Choosing wind turbine blades?

[claudelemonnier]

Hello everyone
I am looking for information about wind turbine blades what diameter is needed for a generator of 1 kw 24v a 400 tours mn has permanent magnets
Should the blades be live or use multiplier gears
I thank you in advance for your answers and advice
cordially

[Obamot]

Hello,

Good question.
The diameter I do not know, but if we find them too pale, is not enough to paint them in white?

(It shows so much that I know nothing about it? )

Some ideas in the document below, but it's "heavy":

https://moodle.insa-toulouse.fr/pluginfile.php/14081/mod_resource/content/0/DIMENSIONNEMENT_D_UN_ROTOR_D_EOLIENNE.pdf

(See 7 page etc ...)

A "simple" avenue for the sizing of the blades and their diameter in relation to the force of the wind and their anchoring on the turbine / alternator (ie their sizing necessarily relating to it) is that the blades must withstand the "moment"exerted on them by the wind:

According to the basic formula [F x lever arm] either force "F" the wind exerted on the blades to be multiplied by the length of the blades "lever arm" (but a little more complex as in the .pdf formula because the blades turn, and they distribute the force of the wind, the pressure of which on the blades is not homogeneous over the entire blade [and this according to the distance between the axis and each point of measurement of "force" exerted by the wind all along] step by step over their entire length, but if this simple formula does not give the result, it allows to understand the principle of the .pdf equations)

[Obamot]

PS. from there, one can get an idea by proceeding empirically, acting as if the wind would exert maximum constant pressure on a disk. Here the lever arm is the radius of the disk, which corresponds to half the diameter of a blade drawing in the sky an imaginary circle, rotating in a single revolution.

[chatelot16]

no need to go into detail because detailed calculation too approximate gives anything

start by using the betz formula to determine how much diameter is needed for a certain wind speed and some power

the formula of betz gives the power of a perfect wind turbine ... to have the chance to have 1KW with a real wind turbine to choose a diameter which gives 2KW

the choice of step will then arrive to get your 400 rpm

the calculation of the force of the wind on the blades is not the first to make: the centrifugal force often makes efforts greater than the wind, when the blade resists the centrifugal force the wind is only a joke in more

see the case of helicopter: the blades are very flexible! if we lift the helicopter by the blades without turning it would break, but when it turns the centrifugal force makes them hold

if the wind turbine does not turn the wind force on the blades is weak: only depand of the blade surface so weak ... when the wind turbine rotates at the right speed with the right step the effort is much more great as if the wind was pushing on a disk of the diameter of the helix falling back to the speed calculated by betz

betz thus makes it possible to calculate the general force on the mast of the whole of the helix which turns at the optimum speed: simply power = force x speed

[lilian07]

Hi,
Empirically to size one can start with 200w / m² apparent surface wind (swept by the blades) for a horizontal axis.
Then we find the speed of rotation with a Lambda around equal to 7 (tip of blade = 7 times the wind speed).
In the case of a wind turbine 1 Kw we have pale 1.3 around m .... and a rotation speed of 21 r / s 90 km / h
Normally with this type of wind turbine it is avoided the gear ratio and the inking must be important of the ores that is high, it is the horizontal thrust which is problematic ... attention is already dangerous with this power. Good design.

[Pierre820]

Hello. I am not a specialist but I am very interested in the wind turbine to complete my photovoltaic panels. During my research I came across the site of soupl'éole. Just type in a search engine to find it.
He proposes the manufacture of a wind turbine with veils. Making it much more efficient with hollow blades that gives them a Magnus effect.
The interest is that it is really accessible to all handyman and obviously very flexible and efficient!
Good luck for your project