The Darrieus rotor is one of the types of rotors used in vertical wind turbines. It vetropriemnye device which uses the lifting power. The rotor consists of two or more wings fixed to the beams, which are symmetrically arranged. The wings are made without the presence of profile of plain elastic tapes. They are very easy to manufacture and installation. Invented by Darrieus rotor and presented in 1931.
Today known рrincip of the rotor, but there is a mathematical model and consecutively the description of all occurring physical processes.
The principle of the Darrieus rotor.
The rotor starts to spin due to differences in aerodynamic resistance, then formed a circulation, and it becomes fast. Now consider in detail. On each blade affects the lift force during their movement relative to the flow of the wind. The magnitude of the lift force depends entirely on the angle between the velocity vectors of the air flow and the blades. The torque developed by the rotor is not constant – variable, due to the fact that the vector of instantaneous speed is cyclical and changes with the movement of the wing. Due to the fact that to generate lift we need a constant movement of the blades of the Darrieus rotor difficult part of it This feature can be improved by use of multiple blades, but for normal operation is still required compulsory prior acceleration.
The disadvantages of the rotor.
During operation of the rotor of the wind turbine tower subject to high loads. Problematic to carry out further modernisation due to the fact that no mathematical model. Also one of the negative factors is that the rotating mechanism is located on the periphery. This leads to the fact that the mechanism operates a large centrifugal load, and it quickly wears out. Therefore, the rotor wears out quickly (broken mechanical components), even in smooth wind. To reduce the weight of the structure, and with it the centrifugal force, the blades are available in curve shape. Another significant disadvantage is noise. The Darrieus rotor is very noisy, with a sharp wind noise breaks into a howl or squeal. Comes to the fact that due to the vibration that occurs, torn ribbon of the blade.
The advantages of Darrieus rotor.
One of the main advantages of the rotor is that it does not depend on the wind direction. Therefore, turbines are equipped with rotor do not need the device orientation, which affects the cost of the wind turbine. The Darrieus rotor even with a minimum flow of wind fairly fast. Also, the rotor high coefficient of utilization of wind energy.
The Darrieus rotor H-shaped type.
This is the most common and technologically advanced type of rotor. It features high speed, virtually silent, and infrasound is completely absent. The rotor of the h-shaped type has a simple structure, and it is more reliable than conventional Darrieus rotor.
The Darrieus rotor has a number of advantages but also many disadvantages.
Decision and minimizing the disadvantages of the device will enable you to compete with the rotors horizontal orientation and along with them to be used in the wind industry.