Integrated piezoelectric microvibration-jet composite resistance reducer capable of being embedded into wall surface

Abstract

The invention discloses an integrated piezoelectric micro-vibration-jet flow composite resistance reducer capable of being embedded into a wall surface, and relates to the technical field of turbulence active resistance reduction control, and the integrated piezoelectric micro-vibration-jet flow composite resistance reducer comprises a plurality of piezoelectric micro-vibration-jet flow composite resistance reducers, the piezoelectric microvibration-jet composite drag reducer is embedded into the outer wall face of a cylinder of an underwater vehicle or an aircraft and the outer wall faces of horizontal wings on the two sides and comprises a drag reducer cavity and a piezoelectric actuator, and the piezoelectric actuator is of a bent type. The piezoelectric actuator comprises a wire, a vibrating membrane with a jet gap and a piezoelectric plate, and the wire is connected with the lower surface of the piezoelectric plate and the lower surface of the vibrating membrane. The integrated piezoelectric microvibration-jet composite drag reducer capable of being embedded into the wall surface is adopted, the problems that an existing drag reducer is complex in structure, large in occupied space, difficult to control and poor in universality are solved, microminiaturization of the drag reducer is achieved, and the integrated piezoelectric microvibration-jet composite drag reducer is one of effective methods for achieving active drag reduction of aircrafts and underwater micro-size aircrafts.

Description

Technical Field

[0001] The present invention relates to the technical field of active drag reduction control for turbulence, and particularly to an integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in a wall surface. Background Art

[0002] Underwater vehicles are widely used in fields such as ocean exploration, pipeline inspection, and underwater search and rescue. When an underwater vehicle is in navigation, the surface in contact with the fluid is prone to generating frictional resistance, which greatly restricts the navigation efficiency of the vehicle and shortens its endurance mileage. Therefore, in order to increase the endurance time of the micro-vehicle and improve its maneuverability, one of the most effective methods is to use active drag reduction technology to reduce the drag on the vehicle wall surface. Currently, the main active drag reduction methods applied to underwater vehicles include bionic drag reduction methods and optimizing the structure of the vehicle. Although these methods have good drag reduction effects, they also have many deficiencies. For example, the bionic surface structure is easily damaged, and the research cycle for optimizing the vehicle structure is long and the cost is high.

[0003] Due to the need for insulation and sealing underwater, most existing active drag reducers are mainly applied to the wings in the air, and there are fewer drag reducers applied to underwater vehicles; the existing underwater drag reducers have complex structures. For example, CN105947105A discloses an underwater vehicle mucus drag reduction device that can adjust and release drag reduction mucus according to the navigation speed during navigation, so that the drag reduction mucus uniformly and continuously covers most of the surface of the underwater vehicle to improve the navigation speed. This drag reduction device consists of a gas cylinder, a piston cylinder, a flow control valve, a controller, a joint, mucus, and air pipes and liquid pipes, with a complex structure and a large required space, and is not suitable for small underwater vehicles and has a complex control system.

[0004] Therefore, there is a need to provide an integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in a wall surface to solve the above problems. Summary of the Invention

[0005] The object of the present invention is to provide an integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in a wall surface. By controlling a single piezoelectric actuator, both piezoelectric micro-vibration drag reduction and piezoelectric jet drag reduction can be achieved simultaneously. Among them, the interference range of micro-vibration drag reduction for turbulence is mainly the inner flow domain of the near-wall turbulent boundary layer, while the interference range of jet drag reduction is mainly the outer flow domain of the near-wall turbulent boundary layer. The micro-vibration and the jet are driven by the same piezoelectric actuator, and strong mutual coupling will occur during operation, so as to act on the inner and outer layers of the near-wall multi-scale turbulent boundary layer simultaneously and efficiently, and obtain efficient drag reduction for micro-sized underwater vehicles.

[0006] To achieve the above object, the present invention provides an integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in a wall surface, including a plurality of piezoelectric micro-vibration - jet composite drag reducers. The piezoelectric micro-vibration - jet composite drag reducers are embedded in the outer wall surface of the cylinder and the outer wall surfaces of the two side horizontal wings of the navigation device. The navigation device includes an underwater vehicle and an aircraft. The piezoelectric micro-vibration - jet composite drag reducer includes a drag reducer cavity and a piezoelectric actuator. The piezoelectric actuator is of a bending type and includes a wire, a vibration membrane with a jet slit, and a piezoelectric sheet. The wire is connected to the lower surface of the piezoelectric sheet and the lower surface of the vibration membrane.

[0007] Preferably, the drag reducer cavity includes an outer wall surface, a sealing groove, an inner cavity, and a reference surface. A process hole is provided in the inner cavity, and a sealing ring is placed in the sealing groove.

[0008] Preferably, the piezoelectric sheet adopts the d 31 working mode, is polarized along the thickness direction of the piezoelectric sheet. By using the inverse piezoelectric effect of the piezoelectric sheet, a micro-vibration in the normal direction is generated by applying an excitation signal to the piezoelectric actuator, and at the same time, it drives the fluid to be inhaled and ejected along the jet slit.

[0009] Preferably, the vibration membrane is adhesively fixed to the reference surface. After installation, the outer surface of the vibration membrane is flush with the outer wall surface of the underwater vehicle. The jet slit is provided on the vibration membrane. The piezoelectric sheet is arranged in the inner cavity and adhesively connected to the vibration membrane. The piezoelectric sheet is respectively fixed below the vibration membrane and on both sides of the jet slit.

[0010] Preferably, the shape and opening position of the jet slit are opened at any position on the vibration membrane according to the actual situation.

[0011] Preferably, the outer wall surface is smoothly transitioned with the cylindrical outer wall surface of the underwater vehicle and the outer wall surfaces of the two side horizontal wings. The outer surface of the vibration membrane in contact with the fluid and the outer wall surface are smoothly transitioned.

[0012] Preferably, the material of the vibration membrane is set as a plastic or metal flexible membrane.

[0013] Preferably, the fixing method of the vibration membrane to the reference surface is fixed around the perimeter or fixed on both sides of the short side.

[0014] Preferably, the material of the piezoelectric sheet is set as piezoelectric ceramic or ferroelectric.

[0015] Therefore, by adopting the above-mentioned integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in a wall surface, the present invention has the following beneficial effects:

[0016] (1) When an external excitation drives a piezoelectric sheet that can generate the inverse piezoelectric effect in the present invention, its contraction, expansion or bending is utilized to cause the piezoelectric actuator to generate micro-vibrations in the normal direction, and at the same time drive the fluid to be inhaled and ejected along the jet slit. By effectively controlling the same piezoelectric actuator, piezoelectric micro-vibration drag reduction and piezoelectric jet drag reduction can be achieved simultaneously. The interference range of piezoelectric micro-vibration drag reduction on turbulence is mainly the inner flow domain of the near-wall turbulent boundary layer, while the interference range of piezoelectric jet drag reduction is mainly the outer flow domain of the near-wall turbulent boundary layer. Therefore, a larger and wider range of coupling effects can act on the turbulent boundary layer, obtaining efficient drag reduction for micro and small underwater vehicles and aircraft.

[0017] (2) In the present invention, the drag reducers arranged on the outer wall surfaces of the cylinders of underwater vehicles and aircraft and the outer wall surfaces of horizontal wings can reduce the frictional drag generated by the contact between the underwater vehicle and the fluid.

[0018] (3) At the places where the underwater vehicles and aircraft in the present invention are embedded with drag reducers, both the outer wall surface of the drag reducer and the wall surface of the navigation device adopt smooth transitions to reduce the influence on the near-wall boundary layer.

[0019] (4) In the present invention, the vibration membrane and the drag reducer cavity are bonded or welded to fix the vibration membrane and achieve sealing at the same time.

[0020] (5) The control method of the present invention is simple, with low energy consumption, simple and compact structure, not affected by electromagnetic interference, and easy to integrate.

[0021] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Description of the Drawings

[0022] Figure 1 is the external structure schematic diagram of an integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in the wall surface of the present invention;

[0023] Figure 2 is the M - M sectional view of the external structure schematic diagram of the present invention;

[0024] Figure 3 is the N - N sectional view of the external structure schematic diagram of the present invention;

[0025] Figure 4 is the three - quarter sectional view schematic diagram of the piezoelectric micro-vibration - jet composite drag reducer of the present invention;

[0026] Figure 5 is the schematic diagram of the drag reducer cavity structure of the present invention;

[0027] Figure 6 is the enlarged view of part B in the M - M sectional view of the external structure schematic diagram of the present invention;

[0028] Reference Signs

[0029] 1. Outer wall surface; 2. Sealing groove; 3. Inner cavity; 4. Reference plane; 5. Process hole; 6. Sealing ring; 7. Conductive wire; 8. Vibration membrane; 9. Jet slit; 10. Piezoelectric sheet; 11. Navigation device; 12. Outer wall surface of horizontal wing; 13. Outer wall surface of cylinder; 14. Piezoelectric micro-vibration-jet composite flow reducer. Specific embodiments

[0030] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0031] Unless otherwise defined, the technical terms or scientific terms used in the present invention shall have the ordinary meanings understood by those of ordinary skill in the field to which the present invention belongs. The "first", "second" and similar terms used in the present invention do not denote any order, quantity or importance, but are only used to distinguish different components. The terms such as "including" or "comprising" mean that the elements or objects appearing before this word cover the elements or objects listed after this word and their equivalents, without excluding other elements or objects. The terms such as "connected" or "coupled" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The terms such as "upper", "lower", "left" and "right" are only used to represent relative positional relationships, and when the absolute position of the object to be described changes, the relative positional relationship may also change accordingly.

[0032] Embodiment

[0033] As Figures 1-6 shown, the present invention provides an integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface, including a plurality of piezoelectric micro-vibration-jet composite flow reducers 14, and the piezoelectric micro-vibration-jet composite flow reducer 14 is embedded in the outer wall surface 13 of the cylinder and the outer wall surfaces 12 of the two-side horizontal wings of the navigation device 11. The navigation device 11 includes an underwater vehicle and an aircraft. The piezoelectric micro-vibration-jet composite flow reducer 14 includes a flow reducer cavity and a piezoelectric actuator. The piezoelectric actuator is of a bending type. The piezoelectric actuator includes a conductive wire 7, a vibration membrane 8 with a jet slit 9, and a piezoelectric sheet 10. The conductive wire 7 is connected to the lower surface of the piezoelectric sheet 10 and the lower surface of the vibration membrane 8. The material of the vibration membrane 8 is set to be a plastic or metal flexible membrane.

[0034] The flow reducer cavity includes an outer wall surface 1, a sealing groove 2, an inner cavity 3 and a reference plane 4. A process hole 5 is arranged in the inner cavity 3, and a sealing ring 6 is placed in the sealing groove 2. The vibration membrane 8 is fixed to the reference plane 4 in a manner of being fixed around the periphery or fixed on both sides of the short side.

[0035] The piezoelectric sheet 10 uses d 31Working mode: Polarized along the thickness direction of the piezoelectric sheet. Utilize the inverse piezoelectric effect of the piezoelectric sheet. By applying an excitation signal, the piezoelectric actuator generates micro-vibrations in the normal direction, and at the same time drives the fluid to be inhaled and ejected along the jet slit 9. The material of the piezoelectric sheet 10 is set as piezoelectric ceramics or ferroelectrics.

[0036] The vibration membrane 8 is adhesively fixed on the reference surface 4. After installation, the outer surface of the vibration membrane 8 is flush with the outer wall surface of the underwater vehicle. A jet slit 9 is opened on the vibration membrane 8. The piezoelectric sheet 10 is arranged in the inner cavity 3 and adhesively fixed to the vibration membrane 8. The piezoelectric sheet 10 is respectively fixed below the vibration membrane 8 and on both sides of the jet slit 9.

[0037] The shape and opening position of the jet slit 9 are opened at any position on the vibration membrane 8 according to the actual situation.

[0038] The outer wall surface 1 is smoothly transitioned with the cylindrical outer wall surface of the underwater vehicle and the outer wall surfaces 12 of the horizontal wings on both sides. The outer surface of the vibration membrane 8 in contact with the fluid and the outer wall surface are smoothly transitioned.

[0039] Therefore, the present invention adopts the above-mentioned integrated piezoelectric micro-vibration - jet composite drag reducer that can be embedded in the wall. The interference range of piezoelectric micro-vibration drag reduction for turbulence is mainly the inner flow domain of the near-wall turbulent boundary layer, while the interference range of piezoelectric jet drag reduction is mainly the outer flow domain of the near-wall turbulent boundary layer. By effectively controlling the same piezoelectric actuator, piezoelectric micro-vibration drag reduction and piezoelectric jet drag reduction can be achieved simultaneously, so as to couple with the turbulent boundary layer in a larger and wider range, and obtain efficient drag reduction for micro-miniature underwater vehicles and vehicles.

[0040] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall, characterized in that: It includes a number of piezoelectric micro-vibration-jet composite flow reducers, and the piezoelectric micro-vibration-jet composite flow reducers are embedded in the outer wall surface of the cylinder of the navigation device and the outer wall surfaces of the two side horizontal wings. The navigation device includes an underwater vehicle and an aircraft. The piezoelectric micro-vibration-jet composite flow reducer includes a flow reducer cavity and a piezoelectric actuator. The piezoelectric actuator is of a bending type. The piezoelectric actuator includes a wire, a vibration membrane with a jet slit, and a piezoelectric sheet. The wire is connected to the lower surface of the piezoelectric sheet and the lower surface of the vibration membrane.

2. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface according to claim 1, characterized in that: The flow reducer cavity includes an outer wall surface, a sealing groove, an inner cavity, and a reference surface. A process hole is arranged in the inner cavity, and a sealing ring is placed in the sealing groove.

3. The integrated piezoelectric micro-vibration - jet composite flow reducer capable of being embedded into a wall surface according to claim 2, characterized in that: The piezoelectric sheet adopts the d 31 working mode, is polarized along the thickness direction of the piezoelectric sheet, and utilizes the inverse piezoelectric effect of the piezoelectric sheet to generate micro-vibrations in the normal direction by applying an excitation signal, and at the same time drives the fluid to be inhaled and ejected along the jet gap.

4. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface according to claim 3, characterized in that: The vibration membrane is adhesively fixed on the reference surface. After installation, the outer surface of the vibration membrane is flush with the outer wall surface of the underwater vehicle. The jet slit is formed in the vibration membrane. The piezoelectric sheet is arranged in the inner cavity and adhesively connected to the vibration membrane. The piezoelectric sheet is respectively fixed below the vibration membrane and on both sides of the jet slit.

5. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface according to claim 1, characterized in that: The shape and opening position of the jet slit are opened at any position of the vibration membrane according to the actual situation.

6. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface according to claim 2, characterized in that: The outer wall surface is smoothly transitioned with the cylindrical outer wall surface of the underwater vehicle and the outer wall surfaces of the two side horizontal wings. The outer surface of the vibration membrane in contact with the fluid is smoothly transitioned with the outer wall surface.

7. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface according to claim 1, characterized in that: The material of the vibration membrane is set to be a plastic or metal flexible membrane.

8. An integrated piezoelectric micro-vibration-jet composite flow reducer that can be embedded in a wall surface according to claim 2, characterized in that: The fixing method of the vibration membrane to the reference surface is fixed around or fixed on both sides of the short sides.

9. The integrated piezoelectric micro-vibration-jet composite flow reducer capable of being embedded into a wall surface according to claim 1, characterized in that: The material of the piezoelectric sheet is set to be piezoelectric ceramic or ferroelectric.

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