The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
The paper is dedicated to the study of hydrodynamic effects in the rotors of flow micro-hydropower plants. There was argued the geometry of hydrodynamic profiles of blades efficient in terms of energy conversion efficiency based on which original concepts of hydrodynamic rotors were developed. Using the CAD models of the proposed rotors: there were performed complex CFD simulations of the transient...
This article introduces a new wind turbine, called resistance type vertical axial wind turbine (VAWT) with soft blades. The blades of the new turbine resist the wind and collect the power along the wind direction, while canceled the resistance against the wind direction. The new work mechanism was conceived to improve the aerodynamic performances of traditional VAWT. To prove the above supposing,...
The micro unmanned helicopter has become a hot spot in the fields of military applications because of its advantages of flexibility, good concealment and the capability of VTOL. In recent years, it has become the focus of the research institutes in various countries. In order to realize the goal of autonomous flight of the micro unmanned helicopter, it is necessary to have a precise model. In this...
The goal of Piccolissimo is to create a small, simple, and self-powered flying vehicle. Piccolissimo has just one motor and two rigid bodies, which are propellers that spin in opposite directions. The mass distribution and relative rotor speeds are designed to maintain passive stability in hover. Cartesian velocity control is obtained by introducing an asymmetry in the rotation axis of the two rotating...
Wind turbines are often sited together in wind farms as it is economically advantageous. However, the wake inevitably created by every turbine will lead to a time-varying interaction between the individual turbines. Common practice in industry has been to control turbines individually and ignore this interaction while optimizing the power and loads of the individual turbines. However, turbines that...
Wave energy is obvious source for renewable energy harvesting in oceans. A new WEC named wave turbine was proposed. The proposed system consists of a floating body and a submerged body. The floating body is same with that of a conventional buoy, and the submerged body is a power take off similar to a turbine which has flap-type blades in a round-frame rotor. To describe the proposed system, we developed...
Ground resonance is an aero-mechanical instability that occurs in soft in-plane rotors where there is a coalescence of low frequency lead-lag motions of the blade with that of the frequencies of the fuselage, when on ground. Such a coalescence results in violent oscillations of the fuselage and can prove catastrophic to the helicopter if not reduced in time. The present work focuses on a nonlinear...
With the development of general aviation, UAVs are increasingly used in all areas of our life. However, electric multi-rotor UAV can't achieve long-endurance, large load transport due to battery energy density. And hybrid power system is a perfect solution to this problem. This paper raised a parameter matching method of the UAV's hybrid power system related to the pulling force, required power and...
Advancements in control theory and the miniaturization of microelectronics has led to significant improvements in the aerial characteristics and performance of single rotor aerial crafts. These single rotor aerial crafts are of particular interest as they can be considered true hybrids between traditional fixed-wing crafts and the maneuverable multi-rotor platforms, allowing both VTOL capabilities...
Due to the manufacturing error, the worm deflection and other problems caused by the turbine rotor eccentricity, in the impeller vortex will cause the internal flow field of time pulsation, which leads to the additional flow excitation and noise. In this paper, the simulation of the centripetal turbine in eccentric rate stable condition, effect of rotor eccentricity on the exciting force, and the...
The principle of autorotation could potentially be utilized for harvesting energy from strong wind fields. Autorotation is a well-known phenomenon where a rotor in a strong wind field experiences significant lift force and aerodynamic torque. With recent works indicating immense, persistent availability of wind energy at high altitudes, autorotation could be used for harvesting wind energy from such...
The mechanical part of the wind turbine is the part that makes direct contact with the wind and it is here that the kinetic energy of wind is converted to mechanical energy. So this part of turbines must respect some conditions, as such must: • Ensure maximum conversion of kinetic wind power to mechanical power; • Resist the maximum possible for different storms (rain, snow …); • Have a long life...
This paper presents an initial work on position control of a floating offshore wind turbine on a semi-submersible platform. The platform positioning is achieved by adjusting the aerodynamic force of the wind through the manipulation of nacelle yaw and blade pitch angles, without introducing any additional actuator at the platform. At each time instant, a proportional velocity feedback controller compensates...
Models are crucial in the engineering design process because they can be used for both the optimisation of design parameters and the prediction of performance. Thus, models can significantly reduce design, development and optimisation costs. This paper establishes bases that can underlie the development of a novel equivalent electrical model for Darrieus-type vertical axis wind turbines (DTVAWTs)...
Models are crucial in the engineering design process because they can be used for both the optimisation of design parameters and the prediction of performance. Thus, models can significantly reduce design, development and optimisation costs. This paper presents the construction process of a novel equivalent electrical model for Darrieus-type vertical axis wind turbines (DTVAWTs). Physical concepts...
Fan blade loss is the most serious condition of typical extreme working conditions in turbofan engines. The transient huge unbalance force leads to the complicated and destructive vibration response of the rotor system. The paper proposed a set of safety design method for the rotor system, which ensured the engine to stop safely after the fan blade lost. The variable stiffness supporting structure...
The rotor-bearing system of a stored energy motor, which is composed of exciter, main generator and asynchronous motor, has typical characteristics of serious unbalanced mass distribution. According to the rotor and bearing system of the stored energy motor, dynamic performance optimization analyses are carried out by means of the finite element analysis method, to give the system optimization method...
This paper presents a systematic and comprehensive modeling approach for the derivation of a nonlinear dynamic model of a unmanned aerial vehicle (UAV) quadrotor. The model incorporates a couple of significant aerodynamic effects impacting on the quadrotor flight in different regimes. The controller is accordingly designed to accommodate both specific and uncertain dynamics of the quadrotor. The control...
This paper proposes a general control-oriented non-linear model for floating offshore wind turbine systems. It contains as many as six platform degrees of freedom as well as the rotor degree of freedom, and can account for full field wind and wave disturbances. Additionally, it accepts individual blade pitch, generator torque and yaw control inputs. The model is derived by assuming that the entire...
This paper presents a computational framework for an optimal aerodynamic blade design. Analysis of the wind turbine rotor is conducted using blade element momentum (BEM) theory. The geometric parameters of the wind turbine also have been calculated by BEM theory. The methodology and design approach is discussed in detail throughout this paper. A small three-bladed horizontal axis wind turbine (HAWT)...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.