Aerodynamic Regulation of Airscrew-, Fan- and Wind Turbine Blades with Bores and/or Cutting and/or Notching

Abstract

Axial airplane airscrew-, fan-, and wind turbine blade of low loading characterised by the fact that the aspect ratio of the airscrew-, fan- and wind turbine blades is low; near to the wide blade ends, but in an appropriate distance an aperture of appropriate length and widthalmost parallel to the side of the blade endis formed, which connects the surfaces of lower and higher pressure. When being operated, the air flowing through this aperture eliminates the turbulence formed at the end of the blades.

With regards to diameter, the choice of the distribution of strings on the airscrew blade (its blade width) caused problems in case of adapting a huge performance, as well as there was a need to form wide blade ends. The losses resulting from the circular flow of the blade ends were, however, increased dramatically.

In case of adapting wide blade ends, the invention uses the phenomenon known from physics as interference, more precisely whirl interference to reduce or eliminate the loss of potential resulting from the circular flow of the blade ends tips on the airscrew.

A whirl of contrary direction and of equal angular momentum (or impulse momentum) is induced at the ends of the airscrew blades, which by this eliminates or significantly reduces the whirls appearing at the end of wide blades and causing losses.

As a result of this, a tractive force evolves on the airscrews and the range of action of the aircraft as well as the time spent on flying can be increased.

Its application is also recommended on wind turbine rotor blades.

If applied, it reduces the resonant vibrations occurring on the blades and the turbines, and thus extending their lifetime significantly. Using aerodynamic braking the forming of the pivoting tip is more effective and less vibrating. The blade edges are working as slotted flaps.

Claims

1. Air screw-, fan-, and wind turbine blades with wide blade tip for use in an axial flow rotor stage, having a body with pressure and suction surfaces on opposite sides of the blade, a span extending between a root and a tip and a chord extending between a leading edge and a trailing edge, characterised in that formed in the end tip of the blade is a notch which extends between the pressure and suction sides, and a channel leading to the notchon the pressure sideformed through the body of the blade between said pressure and suction surfaces, wherein the distance between the end tip of the blade and the notch changes in its diameter from 1.2% to 1.67% along the length of the hole.

2. Air screw-, fan-, and wind turbine blades with wide blade tip as claimed in claim 1 wherein the notchfor ensuring strengthcan be divided to sections with small interruptions.

3. Air screw-, fan-, and wind turbine blades with wide blade tip as claimed in claim 1 or claim 2 wherein the notch forms a radian angle of 0.139623 with the radius.

4. Air screw-, fan-, and wind turbine blades with wide blade tip as claimed in claim 3 wherein the length of the notch is approximately 60% of the length of the tip of the blade.

5. Air screw-, fan-, and wind turbine blades with wide blade tip as claimed in any preceding claim wherein the width of the notch is 3.53% of the length of the notch.

6. Air screw-, fan-, and wind turbine blades with wide blade tip as claimed in any preceding claim wherein the root of the notch is formed near the trailing edge.

Description

2. THE DEVELOPMENT STATE OF THE TECHNOLOGY

[0004] According to the present state of knowledge of declarers no such airscrew, fan, or wind turbine exists in the world and no distributors, manufacturers or investigations are known in this field.

[0005] Similarly to airplane wings only in order to prevent the separation of flowthe forming of turbulent flowan aperture would be applied close to the trailing edge. No practical realisation is known in this respect.