DE4016622A1 - Vane profile for Savonius rotor - has centre of gravity of main profile in front half facing preceding vane - Google Patents

Abstract

Behind the profile end of the main vane profile (1) in the direction of the flow lines (2,3) is a Darieus vane support surface which is asymmetrical. With large profile cross-sections, in the rotation condition in which the inner flow line (2) is turned away from the wind, and the outer flow line (3) is facing the wind, a strong flow difference at the vane end exists in the area (A) in which the pressure drop occurs between outer and inner flow. With three-bladed rotors of the Savonius type, flow division outwards and inwards can be expected in an area (C) adjacent to the blades. The centre of gravity of the main vane profile (1) is located in the front half, i.e. that facing the preceding vane, in the cross-section in relation to its length. USE - As a rotor vane profile functioning in accordance with the Savonius-Darieus and Flettner principles.

Description

The invention relates to a wing profile for a Savo niusrotor, primarily as a vertical rotor for Er generation of electrical and mechanical energy finds.

The invention is an element of Mechanical engineering.

State of the art are usually two or three-leaf winged Savonius rotors, the wing surfaces of which either whether its unstable structure, central in the pivot or strained through it at least diagonally Need to become; or wing profiles with low overall cross section, which are able to self hold, but are not able, currents differences in the wind caused by the profile (e.g. by using a Darieus wing) even with relative to take advantage of low wind speeds. Darieusrotoren, the relatively high wind speeds - high outside diameter - need small Savonius rotors only serve as a starting aid; Darieus rotors because of their high speeds, they are only used to generate electricity related.

Savonius rotor blades, in which the pressure difference on Take appropriate measures to end the blades optimized drive are used, the applicant not known.

The invention has for its object a ma saves material, easy to produce Savonius rotor to develop that is not through or at the pivot must be braced, the optimized running properties  opposite centrally tensioned Savonius rotors (through Resistance reduction of the counter-rotating wind Areas) and the flow pressure gradient of both Wing sides of a single wing when they meet who uses currents.

The basis of the invention is the Savonius-Darieus or the Flettner principle.

In order to do without central bracing, it is the profile cross-section of the individual wings to increase far. This now becomes static justice to torsional moments occurring during operation too with large profile lengths, i.e. Savonius rotor heights to take.

In the case of large profile cross-sections, there is a strong flow difference at the wing end in space (A) between, with the inner flow line ( 2 ) facing away from the wind and the outer flow line ( 3 ) facing the true wind, due to repeated deflection of the braked true inside wind and greatly increased outside wind due to lateral displacement.

The higher the profile, the higher the flow sub divorced; so it is important to have a high profile cross section as possible to create a larger flow difference in room (A).

The other way round, tests in the wind tunnel have to prove what profile height of the single wing the influence of Slipstream of the true wind on the leading Profile has a negative effect and the advantage of a larger profile cross-section with the disadvantage of larger, so faster impact of slipstream on the fore wings are balanced; being three-winged Savonius rotors are an inevitable flow swirl  tion in room (C) is eliminated and the efficiency is reduced elevated.

The focus of the profile must be as close as possible to the rotation point (M) and on the leading wing to reach the End effective flow Ver as long as possible to get crowding; but not the room (B) to disturb.

This flow gradient between the outside and inside flow, which varies because the inside flow line ( 2 ) is exposed from the changing flow direction by rotation of the Savonius rotor, will normally develop a suction, swirl unused behind the flow edge, which we, for example, by attaching an asymmetrical Knowing how to prevent wing ( 4 ) in the border area room (A).

It has to be shown on which profile side the parallel pitch-flow angle adjustments of the asymmetrical Darieus wing (or Flettner rotor) ( 4 a, 5 a) have to be made, because on the inside ( 2 ) the real wind is braked too early when it falls on the back ( 3 ) a too slow braking of the local, displaced flow achieved who can, which, however, their only occasional occurrence in relation to the overall profile length is probably irrelevant.

In the case where the flow line ( 2 ) is inclined to the true wind, the effect of the Darieus wing ( 4 ) will of course decrease, but the wind attack area and the torque triggered, by increasing the effective rotor diameter compared to rotors without Darieus. Wings combined with better stability can be larger, whereby the effect can occur in which the outer - outward flowing "high pressure zone" increases the effective profile length in such a way that weaker true wind flows in opposite directions along the high pressure line (extended 3 line) into the Rotor collapses.

Dynamic lift of the main airfoil ( 1 ) is probably only to be expected with Savonius rotors with two blades, since with three blades a flow separation in the area (C), on the one hand outwards and on the other hand towards the pivot point, is to be expected.

The inner trailing edge ( 7 ) must be as sharp as possible, so as not to cause flow losses due to swirling.

In the case of Savonius rotors with two blades, it can be useful to enable balance weights ( 6 ) on the wing profile ( 1 ) in the manner of a dorsal fin.

It is also for this reason to expect a better running property as compared to an internally braced Savoniusrotoren because the wind surface of the flow line (3) acts streamlined than otherwise related as interior and exterior line line (2) and additionally turbulence at bracing, or - and then nötigem central tube omitted.

The Darieus wing becomes because of the repressed true wind and pressure drop utilization much earlier, i.e. H. at thrust much weaker true winds than pure Darieus rotors despite lower overall through knife of the rotor.  

Features of the invention are:

Great effectiveness through optimized connection of the Savonius with the Darieus or Flettner principle.

Self-supporting, highly efficient single wings, which are light in any length, material, energy-saving, able to withstand all static forces, can be produced.

The wings can, on suitable lattice constructions held, be on support frames or existing towers consolidates, or what seems more meaningful to me, freely given be stretched.

The production can be done in a vacuum process (epoxy, barrier wood, triaxial fabric, carbon, aramid fiber, etc.), or as an endless profile that is only cut to length will be done.

Great safety and variability thanks to strong profiles and the option of braking the rotor of the Savonius rotor by adjusting the setting angle of the Darieus wing or changing the direction of rotation or speed of rotation of the Flettner rotor (e.g. in strong winds); or to optimally adapt the speed of rotation to the intended use (consumer) at any wind speed; or possibility of using the Darieus wing setting ( 5 a) similar to the "Giro Mill Principle" (Just) in stronger winds by uniform adjustment in the rotation process, the buoyancy tips of the Darieus wings to shift against the true wind direction and thus the guy to relieve and support the entire system.

Furthermore, due to the large main wing cross-sections ( 1 ) there is enough space, through an easily realizable pressure drop inside the wings, ( 1 ) boundary layer suction can be realized.

Maintenance is carried out by simple disassembly assembly less stable parts.

Explanation of symbols:

1 : main wing
2 : Inner flow line
3 : Flow outline
4 : Darieus wing
4 a: Variable Darieusflügel approach angle adjustment or bracket
5 : Flettner rotor
5 a: Flettner rotor holder
6 : Weight concentration, worked out as a fin, in relation to the main wing center of gravity for balancing
7 : outflow inner edge (sharp-edged)

Action space

A: Area in which the pressure drop between the outside and inside flow occurs - can be used
B: Area which is subject to changing flow directions, in which optimized shaping of line 3 would otherwise rule out unavoidable turbulence
C: Space in which flow separation (with three-bladed Savonius rotors) is to be expected from inside and outside
M: center point, rotation fulcrum
: Direction of rotation

Claims (4)

1. Wing profile for Savonius rotors, characterized in that the center of gravity of the main profile is in the front, ie facing the leading wing, in cross section of the same in relation to its length. 2. Wing profile for Savonius rotors, characterized in that that behind the profile ends of the main profile in Direction of the flow lines of a Darieus wing support area located. 3. Wing profile for Savonius rotors according to claim 2, there characterized by that it is an asymmetrical Darieus wing acts. 4. Wing profile for Savonius rotors, characterized in that that behind the profile ends of the main profile in A Flettner rotor is located in the direction of the flow lines.