Active type coaxial contra-rotating double-wind-wheel wind turbine with variable axial spacing

Abstract

An active type coaxial contra-rotating double-wind-wheel wind turbine with variable axial spacing comprises a front wind wheel and a rear wind wheel, the front wind wheel and the rear wind wheel are coaxially arranged, and a plurality of front / rear wind wheel blades are evenly distributed on a hub of the front / rear wind wheel; a distance adjusting hydraulic cylinder is connected between the front wind wheel hub and the rear wind wheel hub, and the distance adjusting hydraulic cylinder, the front wind wheel and the rear wind wheel are coaxially arranged; the front wind wheel hub is fixedly connected to the end of a piston rod of the distance adjusting hydraulic cylinder, and the rear wind wheel hub is fixedly connected to the bottom end of a cylinder barrel of the distance adjusting hydraulic cylinder. When the wind turbine is in a starting state, the piston rod of the distance adjusting hydraulic cylinder is in a retraction state, so that the axial distance between the front wind wheel and the rear wind wheel is reduced; when the wind turbine is in a stable operation state, the piston rod of the distance adjusting hydraulic cylinder is in an extending state, so that the axial distance between the front wind wheel and the rear wind wheel is increased; the number of the front wind wheel blades and the number of the rear wind wheel blades are both 2-8. The ratio of the change range of the axial distance between the front wind wheel and the rear wind wheel to the rotating diameter of the front wind wheel blades / the rear wind wheel blades is 0.01%-100%.

Description

Technical Field

[0001] The utility model belongs to the technical field of wind turbines, and particularly relates to an active coaxial counter-rotating double-wind-wheel wind turbine with variable axial spacing. Background Art

[0002] At present, wind energy is leading the global renewable energy market, and the installed capacity of wind turbines continues to grow every year. The coaxial counter-rotating twin-rotor wind turbine is a type of wind turbine.

[0003] The so-called coaxial counter-rotating twin-rotor wind turbine is a wind turbine composed of two twin wind rotors rotating around the same rotation axis and in opposite directions. The air flows toward the wind turbine. The upstream wind rotor of the wind turbine is called the front wind rotor, and the downstream wind rotor is called the rear wind rotor. The front wind rotor and the rear wind rotor can have the same geometric parameters or airfoil shapes, or they can use different geometric parameters or airfoil shapes according to the aerodynamic performance requirements.

[0004] However, since the rear wind wheel in the coaxial counter-rotating twin-rotor wind turbine is completely in the slipstream generated by the front wind wheel, the aerodynamic performance of the rear wind wheel is directly affected by the front wind wheel. At the same time, if the axial spacing between the front wind wheel and the rear wind wheel is small, the aerodynamic performance of the front wind wheel will also be affected by the rear wind wheel.

[0005] The axial spacing between the front and rear wind rotors of a coaxial counter-rotating twin-rotor wind turbine is one of the important parameters that affect its starting performance and aerodynamic performance. In order to explore the influence of the axial spacing on the starting and aerodynamic performance of a twin-rotor wind turbine, the starting performance and aerodynamic performance of different axial spacings of wind rotors are compared by numerical simulation. The study found that the smaller the axial spacing of the coaxial counter-rotating twin-rotor wind turbine, the greater the static torque, and the better the corresponding starting performance; with the increase of the axial spacing, the corresponding maximum power coefficient first increases and then decreases, so the aerodynamic performance is also from good to bad. In order to obtain the axial spacing corresponding to better aerodynamic performance, after a large number of numerical simulation calculations, it is found that when the axial spacing is one times the diameter of the wind rotor, the wind turbine can obtain a larger power coefficient, and thus obtain better aerodynamic performance.

[0006] At present, the axial spacing of existing coaxial counter-rotating twin-rotor wind turbines is fixed, so that the existing coaxial counter-rotating twin-rotor wind turbines can only have the best performance in a single state, but cannot match the axial spacing that can achieve the best starting performance and aerodynamic performance according to the incoming wind speed. Utility Model Content

[0007] In view of the problems existing in the prior art, the utility model provides a coaxial counter-rotating twin-rotor wind turbine with an active variable axial spacing, which can actively change the axial spacing between the front and rear wind wheels according to the starting and stable operation conditions; when the wind turbine is started, the wind turbine requires a larger starting torque, and the axial spacing between the front and rear wind wheels can be actively adjusted to become smaller, thereby further increasing the starting torque of the wind turbine, which is more conducive to the starting of the wind turbine; when the wind turbine reaches a stable operation state, the torque of the wind turbine is reduced, and the axial spacing between the front and rear wind wheels can be actively adjusted to increase, so that the aerodynamic efficiency of the wind turbine is higher, thereby improving the economy of the wind turbine.

[0008] In order to achieve the above-mentioned purpose, the utility model adopts the following technical scheme: an active coaxial counter-rotating twin-rotor wind turbine with variable axial spacing, comprising a front wind wheel and a rear wind wheel, the front wind wheel and the rear wind wheel are coaxially arranged, a plurality of front wind wheel blades are evenly arranged on the front wind wheel hub, and a plurality of rear wind wheel blades are evenly arranged on the rear wind wheel hub; a pitch-adjusting hydraulic cylinder is connected between the front wind wheel hub and the rear wind wheel hub, the pitch-adjusting hydraulic cylinder is coaxially arranged with the front wind wheel and the rear wind wheel; the front wind wheel hub is fixedly connected to the end of the piston rod of the pitch-adjusting hydraulic cylinder, and the rear wind wheel hub is fixedly connected to the bottom end of the cylinder barrel of the pitch-adjusting hydraulic cylinder.

[0009] When the wind turbine is in the starting state, the piston rod of the pitch-adjusting hydraulic cylinder is in the retracted state, so that the axial distance between the front wind wheel and the rear wind wheel is reduced.

[0010] When the wind turbine is in a stable operating state, the piston rod of the pitch-adjusting hydraulic cylinder is in an extended state, so that the axial distance between the front wind wheel and the rear wind wheel is increased.

[0011] The number of the front wind wheel blades and the number of the rear wind wheel blades are both 2 to 8.

[0012] The ratio of the axial spacing variation range between the front wind wheel and the rear wind wheel to the rotation diameter of the front wind wheel blades / rear wind wheel blades is 0.01% to 100%.

[0013] Beneficial effects of the utility model:

[0014] The coaxial counter-rotating twin-rotor wind turbine with active variable axial spacing of the utility model can actively change the axial spacing between the front wind wheel and the rear wind wheel according to the starting and stable operation conditions; when the wind turbine is started, the wind turbine requires a larger starting torque, and the axial spacing between the front wind wheel and the rear wind wheel can be actively adjusted to become smaller, thereby further increasing the starting torque of the wind turbine, which is more conducive to the starting of the wind turbine; when the wind turbine reaches a stable operation state, the torque of the wind turbine decreases, and the axial spacing between the front wind wheel and the rear wind wheel can be actively adjusted to increase, so that the aerodynamic efficiency of the wind turbine is higher, thereby improving the economy of the wind turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a structural schematic diagram of an active variable axial spacing coaxial counter-rotating twin-rotor wind turbine of the utility model (viewing angle 1);

[0016] Figure 2 This is a structural schematic diagram of the active variable axial spacing coaxial counter-rotating twin-rotor wind turbine of the utility model (viewing angle 2);

[0017] In the figure, 1 is the front wind wheel hub, 2 is the front wind wheel blade, 3 is the rear wind wheel hub, 4 is the rear wind wheel blade, 5 is the pitch adjustment hydraulic cylinder, DETAILED DESCRIPTION

[0018] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0019] like Figure 1 , 2 As shown, an active coaxial counter-rotating twin-rotor wind turbine with variable axial spacing includes a front wind wheel and a rear wind wheel, the front wind wheel and the rear wind wheel are coaxially arranged, a plurality of front wind wheel blades 2 are evenly arranged on the front wind wheel hub 1, and a plurality of rear wind wheel blades 4 are evenly arranged on the rear wind wheel hub 3; a pitch-adjusting hydraulic cylinder 5 is connected between the front wind wheel hub 1 and the rear wind wheel hub 3, and the pitch-adjusting hydraulic cylinder 5 is coaxially arranged with the front wind wheel and the rear wind wheel; the front wind wheel hub 1 is fixedly connected to the end of the piston rod of the pitch-adjusting hydraulic cylinder 5, and the rear wind wheel hub 3 is fixedly connected to the bottom end of the cylinder barrel of the pitch-adjusting hydraulic cylinder 5.

[0020] When the wind turbine is in the starting state, the piston rod of the pitch-adjusting hydraulic cylinder 5 is in the retracted state, so that the axial distance between the front wind wheel and the rear wind wheel is reduced.

[0021] When the wind turbine is in a stable operating state, the piston rod of the pitch-adjusting hydraulic cylinder 5 is in an extended state, so that the axial distance between the front wind wheel and the rear wind wheel is increased.

[0022] The number of the front wind wheel blades and the number of the rear wind wheel blades are both 3.

[0023] The ratio of the variation range of the axial spacing between the front wind wheel and the rear wind wheel to the rotation diameter of the front wind wheel blades / rear wind wheel blades is 50%.

[0024] When the wind turbine adopts the coaxial counter-rotating twin-rotor wind turbine of the utility model, when the wind turbine is started, the front wind wheel and the rear wind wheel are both in the maximum torque state. At this time, the piston rod of the pitch-adjustable hydraulic cylinder 5 is controlled to retract inward to reduce the axial distance between the front wind wheel and the rear wind wheel. As the axial distance between the front wind wheel and the rear wind wheel decreases, the torque of the front wind wheel and the rear wind wheel will be further increased. Although the aerodynamic efficiency of the wind turbine will be reduced at this time, it is beneficial to the starting of the wind turbine. When the wind turbine is in a stable operating state, the torque of the front wind wheel and the rear wind wheel will decrease, and the piston rod of the pitch-adjustable hydraulic cylinder 5 will be controlled to extend outward to increase the axial distance between the front wind wheel and the rear wind wheel. At this time, the aerodynamic efficiency of the wind turbine is higher, thereby improving the economy of the wind turbine.

[0025] The solutions in the embodiments are not intended to limit the protection scope of the present utility model. All equivalent implementations or changes that do not deviate from the protection scope of the present utility model are included in the protection scope of the present utility model.

Claims

1. An active variable axial spacing coaxial counter-rotating twin-rotor wind turbine, characterized in that: It comprises a front wind wheel and a rear wind wheel, which are coaxially arranged with the front wind wheel, a plurality of front wind wheel blades are evenly arranged on the front wind wheel hub, and a plurality of rear wind wheel blades are evenly arranged on the rear wind wheel hub; a pitch-adjusting hydraulic cylinder is connected between the front wind wheel hub and the rear wind wheel hub, and the pitch-adjusting hydraulic cylinder is coaxially arranged with the front wind wheel and the rear wind wheel; the front wind wheel hub is fixedly connected to the end of the piston rod of the pitch-adjusting hydraulic cylinder, and the rear wind wheel hub is fixedly connected to the bottom end of the cylinder barrel of the pitch-adjusting hydraulic cylinder.

2. The active variable axial spacing coaxial counter-rotating twin-rotor wind turbine according to claim 1 is characterized in that: When the wind turbine is in the starting state, the piston rod of the pitch-adjusting hydraulic cylinder is in the retracted state, so that the axial distance between the front wind wheel and the rear wind wheel is reduced.

3. The active variable axial spacing coaxial counter-rotating twin-rotor wind turbine according to claim 1, characterized in that: When the wind turbine is in a stable operating state, the piston rod of the pitch-adjusting hydraulic cylinder is in an extended state, so that the axial distance between the front wind wheel and the rear wind wheel is increased.

4. The active variable axial spacing coaxial counter-rotating twin-rotor wind turbine according to claim 1 is characterized in that: The number of the front wind wheel blades and the number of the rear wind wheel blades are both 2 to 8.

5. The active variable axial spacing coaxial counter-rotating twin-rotor wind turbine according to claim 1, characterized in that: The ratio of the axial spacing variation range between the front wind wheel and the rear wind wheel to the rotation diameter of the front wind wheel blades / rear wind wheel blades is 0.01% to 100%.

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