Cross-shaft tidal current energy water turbine with passive pitching adjusting device
Technical Field
The invention belongs to the technical field of a transverse-shaft tidal current energy water turbine, and particularly relates to a transverse-shaft tidal current energy water turbine with a passive pitching adjusting device.
Background
Energy is a necessity of our life and also a strategic resource of national development. Since fossil energy is limited and a large amount of pollution is generated during consumption, it is imperative to develop and utilize various forms of renewable energy.
Tidal current energy is a clean renewable energy source, has the characteristics of large reserves, good predictability and high energy density, and is an ideal resource for replacing fossil energy. The tidal current energy water turbine with the cross shaft is a device utilizing tidal current energy, and can convert the tidal current energy into kinetic energy of the water turbine and further into electric energy.
However, when a cross-axis tidal current energy turbine extracts energy from the tidal current, the efficiency of the turbine is reduced because the direction of the tidal current is not perpendicular to the swept plane of the turbine blades.
Disclosure of Invention
Technical problem to be solved
Aiming at the existing technical problems, the invention provides a transverse-axis tidal current energy water turbine with a passive pitching adjusting device, wherein a sweeping plane of the transverse-axis tidal current energy water turbine is always vertical to the incoming current direction, so that the energy utilization efficiency of tidal current energy is improved.
(II) technical scheme
The invention provides a transverse-axis tidal current energy water turbine with a passive pitch adjusting device, which comprises water turbine blades, a hub, an engine room and the passive pitch adjusting device, wherein the water turbine blades are fixedly connected with a first end of the engine room through the hub;
the passive pitch adjusting device comprises a connecting rod, adjusting blades and a counterweight which is positioned in the adjusting blades and used for adjusting the weight of the passive pitch adjusting device, wherein the first end of the connecting rod is fixedly connected with the second end of the cabin, and the second end of the connecting rod is fixedly connected with the adjusting blades;
the adjusting blade is a closed structure which is composed of a plurality of wing surfaces and used for generating lift force, and the cross-shaft tidal current energy water turbine is kept in a balanced state by changing the structure of the adjusting blade and the weight of a counterweight.
Preferably, the counterweights are uniformly distributed in the adjusting blade.
Preferably, the weight is provided at the center of the adjustment blade.
Preferably, the aircraft further comprises a vertical support and a cabin support, wherein the cabin support is of a concave structure, and the bottom of the concave structure is fixedly connected with the vertical support.
Preferably, the side wall of the nacelle is provided with a nacelle connecting shaft, which is rotatably connected with a nacelle stand by means of a radial bearing.
Preferably, the rotation angle of the rotary connection is-24 to-24 degrees, and the rotation angle is an included angle between the main shaft and the horizontal plane.
Preferably, the wind driven generator further comprises a generator and a transmission mechanism, wherein the generator and the transmission mechanism are arranged inside the engine room and fixedly connected with the hub.
Preferably, the connecting rod is a telescopic connecting rod.
Preferably, the adjusting blade is made of corrosion-resistant materials.
(III) advantageous effects
The invention provides a transverse-shaft tidal current energy water turbine, which is characterized in that a hub, a cabin and a passive pitching adjusting device are sequentially arranged to form a main shaft. The passive pitching adjusting device comprises a cabin connecting shaft, a cabin support, a connecting rod, adjusting blades and a counterweight, the adjusting blades are designed into a closed structure which is formed by a plurality of wing surfaces and used for generating lift force, the counterweight is arranged in the adjusting blades, the passive pitching adjusting device helps the cross-shaft tidal current energy water turbine to adjust the pitching angle of the water turbine according to the incoming flow direction, finally, the passive adjustment of the swept plane of the water turbine blade along with the incoming flow direction is realized, the incoming flow direction is always perpendicular to the swept plane, and therefore the efficiency of the water turbine is improved. Meanwhile, the passive pitching adjusting device is simple in structure and low in installation, maintenance and use cost.
Drawings
Fig. 1 is a schematic structural diagram of a horizontal-axis tidal current energy water turbine provided by the invention;
FIG. 2 is a schematic view of a horizontal axis tidal current energy water turbine and an incoming flow angle provided by the present invention;
fig. 3 is a diagram of the initial state of the horizontal-axis tidal current energy water turbine provided by the invention.
[ description of reference ]
1: a water turbine blade;
2: a hub;
3: a vertical support;
4: a nacelle stand;
5: a radial bearing;
6: a cabin connecting shaft;
7: a nacelle;
8: a connecting rod;
9: adjusting the blades;
i: the incoming flow is parallel to the main shaft;
II: the angle between the incoming flow and the main shaft is negative;
III: the angle between the incoming flow and the main shaft is positive;
l1: the distance from the center of gravity of the hub and the water turbine blade to the cabin connecting shaft;
l2: the distance from the cabin connecting shaft to the gravity centers of the adjusting blades and the counterweight;
mg: adjusting the total weight of the blade and the internal counterweight;
M1g: total weight of turbine blades and hub;
f: the lift force borne by the blades is adjusted.
Detailed Description
For the purpose of better explaining the present invention and to facilitate understanding, the present invention will be described in detail by way of specific embodiments with reference to the accompanying drawings.
As shown in figure 1, the transverse-axis tidal current energy water turbine with the passive pitch adjusting device comprises a generator, water turbine blades 1, a hub 2, a vertical support 3, a cabin support 4, a cabin connecting shaft 6, a cabin 7, a connecting rod 8, adjusting blades 9 and a counterweight. The cabin support 4, the cabin connecting shaft 6, the connecting rod 8, the adjusting blade 9 and the counterweight jointly form a passive pitching adjusting device.
The hub 2, the engine room 7 and the connecting rod 8 are sequentially detachably and fixedly connected, and the axes of the hub 2, the engine room 7 and the connecting rod 8 are on the same horizontal line to form a main shaft of the transverse-shaft tidal current energy water turbine. Preferably, the connecting rod 8 is a telescopic connecting rod, and the length of the connecting rod 8 can be adjusted according to the requirement in practical application.
The blades 1 of the water turbine are uniformly distributed on the side surface of the hub 2 and are detachably and fixedly connected with the hub 2, and the end part of the hub 2 is connected with a generator and a transmission mechanism which are arranged in the engine room 7 and further connected with one end of the engine room 7. The blades 1 of the water turbine, the hub 2, the generator and the transmission mechanism form a rotary energy pumping part of the transverse-axis tidal current energy water turbine. The other end of the nacelle 7 is detachably and fixedly connected with one end of the connecting rod 8. The other end of the connecting rod 8 is detachably and fixedly connected with the adjusting blade 9.
Further, the number of the turbine blades 1 may be selected according to the requirements in actual operation, and the profile geometry parameters related to the turbine blades 1, such as the airfoil shape, the chord length distribution, the twist angle distribution, etc., are not particularly limited in the present invention.
A nacelle connecting shaft 6 is arranged on the side wall of the nacelle 7 and is rotatably connected with the nacelle support 4 through a radial bearing 5. One end of the vertical support 3 is used for being fixedly connected with the seabed, and the other end of the vertical support is used for being fixedly connected with the cabin support 4 in a detachable mode. The nacelle stand 4 is of a concave structure comprising two oppositely arranged side faces and a bottom face integral with the side faces. The bottom surface of the concave structure is detachably and fixedly connected with the vertical bracket 3. Each side face of the concave structure is provided with a slotted hole used for being connected with the cabin connecting shaft 6, and the radial bearing 5 is fixedly connected with the cabin connecting shaft 6 through the slotted hole, so that the cabin support 4 is rotatably connected with the cabin 7, and the cabin 7 can rotate above the cabin support 4 by taking the cabin connecting shaft 6 as a rotating center. The rotating angle is an included angle between the main shaft and the horizontal plane, and the rotating range is-24 degrees to-24 degrees.
Further, the adjusting blade 9 is a closed structure composed of a plurality of airfoils for generating lift. The adjusting blade 9 is internally provided with a counterweight, and the adjusting blade 9 and the counterweight jointly play a role in adjusting the pitching operation of the water turbine. The counterweights can be distributed uniformly in the adjusting blade 9 or can be arranged in the center of the adjusting blade 9.
The magnitude of the lift force F borne by the adjusting blade 9 changes with the angle of attack (included angle between the incoming flow velocity vector and the chord line of the adjusting blade 9) borne by the adjusting blade 9: when the angle of attack is increased, the lift force borne by the adjusting blade 9 is increased; when the angle of attack decreases, the lift experienced by the regulating blade 9 decreases.
As shown in fig. 2, the following conditions should be satisfied during initial installation of the horizontal-axis tidal current energy water turbine provided by the invention: under the condition that the incoming flow speed is a rated speed and the incoming flow direction is parallel to a main shaft (shown as I in figure 2), the main shaft is vertical to the vertical support 3, and the transverse-shaft tidal current energy water turbine satisfies the following relation:
M1g×L1=(Mg–F)×L2 (1)
wherein L1 is the distance from the center of gravity of the hub and the turbine blade to the connecting shaft of the engine room; l2 is the distance from the connecting shaft of the engine room to the gravity center of the adjusting blade and the counterweight; mg is the total weight of the adjusting blade and the counterweight; m1g is the total weight of the blades and the hub of the water turbine; f is the lift force borne by the adjusting blade. The invention is directed to the above-mentioned L1, L2, Mg and M1g is not specifically limited, and can be designed according to actual conditionsAnd (3) making the horizontal-axis tidal current energy water turbine satisfy the balance relation of the formula (1).
Principle of operation
When the cross-shaft tidal current energy water turbine operates, blades of the water turbine need to be over against the incoming flow direction to achieve the optimal working state. As shown in fig. 3, when the incoming flow is parallel to the main shaft (as shown in i in fig. 3), the passive pitch control device does not work, and the horizontal shaft tidal current energy water turbine is in a balanced state.
When the angle between the incoming flow and the main shaft is negative (as shown in fig. 3, ii), the attack angle borne by the adjusting blade 9 is increased, the lift force of the adjusting blade 9 is increased, and at this time, the stress of the transverse-shaft tidal current energy water turbine satisfies the following relationship:
M1g×L1>(Mg–F)×L2 (2)
the stress change of the adjusting blade 9 causes the hub 2, the engine room 7, the connecting rod 8 and the adjusting blade 9 to rotate anticlockwise (in the overlooking direction) around the engine room connecting shaft 6, the position of the adjusting blade 9 is raised, the position of the water turbine blade 1 is lowered, and finally when the stress of the water turbine is balanced again by the tidal current of the transverse shaft, the sweeping plane of the water turbine blade 1 is perpendicular to the current incoming flow.
When the angle between the incoming flow and the main shaft is positive (as shown in fig. 3, iii), the attack angle borne by the adjusting blade 9 is reduced, the lift force borne by the adjusting blade 9 is reduced, and at this time, the stress of the transverse-shaft tidal current energy water turbine satisfies the following relationship:
M1g×L1<(Mg–F)×L2 (3)
the stress change of the adjusting blade 9 causes the hub 2, the engine room 7, the connecting rod 8 and the adjusting blade 9 to rotate clockwise (looking up at the direction) around the engine room connecting shaft 6, the position of the adjusting blade 9 becomes low, the position of the water turbine blade 1 rises, and finally when the stress of the horizontal-axis tidal current energy water turbine is balanced again, the sweeping plane of the water turbine blade 1 is perpendicular to the current incoming flow.
The transverse-shaft tidal current energy water turbine provided by the invention realizes that the swept plane of the water turbine is vertical to the incoming flow direction in the pitching direction by using the passive pitching adjusting device under the condition of not using an additional power mechanism, and the energy utilization efficiency of tidal current energy is improved.
The technical principles of the present invention have been described above in connection with specific embodiments, which are intended to explain the principles of the present invention and should not be construed as limiting the scope of the present invention in any way. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive efforts, which shall fall within the scope of the present invention.