CN1318756C - Lift force, resistance combined vertical axis wind mill - Google Patents

Abstract

The utility model relates to a combined lift and drag vertical axis wind turbine, which is used in the technical field of wind power generation equipment. Including: deflector, frame, rotor fixing disc, blades, deflector. Rotor fixed disk, blades and deflectors constitute the rotor. The blades are vertically arranged on the rotor fixed disk. The center of the deflector coincides with the rotation axis of the rotor. The setting direction of the deflector is consistent with the chord direction of the blade. The rotor and The deflector is fixed on the frame. In the present invention, when the included angle between the blade and the incoming flow is small, the blade is subjected to the lift force of the airflow acting on the blade; when the included angle between the blade and the incoming flow is large, the blade is subjected to the resistance of the airflow acting on the blade. In this way, the blades in the downwind position can make full use of wind energy. For the blades in the upwind position, the air flow acts on the blades in the opposite direction, which can also drive the rotor to rotate, thus greatly improving the efficiency of the wind rotor.

Description

Combined lift and drag vertical axis wind turbine

technical field

The invention relates to a vertical axis wind turbine, in particular to a combined lift and resistance vertical axis wind turbine, which is used in the technical field of wind power generation equipment.

technical background

As an inexhaustible new energy source, wind energy has good application prospects and development potential. my country's wind energy resources are relatively rich, and vigorously developing wind power is in line with the requirements of my country's sustainable development strategy. Wind turbine is the main device for wind energy utilization. Existing wind generators are mainly horizontal-axis high-speed wind rotors. Its main disadvantage is that it needs to have a high starting wind speed, and it is necessary to adjust the direction of the wind rotor according to the change of the wind direction. Vertical axis wind turbines do not need to adjust the orientation of the rotor.

According to the retrieval of prior art documents, it is found that there are currently two types of vertical axis wind turbines: lift wind turbines and drag wind turbines. David A Spear, PHD, "Wind Turbine Technology Fundamental Conception Of Wind Turbine Engineering", edited by New York ASME (The American Society of Mechanical Engineers) PRESS 1994 (New York American Society of Mechanical Engineers Press 1994), the second chapter (49, 58, 60 pages) and the third chapter (93, 94 pages) of the book mentioned: the lift type wind turbine uses the lift force of the air flow on the blades to drive the wind wheel to rotate, and needs a Relatively large starting wind speed. The resistance type wind turbine uses the resistance of the airflow to the blades to drive the wind rotor to rotate, and does not require a large starting wind speed, so it can also be used in areas with low average wind speeds. However, when the angle between the blade and the wind speed direction is relatively small, the blade basically cannot obtain the power to drive the wind wheel to rotate. The combined lift and drag vertical axis wind turbine can make full use of the lift and drag of the incoming air on the blades, so the efficiency of the wind rotor can be greatly improved. In further searches, no literature reports on combined lift and drag vertical axis wind turbines have been found.

Contents of the invention

The purpose of the present invention is to improve the deficiencies of the existing vertical axis wind turbines and provide a combined lift and drag vertical axis wind turbine so as to reduce the requirements of the vertical axis wind turbine for the working wind speed and improve the working efficiency of the vertical axis wind turbine .

The present invention is realized through the following technical solutions, including: a flow guide device, a frame, a rotor fixing disk, blades, and a flow guide plate. Rotor fixed disc, blades and deflectors constitute the rotor. The blades are vertically arranged on the rotor fixed disc. The center of the deflector coincides with the rotation axis of the rotor. The setting direction of the deflector is consistent with the chord direction of the blade. The rotor and The deflector is fixed on the frame.

Each rotor consists of two blades, which are parallel and vertically fixed on the rotor fixed disc, and the blades are symmetrically placed on both sides of the rotor shaft, which can increase the time for the airflow to do positive work on the blades per unit time. The blades are made of high strength and high density. For small materials, the height of the blade is 3~4 times of its chord length, and the blade offset distance is much smaller than the chord length of the blade, and a deflector parallel to the blade chord line is installed at the rotating shaft. In order to prevent the airflow acting on the blades through the deflector and the airflow directly acting on the blades without the deflector at the rear end of the two blades, that is, at the rotating shaft, so as not to interfere with each other and reduce the working efficiency of the wind wheel, the two blades are placed staggered, and Install deflectors. In this way, the mutual interference of the airflow passing through the two blades can be reduced, the output power of the wind wheel can be increased, and the efficiency of the wind wheel can be improved.

When the direction of rotation of the blades is opposite to the wind speed, the force of the airflow acting on the blades is the force that prevents the rotor from rotating. In order to avoid this situation, the present invention uses a guide device, which is a casing with an air inlet and two air outlets. The height of the guide device is the same as that of the blade, and its width is slightly greater than the chord length of the blade. In this way, the airflow at the upwind position can all enter the deflector. The inner cavity of the flow guiding device is similar to C-type, and its airflow inlet is in the same direction as the airflow outlet, so that the airflow in the upwind position can reversely act on the blades. The shapes of the airflow inlet and the airflow outlet are rectangles with the same height as the vane and different widths. And the width of the airflow inlet is greater than the width of the airflow outlet. In order to make this part of the airflow acting on the blades flow out of the wind wheel, a second airflow outlet is added near the airflow inlet. The second airflow outlets are two cylindrical passages, the diameter of which is roughly half the chord length of the blade. In order to allow the airflow to flow out of the wind wheel from the columnar channel, a baffle is installed outside the flow guiding device before the outlet of the columnar channel. The baffle is on the same plane as the air inlet.

In order to ensure that the airflow in the upwind position does not directly act on the blades so as to generate a torque that hinders the rotation of the rotor, the airflow inlet of the flow guiding device should always face the local wind direction. Considering the instantaneous variability of the wind direction, it is only necessary to ensure that the angle between the direction of the airflow inlet of the deflector and the local wind direction is within plus or minus 5°. But because the wind direction varies widely throughout the year, the deflector installed on the frame is designed to be a deflector that can rotate around the rotor shaft.

When the angle of attack between the incoming air and the blades is small, the rotor makes full use of the lift force of the air on the blades to drive the rotor. When the angle of attack between the incoming air and the blades is large, the rotor uses the resistance of the air to the blades to drive the rotor, so that the blades at different positions can fully utilize the energy of the incoming air. When the blade is in the upwind position, the air exerts a force on the blade to prevent the rotor from rotating. A flow guide device is installed so that the airflow in the upwind position passes through the flow guide device and then acts on the blade in the opposite direction. After the airflow enters the airflow guide device from the airflow inlet, it flows out of the airflow guide device from the airflow outlet along the reverse direction of the box body. This part of the airflow acts on the blades at the upwind position, and then is discharged from the second airflow outlet of the airflow guide device. The rotor converts wind energy into mechanical energy, and the invention uses two rotors deflected by 90 degrees to balance the negative torque that may occur when the wind wheel is running.

In the wind turbine of the present invention, when the angle between the blade and the incoming flow is small, the blade is subjected to the lift force of the airflow acting on the blade; when the angle between the blade and the incoming flow is large, the blade is subjected to the resistance of the airflow acting on the blade. In this way, the blades in the downwind position can make full use of wind energy. For the blades in the upwind position, the air flow acts on the blades in the opposite direction, which can also drive the rotor to rotate, thus greatly improving the efficiency of the wind wheel.

Description of drawings

Figure 1 is a schematic diagram of the overall structure of the present invention.

In Fig. 1, 1-guiding device, 2-frame, 3-rotor fixed disc, 4-blade, 5-baffle.

Fig. 2 is a schematic diagram of relative positions of blades and deflectors in the rotor.

Fig. 3 is a schematic diagram of the structure of the flow guiding device.

In Fig. 3, 7-airflow inlet, 8-airflow outlet 2, 9-airflow outlet 1, 10-baffle.

Fig. 4 is a schematic top view structural diagram of the flow guiding device.

Detailed ways

As shown in Figure 1, the present invention comprises: deflector 1, frame 2, rotor fixed disk 3, blade 4, deflector 5, rotor fixed disk 3, blade 4, deflector 5 form rotor, blade 4 Vertically arranged on the rotor fixed disk 3, the center of the deflector 5 coincides with the rotation axis of the rotor, the installation direction of the deflector 5 is consistent with the direction of the chord line of the blade 4, and the rotor and the deflector 1 are fixed on the frame 2 superior.

Each rotor includes two blades, which are parallel and vertically fixed on the rotor fixed disc 3, and are symmetrical to the rotor shaft. The blade 4 is made of a material with high strength and low density, and its height is 3 to 4 times the chord length, and the offset distance between the two blades 4 is much smaller than the chord length of the blade 4 . A deflector 5 parallel to the chord line of the blade 4 is arranged at the rotating shaft.

The flow guiding device 1 is a casing with an airflow inlet 7 and two airflow outlets 8, 9, the width of the flow guiding device, and the second airflow outlet 8 is two cylindrical passages, and its diameter is half of the chord length of the blades. In order to allow the airflow to flow out of the wind wheel from the cylindrical channel, a baffle 10 is installed on the outside of the deflector 1 before the second airflow outlet 8, and the baffle 10 is on the same plane as the airflow inlet 7.

Examples of devices of the present invention are provided below:

In this embodiment, blade chord length: 1=a, blade height: H=3~4a, deflector length: _1d =0.5a, fixed disk diameter: D=2.2a, fixed disk thickness: 1, =0.1~0.2a.

In order not to make the two incoming flows interfere with each other at the rear end of the blades and reduce the performance of the wind rotor, the two blades are offset from each other by a certain distance (horizontal offset e=0.2a, vertical offset d=0.35a). And use deflectors, as shown in Figure 2.

In order to balance the negative torque situation that occurs during rotation, the wind wheel uses two rotors that are deflected by 90° relative to each other.

According to the difference of the local average wind speed, the value of the chord length a of the blade also changes accordingly. The greater the local wind speed, the greater the value of the blade chord length a (m). Assuming that the local average wind speed is v (m/s), then the relationship between the chord length a and v is roughly as follows: a=0.8~1.2v.

The flow guiding device is another important part in this design, and its structure is shown in Figure 3. The airflow at the upwind position enters the airflow inlet 7 in the flow guiding device 1 and flows out from the first airflow outlet 9 , and this part of the airflow flows out from the second airflow outlet 8 after acting on the blades.

Wherein the height of the guide device is the same as that of the blades, and the width of the airflow inlet 7 is 4/5 of the radius of the rotor. The width of the first air outlet 9 is 2/5 of the radius of the rotor. The angle β between the air inlet 7 and the normal line of the first air outlet 9 is 15°-20°. The inside of the flow guiding device 1 is smooth, so as to minimize the resistance of the air along the inside. The second air outlet 8 is two cylindrical pipes, the diameter of which is 1/2 of the radius of the rotor. The distance between the centers of the two pipes is 1/2 of the height H of the flow guiding device 1 . The distance between the center of the low position pipeline and the bottom of the flow guiding device 1 is 1/4 of H. The included angle between the normals of the pipeline centerline (that is, the second air outlet 8 and the air inlet 7) is γ=45°～50°

Claims (5)

1. A combined lift and drag vertical axis wind turbine, comprising: a frame (2), a fixed rotor disc (3), and blades (4), characterized in that it also includes: a flow guide device (1) and a guide Flow plate (5), rotor fixed disc (3), blades (4), and deflector (5) form the rotor, and the deflector (1) rotates around the rotor shaft, and blades (4) are vertically arranged on the rotor fixed disc (3), the center of the deflector (5) coincides with the rotation axis of the rotor, the installation direction of the deflector (5) is consistent with the direction of the chord line of the blade (4), and the rotor and the deflector (1) are fixed on the machine on the frame (2); the deflector (1) is a box body provided with an air inlet (7) and first and second air outlets (9, 8), its height is the same as that of the blade (4), and its width is slightly larger than Blade (4) chord length, inner chamber is similar to C type, airflow inlet (7) and the first airflow outlet (9) are in the same direction, and the shape of airflow inlet (7) and first airflow outlet (9) is height and blade ( 4) Rectangular with the same height, and the width of the airflow inlet (7) is greater than the width of the first airflow outlet (9), and the second airflow outlet (8) is two cylindrical passages, and its diameter is the blade (4) chord length half. 2. The combined lift and drag vertical axis wind turbine according to claim 1, characterized in that each rotor includes two blades (4), the height of which is 3 to 4 times the chord length, and the two blades (4) are parallel, Vertically fixed on the rotor fixed disk (3), and symmetrically arranged on the rotor shaft, the offset distance is much smaller than the chord length of the blade (4), and a deflector parallel to the chord line of the blade (4) is set at the shaft (5), or the two blades (4) are staggered, and the deflector (5) is installed. 3. The combined lift and drag vertical axis wind turbine according to claim 1, characterized in that, a baffle (10) is arranged outside the flow guiding device (1) before the second air outlet (8), and the baffle (10 ) is on the same plane as the air inlet (7). 4. The combined lift and drag vertical axis wind turbine according to claim 1, characterized in that the angle between the airflow inlet (7) and the local wind direction is within plus or minus 5°. 5. The combined lift and drag vertical axis wind turbine according to claim 1, characterized in that the included angle between the airflow inlet (7) of the flow guiding device and the normal line of the first airflow outlet (9) is β=15°～ 20°, the angle γ between the center line of the two cylindrical passages and the normal line of the air inlet (7) = 45° to 50°, the width of the air inlet (7) is 4/5 of the radius of the rotor, the first air flow The width of the outlet (9) is 2/5 of the radius of the rotor, and the diameter of the second air outlet (8) is 1/2 of the radius of the rotor.

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