Gas-liquid separation device for salt cavern compression energy storage system

Abstract

The invention discloses a gas-liquid separation device for a salt cavern compression energy storage system, which comprises a dehumidification rotary cabin, an acceleration rotary cabin, a centrifugal assembly and an acceleration assembly, the centrifugal assembly and the acceleration assembly are respectively positioned in the dehumidification rotary cabin and the acceleration rotary cabin, and the bottom end of the acceleration rotary cabin is fixedly connected with a gas expansion cover for communicating with the top end of the dehumidification rotary cabin; a cyclone disc cabin is fixedly installed at the top end of the acceleration rotating cabin, a flow guide inner pipe is fixedly installed on the inner side of the acceleration rotating cabin, the acceleration assembly comprises a driving disc and an acceleration impeller, the driving disc is fixed to the surface of the flow guide inner pipe and used for driving the acceleration impeller to rotate, and a main shaft is arranged at the axis of the acceleration impeller. According to the invention, by separately arranging the structures of the dehumidification rotary cabin and the acceleration rotary cabin, under the boosting effect of the acceleration assembly in the acceleration rotary cabin, the salt-cavern compression energy storage working medium airflow swirling and acceleration are performed, so that the airflow is introduced into the dehumidification rotary cabin at a high speed, the airflow movement rate is increased, and the high-speed centrifugal effect is generated; and the working effect of gas-liquid treatment is improved.

Description

Technical Field

[0001] The invention relates to the technical field of salt cavern compression energy storage systems, and in particular to a gas-liquid separation device for a salt cavern compression energy storage system. Background Art

[0002] The salt cavern compression energy storage system is a large-scale energy storage and power generation technology. Its principle is similar to that of a pumped storage power station, but the upper reservoir is replaced by an underground salt cavern and the water is replaced by air. When the power grid is in a low power consumption period, the system uses electricity to extract and compress air into underground salt caverns for storage; when the power grid is in a peak power consumption period, the compressed air is released to generate electricity through a turbine expander, and the electricity is fed back to the grid. This technology can achieve large-scale clean energy storage of electricity, effectively improve the time and space structure of power generation and power consumption, and achieve "peak shaving and valley filling" of power supply and demand. During the use of the salt cavern compression energy storage system, since the underground salt cavern may contain a certain amount of water (such as brine), when the compressed air is released from the salt cavern, it may carry a certain amount of water. If this water directly enters the turbine expander or other power generation equipment, it will cause erosion damage to the equipment, reducing the service life of the equipment and the power generation efficiency.

[0003] The gas-liquid separator is a commonly used gas-liquid separation device in the salt cavern compressed air energy storage system. When the compressed air is released from the salt cavern and passes through a series of pipelines, it enters the gas-liquid separator. Inside the gas-liquid separator, the gas and liquid are separated due to the density difference through specific structural design and fluid mechanics principles. The gas continues to flow to the subsequent power generation equipment, while the liquid is collected and discharged from the system. The separation efficiency of some traditional gas-liquid separators (such as baffle separators, centrifugal separators, etc.) is highly dependent on the gas flow rate. When the gas flow rate exceeds a certain range, the separation efficiency will drop significantly. This requires strict control of the gas flow rate in practical applications, which increases the difficulty and cost of operation. In some cases, in order to further improve the gas-liquid separation effect, condensation may be used as an auxiliary means. This method achieves gas-liquid separation by lowering the temperature of the compressed air so that the water vapor in it condenses into liquid water. The condensation method can be used in combination with the gas-liquid separator to further improve the separation efficiency. In addition to the above two methods, filtration may also be used for gas-liquid separation. The filtration method uses filter media (such as filter screens, filter cloths, etc.) to filter compressed air to remove liquid particles. However, the filtration method may not be able to completely remove all liquids, especially for liquids in tiny droplets or aerosol states.

[0004] In view of this, research and improvement are carried out on the existing problems, and a gas-liquid separation device for a salt cavern compression energy storage system is provided to solve the current problems. The purpose is to achieve the purpose of solving the problems and improving the practical value through this technology. Summary of the invention

[0005] The present invention aims to solve one of the technical problems existing in the prior art or related technology.

[0006] To this end, the technical solution adopted by the present invention is: a gas-liquid separation device for a salt cavern compression energy storage system, comprising: a dehumidifying cyclone cabin, an accelerating cyclone cabin, and a centrifugal assembly and an accelerating assembly respectively located inside the dehumidifying cyclone cabin and the accelerating cyclone cabin, the bottom end of the accelerating cyclone cabin is fixedly connected with an air diffuser hood for communicating with the top end of the dehumidifying cyclone cabin, the top end of the accelerating cyclone cabin is fixedly installed with a cyclone disc cabin, the inner side of the accelerating cyclone cabin is fixedly installed with a guide inner tube, the accelerating assembly comprises a driving disc and an accelerating impeller, and the driving disc is fixed to the surface of the guide inner tube for driving the accelerating impeller to rotate, a main shaft is provided at the axis center of the accelerating impeller, and the top end of the main shaft is fixedly connected with a swirl blade rotatably installed on the inner side of the cyclone disc cabin, and the surface of the cyclone disc cabin is provided with an air inlet port; An air outlet guide ring and a driving motor are fixedly installed at the bottom end of the dehumidification rotary chamber, and the air outlet guide ring is sleeved on the surface of the driving motor, and a tangentially arranged exhaust pipe is provided on the surface of the air outlet guide ring, and a driving motor and an absorption filter chamber are fixedly installed on the inner side of the dehumidification rotary chamber, and the output end of the driving motor is fixedly connected to the bottom end of the centrifugal assembly, and the centrifugal assembly comprises a conical impeller, an axial flow wheel and a centrifugal impeller coaxially connected from top to bottom, a plurality of evenly distributed filter holes are provided on the surface of the absorption filter chamber, and anhydrous silica gel particles are filled on the inner side of the absorption filter chamber, and an exhaust compartment is provided on the bottom surface of the absorption filter chamber, and a centrifugal groove is provided on the surface of the absorption filter chamber, and the acceleration impeller is rotationally installed on the inner side of the centrifugal groove.

[0007] In a preferred example, the present invention can be further configured as follows: the air diffuser hood and the conical impeller are both conical structures, and the conical impeller is rotatably installed on the inner side of the air diffuser hood, the blades on the surface of the conical impeller are arranged in a spiral strip shape, and the gas-liquid mixer accelerated inside the dehumidification cyclone chamber is discharged along the gap between the air diffuser hood and the conical impeller, and the rotation of the conical impeller performs swirl treatment on the accelerated airflow, so that the airflow exhibits swirl motion.

[0008] In a preferred example, the present invention can be further configured as follows: a plurality of evenly distributed drainage holes are provided on the surface of the dehumidification rotary chamber and the driving motor, and a valve port for controlling the drainage is provided on the surface of the drainage hole, water is discharged from the air outlet guide ring and the driving motor through the valve port, and the valve port is closed to avoid affecting the airflow of the vortex.

[0009] In a preferred example, the present invention can be further configured as follows: the absorption filter chamber is double-layered and annular, and the top surface is fixedly connected to the top surface of the inner cavity of the dehumidification rotary chamber; the top of the dehumidification rotary chamber is provided with an annular gap connected to the outer periphery of the absorption filter chamber for the discharge of the conical impeller vortex gas; after passing through the filter hole, the airflow enters the absorption filter chamber, and the centrifugal groove further adsorbs and removes the water inside the airflow.

[0010] In a preferred example, the present invention can be further configured as follows: the bottom periphery of the exhaust compartment is fixedly connected to the surface of the drive motor, and the surface of the drive motor is provided with an annular guide port connected to the periphery of the centrifugal impeller for discharging the swirling water of the centrifugal impeller, and guiding the high-speed swirling water into the interior of the drive motor for storage.

[0011] In a preferred example, the present invention can be further configured as follows: a plurality of coil disks are provided on the surface of the driving disk, a top surface of the accelerating impeller is provided with an embedding groove, and a permanent magnet block arranged opposite to the coil disk is embedded and installed on the surface of each embedding groove, the number of the cyclone disk cabins and the accelerating impellers is several and arranged at intervals from each other, and the multi-stage accelerating impeller is driven at high speed to accelerate the airflow.

[0012] In a preferred example, the present invention can be further configured as follows: the top surface of the centrifugal impeller and the bottom end of the exhaust compartment are arranged relative to each other for the introduction of airflow, the outer periphery of the centrifugal impeller is provided with a dehydration groove connected to the inner side of the drive motor, and the bottom surface of the centrifugal impeller is provided with an air guide hole close to the axis of the centrifugal impeller, air is taken in through the bottom surface during the rotation of the centrifugal impeller, and under the high-speed rotation of the centrifugal impeller, water vapor is discharged through the dehydration groove, and due to the positive pressure of the airflow inside the drive motor and the centrifugal impeller, the dry airflow close to the axis of the centrifugal impeller is discharged through the air guide hole.

[0013] The beneficial effects achieved by the present invention are: 1. In the present invention, by separately arranging a dehumidification vortex chamber and an accelerating vortex chamber structure, the airflow of the salt cavern compression energy storage working medium is swirled and accelerated under the boosting effect of the accelerating component inside the accelerating vortex chamber, so that it passes into the dehumidification vortex chamber at a high speed, thereby increasing the airflow movement rate, generating a high-speed centrifugal effect, and improving the gas-liquid treatment working effect.

[0014] 2. In the present invention, the high-speed rotation of the conical impeller, the axial flow wheel and the centrifugal impeller is driven by a driving motor, so that the airflow of the salt cavern compressed energy storage working medium further produces a high-speed cyclone effect, and the gas-liquid density difference is utilized to make the liquid particles flow along the inner wall of the dehumidification cyclone chamber, and the airflow is introduced into the centrifugal impeller after passing through the absorption filter chamber. Under the further centrifugation of the centrifugal impeller, the gas-liquid centrifugal separation is further carried out. The multiple centrifugal effects improve the gas-liquid separation effect, and the tiny droplets or liquids in aerosol state can also be effectively adsorbed and retained.

[0015] 3. In the present invention, a driving motor structure is provided, air flow is introduced through the filter holes, and water vapor is captured and adsorbed by the anhydrous silica gel particles inside, and the water vapor is subjected to cyclone separation and adsorption removal, thereby achieving a double water vapor separation and removal effect, with a simple structure and high practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the overall structure of an embodiment of the present invention; Figure 2 This is a schematic diagram of the internal structure of a dehumidifying spin chamber and an accelerating spin chamber according to an embodiment of the present invention; Figure 3 A schematic diagram of a cross section of an accelerating component and a centrifugal component structure according to an embodiment of the present invention; Figure 4 This is a schematic diagram of the cross-sectional structure of an accelerating spin cabin according to an embodiment of the present invention; Figure 5 A schematic diagram of the decomposition structure of an acceleration component according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the structure of an absorption filter cabin according to an embodiment of the present invention; Figure 7 The figure is a schematic diagram of the structure of a centrifugal impeller according to an embodiment of the present invention.

[0017] Reference numerals: 100, dehumidification rotary chamber; 110, air outlet guide ring; 120, driving motor; 130, absorption filter chamber; 140, separation liquid chamber; 111, exhaust pipe; 131, filter hole; 132, anhydrous silica gel particles; 133, centrifugal tank; 134, exhaust compartment; 200, accelerating cyclone cabin; 210, cyclone disc cabin; 220, air expansion cover; 230, flow guide inner tube; 211, air inlet port; 212, swirl blade; 300, acceleration assembly; 310, driving disk; 320, acceleration impeller; 311, coil disk; 321, embedded slot; 322, permanent magnet block; 400, centrifugal assembly; 410, conical impeller; 420, axial flow wheel; 430, centrifugal impeller; 431, dehydration tank; 432, air guide hole. DETAILED DESCRIPTION

[0018] To make the purpose, technical solution and advantages of the present invention more clear, the present invention is further described in detail below in combination with specific implementations and with reference to the accompanying drawings. It should be noted that the embodiments of the present invention and the features in the embodiments can be combined with each other without conflict.

[0019] It is to be understood that these descriptions are exemplary only and are not intended to limit the scope of the invention.

[0020] A gas-liquid separation device for a salt cavern compression energy storage system provided by some embodiments of the present invention will be described below in conjunction with the accompanying drawings.

[0021] Combination Figure 1-Figure 7As shown, a gas-liquid separation device for a salt cavern compression energy storage system provided by the present invention comprises: a dehumidifying cyclone cabin 100, an accelerating cyclone cabin 200, and a centrifugal assembly 400 and an accelerating assembly 300 respectively located inside the dehumidifying cyclone cabin 100 and the accelerating cyclone cabin 200, wherein the bottom end of the accelerating cyclone cabin 200 is fixedly connected with an air diffuser 220 for communicating with the top end of the dehumidifying cyclone cabin 100, the top end of the accelerating cyclone cabin 200 is fixedly installed with a cyclone disc cabin 210, the inner side of the accelerating cyclone cabin 200 is fixedly installed with a guide inner tube 230, the accelerating assembly 300 comprises a driving disc 310 and an accelerating impeller 320, and the driving disc 310 is fixed to the surface of the guide inner tube 230 for driving the accelerating impeller 320 to rotate, a main shaft is provided at the axis center of the accelerating impeller 320, and the top end of the main shaft is fixedly connected with a swirl blade 212 rotatably installed on the inner side of the cyclone disc cabin 210, and the surface of the cyclone disc cabin 210 is provided with an air inlet port 211; An air outlet guide ring 110 and a driving motor 120 are fixedly installed at the bottom end of the dehumidification rotary cabin 100, and the air outlet guide ring 110 is sleeved on the surface of the driving motor 120. A tangentially arranged exhaust pipe 111 is provided on the surface of the air outlet guide ring 110. The driving motor 120 and the absorption filter cabin 130 are fixedly installed on the inner side of the dehumidification rotary cabin 100. The output end of the driving motor 120 is fixedly connected to the bottom end of the centrifugal assembly 400. The centrifugal assembly 400 includes a conical impeller 410, an axial flow wheel 420 and a centrifugal impeller 430 coaxially connected from top to bottom. A plurality of evenly distributed filter holes 131 are provided on the surface of the absorption filter cabin 130. The inner side of the absorption filter cabin 130 is filled with anhydrous silica gel particles 132. The bottom surface of the absorption filter cabin 130 is provided with an exhaust compartment 134, and the surface of the absorption filter cabin 130 is provided with a centrifugal groove 133. The acceleration impeller 320 is installed on the inner side of the centrifugal groove 133.

[0022] In this embodiment, both the air diffuser 220 and the conical impeller 410 are conical structures, and the conical impeller 410 is rotatably mounted on the inner side of the air diffuser 220, and the blades on the surface of the conical impeller 410 are arranged in a spiral strip shape.

[0023] Specifically, the accelerated gas-liquid mixer inside the dehumidification cyclone chamber 100 is led out along the gap between the air diffuser 220 and the conical impeller 410, and the rotation of the conical impeller 410 performs swirl processing on the accelerated airflow, so that the airflow exhibits swirl motion.

[0024] In this embodiment, a plurality of evenly distributed drainage holes are provided on the surface of the dehumidifying rotary chamber 100 and the driving motor 120, and a valve port for controlling the drainage is provided on the surface of the drainage hole.

[0025] Specifically, the water is discharged through the valve port in the air outlet guide ring 110 and the drive motor 120, and the valve port is closed to avoid affecting the swirl airflow.

[0026] In this embodiment, the absorption filter cabin 130 is double-layered and annular, and its top surface is fixedly connected to the top surface of the inner cavity of the dehumidification rotary cabin 100. The top of the dehumidification rotary cabin 100 is provided with an annular gap connected to the outer periphery of the absorption filter cabin 130 for the discharge of the cyclone gas of the conical impeller 410.

[0027] Specifically, after passing through the filter holes 131 , the airflow enters the absorption filter cabin 130 , and the centrifugal groove 133 further adsorbs and removes the water in the airflow.

[0028] In this embodiment, the outer periphery of the bottom end of the exhaust compartment 134 is fixedly connected to the surface of the drive motor 120. The surface of the drive motor 120 is provided with an annular guide port connected to the outer periphery of the centrifugal impeller 430 for discharging the swirling water of the centrifugal impeller 430, and guiding the high-speed swirling water into the interior of the drive motor 120 for storage.

[0029] In this embodiment, a plurality of coil disks 311 are provided on the surface of the driving disk 310, a top surface of the accelerating impeller 320 is provided with an embedding groove 321, and a permanent magnet block 322 arranged opposite to the coil disk 311 is embedded and installed on the surface of each embedding groove 321, and the number of the cyclone disk cabin 210 and the accelerating impeller 320 is several and they are arranged at intervals from each other.

[0030] Specifically, through multiple driving disks 310 and accelerating impellers 320, the coil disk 311 generates inductance during current input and acts on the permanent magnet block 322 to drive the accelerating impeller 320, thereby achieving high-speed driving of the multi-stage accelerating impeller 320 and accelerating the airflow.

[0031] In this embodiment, the top surface of the centrifugal impeller 430 is arranged relative to the bottom end of the exhaust chamber 134 for the introduction of airflow, the outer periphery of the centrifugal impeller 430 is provided with a dehydration groove 431 connected to the inner side of the drive motor 120, and the bottom surface of the centrifugal impeller 430 is provided with an air guide hole 432 close to the axis of the centrifugal impeller 430.

[0032] Specifically, air is taken in through the bottom surface during the rotation of the centrifugal impeller 430, and the water vapor is discharged through the dehydration groove 431 under the high-speed rotation of the centrifugal impeller 430. Due to the positive air pressure inside the driving motor 120 and the centrifugal impeller 430, the dry air flow close to the axis of the centrifugal impeller 430 is discharged through the air guide hole 432.

[0033] The working principle and use process of the present invention: In the use of the gas-liquid separation device, the air inlet port 211 and the exhaust pipe 111 are connected to the air inlet pipe and the exhaust pipe, respectively, and the coil disk 311 on the surface of the driving disk 310 exerts electromagnetic action on the permanent magnet block 322 on the surface of the accelerating impeller 320 to drive the accelerating impeller 320 to rotate, so that the accelerating impeller 320 and the swirl blades 212 perform high-speed swirl thrust of the airflow, so that the airflow is accelerated and thrusted along the gap between the inside of the accelerating swirl chamber 200 and the outer periphery of the guide inner tube 230; The synchronous driving motor 120 drives the conical impeller 410, the axial flow wheel 420 and the centrifugal impeller 430 to rotate synchronously at a high speed. The airflow generates a cyclone effect under the action of the surface of the conical impeller 410, so that the gas and liquid undergo the first step of high-speed cyclone centrifugal separation. The gas-liquid density difference is used to make the liquid particles flow along the inner wall of the dehumidification cyclone cabin 100 and gather and condense, and the low-density airflow passes through the absorption filter cabin 130 under the action of air pressure. After passing through the filter hole 131, the airflow enters the absorption filter cabin 130, and the centrifugal groove 133 further adsorbs and removes the water in the airflow. After passing through the exhaust compartment 134, the axial flow wheel 420 further accelerates and boosts it, while the water is retained in the dehumidification cyclone cabin 100 and adsorbed and stored by the centrifugal groove 133. After passing through the absorption filter cabin 130, the airflow is introduced into the centrifugal impeller 430. Under the further centrifugation of the centrifugal impeller 430, the gas-liquid centrifugal separation is further performed. The multiple centrifugal effects improve the gas-liquid separation effect, and the pure dry airflow is discharged through the air outlet guide ring 110 and the exhaust pipe 111.

[0034] In the description of this specification, the description of the terms "one embodiment", "some embodiments", "specific embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0035] Although the embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the claims and their equivalents.

Claims

1. A gas-liquid separation device for a salt cavern compression energy storage system, characterized in that: include: A dehumidifying cyclone chamber (100), an accelerating cyclone chamber (200), and a centrifugal assembly (400) and an accelerating assembly (300) respectively located inside the dehumidifying cyclone chamber (100) and the accelerating cyclone chamber (200), wherein the bottom end of the accelerating cyclone chamber (200) is fixedly connected to an air diffuser hood (220) for communicating with the top end of the dehumidifying cyclone chamber (100), the top end of the accelerating cyclone chamber (200) is fixedly mounted with a cyclone disc chamber (210), and the inner side of the accelerating cyclone chamber (200) is fixedly mounted with a guide The inner tube (230), the acceleration assembly (300) comprising a driving disk (310) and an accelerating impeller (320), the driving disk (310) being fixed to the surface of the guide inner tube (230) for driving the accelerating impeller (320) to rotate, a main shaft being provided at the axis of the accelerating impeller (320), and a swirl vane (212) being rotatably mounted on the inner side of the cyclone disk cabin (210) being fixedly connected to the top of the main shaft, and an air inlet port (211) being provided on the surface of the cyclone disk cabin (210); An air outlet guide ring (110) and a drive motor (120) are fixedly mounted on the bottom end of the dehumidifying rotary chamber (100), and the air outlet guide ring (110) is sleeved on the surface of the drive motor (120). A tangentially arranged exhaust pipe (111) is provided on the surface of the air outlet guide ring (110). The drive motor (120) and an absorption filter chamber (130) are fixedly mounted on the inner side of the dehumidifying rotary chamber (100). The output end of the drive motor (120) is fixedly connected to the bottom end of a centrifugal assembly (400). The centrifugal assembly (400) includes The invention comprises a conical impeller (410), an axial flow wheel (420) and a centrifugal impeller (430) which are coaxially connected in sequence from top to bottom; the surface of the absorption filter cabin (130) is provided with a plurality of evenly distributed filter holes (131); the inner side of the absorption filter cabin (130) is filled with anhydrous silica gel particles (132); the bottom surface of the absorption filter cabin (130) is provided with an exhaust cavity (134); the surface of the absorption filter cabin (130) is provided with a centrifugal groove (133); and the acceleration impeller (320) is rotatably mounted on the inner side of the centrifugal groove (133).

2. A gas-liquid separation device for a salt cavern compression energy storage system according to claim 1, characterized in that: The air diffuser hood (220) and the conical impeller (410) are both conical structures, and the conical impeller (410) is rotatably mounted on the inner side of the air diffuser hood (220), and the blades on the surface of the conical impeller (410) are arranged in a spiral strip shape.

3. A gas-liquid separation device for a salt cavern compression energy storage system according to claim 1, characterized in that: The surfaces of the dehumidifying rotary chamber (100) and the driving motor (120) are provided with a plurality of evenly distributed drainage holes, and the surfaces of the drainage holes are provided with valve ports for controlling the drainage.

4. The gas-liquid separation device for a salt cavern compression energy storage system according to claim 1, characterized in that: The absorption filter cabin (130) is double-layered and annular, and its top surface is fixedly connected to the top surface of the inner cavity of the dehumidification rotary cabin (100). The top of the dehumidification rotary cabin (100) is provided with an annular gap that is in communication with the outer periphery of the absorption filter cabin (130) and is used for the discharge of the cyclone gas of the conical impeller (410).

5. The gas-liquid separation device for a salt cavern compression energy storage system according to claim 1, characterized in that: The outer periphery of the bottom end of the exhaust compartment (134) is fixedly connected to the surface of the drive motor (120), and the surface of the drive motor (120) is provided with an annular guide port that is in communication with the outer periphery of the centrifugal impeller (430) and is used to guide the swirling water liquid of the centrifugal impeller (430) out, thereby guiding the high-speed swirling water liquid into the interior of the drive motor (120) for storage.

6. The gas-liquid separation device for a salt cavern compression energy storage system according to claim 1, characterized in that: The surface of the driving disk (310) is provided with a plurality of coil disks (311); the top surface of the accelerating impeller (320) is provided with an embedding groove (321); and a permanent magnet block (322) arranged opposite to the coil disk (311) is embedded and installed on the surface of each embedding groove (321); and the cyclone disk cabin (210) and the accelerating impeller (320) are provided in a plurality and are arranged at intervals from each other.

7. The gas-liquid separation device for a salt cavern compression energy storage system according to claim 1, characterized in that: The top surface of the centrifugal impeller (430) and the bottom end of the exhaust compartment (134) are arranged opposite to each other for introducing airflow; the outer periphery of the centrifugal impeller (430) is provided with a dehydration groove (431) which is connected to the inner side of the drive motor (120); and the bottom surface of the centrifugal impeller (430) is provided with an air guide hole (432) close to the axis of the centrifugal impeller (430).

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