Sewage treatment stirring device and method

Abstract

The invention discloses a sewage treatment stirring device and method.The sewage treatment stirring device comprises a stirring pool, the middle of the stirring pool is provided with a stirring device, the periphery of the stirring device is provided with a vortex-induced column array, the vortex-induced column array is composed of a plurality of vortex-induced column units, and the lower ends of the vortex-induced column units are connected with lower displacement mechanisms; the lower displacement mechanism is mounted at the bottom of the inner wall of the stirring tank, the upper end of each vortex-induced column unit is connected with an upper displacement mechanism, the upper displacement mechanisms are mounted on a suspension arm, the suspension arm is fixed outside the stirring tank, and the vortex-induced column units can perform two-degree-of-freedom movement; on the basis of computational fluid mechanics and ocean structure dynamics, a vortex-induced vibration principle is reversely utilized, and energy for damaging a structure by vortex-induced vibration is converted into mechanical energy for stirring fluid through a special structural design and two vortex-induced vibration excitation methods.

Description

Technical Field

[0001] The invention belongs to the field of sewage treatment equipment, and in particular relates to a sewage treatment stirring device and method. Background Art

[0002] The sewage treatment process includes sedimentation pretreatment, biological treatment, chemical mixing, tertiary treatment, sludge treatment, and reuse. Among them, biological treatment, chemical mixing, and sludge treatment usually require stirring to promote reaction, mixing, or prevent precipitation, and maintain reaction uniformity. Traditional sewage treatment stirring devices rely on motors to drive rotating impellers or aeration systems. The inventor believes that the existing technology has defects such as high energy consumption and mechanical wear.

[0003] Vortex-induced vibration is a special fluid-structure coupling phenomenon, also known as resonance, which can cause devastating damage to bridges and high-rise buildings. Vortex-induced vibration refers to the release of wake vortices at a certain frequency in the flow field formed by the fluid. The vortex shedding generates periodic fluid forces that cause the structure to produce double-degree-of-freedom displacements; the displacement response in turn affects the fluid force and vortex release morphology, and this positive feedback will occur multiple times in a short period of time, causing strong displacements. When the vortex release frequency is close to the natural frequency of the column structure, resonance will occur.

[0004] The vortex-induced vibration effect is often regarded as a safety hazard for structures such as pipelines and bridges. Existing research focuses on how to suppress vortex-induced vibration, and vortex-induced vibration has not yet been applied to the field of sewage treatment. If we use reverse thinking and computational fluid dynamics to convert the destructive energy generated by vortex-induced vibration into usable stirring power, it will effectively improve energy utilization efficiency.

[0005] For the reverse utilization of vortex-induced vibration effect, the prior art only discloses the technology of generating electricity by utilizing vortex-induced vibration effect, such as Chinese invention patent CN113489375A discloses a vortex-induced vibration energy collection and power generation device, which includes a bluff body, a connection device is fixedly connected to the upper end of the bluff body, a linear vibration generator is fixedly and symmetrically arranged on the outer side of the connection device, and a spring group is installed on the upper end of the connection device. The bluff body can generate vibration after the fluid flows through, driving the connection device and the linear vibration generator to vibrate synchronously, and the linear vibration generator can generate an induced electromotive force. Its disadvantage is that it only discloses an ocean power generation structure, and does not provide any ideas or structures for realizing the fluid-solid coupling control of the bluff body and seawater, so the disclosure is insufficient.

[0006] The key to reversely utilizing the vortex-induced vibration effect lies in how to stimulate vortex-induced vibration, that is, how to place the vibrating object in a liquid flow velocity environment where its self-vibration frequency is close to the vortex leakage frequency. Chinese invention patent CN105203282A provides a way of thinking, that is, using a guide plate to increase the local flow velocity of the fluid. It discloses a vortex-induced vibration test device for a marine riser bundle with a local flow velocity increase and an inclined stepped flow, which includes a marine riser bundle composed of multiple marine riser models, a lateral test support frame, a flow velocity increase device, a trailer, a strain collector and a computer. A streamlined fairing is fixed on the inner side of the guide plate on one side of the submarine pipeline model, and the streamlined fairing covers the shaft section at one end of the marine riser model; a flow velocity increase device is arranged in the middle of the marine riser bundle, and the flow velocity increase device includes a speed increase section and a flow stabilization section, and the speed increase section is trumpet-shaped; the vortex-induced vibration test observation of a deep-sea riser bundle with a large Reynolds number and a large aspect ratio can be realized. Summary of the invention

[0007] In order to solve the problems raised in the above background technology, the present invention provides a sewage treatment stirring device and method, which has the characteristics of high energy utilization rate.

[0008] In order to achieve at least one of the above purposes, the technical solution adopted by the present invention is: A sewage treatment stirring device comprises a stirring tank, wherein a stirring device is arranged in the middle of the stirring tank, a vortex column array is arranged around the stirring device, the vortex column array is composed of a plurality of vortex column units, the lower ends of the vortex column units are connected with lower displacement mechanisms, the lower displacement mechanisms are installed at the bottom of the inner wall of the stirring tank, the upper ends of the vortex column units are connected with upper displacement mechanisms, the upper displacement mechanisms are installed on a suspension arm, the suspension arm is fixed to the outside of the stirring tank, the vortex column units can perform double-degree-of-freedom motion, and the sides of the vortex column units are also provided with guide plates, and the horizontal cross-section of the guide plates is in an "eight" shape.

[0009] Further, the vortex column unit is cylindrical, the vortex column unit is movably connected to the sliding displacement mechanism through a damping universal joint, the sliding displacement mechanism comprises a pool bottom chute installed at the bottom of the mixing tank, a pool bottom slider is slidably connected in the pool bottom chute, and a lower locking mechanism is arranged in the pool bottom chute; The vortex-induced column unit is movably connected to the upper displacement mechanism via a preload spring group. The upper displacement mechanism includes an upper slide groove, which is installed on the lower surface of the boom. An upper slider is slidably connected inside the upper slide groove, and an upper locking mechanism is arranged inside the upper slide groove.

[0010] Furthermore, there are two guide plates, which are connected by gear transmission and can rotate relative to each other. The top of the guide plate is integrated with a gear structure, and a motor is connected above the gear structure. The relative angle between the two guide plates is changed by controlling the motor. The bottom end of the guide plate is integrated with a counterweight plate for lowering the center of gravity of the guide plate.

[0011] Furthermore, the vortex column unit is made of a flexible material, and the surface of the vortex column unit is coated with a corrosion-resistant coating. The anti-fouling and self-maintenance design of the vortex column unit is that the surface is coated with a graphene and carbon nitride composite coating with a thickness of 20 μm, which generates hydroxyl radicals under ultraviolet light to decompose attached organic matter.

[0012] Furthermore, the inner wall of the stirring tank is circular.

[0013] Furthermore, the outer surface diameter of the vortex column unit is 10-20 cm, and the unit cylinder mass is 0.2-0.5 kg.

[0014] Furthermore, the system damping coefficient formed by the damping universal joint and the preload spring group is 0.1-2.5 N·s / mm.

[0015] Furthermore, a spiral guide groove is provided on the surface of the vortex column unit.

[0016] Furthermore, an ultrasonic cleaning device is embedded in the vortex column unit, which is an electric ceramic plate with a frequency of 25-30kHz, and emits ultrasonic pulses at regular intervals every day to remove surface deposits.

[0017] A sewage treatment stirring method comprises the following steps: S1. After water is injected into the stirring tank, the stirring device is started, 5-20 positions are evenly selected from the surface of the water body, and the liquid flow rate U at each position is measured using a flow meter; S2. It is known that when the Reynolds number Re is in the range of 300-300000, the Strouhal coefficient St is about 0.21. In addition, if the outer surface diameter D of the vortex-induced column unit is 0.12m, the damping ratio ζ is 0.03, and the unit cylinder mass m is 0.29kg, then its natural frequency can be obtained according to its damping coefficient and other conditions. , when the natural frequency Vortex shedding frequency When the vortex-induced column unit excites vortex-induced vibration, the natural frequency Formula and vortex shedding frequency Formula, we get: , (where D=0.12, St=0.21, ); Then the matching value of flow velocity U is obtained: m / s; S3. According to the matching value of flow velocity U of 0.2 m / s, the horizontal position of each vortex column unit in the vortex column array is adjusted to the position closest to 0.2 m / s measured in S1, and fixed by the lower locking mechanism and the upper locking mechanism, and the spring damping structure composed of the damping universal joint, the preload spring group and the vortex column unit is used to make the vortex column unit vibrate with two degrees of freedom in the horizontal direction, and the two-degree-of-freedom amplitude of the vortex column unit is 10-15 cm; S4. When the flow velocity U is too small to reach the excitation threshold of vortex-induced vibration, the guide plate in front of the vortex-induced column unit is lowered. The tapered design of the guide plate increases the local flow velocity U of the fluid until vortex-induced vibration is excited.

[0018] A sewage treatment stirring method comprises the following steps: S1. Measure the outer surface diameter D, damping ratio ζ, unit cylinder mass m of the vortex-induced column unit, and its natural frequency can be obtained based on its damping coefficient and other conditions , when the natural frequency Vortex shedding frequency When the vortex-induced column unit excites vortex-induced vibration, the natural frequency Formula and vortex shedding frequency Formula, we get: , it is known that when the Reynolds number Re is in the range of 300-300000, the Strouhal coefficient St is about 0.21, and the matching value of the flow velocity U is further obtained; S2. After water is poured into the stirring pool, the stirring device is started, and the overall flow velocity at the radial position where the vortex-induced vibration array is located is measured. There is a functional relationship between the overall flow velocity of the fluid, the local flow velocity and the relative angle between the guide plates. The angle is calculated according to the matching value of the flow velocity U. The relative angle between the two guide plates is increased by controlling the motor. The relative angle between the guide plates is gradually increased to increase the local flow velocity U of the fluid, until the vortex-induced vibration is excited and then stops; S3. Using the spring damping structure composed of the damping universal joint, the preload spring group and the vortex-induced column unit, the vortex-induced column unit is made to vibrate with two degrees of freedom in the horizontal direction, and the two degrees of freedom amplitude of the vortex-induced column unit is 10-15cm.

[0019] The beneficial effects of the present invention compared with the prior art are as follows: 1. The present invention is based on computational fluid dynamics and marine structure dynamics, and reversely utilizes the vortex-induced vibration effect. Through a special structural design, the vibration energy caused by the vortex-induced vibration to the structure is converted into mechanical energy for stirring the fluid, that is, the vortex-induced column unit with double-degree-of-freedom vibration is used to generate a Karman vortex street, and the matching flow velocity is calculated through a related method, and the vortex-induced column unit is moved to the matching flow velocity position through a displacement device, or the local flow velocity is changed by a guide plate so that the vortex discharge frequency is consistent with the self-vibration frequency, thereby stimulating the vortex-induced vibration effect. The vortex-induced column units of the present invention surround to form a vortex-induced column array, capture the kinetic energy of the fluid and convert it into controllable vibration, and combine its adaptive frequency locking and traveling wave coordination mechanism to achieve efficient, silent, and low-energy liquid mixing. The device is particularly suitable for scenes such as sewage treatment and river management, and improves energy utilization; 2. The present invention has made many adaptive designs, such as using the guide plate to excite vortex-induced vibration, the anti-corrosion and anti-deposition design of the vortex-induced column unit, and the counterweight plate to lower the center of gravity of the guide plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a cross-sectional view of the overall structure of the present invention; Figure 2 Schematic diagram of the vortex column unit in the present invention; Figure 3 It is a schematic diagram of the working state of the present invention; Figure 4 It is a cross-sectional view of the overall structure of the present invention when no guide plate is installed; Figure 5 It is a schematic diagram of the internal structure of the present invention; Figure 6 Schematic diagram of the overall structure of the guide plate in the second embodiment of the present invention; The components in the figure are marked as follows: 1. stirring tank; 2. stirring device; 3. vortex column array; 4. lower displacement mechanism; 401. tank bottom slide; 402. tank bottom slider; 403. lower locking mechanism; 5. damping universal joint; 6. upper displacement mechanism; 601. upper slide; 602. upper slider; 603. upper locking mechanism; 7. preload spring group; 8. boom; 9. guide plate; 901. gear structure; 902. motor; 903. counterweight plate. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be further described below in conjunction with the accompanying drawings, and the advantages and features of the present invention will become clearer as the description proceeds. However, it should be understood that the embodiments are merely exemplary and do not limit the scope of the present invention.

[0022] It should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", etc. in the claims and specifications of this application document are based on the orientation or positional relationship shown in the drawings, and it is not necessary to understand that the device or component referred to must have a specific orientation, be constructed or operate in a specific orientation.

[0023] In the present invention, unless otherwise clearly specified and limited, the terms such as "fixed" and "connected" should be understood in a broad sense, for example, it can be fixed connection, detachable connection, or integrated; it can be mechanical connection or electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0024] See also Figures 1 to 5 , which is Embodiment 1 of the present invention: A sewage treatment stirring device and method, comprising a stirring tank 1, the inner wall of which is circular. A stirring device 2 is arranged in the middle of the stirring tank 1, and a vortex column array 3 is arranged around the stirring device 2. The vortex column array 3 is composed of a plurality of vortex column units, and the lower ends of the vortex column units are connected to lower displacement mechanisms 4, which are installed at the bottom of the inner wall of the stirring tank 1, and the upper ends of the vortex column units are connected to upper displacement mechanisms 6, which are installed on a suspension arm 8, which is fixed outside the stirring tank 1, and the vortex column units can perform double-degree-of-freedom motion.

[0025] The vortex column unit is cylindrical, and the vortex column unit is movably connected to the sliding displacement mechanism 4 through a damping universal joint 5. The sliding displacement mechanism 4 includes a pool bottom chute 401 installed at the bottom of the mixing tank 1, a pool bottom slider 402 is slidably connected in the pool bottom chute 401, and a lower locking mechanism 403 is arranged in the pool bottom chute 401; The vortex column unit is movably connected to the upper displacement mechanism 6 through the preload spring group 7. The upper displacement mechanism 6 includes an upper slide groove 601, which is installed on the lower surface of the boom 8. An upper slider 602 is slidably connected inside the upper slide groove 601, and an upper locking mechanism 603 is arranged inside the upper slide groove 601. The damping coefficient of the system formed by the damping universal joint 5 and the preload spring group 7 is 0.1-2.5N·s / mm.

[0026] A guide plate 9 is also provided on the side of the vortex column unit. The horizontal cross-section of the guide plate 9 is in an "eight" shape. When the flow velocity U is too small to reach the excitation threshold of vortex-induced vibration, the guide plate 9 in front of the vortex column unit is lowered. The tapered design of the guide plate 9 increases the local flow velocity U of the fluid until vortex-induced vibration is excited.

[0027] The design of the vortex column unit is as follows: the vortex column unit is made of flexible material, the surface of the vortex column unit is coated with a corrosion-resistant coating, and the anti-fouling and self-maintenance design of the vortex column unit is that the surface is coated with a 20μm thick graphene and carbon nitride composite coating, which produces hydroxyl radicals under ultraviolet light to decompose attached organic matter. A spiral guide groove is opened on the surface of the vortex column unit. An ultrasonic cleaning device is embedded in the interior of the vortex column unit. The ultrasonic cleaning device is an electric ceramic sheet with a frequency of 25-30kHz, which emits ultrasonic pulses at regular intervals every day to remove surface deposits.

[0028] The implementation of this embodiment includes the following steps: 1. After water is poured into the stirring tank 1, the stirring device 2 is started, 5-20 positions from the center of the stirring tank 1 are evenly selected on the surface of the water body, and the liquid flow rate U at each position is measured using a flow meter; 2. It is known that when the Reynolds number Re is in the range of 300-300000, the Strouhal coefficient St is about 0.21. In this embodiment: the outer surface diameter D of the vortex column unit is 0.12m, the damping ratio ζ is 0.03, and the unit cylinder mass m is 0.29kg. Then, according to its damping coefficient and other conditions, its natural frequency can be obtained. is 3.5Hz, when the natural frequency Vortex shedding frequency When the vortex-induced column unit excites vortex-induced vibration, the natural frequency Formula and vortex shedding frequency Formula, we can get: diameter D and natural frequency The product is equal to the product of the Strouhal coefficient St of twice pi and the flow velocity U. Therefore, the matching value of the flow velocity U is calculated to be 0.2m / s; 3. According to the matching value of flow velocity U of 0.2 m / s, the horizontal position of each vortex column unit in the vortex column array 3 is adjusted to the position point closest to 0.2 m / s measured in S1, and fixed by the lower locking mechanism 403 and the upper locking mechanism 603, and the spring damping structure composed of the damping universal joint 5, the preload spring group 7 and the vortex column unit is used to make the vortex column unit vibrate with two degrees of freedom in the horizontal direction, and the two-degree-of-freedom amplitude of the vortex column unit is 10-15 cm; 4. When the flow velocity U is too small to reach the excitation threshold of vortex-induced vibration, the guide plate 9 in front of the vortex-induced column unit is lowered. The tapered design of the guide plate 9 increases the local flow velocity U of the fluid until vortex-induced vibration is excited.

[0029] See also Figures 1 to 6 , which is the second embodiment of the present invention: A sewage treatment stirring device and method, comprising a stirring tank 1, the inner wall of which is circular. A stirring device 2 is arranged in the middle of the stirring tank 1, and a vortex column array 3 is arranged around the stirring device 2. The vortex column array 3 is composed of a plurality of vortex column units, and the lower ends of the vortex column units are connected to lower displacement mechanisms 4, which are installed at the bottom of the inner wall of the stirring tank 1, and the upper ends of the vortex column units are connected to upper displacement mechanisms 6, which are installed on a suspension arm 8, which is fixed outside the stirring tank 1, and the vortex column units can perform double-degree-of-freedom motion.

[0030] The vortex column unit is cylindrical, and the vortex column unit is movably connected to the sliding displacement mechanism 4 through a damping universal joint 5. The sliding displacement mechanism 4 includes a pool bottom chute 401 installed at the bottom of the mixing tank 1, a pool bottom slider 402 is slidably connected in the pool bottom chute 401, and a lower locking mechanism 403 is arranged in the pool bottom chute 401; The vortex column unit is movably connected to the upper displacement mechanism 6 through the preload spring group 7. The upper displacement mechanism 6 includes an upper slide groove 601, which is installed on the lower surface of the boom 8. An upper slider 602 is slidably connected inside the upper slide groove 601, and an upper locking mechanism 603 is arranged inside the upper slide groove 601. The damping coefficient of the system formed by the damping universal joint 5 and the preload spring group 7 is 0.1-2.5N·s / mm.

[0031] There are two guide plates 9, which are connected by gear transmission and can rotate relative to each other. The top of the guide plate 9 is integrated with a gear structure 901, and a motor 902 is connected above the gear structure 901. The relative angle between the two guide plates 9 is changed by controlling the motor 902. The bottom of the guide plate 9 is integrated with a counterweight plate 903 for lowering the center of gravity of the guide plate 9.

[0032] The design of the vortex column unit is as follows: the vortex column unit is made of flexible material, the surface of the vortex column unit is coated with a corrosion-resistant coating, and the anti-fouling and self-maintenance design of the vortex column unit is that the surface is coated with a 20μm thick graphene and carbon nitride composite coating, which produces hydroxyl radicals under ultraviolet light to decompose attached organic matter. A spiral guide groove is opened on the surface of the vortex column unit. An ultrasonic cleaning device is embedded in the interior of the vortex column unit. The ultrasonic cleaning device is an electric ceramic sheet with a frequency of 25-30kHz, which emits ultrasonic pulses at regular intervals every day to remove surface deposits.

[0033] In Example 1, the staff calculated the liquid flow rate matching the vortex-induced column unit through a relevant method, and then moved the vortex-induced column unit to a matching flow rate position through a displacement device to excite vortex-induced vibration. In the present embodiment, the inventor provides a new idea for exciting vortex-induced vibration, namely, using the relative angle change of the guide plate 9 to change the local flow rate, so that the vortex discharge frequency of the vortex-induced column unit behind the guide plate 9 is consistent with the self-vibration frequency, thereby exciting the vortex-induced vibration effect.

[0034] The implementation of this embodiment includes the following steps: 1. Measure the outer surface diameter D, damping ratio ζ, unit cylinder mass m of the vortex-induced cylinder unit, and its natural frequency can be obtained based on its damping coefficient and other conditions , when the natural frequency Vortex shedding frequency When the vortex-induced column unit excites vortex-induced vibration, the natural frequency Formula and vortex shedding frequency Formula, we get: , it is known that when the Reynolds number Re is in the range of 300-300000, the Strouhal coefficient St is about 0.21, and the matching value of the flow velocity U is further obtained; 2. After water is poured into the stirring pool 1, the stirring device 2 is started, and the overall flow velocity at the radial position where the vortex-induced vibration array is located is measured. There is a functional relationship between the overall flow velocity of the fluid, the local flow velocity and the relative angle between the guide plates 9. The angle is calculated according to the matching value of the flow velocity U. The relative angle between the two guide plates 9 is increased by controlling the motor 902. The relative angle between the guide plates 9 is gradually increased to increase the local flow velocity U of the fluid until the vortex-induced vibration is excited and then stops; 3. The spring damping structure composed of the damping universal joint 5, the preload spring group 7 and the vortex-induced column unit is used to make the vortex-induced column unit vibrate with two degrees of freedom in the horizontal direction. The amplitude of the two degrees of freedom of the vortex-induced column unit is 10-15 cm.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A sewage treatment stirring device, comprising a stirring tank (1), wherein a stirring device (2) is arranged in the middle of the stirring tank (1), characterized in that: A vortex column array (3) is arranged around the stirring device (2), the vortex column array (3) is composed of a plurality of vortex column units, the lower ends of the vortex column units are connected to a lower displacement mechanism (4), the lower displacement mechanism (4) is installed at the bottom of the inner wall of the stirring tank (1), the upper ends of the vortex column units are connected to an upper displacement mechanism (6), the upper displacement mechanism (6) is installed on a suspension arm (8), the suspension arm (8) is fixed outside the stirring tank (1), the vortex column units are capable of double-degree-of-freedom movement, and the side of the vortex column unit is also provided with a guide plate (9), the horizontal cross-section of the guide plate (9) is in an "eight" shape.

2. The sewage treatment stirring device according to claim 1, characterized in that: The vortex-induced column unit is cylindrical, and the vortex-induced column unit is movably connected to the sliding displacement mechanism (4) via a damping universal joint (5), and the sliding displacement mechanism (4) comprises a pool bottom chute (401) installed at the bottom of the stirring pool (1), a pool bottom sliding block (402) is slidably connected in the pool bottom chute (401), and a lower locking mechanism (403) is arranged in the pool bottom chute (401); The vortex-induced column unit is movably connected to the upper displacement mechanism (6) via a preload spring group (7); the upper displacement mechanism (6) comprises an upper slide groove (601); the upper slide groove (601) is mounted on the lower surface of the boom (8); an upper slider (602) is slidably connected inside the upper slide groove (601); an upper locking mechanism (603) is arranged inside the upper slide groove (601).

3. The sewage treatment stirring device according to claim 1, characterized in that: The number of the guide plates (9) is two, the two guide plates (9) are connected via gear transmission and are relatively rotatable, the top of the guide plate (9) is integrally connected to a gear structure (901), the upper part of the gear structure (901) is connected to a motor (902), the relative angle between the two guide plates (9) is changed by controlling the motor (902), and the bottom end of the guide plate (9) is integrally connected to a counterweight plate (903).

4. The sewage treatment stirring device according to claim 2 or 3, characterized in that: The vortex column unit is made of a flexible material, and the surface of the vortex column unit is coated with a corrosion-resistant coating.

5. The sewage treatment stirring device according to claim 2 or 3, characterized in that: The inner wall of the stirring tank (1) is circular.

6. The sewage treatment stirring device according to claim 2 or 3, characterized in that: The outer surface diameter of the vortex column unit is 10-20 cm, and the unit cylinder mass is 0.2-0.5 kg.

7. The sewage treatment stirring device according to claim 2 or 3, characterized in that: The damping coefficient of the system formed by the damping universal joint (5) and the preload spring group (7) is 0.1-2.5 N·s / mm.

8. The sewage treatment stirring device according to claim 2 or 3, characterized in that: A spiral guide groove is provided on the surface of the vortex column unit, and an ultrasonic cleaning device is embedded in the interior of the vortex column unit.

9. A sewage treatment stirring method according to claim 2, characterized in that: The steps include: S1. After water is poured into the stirring tank (1), the stirring device (2) is started, and 5-20 radial position points from the center of the stirring tank (1) are uniformly selected on the surface of the water body, and the liquid flow rate U at each radial position point is measured using a flow meter; S2. It is known that when the Reynolds number Re is in the range of 300-300000, the Strouhal coefficient St is about 0.

21. In addition, if the outer surface diameter D of the vortex-induced column unit is 0.12m, the damping ratio ζ is 0.03, and the unit cylinder mass m is 0.29kg, then its natural frequency can be obtained according to its damping coefficient and other conditions. , when the natural frequency Vortex shedding frequency When the vortex-induced column unit excites vortex-induced vibration, the natural frequency Formula and vortex shedding frequency Formula, we get: , (where D=0.12, St=0.21, ); Then the matching value of flow velocity U is obtained: m / s; S3. According to the matching value of the flow velocity U of 0.2 m / s, the horizontal position of each vortex column unit in the vortex column array (3) is adjusted to the radius position closest to 0.2 m / s measured in S1, and fixed by the lower locking mechanism (403) and the upper locking mechanism (603), and the vortex column unit is vibrated with two degrees of freedom in the horizontal direction by using the spring damping structure composed of the damping universal joint (5), the preload spring group (7) and the vortex column unit, and the two-degree-of-freedom amplitude of the vortex column unit is 10-15 cm; S4. When the flow velocity U is too small to reach the excitation threshold of vortex-induced vibration, the guide plate (9) in front of the vortex-induced column unit is lowered, and the tapered design of the guide plate (9) increases the local flow velocity U of the fluid until vortex-induced vibration is excited.

10. A sewage treatment stirring method according to claim 3, characterized in that: The steps include: S1. Measure the outer surface diameter D, damping ratio ζ, unit cylinder mass m of the vortex-induced column unit, and its natural frequency can be obtained based on its damping coefficient and other conditions , when the natural frequency Vortex shedding frequency When the vortex-induced column unit excites vortex-induced vibration, the natural frequency Formula and vortex shedding frequency Formula, we get: , it is known that when the Reynolds number Re is in the range of 300-300000, the Strouhal coefficient St is about 0.21, and the matching value of the flow velocity U is further obtained; S2. After water is injected into the stirring pool (1), the stirring device (2) is started, and the overall flow velocity at the radial position where the vortex-induced vibration array is located is measured. There is a functional relationship between the overall flow velocity of the fluid, the local flow velocity and the relative angle between the guide plates (9). The angle is calculated according to the matching value of the flow velocity U. The relative angle between the two guide plates (9) is increased by controlling the motor (902). The relative angle between the guide plates (9) is gradually increased to increase the local flow velocity U of the fluid, until the vortex-induced vibration is excited and then stops; S3. Using the spring damping structure composed of the damping universal joint (5), the preload spring group (7) and the vortex-induced column unit, the vortex-induced column unit is made to vibrate with two degrees of freedom in the horizontal direction, and the two-degree-of-freedom amplitude of the vortex-induced column unit is 10-15 cm.

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