlled with the introduction and the implementation of new and greener technologies which can provide both a reduced carbon foot-print and increased efficiency. Therefore, the simulation of new designs with tools that can capture the flow physics accurately is crucial, on the grounds that an accurate simulation could provide novel designs and new ways in order to design from scratch new vehicles as well as providing a better appreciation of the physics that are involved. This work has a central aim to propose a methodology which combines CFD simulations and the method of performance mapping. It focuses on the application of a ducted tail rotor which can offer significant performance benefits compared to a conventional tail rotor. The developed methodology was tested against the results of an in-house rotorcraft comprehensive code and provided a reasonable qualitative correlation. In principle, this methodology can work for all helicopter flight phases such as hover, climb, cruise, descend but due to the complexity of the investigations, together with the lack of experimental data that can be used to refine the CFD model, only the hover and forward flight were considered. Although CFD studies of a ducted tail rotor currently exist in the literature (though scarce), this work can be considered, to the best knowledge of the author as a first attempt in investigating the performance of the configuration, from low to high forward flight speed, by combining CFD and performance mapping.
APA, Harvard, Vancouver, ISO, and other styles
2

Riley, Troy M. "Aeroacoustics and Fluid Dynamics Investigation of Open and Ducted Rotors." University of Cincinnati / OhioLINK, 2021. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1627667464605408.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Regmi, Krishna. "Investigation of Perforated Ducted Propellers to use with a UAV." ScholarWorks@UNO, 2013. http://scholarworks.uno.edu/honors_theses/45.

Full text
Abstract:
Unmanned Aerial Vehicle (UAV) is any flying vehicle which is not controlled by actual human pilots sitting in the cockpit but is installed with proper avionics that can either fly autonomously or by using the commands from its base. Some rotorcraft UAVs use a ducted propeller for two main reasons- safety and to increase the thrust produced by the propellers. While ducted rotors can increase the thrust produced, it also adds weight to the UAV. It was therefore hypothesized that by removing part of the duct materials (i.e. adding perforations in the duct) would benefit from both decreased duct weight and increased thrust. However, it is not clear how much trade-off would be between these two factors. Hence, the objective of this study is to explore the relationship between the change of thrust and addition of different numbers or sizes of perforations. Cases with and without duct, and duct with perforations were simulated using a commercial computational fluid dynamic (CFD) software Ansys/Fluent. The physics of the rotating propeller was modeled by a simplified disc with a pressure jump across an infinitesimal volume. Three different RPM speeds of the propellers were simulated by varying the strength of the pressure jump. The results show that the thrust decreases as the duct is added. As perforations are added, the result shows that with more perforations (i.e. more open area on the duct wall), the thrust increases accordingly until the thrust reaches a maximum value without the duct. The result is in contrast to a published experimental data stating that installation of duct can increase thrust. It is speculated that the current duct with a flat wall has caused such difference from the experimental data. Further study is recommended to continue more detailed computational simulation using a duct with cambered airfoil configuration to reduce the aerodynamic losses.
APA, Harvard, Vancouver, ISO, and other styles
4

Quaranta, Erika. "Noise radiation from a ducted rotor in a swirling-translating flow." Thesis, Cranfield University, 2009. http://dspace.lib.cranfield.ac.uk/handle/1826/4577.

Full text
Abstract:
This PhD dissertation investigates the noise radiation produced by a rotor inside a duct, which is convected by a swirling-translating mean flow. The study is based on an extension of Gennaretti's and Morino's boundary element method to the frequency domain for scattering problems in conjunction with a spinning rotor source model in the presence of a swirling-translating flow. Firstly, two different source models of the rotor are analyzed in absence of mean flow. The parametric study of the two dipole components distributed over a ring or a disc shows that the source radius is a crucial parameter. The scattered pressure directivity patterns of the ring and disc source models are in perfect agreement when a particular ratio between the two model radii is adopted. Therefore, the present analysis justifies the preference for the ring source model due to its simplicity. The proposed formulation is validated by means of exact solutions and used to investigate the effects of the translating flow Mach number and swirling flow angular velocity on noise radiation both in the far and in the near field. The scattered sound is highly affected by the convecting mean flow. The modal content of the scattered field increases when increasing the translating flow Mach number, while a swirling flow leads to a reduction of the mode propagation, if co-rotating with respect to the azimuthal order of the spinning source, or an increase of the modal content, if counter-rotating with respect to the source. This is clearly confirmed by the scattered pressure patterns and levels both in the far and in the near field for all the source frequencies. In general, the mean translating flow moves the main lobes of the directivity patterns downstream, whereas in some cases the mean swirling flow appears to neglect this effect and the downstream lobe is completely shifted. However, the investigation on the in-duct propagation shows that the main effect of the convecting mean flow is to change the modal duct characteristics, more than the pattern itself. This results in turn in the strong modification of the patterns noted in the far field.
APA, Harvard, Vancouver, ISO, and other styles
5

Flack, Timothy John. "Induction motor modelling using finite elements." Thesis, Imperial College London, 1990. http://hdl.handle.net/10044/1/7405.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Turkdogru, Nurkan. "Validity of the point source assumption of a rotor for farfield acoustic measurements with and without shielding." Diss., Georgia Institute of Technology, 2010. http://hdl.handle.net/1853/37226.

Full text
Abstract:
Measuring the farfield noise levels of full-scale rotor systems is not trivial and can be costly. Researchers prefer to perform small-scale experiments in the laboratory so that they can extrapolate the model scaled results to the larger scale. Typically Inverse Square Law (ISL) is used to extrapolate the sound pressure levels (SPL), obtained from model-scale experiments at relatively small distances to predict noise at much larger distances for larger scale systems. The assumption underlying this extrapolation is that the source itself can be treated as a point sound source. At what distance from a rotor system it can be treated as a point source has never been established. Likewise, many theoretical models of shielding by hard surfaces assume the source to be a point monopole source. If one is interested in shielding the noise of a rotor system by interposing a hard surface between the rotor and the observer, can the rotor system really be considered to be a monopole? If rotating noise sources are under consideration what is the effect of configuration and design parameters? Exploring the validity of point source assumption alluded to above for a rotor for farfield acoustic measurements with and without shielding form the backbone of the present work.
APA, Harvard, Vancouver, ISO, and other styles
7

Ohanian, Osgar John. "Ducted Fan Aerodynamics and Modeling, with Applications of Steady and Synthetic Jet Flow Control." Diss., Virginia Tech, 2011. http://hdl.handle.net/10919/27687.

Full text
Abstract:
Ducted fan vehicles possess a superior ability to maximize payload capacity while minimizing vehicle size. Their ability to both hover and fly at high speed is a key advantage for information-gathering missions, particularly when close proximity to a target is essential. However, the ducted fanâ s aerodynamic characteristics pose difficulties for stable vehicle flight and therefore require complex control algorithms. In particular, they exhibit a large nose-up pitching moment during wind gusts and when transitioning from hover to forward flight. Understanding ducted fan aerodynamic behavior and how it can be altered through flow control techniques are the two prime objectives of this work. This dissertation provides a new paradigm for modeling the ducted fanâ s nonlinear behavior and new methods for changing the duct aerodynamics using active flow control. Steady and piezoelectric synthetic jet blowing are employed in the flow control concepts and are compared. The new aerodynamic model captures the nonlinear characteristics of the force, moment, and power data for a ducted fan, while representing these terms in a set of simple equations. The model attains excellent agreement with current and legacy experimental data using twelve non-dimensional constants. Synthetic jet actuators (SJA) have potential for use in flow control applications in UAVs with limited size, weight, and power budgets. Piezoelectric SJAs for a ducted fan vehicle were developed through two rounds of experimental designs. The final SJA design attained peak jet velocities in the range of 225 ft/sec (69 m/s) for a 0.03â x 0.80â rectangular slot. To reduce the magnitude of the nose-up pitching moment in cross-winds, two flow control concepts were explored: flow separation control at the duct lip, and flow turning at the duct trailing edge using a CoandÄ surface. Both concepts were experimentally proven to be successful. Synthetic jets and steady jets were capable of modifying the ducted fan flow to reduce pitching moment, but some cases required high values of steady blowing to create significant responses. Triggering leading edge separation on the duct lip was one application where synthetic jets showed comparable performance to steady jets operating at a blowing coefficient an order of magnitude higher.
Ph. D.
APA, Harvard, Vancouver, ISO, and other styles
8

Siddappaji, Kiran. "On the Entropy Rise in General Unducted Rotors using Momentum, Vorticity and Energy Transport." University of Cincinnati / OhioLINK, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1535464679934565.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Unlu, Tugba. "Flight Control Of A Tilt Duct Uav With Emphasis On The Over Actuated Transition Flight Phase." Master's thesis, METU, 2009. http://etd.lib.metu.edu.tr/upload/2/12611078/index.pdf.

Full text
Abstract:
In the thesis, automatic flight control system is designed for Tilt Duct Unmanned Aerial Vehicle (UAV). The vehicle is a Vertical Take-Off Landing (VTOL) type with two symmetric rotors on the wings, one aft rotor on the aft body. It behaves like a helicopter but with higher speeds in forward flight. Transition flight of the aircraft from hover to cruise or take-off to forward flight is the primary concern of the thesis study with the nonlinearities and instabilities encountered, together with the over-actuated controls in this mode. A nonlinear simulation code is developed including nonlinear equations of motion together with the nonlinear aerodynamics, environmental eects, and rotor dynamics. Trim and linearization codes are also developed. Trim conditions for the transition flight phase are calculated for two different transition scenarios. Linear controllers are developed and nonlinear controller is designed for the transition mode. Nonlinear controller uses the state dependent Ricatti equation SDRE approach by using extended linearization. Two loop approach is used in order to increase controllability. In the inner loop, attitude rates are fed back and SDRE approach is used to calculate the feedback gain matrix online. In the outer loop, vehicle attitude is controlled using the eigenvalue assignment. Blended inverse algorithm based control allocation method is used in control of the over-actuated transition phase. This algorithm is shown to be quite effective among different methods in not only generating necessary forces needed for the control, but also allocating with more control authority on the desired actuator.
APA, Harvard, Vancouver, ISO, and other styles
10

Junior, Carlos Cesar Brochine. "Metodologia semi-analítica para predição de ruído de banda larga causado pela interação entre a esteira turbulenta do rotor com as aletas da estatora em motores turbofans." Universidade de São Paulo, 2013. http://www.teses.usp.br/teses/disponiveis/18/18148/tde-26102016-101909/.

Full text
Abstract:
A maior parte do ruído de aeronaves é advinda dos motores. Como houve grande avanço no controle do ruído tonal, atualmente grande parte do esforço se dá para redução do ruído de banda larga, que é menos compreendido. O ruído de banda larga é gerado pela interação entre um escoamento turbulento e uma superfície, como por exemplo, a turbulência ingerida interagindo com o rotor, o escoamento na ponta das pás, entre outros. Apesar das diversas fontes citadas, sabe-se que a principal fonte de ruído de banda larga em tal tipo de motor é a interação da esteira turbulenta do rotor com as aletas da estatora. Assim, o presente estudo manterá seu enfoque apenas em tal causa. O objetivo deste então é o desenvolvimento de um modelo capaz de previsão do ruído de banda larga pela interação da esteira turbulenta causada pelo rotor, interagindo com as aletas da estatora, bem como o entendimento da propagação do ruído em duto. A primeira abordagem em relação a tal tipo de ruído é através da previsão do ruído gerado. Para previsão de ruído podem ser utilizados métodos analíticos, numéricos, ou empíricos, cada qual com suas vantagens e penalizações. Para tal, foi utilizado um método semi-analítico, em tais métodos utiliza-se simulação numérica para previsão da característica da turbulência e uma teoria analítica para a geração e propagação do ruído no duto. A principal motivação para o método semi-analítico é sua vantagem em relação aos métodos numéricos que demandam custo computacional extremamente alto e vantagem em relação a métodos analíticos que necessitariam uma demasiada simplificação geométrica. Dessa maneira, utilizou-se a geometria do ANCF, uma plataforma de ensaios desenvolvida pela NASA, onde havia geometria e resultados divulgados, tornando possível a verificação dos resultados obtidos. Os resultados mostram que as tendências capturadas são condizentes com o esperado, e então com um tempo relativamente baixo, de maneira prática, é possível a previsão do ruído de interação e sua propagação em dutos nos motores turbofans.
The major noise source in aircraft is the engine. Since tonal noise control is well developed, the current effort concentrates on broadband noise reduction, which is less understood. The broadband noise is generated when a turbulent flow interacts with a surface as, for example, rotor blade tip flow, boundary layer and the rotor interaction. Although there are different sources of broadband noise it is known that the major broadband source in turbofan engine is the rotor turbulent wake interacting with the stator vanes. This study is focused in that source of noise and the goal is to develop a model capable of predicting the rotor/stator interaction noise as well as in duct noise propagation. Noise prediction can be carried out by analytical, numerical or empirical methods, each one with advantages and disadvantages. In the present work the semi-analytical method was used. Turbulence characteristics were estimated by a numerical method and the noise generation and duct propagation was estimated by an analytical method. The biggest advantage comparing with the numerical methods is that this method is less time consuming. A purely analytical method would require excessive geometric simplification. The ANCF, a rig developed by NASA was used as basis for the simulations, since its geometry and noise data are available. The results show that the correct trends are consistently captured. So it is concluded that it is possible to predict the broadband noise and its propagation in turbofans engines with a practical and low cost method.
APA, Harvard, Vancouver, ISO, and other styles

Books on the topic "Ducted Rotor"

1

Martinez, R. The use of cowl camber and taper to reduce rotor/stator interaction noise. [Washington, D.C: National Aeronautics and Space Administration, 1995.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
2

United States. National Aeronautics and Space Administration., ed. Wave rotor demonstrator engine assessment. [Washington, DC]: National Aeronautics and Space Administration, 1996.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
3

United States. National Aeronautics and Space Administration., ed. Wave rotor demonstrator engine assessment. [Washington, DC]: National Aeronautics and Space Administration, 1996.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
4

Comparison of predicted low speed fan rotor/stator interaction modes to measured. Washington, DC: National Aeronautics and Space Administration, 1997.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
5

J, Heidelberg Laurence, Envia Edmane, and NASA Glenn Research Center, eds. Coupling of low speed fan stator vane unsteady pressures to duct modes: Measured versus predicted. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 1999.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
6

J, Heidelberg Laurence, Envia Edmane, and NASA Glenn Research Center, eds. Coupling of low speed fan stator vane unsteady pressures to duct modes: Measured versus predicted. [Cleveland, Ohio]: National Aeronautics and Space Administration, Glenn Research Center, 1999.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
7

United States. National Aeronautics and Space Administration., ed. The use of cowl camber and taper to reduce rotor/stator interaction noise. [Washington, D.C: National Aeronautics and Space Administration, 1995.

Find full text
APA, Harvard, Vancouver, ISO, and other styles
8

A numerical simulator for three-dimensional flows through vibrating blade rows. [Cleveland, Ohio]: National Aeronautics and Space Administration, Lewis Research Center, 1998.

Find full text
APA, Harvard, Vancouver, ISO, and other styles

Book chapters on the topic "Ducted Rotor"

1

"Ducted Rotors." In Innovation in Wind Turbine Design, 335–44. Chichester, UK: John Wiley & Sons Ltd, 2018. http://dx.doi.org/10.1002/9781119137924.ch18.

Full text
APA, Harvard, Vancouver, ISO, and other styles

Conference papers on the topic "Ducted Rotor"

1

Qing, Jixiang, Yu Hu, Yanling Wang, Zhonghuan Liu, Xuyang Fu, and Wenmeng Liu. "Kriging Assisted Integrated Rotor-Duct Optimization for Ducted Fan in Hover." In AIAA Scitech 2019 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2019. http://dx.doi.org/10.2514/6.2019-0007.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Mohamed, Amr, Ahmed El-Baz, Nabil Abd-ELaziz, and Ashraf Mostafa. "Computational Investigation Of Ducted Dual Rotor Wind Turbine." In 2019 Novel Intelligent and Leading Emerging Sciences Conference (NILES). IEEE, 2019. http://dx.doi.org/10.1109/niles.2019.8909321.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Qing, Jixiang, Yu Hu, Yanling Wang, Zhonghuan Liu, Xuyang Fu, and Wenmeng Liu. "Correction: Kriging Assisted Integrated Rotor-Duct Optimization for Ducted Fan in Hover." In AIAA Scitech 2019 Forum. Reston, Virginia: American Institute of Aeronautics and Astronautics, 2019. http://dx.doi.org/10.2514/6.2019-0007.c1.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Lind, Robert, James Nathman, and Ian Gilchrist. "Ducted Rotor Performance Calculations and Comparison with Experimental Data." In 44th AIAA Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2006. http://dx.doi.org/10.2514/6.2006-1069.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Kondor, Shayne, and Michael Heiges. "Active flow control for control of ducted rotor systems." In 39th Aerospace Sciences Meeting and Exhibit. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2001. http://dx.doi.org/10.2514/6.2001-117.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Wallscheid, L., F. Eulitz, and R. Heinecke. "Investigation of Unsteady Flow Phenomena in a Counterrotating Ducted Propfan." In ASME 1998 International Gas Turbine and Aeroengine Congress and Exhibition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/98-gt-251.

Full text
Abstract:
Experimental and numerical investigations on a counterrotating propfan (CRISP) have been carried out to study unsteady flow phenomena generated by the interaction of the two rotors. This paper focuses mainly on the downstream effects of rotor 1 on rotor 2. Therefore unsteady Laser-2-Focus, unsteady total pressure measurements and an unsteady simulation have been carried out. The total pressure measurements behind the rotors show variations of the absolute total pressure outside the wake regions up to 30 percent of the average total pressure rise. Some of these are caused by the interaction of the rotor 1-generated wakes with the leading edge of rotor 2. The others may result from the pressure waves generated by the reflection of the rotor 2-shockwaves by the blades of rotor 1.
APA, Harvard, Vancouver, ISO, and other styles
7

Singh, Rajneesh, and Surya Dinavahi. "Shape Optimization of a Ducted Rotor System for Aerodynamic Performance." In 49th AIAA Aerospace Sciences Meeting including the New Horizons Forum and Aerospace Exposition. Reston, Virigina: American Institute of Aeronautics and Astronautics, 2011. http://dx.doi.org/10.2514/6.2011-1203.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Xu, Jian, Guoqiang Tian, and Zhijian Hu. "Attitude control of ducted fan UAV with three auxiliary rotor." In 2016 35th Chinese Control Conference (CCC). IEEE, 2016. http://dx.doi.org/10.1109/chicc.2016.7555085.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Chesnakas, Christopher J., and Stuart D. Jessup. "Tip-Vortex Induced Cavitation on a Ducted Propulsor." In ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference. ASMEDC, 2003. http://dx.doi.org/10.1115/fedsm2003-45320.

Full text
Abstract:
An extensive experimental investigation was carried out to examine tip-vortex induced cavitation on a ducted propulsor. The flowfield about a 3-bladed, ducted rotor operating in uniform inflow was measured in detail with three-dimensional LDV; cavitation inception was measured; and a correlated hydrophone/high-speed video system was used to identify and characterize the early, sub-visual cavitation events. Two geometrically-similar, ducted rotors were tested over a Reynolds number range from 1.4×106 to 9×106 in order to determine how the tip-vortex cavitation scales with Reynolds number. Analysis of the data shows that exponent for scaling tip-vortex cavitation with Reynolds number is smaller than for open rotors. It is shown that the parameters which are commonly accepted to control tip-vortex cavitation, vortex circulation and vortex core size, do not directly control cavitation inception on this ducted rotor. Rather it appears that cavitation is initiated by the stretching and deformation of secondary vortical structures resulting from the merger of the leakage and tip vortices.
APA, Harvard, Vancouver, ISO, and other styles
10

Nouri, Hussain, Florent Ravelet, Farid Bakir, and Christophe Sarraf. "Experimental Investigation on Ducted Counter-Rotating Axial Flow Fans." In ASME-JSME-KSME 2011 Joint Fluids Engineering Conference. ASMEDC, 2011. http://dx.doi.org/10.1115/ajk2011-22061.

Full text
Abstract:
An experimental study on counter-rotating axial-flow fans was carried out. The fans of diameter D = 375 mm were designed using an inverse method. The counter-rotating fans operate in a ducted-flow configuration and the overall performances are measured in a normalized test bench. The rotation rate of each fan is independently controlled. The axial spacing between the fans can vary from 10 to 50 mm by steps of 10 mm. The results show that the efficiency is strongly increased compared to a conventional rotor or to a rotor-stator stage. The effects of varying the rotation rates ratio on the overall performances are studied and show that the system is highly efficient on a wide range of flow-rates and pressure rises. However, the change of the axial distance between rotors from 10 to 50 mm does not seem to change the overall performances. This system has thus a very flexible use, with a large patch of high efficient operating points in the parameter space. Further local studies including velocity measurements and wall-pressure fluctuations in the space between the rotors are needed to better understand the interactions between the rotors and to optimize the system.
APA, Harvard, Vancouver, ISO, and other styles

Reports on the topic "Ducted Rotor"

1

Yang, Cheng-I., Minyee Jiang, Christopher J. Chesnakas, and Stuart D. Jessup. Numerical Simulation of Tip Vortices of a Ducted Rotor. Fort Belvoir, VA: Defense Technical Information Center, September 2004. http://dx.doi.org/10.21236/ada426510.

Full text
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the extended bibliographies on the topic 'Ducted Rotor' for particular source types:
Journal articles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography