阅读说明：本技术 一种涡激振动俘能器 (Vortex-induced vibration energy harvester ) 是由 张忠华 林仕杰 毛燕飞 陈贤卿 黄芳胜 吴亚奇 曾平 于 2019-05-18 设计创作，主要内容包括：本发明涉及一种涡激振动俘能器,属新能源技术领域。支架挡板上下两端设有内壁带滑道的上下梁,下梁的滑道内装有定磁铁；耦合器的钝体外壁上设有耳板,钝体为空心的圆柱或长方形壳体；两个销轴的两端都套有轴套,轴套安装在上梁或下梁的滑道内,销轴中间段设窄缝；簧片的一端固定在耦合器的耳板上、另一端经两个销轴的窄缝穿过后再与两销轴分别固定,耦合器靠近挡板安装；两个限形架的压板固定在一起且其间压接有两个由基板和压电片粘接而成压电振子和一个弹性梁,限形架的压板安装在钝体的顶壁上,悬臂结构的压电振子和弹性梁置于钝体内部,弹性梁自由端装有动磁铁和质量块,动定磁铁相吸；限形架的压板两端都设有带限形面的限形块。(The invention relates to a vortex-induced vibration energy harvester, and belongs to the technical field of new energy. The upper end and the lower end of the bracket baffle are provided with an upper beam and a lower beam with inner walls provided with slideways, and fixed magnets are arranged in the slideways of the lower beams; the outer wall of the blunt body of the coupler is provided with an ear plate, and the blunt body is a hollow cylindrical or rectangular shell; the two ends of the two pin shafts are sleeved with shaft sleeves, the shaft sleeves are arranged in the slide ways of the upper beam or the lower beam, and the middle sections of the pin shafts are provided with narrow slits; one end of the reed is fixed on an ear plate of the coupler, the other end of the reed is fixed with the two pin shafts after passing through a narrow slit of the two pin shafts, and the coupler is arranged close to the baffle; the pressing plates of the two limiting frames are fixed together, two piezoelectric vibrators and an elastic beam which are formed by bonding a substrate and a piezoelectric sheet are pressed between the two limiting frames, the pressing plates of the limiting frames are arranged on the top wall of the blunt body, the piezoelectric vibrators and the elastic beam of the cantilever structure are arranged in the blunt body, the free end of the elastic beam is provided with a movable magnet and a mass block, and the movable magnet and the fixed magnet are attracted; and two ends of the pressure plate of the limiting frame are provided with limiting blocks with limiting surfaces.)

1. A vortex-induced vibration energy harvester is characterized in that: the upper end and the lower end of a baffle of the bracket are symmetrically provided with an upper beam and a lower beam which are parallel to each other, the upper beam and the lower beam are vertical to the baffle, the inner walls of the upper beam and the lower beam are provided with slideways, two ends of the lower beam are provided with support legs, and the slideways of the lower beam are internally provided with fixed magnets; the outer wall of the blunt body of the coupler is provided with an ear plate, and the blunt body is a hollow cylindrical or rectangular shell; the two ends of the two pin shafts are sleeved with shaft sleeves, the shaft sleeves are arranged in the slide ways of the upper beam or the lower beam, and the middle sections of the pin shafts are provided with narrow slits; one end of the reed is fixed on an ear plate of the coupler, the other end of the reed is respectively fixed with the two pin shafts after passing through a narrow slit of the two pin shafts, and the coupler is arranged close to the baffle; the pressing plates of the two limiting frames are fixed together, two piezoelectric vibrators and an elastic beam are pressed between the two limiting frames, the pressing plates of the limiting frames are installed on the top wall of the blunt body, and the piezoelectric vibrators and the elastic beam are arranged in the blunt body; the piezoelectric vibrator is formed by bonding a substrate and a piezoelectric sheet, the substrate is arranged close to the elastic beam, the piezoelectric vibrator and the elastic beam are of cantilever structures, both sides of the free end of the elastic beam are provided with a movable magnet and a mass block, and the opposite magnetic poles of the movable magnet and the fixed magnet are oppositely arranged; limiting blocks with limiting surfaces are arranged at two ends of a pressing plate of the limiting frame, the limiting surfaces are arc surfaces, and the limiting surfaces are tangent to the surfaces, which are contacted with the piezoelectric vibrators, of the pressing plate; the distance between the two limiting blocks on the same limiting frame is wider than that of the piezoelectric sheet and narrower than that of the substrate, and the substrate at the fixed end of the piezoelectric vibrator is in contact with the limiting surface; when the piezoelectric vibrator does not work, the reed, the elastic beam and the piezoelectric vibrator are in a natural state without deformation; the width ratio and the spacing ratio of the baffle are respectively in the ranges of lambda H/D1-3 and delta L/D0-3, wherein: d is the external diameter when the bluff body is the cylinder or the width in reed thickness direction when the cuboid, H is the width of baffle in reed thickness direction, L is the shortest distance between bluff body and the adjacent surface of baffle.

Technical Field

The invention belongs to the technical field of new energy, and particularly relates to a vortex-induced vibration energy harvester which is used for constructing a self-powered river monitoring system.

Background

There are thousands of rivers in China. In recent years, due to the reasons of insufficient treatment of industrial waste water and sewage, water and soil loss, improper use of pesticides, chemical fertilizers and the like, a part of rivers have a certain pollution problem, and the requirements of resident life and farmland irrigation cannot be met. In addition, because the flood control facilities of small and medium rivers in some areas are imperfect at present and lack of related flood control facilities, the danger of bank breaking or bank overflowing exists when the flood season comes, and the safety of lives and properties of people along the bank is threatened directly. Therefore, river monitoring has received high attention from relevant national departments; meanwhile, domestic experts and scholars also put forward corresponding monitoring methods and means in succession, including a water quality monitoring technology aiming at river water pollution, monitoring technologies aiming at rainfall, water level, river water flow speed and the like of natural disasters such as flood control, debris flow and the like, and various micro energy harvesters for supplying power to a monitoring system, but the existing micro energy harvesters have certain problems in the aspects of reliability, flow speed adaptability and the like, and the popularization and application of the micro energy harvesters are seriously hindered.

Disclosure of Invention

The invention provides a vortex-induced vibration energy harvester, which adopts the following implementation scheme: the upper end and the lower end of a baffle of the bracket are symmetrically provided with an upper beam and a lower beam which are parallel to each other, the upper beam and the lower beam are vertical to the baffle, the inner walls of the upper beam and the lower beam are provided with slideways, two ends of the lower beam are provided with support legs, and the slideways of the lower beam are internally provided with fixed magnets through screws; the outer wall of the blunt body of the coupler is provided with an ear plate, and the blunt body is a hollow cylindrical or rectangular shell; the two ends of the two pin shafts are sleeved with shaft sleeves, the shaft sleeves are installed in the slide ways of the upper beam or the lower beam through screws, a narrow slit is arranged at the axis of the middle section of each pin shaft, and the axis of each pin shaft is positioned in the symmetrical center plane of the narrow slit; one end of the reed is fixed on an ear plate of the coupler through a screw, the other end of the reed is fixed with the two pin shafts through screws after passing through narrow slits of the two pin shafts, and the coupler is arranged close to the baffle; the pressing plates of the two limiting frames are fixed together through screws, two piezoelectric vibrators and an elastic beam are pressed between the pressing plates of the two limiting frames, the pressing plates of the limiting frames are installed on the top wall of the blunt body through screws, and the piezoelectric vibrators and the elastic beam are arranged in the blunt body; the piezoelectric vibrator is formed by bonding a substrate and a piezoelectric sheet, the substrate is arranged close to an elastic beam, the piezoelectric vibrator and the elastic beam are of cantilever structures, both sides of the free end of the elastic beam are provided with a movable magnet and a mass block through screws, and the opposite magnetic poles of the movable magnet and the fixed magnet are oppositely arranged; the two ends of a pressure plate of the limiting frame are provided with limiting blocks, limiting surfaces are arranged on the limiting blocks, the limiting surfaces are arc surfaces, and the limiting surfaces are tangent to the surfaces, which are contacted with the piezoelectric vibrators, of the pressure plate; the distance between the two limiting blocks on the same limiting frame is wider than that of the piezoelectric sheet and narrower than that of the substrate, and the substrate at the fixed end of the piezoelectric vibrator is in contact with the limiting surface; when the piezoelectric vibrator does not work, the reed, the elastic beam and the piezoelectric vibrator are in a natural state without deformation; the width ratio and the spacing ratio of the baffle are respectively in the ranges of lambda H/D1-3 and delta L/D0-3, wherein: d is the external diameter when the bluff body is the cylinder or the width in reed thickness direction when the cuboid, H is the width of baffle in reed thickness direction, L is the shortest distance between bluff body and the adjacent surface of baffle.

In the invention, water flows from the blunt body to the baffle, the water flows through the blunt body to generate a Karman vortex street, and the alternating generation and falling of the vortex can lead the water pressure on the front side and the rear side of the blunt body to be changed alternately, thereby generating an exciting force which can lead the coupler to swing back and forth; in the swinging process of the coupler, the elastic beam generates reciprocating bending deformation under the action of inertia force of a mass block at the free end of the elastic beam and attraction force between the movable magnets and the fixed magnets and forces the piezoelectric vibrator to bend and deform in a direction that the piezoelectric sheet bears pressure stress, namely water flow energy is converted into electric energy in the reciprocating bending deformation process of the piezoelectric vibrator; when water flow is blocked by the baffle after passing through the blunt body, the flow direction, the vortex form and the dynamic characteristic are changed, so that the amplitude of the exciting force is changed, and the vibration amplitude is increased or reduced; when the blunt body swings and the amplitude of the elastic beam reaches a rated value, the elastic beam presses the substrate of the piezoelectric vibrator against the limiting surface, and the pressure stress of each point in the length direction of the piezoelectric sheet is equal and smaller than the allowable value, so that the piezoelectric vibrator has higher power generation capacity and higher reliability.

In the invention, the distance between the two pin shafts can be adjusted by adjusting the positions of the shaft sleeves at the two ends of the pin shaft, and the distance between the baffle and the bluff body can be adjusted by adjusting the mounting position of the baffle, so that the bending rigidity and the cantilever length of the reed can be changed by changing the distance between the two pin shafts, and the fundamental frequency of a vibration system formed by the bluff body and the reed and the amplitude of the bluff body are changed, so that the fundamental frequency of the energy harvester is adapted to the vortex-induced vibration frequency, and resonance is realized; the distance between the baffle and the outer surface of the blunt body can be changed to adjust the spacing ratio, so that the effective control of the amplitude of the blunt body is realized, even if the amplitude is increased or decreased.

In the invention, the thickness of the substrate is equal to that of the piezoelectric sheet, and the radius of the limiting surface isThe allowable deformation of the free end of the piezoelectric vibrator when the shape limiting surface is not used is

Wherein l is the cantilever length of the piezoelectric vibrator, H is the total thickness of the piezoelectric vibrator, β ═ E_m/E_p，E_mAnd E_pThe modulus of elasticity, T, of the substrate and piezoelectric sheet material, respectively_pAnd k₃₁Respectively, the allowable stress and the electromechanical coupling coefficient of the piezoelectric sheet material.

The energy harvester has the advantages and characteristics that ① is easy to change the natural frequency of the energy harvester through the rigidity adjustment of the reed, so that the natural frequency of the energy harvester is adaptive to the vortex-induced vibration frequency, the response characteristic and the power generation capacity are improved, the baffle plate arranged behind the ② blunt body can effectively adjust the coupling vibration response characteristic of the blunt body, the required vibration amplification ratio, the flow rate adaptability and the power generation capacity of the blunt body can be easily obtained through adjusting the distance, the scale and other parameters of the blunt body, the ③ piezoelectric vibrator is not in contact with water flow, and is only subjected to controllable unidirectional bending deformation, so that the stress distribution is uniform, and the power generation capacity and the.

Drawings

FIG. 1 is a schematic diagram of an energy harvester according to a preferred embodiment of the invention;

FIG. 2 is a top view of FIG. 1;

FIG. 3 is a cross-sectional view A-A of FIG. 1;

FIG. 4 is a schematic structural view of a bracket according to a preferred embodiment of the present invention;

FIG. 5 is a schematic view of a retainer according to a preferred embodiment of the present invention;

fig. 6 is a right side view of fig. 5.

Detailed Description

An upper beam a1 and a lower beam a2 are respectively arranged at the upper end and the lower end of a baffle a3 of the bracket a, the upper beam a1 and the lower beam a2 are parallel and symmetrically arranged at the upper side and the lower side of a baffle a3, the upper beam a1 and the lower beam a2 are perpendicular to the baffle a3, slide ways a4 are respectively arranged on the inner walls of an upper beam a1 and the lower beam a2, supporting legs a5 are arranged at the two ends of the lower beam a2, and a fixed magnet f is arranged in the slide way a4 of the lower beam a2 through screws; an ear plate d2 is arranged on the outer wall of a blunt body d1 of the coupler d, and the blunt body d1 is a hollow cylindrical or rectangular shell; two ends of two pin shafts b are sleeved with shaft sleeves e, the shaft sleeves e are arranged in the slide ways a4 of the upper beam a1 or the lower beam a2 through screws, a narrow slit is arranged at the axis of the middle section of each pin shaft b, and the axis of each pin shaft b is positioned in the symmetrical center plane of the narrow slit; one end of the reed c is fixed on an ear plate d2 of the coupler d through a screw, the other end of the reed c penetrates through a narrow slit b1 of two pin shafts b and then is fixed with the two pin shafts b through the screw, and the coupler d is installed close to the baffle a 3; the pressing plates g1 of the two limiting frames g are fixed together through screws, two piezoelectric vibrators h and an elastic beam j are pressed between the two pressing plates g1, the pressing plate g1 of the limiting frame g is installed on the top wall of the blunt body d1 through screws, and the piezoelectric vibrators h and the elastic beam j are arranged inside the blunt body d 1; the piezoelectric vibrator h is formed by bonding a substrate h1 and a piezoelectric sheet h2, the substrate h1 is arranged close to an elastic beam j, the piezoelectric vibrator h and the elastic beam j are of cantilever structures, both sides of the free end of the elastic beam j are provided with a moving magnet k and a mass block n through screws, and the moving magnet k and the fixed magnet f are oppositely arranged in terms of opposite magnetic poles; two ends of a pressure plate g1 of the limiting frame g are provided with limiting blocks g2, a limiting surface g3 is arranged on the limiting block g2, the limiting surface g3 is an arc surface, and the surfaces, which are contacted with the piezoelectric vibrator h, of the limiting surface g3 and the pressure plate g1 are tangent; the distance between two limiting blocks g2 on the same limiting frame g is wider than that of a piezoelectric sheet h2 and narrower than that of a substrate h1, and a substrate h1 at the fixed end of the piezoelectric vibrator h is in contact with the limiting surface g 3; when the piezoelectric vibrator is not in work, the reed c, the elastic beam j and the piezoelectric vibrator h are in a natural state without deformation; the width ratio lambda and the delta spacing ratio of the baffle plate a3 respectively range from 1-3 for lambda H/D and 0-3 for delta L/D, wherein: d is the outer diameter of the blunt body D1 when it is a cylinder or the width of the rectangular parallelepiped in the thickness direction of the reed c, H is the width of the baffle a3 in the thickness direction of the reed c, and L is the shortest distance between the blunt body D1 and the adjacent surface of the baffle a 3.

In the invention, water flows from the bluff body d1 to the baffle plate a3, karman vortex street is generated after the water flows through the bluff body d1, and the alternating generation and falling of the vortex can lead the water pressure at the front side and the rear side of the bluff body d1 to be changed alternately, thereby generating exciting force for enabling the coupler d to swing back and forth; in the swinging process of the coupler d, the elastic beam j generates reciprocating bending deformation under the action of the inertia force of the mass block n at the free end of the elastic beam j and the attraction force between the moving magnet k and the fixed magnet f, and forces the piezoelectric vibrator h to bend and deform in the direction of enabling the piezoelectric sheet h2 to bear the pressure stress, namely, the water flow energy is converted into electric energy in the reciprocating bending deformation process of the piezoelectric vibrator h; when water flow is blocked by the baffle plate a3 after passing through the bluff body d1, the flow direction, the vortex form and the dynamic characteristic are changed, so that the amplitude of the exciting force is changed, and the vibration amplitude is increased or reduced; when the blunt body d1 swings and the amplitude of the elastic beam j reaches a rated value, the elastic beam j presses the substrate h1 of the piezoelectric vibrator h against the limit surface g3, and the compressive stress of each point in the length direction of the piezoelectric sheet h2 is equal and smaller than the allowable value, so that the piezoelectric vibrator has high power generation capacity and high reliability.

In the invention, the distance between the two pin shafts b can be adjusted by adjusting the positions of shaft sleeves e at the two ends of the pin shaft b, the minimum distance L between the baffle a3 and the blunt body d1 can be adjusted by adjusting the installation position of the baffle a3, and the bending rigidity and the cantilever length of the reed c can be changed by changing the distance between the two pin shafts b, so that the fundamental frequency of a vibration system formed by the blunt body d1 and the reed c and the amplitude of the blunt body d1 are changed, so that the fundamental frequency of the energy harvester is adapted to the vortex-induced vibration frequency, and resonance is realized; the distance ratio can be adjusted by changing the minimum distance L between the baffle plate a3 and the outer surface of the blunt body d1, and the effective control of the amplitude of the blunt body d1 is realized, namely the amplitude is increased or decreased.

In the invention, the substrate h1 and the piezoelectric sheet h2 have equal thickness, and the radius of the shape limiting surface g3 isAllowable change of free end of piezoelectric vibrator h when shape limiting surface is not usedThe shape is as follows

Wherein l is the cantilever length of the piezoelectric vibrator H, H is the total thickness of the piezoelectric vibrator H, β ═ E_m/E_p，E_mAnd E_pThe elastic moduli, T, of the materials of the substrate h1 and the piezoelectric sheet h2_pAnd k₃₁The allowable stress and electromechanical coupling coefficient of the piezoelectric sheet h2 material respectively.