|Publication number||WO2012028890 A1|
|Publication date||8 Mar 2012|
|Filing date||10 Aug 2011|
|Priority date||1 Sep 2010|
|Also published as||CN102918263A|
|Publication number||PCT/2011/33, PCT/GR/11/000033, PCT/GR/11/00033, PCT/GR/2011/000033, PCT/GR/2011/00033, PCT/GR11/000033, PCT/GR11/00033, PCT/GR11000033, PCT/GR1100033, PCT/GR2011/000033, PCT/GR2011/00033, PCT/GR2011000033, PCT/GR201100033, WO 2012/028890 A1, WO 2012028890 A1, WO 2012028890A1, WO-A1-2012028890, WO2012/028890A1, WO2012028890 A1, WO2012028890A1|
|Inventors||Emmanuel Michalis, Theodoros Toulas|
|Applicant||Theodoros Toulas, Emmanuel Michalis|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Non-Patent Citations (1), Referenced by (8), Classifications (7), Legal Events (3)|
|External Links: Patentscope, Espacenet|
WIND TURBINE BLADES WITH DIMPLES
The invention refers to a technique applied on horizontal axis wind turbine blades which are placed on the rotor, on wind turbine's tower. Wind turbines of such type with blades are known, made from known materials such as light plastic reinforced with glass, aluminum, thin wooden layers, etc. The back side of these blades is more curved than the front side. After length, which is of crucial contribution for wind turbine's performance, other factors such as width, thickness and weight are as well contributing for maximizing their rotation which is characterized from a concession between the need for aero dynamical design and durability.
Wind turbine blades are designed and manufactured in a particular way, placed on rotor in order to take advantage the most out of the passing, through them, wind energy that causes their rotational motion. Through blade rotation on the axis, conversion is occurred, through the generator, from motional (rotational) energy to electrical. Rotation of these blades is caused and conducted by been affected exclusively from the pressure masses and gusts exercised by the wind. Depending on the proportional implemented rotational velocity can be judged either as negative (economically unprofitable or dangerous) or positive (proper and useful). During wind's molecules collision frontally to the rotating blades, wind's velocity declines, creating increased pressure at front blade's side and decreased at its back side, where eddies and vortexes take place. When blades rotate with enough speed, significant eddies and vortexes are created at the back side of them, creating a pressure difference (uneven distribution) affecting negatively rotation, in consequence obstructing both wind's turbine proper operation and performance. Blades accept wind's aero dynamical pressure initially frontally and their rotational motion is caused, thereafter just because of the accrued pressure difference which is mainly expressed at blade's back side, a negative aerodynamical phenomenon (eddies and vortexes) is created, causing speed deceleration and other complications against to an ideal rotation. Accordingly, these consequences comprise an adversely aim for wind turbine operation, not permitting to maximize its performance. The bigger the turbulence caused by the impacted wind onto them, the bigger is the transmitted energy from blades to the wind and vice versa. This energy interaction between blades and wind is the aero dynamical resistance and more specifically it contains the horizontal wind resistance (drag force) and the vertical or dynamical wind uplift (lift force). The horizontal wind resistance (drag force) acts in the contrary to wind direction decelerating blade's rotational rate, causing the pressure difference, a force (expressed as drag form or pressure resistance) is directing from an area with larger pressure (front blade side) towards an area with smaller pressure (back blade side).
The advantage of this invention is that dimples of hemispherical shape are arranged in specific order on the surface of wind turbine blades, a technique transferred directly from the hemispherical or polygonal (e.g. hexagonal) dimples arranged on golf balls. This technique is taking full advantage of the aero dynamical phenomena, managing to the maximum initially the impacted wind on blades frontally, while passing through them and finally on the outgoing wind masses (exiting) from them contributing at these points to a proper and manageable laminar air flow and a steadier blade rotation offering a quality, reliable, economical and silent wind turbine operation. The reason for transferring gol s ball dimple arrangement technique identically to wind turbine blades surface is to reproduce the formation of the most possible laminar air flow and eventually to manage in the most effective way the attached, incoming and outgoing wind, defusing pressure difference between blade's two sides at the maximum possible degree.
In the case of these wind turbine blades, the outcome is again succeeded, in the form of the fastest possible blade rotation (more rounds per minute) only this time by maximizing electrical energy production. Applying this dimple arrangement technique, alongside blade's both sides surface, wind management is stimulated and simultaneously beneficial maximized, as well as a methodically eddy and vortex relief that tend to accrue, contributing to reduction in the most effective way against the negative impact of horizontal wind resistance (drag force) on blade's back side, reducing drag form. With the specific dimple arrangement technique, wind turbine blades are now performing maximum rotation and manage most effectively the impacted to them and then ingoing through them wind, as well as balancing wind eddies and vortexes, formed at their back side, maximizing lift force. On other words, at the same wind loads now is transmitted to the wind turbine more electric energy, just as in analogue occurs on golf balls where thanks to the already applied and proven successful dimple arrangement technique, either concerning hemispherical or polygonal shaped dimples, applied on its surface, as many and close to one another as possible, in rows and alternately among them, so as covering its surface completely minimizing any flat surfaces, with an equal's strength strike commenced from player's club, a significant larger distance is covered in comparison to older golf balls that had their surface smooth. Accordingly, at a specific wind force manifested on wind turbine blades surface, where the specific dimple arrangement technique is applied, at an exact layout as in golf balls, then blade's rotational maximization is eventually succeeded. Wind turbine blades, according to the present invention are characterized by being applied on their surface precisely the dimple arrangement technique of golf balls, covering either their surface totally or just the back side only, in order for the drag force phenomenon only to be encountered effectively.
A simple way for presenting this particular dimple arrangement technique on wind turbine blades is made according to the invention by using as many as possible (the dimple number is in ratio to the surface covered) hemispherical or polygonal (e.g. hexagonal) shaped dimples arranged as much as closer to one another, in rows and alternately among them resulting to be tangential, covering totally both blade's surfaces exploiting and managing to the most beneficial degree the aerodynamic phenomena occurred during wind's frontal impact at the front side as well as during wind's movement towards the back side maximizing lift force and at the same time eliminating the negative and retarding pressure (drag force).
Applying this relatively cheap dimple arrangement technique on existing blades surface as well as by constructing from now on new such a type blades the ratio between cost to produce and effectiveness in energy production is improved significantly, operating at the same time more noiselessly and in general more trouble free by offering wind turbine simultaneously a more economical, controlled and rewarding operation. According to the dimple arrangement technique of the present invention, it is permitted on the wind turbine blades surface to be placed hemispherical or polygonal dimples, as many as possible of them, arranged in an as much as closer to one another approach, in rows and alternately among them resulting to be tangential, maximizing laminar air flow and air management displacement, creating less frontal resistance and as a result to maximize lift force causing friction minimization, since next wind mass's molecules are contacting previous air molecules, entrapped in these dimples instead of directly with blade's detrimental smoothly surface or material. Figure 1 shows a front view of three wind turbine blades.
Figure 2 shows a blade's magnification front view.
Figure 3 shows a back view of three wind turbine blades.
A method for applying the dimple arrangement technique on wind turbine blade surfaces is described in reference to the figures. Wind turbine consisting of a rotor (1) blades (2) and hemispherical dimples (3) which are implemented, depending on blade's surface size, at a highest number and at an ideal effectual size, arranged on blade's surface in rows, as much as closer to one another and alternately among them resulting to be tangential, and finally the wind turbine tower (4).
At the figures shown here, on blade's surfaces have been implemented same sized hemispherical shaped dimples only, not however prohibited the implementation of a polygonal shaped dimple arrangement only (e.g. hexagonal shaped dimples) arranged on the basis of hemispherical dimple arrangement technique in order to be as close as possible to one another, in rows and alternately among them resulting to be tangential and thus, covering totally blade's surface both on the front and on the back side.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|WO2006119648A1 *||15 May 2006||16 Nov 2006||Arrowind Corporation||Helical wind turbine|
|WO2007065434A1 *||5 Dec 2006||14 Jun 2007||Lm Glasfiber A/S||Blade for a wind turbine rotor|
|EP1469198A1 *||16 Apr 2004||20 Oct 2004||Eugen Radtke||Wind energy converter with lift improving surface structure.|
|EP2031241A1 *||29 Aug 2007||4 Mar 2009||Lm Glasfiber A/S||Blade for a rotor of a wind turbine provided with barrier generating means|
|US20060245928 *||21 Oct 2003||2 Nov 2006||Manfred Herbst||Wind power unit with structured surfaces for improvement of flow|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|WO2014023739A1 *||6 Aug 2013||13 Feb 2014||New World Energy Enterprises Limited||A blade for a rotary machine|
|WO2017052371A1 *||21 Sep 2016||30 Mar 2017||Home Turbine B.V.||Device for converting wind energy into at least mechanical energy|
|US9475141||3 Aug 2012||25 Oct 2016||Milwaukee Electric Tool Corporation||Reciprocating saw blade|
|US9777712 *||24 Mar 2015||3 Oct 2017||Rainer Marquardt||Wind power station for rooftops|
|US20150275865 *||24 Mar 2015||1 Oct 2015||Rainer Marquardt||Wind Power Station for Rooftops|
|USD688543||2 Oct 2012||27 Aug 2013||Milwaukee Electric Tool Corporation||Saw blade|
|USD723892||2 Jul 2013||10 Mar 2015||Milwaukee Electric Tool Corporation||Saw blade|
|USD729600||6 May 2014||19 May 2015||Milwaukee Electric Tool Corporation||Saw blade|
|Cooperative Classification||Y02E10/721, F03D1/0633, F05B2240/32, F05B2250/28, F05B2250/241|
|25 Apr 2012||121||Ep: the epo has been informed by wipo that ep was designated in this application|
Ref document number: 11749896
Country of ref document: EP
Kind code of ref document: A1
|1 Mar 2013||NENP||Non-entry into the national phase in:|
Ref country code: DE
|9 Oct 2013||122||Ep: pct app. not ent. europ. phase|
Ref document number: 11749896
Country of ref document: EP
Kind code of ref document: A1