Magnetic levitation booster fan for conveying low-pressure, thin gases

Abstract

A magnetic levitation booster fan for conveying low-pressure rarefied gas relates to the field of fan technology. The technical solution includes an outer pipe, a motor, a centrifugal impeller, and a flow channel. The outer pipe includes an inlet pipe, a straight pipe, and an outlet pipe. The inlet pipe has an air inlet, and the outlet pipe has an air outlet. The motor includes a motor housing, a motor stator, and a motor rotor. The motor housing includes a tubular body with a front end cover at one end and a rear end cover at the other end. The outer diameter of the tubular body is larger than the inner diameter of the air inlet. The centrifugal impeller includes a hub and multiple blades. The flow channel includes a centrifugal flow channel and a diffuser flow channel. This invention improves the flow channel structure and uses electromagnetic bearings, which can increase the pressure difference between the air outlet and the air inlet by at least 1 kPa and ensure continuous operation over a long period.

Description

Technical Field

[0001] This invention relates to the field of fan technology, and in particular to a magnetic levitation booster fan for conveying low-pressure rarefied gas. Background Technology

[0002] Data centers are crucial for data transmission, acceleration, visualization, computation, and storage. Their most significant characteristic is 24 / 7 operation, generating substantial amounts of heat. Therefore, cooling systems are essential to dissipate this heat and prevent equipment damage from high temperatures. Immersion phase change cooling systems are a highly efficient solution suitable for data centers. They utilize the latent heat of the boiling phase change of the cooling medium to remove heat. The equipment is immersed in the cooling medium, and the heat generated raises the temperature of the medium. When the medium reaches its boiling point, a boiling phase change occurs on the equipment surface, carrying away the heat. The steam generated from boiling travels through steam pipes to the condenser, where it condenses into a liquid and is recirculated.

[0003] The steam is a low-pressure, rarefied gas, and the inside of the steam pipe is close to a vacuum, making it difficult for the steam to flow. A fan is needed to pressurize the steam, and the number of bends should be minimized to reduce pressure loss. However, since the air pressure at the fan inlet is only about 6 kPa, conventional axial flow fans have poor pressurization effects. Centrifugal fans have better pressurization effects than axial flow fans, but the inlet and outlet of conventional centrifugal fans are usually at a 90° angle, changing the gas delivery direction and requiring multiple bends. Data centers operate continuously year-round, requiring fans with a continuous operating life of over 10 years. Therefore, there is an urgent need to design a new type of fan that meets these requirements. Summary of the Invention

[0004] To address the problems of poor pressurization effect of conventional axial flow fans for low-pressure rarefied gases, the alteration of gas delivery direction and the requirement for long service life of conventional centrifugal fans in existing technical solutions, this invention provides a magnetic levitation booster fan for conveying low-pressure rarefied gases.

[0005] This invention provides the following technical solution: a magnetic levitation booster fan for conveying low-pressure rarefied gas, comprising: The outer pipe includes an inlet pipe, a straight pipe and an outlet pipe connected in sequence. The inlet pipe is provided with an air inlet and the outlet pipe is provided with an air outlet. An electric motor includes a motor housing, a motor stator, and a motor rotor. The motor housing is disposed inside the outer tube and coaxial with the outer tube. The motor housing includes a tubular body with a front end cap at one end facing the inlet pipe and a rear end cap at the other end. The outer diameter of the tubular body is larger than the inner diameter of the air inlet. The motor stator is disposed on the inner wall of the tubular body. The motor rotor is rotatably connected to the tubular body via an electromagnetic bearing and also includes an output shaft. The centrifugal impeller includes a hub disposed on the output shaft and multiple blades disposed on the hub. The hub is conical, and the bottom surface of the hub with a larger area faces the front end cover. The flow channel connects the air inlet and the air outlet. The flow channel includes a centrifugal flow channel formed by the inlet pipe, the hub, and the motor housing, and a diffuser flow channel formed by the outlet pipe and the motor housing. The blade is disposed at the end of the centrifugal flow channel facing the air inlet. The diffuser flow channel has the largest cross-sectional area at the end facing the air outlet.

[0006] Preferably, the tubular body is connected to the straight pipe via multiple connecting plates, the connecting plates extending along the axial direction of the straight pipe.

[0007] Preferably, the inlet pipe is further provided with a constricted section, which is the area between the air inlet and the hub. The inner diameter of the constricted section gradually decreases from the air inlet to the end of the constricted section facing the hub, and the outer diameter of the tubular body is greater than the maximum inner diameter of the constricted section.

[0008] Preferably, the inner diameter of the inlet pipe gradually increases from the air inlet to the straight end of the inlet pipe, and the inner diameter of the outlet pipe gradually decreases from the straight end of the outlet pipe to the air outlet.

[0009] Preferably, the outer diameter of the rear end cover gradually decreases from one end of the rear end cover toward the air inlet to the other end.

[0010] Preferably, the motor speed is at least 20,000 rpm.

[0011] Preferably, the electromagnetic bearing includes a first radial electromagnetic bearing and a second radial electromagnetic bearing respectively disposed at both ends of the motor stator, and a thrust electromagnetic bearing disposed on the side of the first radial electromagnetic bearing away from the motor stator.

[0012] Preferably, both the front end cover and the rear end cover are provided with protective bearings between them and the motor rotor.

[0013] Preferably, the flow channel further includes a flat DC channel formed by the straight pipe and the motor housing, wherein the cross-sectional area of ​​the flat DC channel remains constant from one end of the straight pipe to the other end.

[0014] Preferably, the straight pipe is further provided with a lead pipe.

[0015] The beneficial effects of this invention are: 1. The motor rotor is rotatably connected to the motor housing by an electromagnetic bearing. The electromagnetic bearing eliminates mechanical friction, and the motor speed can be increased to at least 20,000 rpm. The high speed can provide stronger boosting capability. 2. The flow channel structure has been improved. Centrifugal impellers and centrifugal flow channels are used to pressurize and accelerate low-pressure rarefied gas. The static pressure is further improved by using a diffuser flow channel. With the support of high-speed centrifugal impellers, the outlet gas pressure can be increased to more than 7 kPa, which is at least 1 kPa higher than the inlet gas pressure of only 6 kPa, thus promoting the pressurized flow of low-pressure rarefied gas. 3. The air inlet and outlet of the flow channel are coaxial, which can transport low-pressure rarefied gas along the axial direction of the fan, and no elbow is needed at the connection with the steam pipe. 4. Electromagnetic bearings have no mechanical wear, no lubrication requirements, and no risk of oil contamination. Furthermore, low-pressure rarefied gas is difficult to enter the motor, reducing the risk of damage to internal motor components. The fan's service life can reach more than 10 years, supporting long-term operation. Attached Figure Description

[0016] Figure 1 This is a cross-sectional view of one embodiment of a magnetic levitation booster fan.

[0017] Figure 2 This is a schematic diagram of one embodiment of a centrifugal flow channel.

[0018] Reference numerals: 11. Inlet pipe; 12. Straight pipe; 13. Outlet pipe; 14. Air inlet; 15. Air outlet; 16. Narrowing section; 21. Tubular body; 22. Motor rotor; 23. Motor stator; 24. Front end cover; 25. Rear end cover; 31. First radial electromagnetic bearing; 32. Second radial electromagnetic bearing; 33. Thrust electromagnetic bearing; 34. Protective bearing; 41. Hub; 42. Blade; 51. Centrifugal flow channel; 52. Straight straight flow channel; 53. Diffuser flow channel. Detailed Implementation

[0019] The embodiments of the present invention will be described in more detail below with reference to the accompanying drawings and reference numerals, so that those skilled in the art can implement them after reading this specification. It should be understood that the specific embodiments described herein are only for explaining the present invention and are not intended to limit the present invention.

[0020] This invention provides a magnetic levitation booster fan for conveying low-pressure rarefied gas, which is applied to the steam pipe of a heat dissipation system. It achieves pressurization and circulation of low-pressure rarefied gas through high-speed centrifugal impeller and improved flow channel, and uses electromagnetic bearings to ensure long-term stable operation at high speed.

[0021] Please refer to Figure 1 The magnetic levitation booster fan includes an outer pipe, a motor installed inside the outer pipe, a centrifugal impeller driven by the motor, and a flow channel for the flow of low-pressure rarefied gas.

[0022] The outer pipe comprises an inlet pipe 11, a straight pipe 12, and an outlet pipe 13 connected in sequence by flanges, all three being coaxial. The inlet pipe 11 is provided with an air inlet 14, and the outlet pipe 13 is provided with an air outlet 15. Both the air inlet 14 and the air outlet 15 are connected to a steam pipe, and their inner diameters are the same as those of the steam pipe. Low-pressure rarefied gas enters the outer pipe through the air inlet 14, passes sequentially through the inlet pipe 11, the straight pipe 12, and the outlet pipe 13, and flows out through the air outlet 15. The straight pipe 12 is also provided with a lead-in conduit from which the cables for the motor and electromagnetic bearing are led out.

[0023] The motor includes a motor housing, which comprises a tubular body 21 connected to the inner wall of a straight pipe 12 via a connecting plate. The tubular body 21 is coaxial with the outer pipe, and the connecting plate extends linearly or spirally along the axial direction of the outer pipe. A motor rotor 22 is rotatably connected to the inner wall of the tubular body 21 via an electromagnetic bearing, and a motor stator 23 is also provided on the inner wall of the tubular body 21, which surrounds the motor rotor 22. An output shaft is also provided at one end of the motor rotor 22. The specific structure of the motor rotor 22 and the motor stator 23 can be referred to in related technologies, and this invention does not limit them. A front end cover 24 is provided at one end of the tubular body 21 facing the inlet pipe 11, and a rear end cover 25 is provided at the other end. The front and rear end covers enclose the tubular body, and the sealing performance is enhanced by providing sealing rings between the front and rear end covers and the tubular body, and by providing labyrinth seals between the front and rear end covers and the motor rotor, thus avoiding direct contact between the motor stator 23 and the medium, reducing the risk of motor damage, and improving stability.

[0024] Electromagnetic bearings enable the motor rotor to float without mechanical support from the motor housing, eliminating mechanical friction and wear, and providing higher rotational speeds for the motor rotor. They also eliminate the need for any lubrication and the risk of oil contamination. These advantages ensure that the fan can operate stably for a long time.

[0025] Specifically, the electromagnetic bearing includes a first radial electromagnetic bearing 31 and a second radial electromagnetic bearing 32 respectively disposed at both ends of the motor stator 23, and a thrust electromagnetic bearing 33 disposed on the side of the first radial electromagnetic bearing 31 facing away from the motor stator 23. A protective bearing 34 is also disposed between the front end cover 24, the rear end cover 25, and the motor rotor 22. Under normal circumstances, the motor rotor does not contact the protective bearing. However, in the event of a sudden situation, such as an electromagnetic system failure or power outage, the electromagnetic bearing loses its function, and the protective bearing will mechanically bear the load of the motor rotor, protecting the fan from severe damage. The specific structures of the radial electromagnetic bearing, the thrust electromagnetic bearing, and the protective bearing can be referred to in related technologies; this invention does not impose any limitations on them.

[0026] The centrifugal impeller includes a hub 41 mounted on the output shaft of the motor rotor 22 and multiple blades 42 mounted on the hub 41, with only a small gap between the hub 41 and the front cover 24. The blades 42 can be similar to those used in centrifugal fans, such as three-dimensional impellers. The motor rotor 22 drives the centrifugal impeller to rotate at high speed, transferring energy to the low-pressure rarefied gas. In one embodiment, with the support of electromagnetic bearings, the motor speed is at least 20,000 rpm, significantly improving the pressurization capacity of the low-pressure rarefied gas through high speed.

[0027] The outer pipe, hub 41, and motor housing form a flow channel, connecting the air inlet 14 and outlet 15. Low-pressure, rarefied gas enters through the air inlet 14, is pressurized by the fan in the flow channel, and then flows out through the outlet 15. The inner wall of the outer pipe, the outer surface of the hub, and the outer surface of the motor housing are all rounded to reduce fluid disturbance and pressure loss. Please refer to... Figure 1 The flow channel includes a centrifugal flow channel 51, a straight flow channel 52, and a diffuser flow channel 53.

[0028] The centrifugal flow channel 51 is formed by the inlet pipe 11, hub 41, front end cap 24, and tubular body 21. Please refer to... Figure 2 , Figure 2 The blades are concealed. The inner diameter of the inlet pipe 11 gradually increases from the air inlet 14 to the end of the inlet pipe 11 facing the straight pipe 12, forming a flared opening with a gradually increasing cross-sectional area at the end of the inlet pipe 11 facing the straight pipe 12. Specifically, the change in the inner diameter of the inlet pipe 11 along the axial direction can cause the inner wall of the inlet pipe 11 to form a shape similar to... Figure 2 The ellipsoidal surface shown can also form a conical surface. The hub 41 has a conical structure, with its larger bottom surface facing the front cover 24. The diameters of the front cover 24 and the tubular body 21 gradually increase from the inlet to the outlet. This structure creates a centrifugal flow channel 51 formed by the inlet pipe 11, hub 41, front cover 24, and tubular body 21 that gradually diffuses radially outward from the inlet 14 to the end of the inlet pipe 11 facing the straight pipe 12. The blades 42 of the centrifugal impeller are located at the end of the centrifugal flow channel 51 facing the inlet 14. Low-pressure rarefied gas enters from the inlet 14, and the high-speed rotation of the centrifugal impeller increases the pressure and speed of the low-pressure rarefied gas. Under the action of centrifugal force, the gas is thrown out and compressed along the centrifugal flow channel 51, further increasing the static pressure.

[0029] like Figure 2In one embodiment shown, the portion of the inlet pipe 11 between the air inlet 14 and the hub 41 is a constricted section 16. The inner diameter of the constricted section 16 gradually decreases from the air inlet 14 towards the hub 41, forming a constriction. Low-pressure, rarefied gas enters from the air inlet 14, converges through the constricted section 16, and is then accelerated and pressurized by the centrifugal impeller. The outer diameter of the tubular body 21 is increased to be greater than the maximum inner diameter of the constricted section 16, further strengthening the centrifugal force compared to the prior art, which is more conducive to improving the static pressure of the gas.

[0030] In another embodiment, the portion of the inlet pipe 11 between the air inlet 14 and the hub 41 is a straight pipe with a constant inner diameter; the outer diameter of the tubular body 21 is increased to be greater than the inner diameter of the air inlet 14.

[0031] The horizontal straight channel 52 is formed by the straight pipe 12 and the tubular body 21, connecting the centrifugal channel 51 and the diffuser channel 53. In the axial direction, the inner diameter of the straight pipe 12 remains unchanged, and the outer diameter of the tubular body 21 at the horizontal straight channel 52 also remains unchanged, so that the cross-sectional area of ​​the horizontal straight channel 52 remains unchanged from one end of the straight pipe 12 to the other end.

[0032] The diffuser channel 53 is formed by the outlet pipe 13 and the rear end cap 25. The inner diameter of the outlet pipe 13 gradually decreases from the end of the outlet pipe 13 toward the straight pipe 12 to the outlet 15, until it reaches the inner diameter of the outlet 15. The inner diameter of the outlet 15 is the same as the inner diameter of the steam pipe, forming a straight pipe at the end of the outlet pipe 13, with one end of the straight pipe being the outlet 15. The outer diameter of the rear end cap 25 gradually decreases from the end of the rear end cap 25 toward the inlet 14 to the other end, for example, forming a semi-ellipsoid, which can reduce the disturbance to the airflow. The above structure makes the cross-sectional area of ​​the diffuser channel 53 at the end toward the outlet 15 the largest, and in the straight pipe at the end of the outlet pipe 13, the cross-sectional area of ​​the diffuser channel is larger the closer to the outlet 15. According to Bernoulli's principle, as the cross-sectional area of ​​the diffuser channel 53 increases, the flow velocity of the low-pressure rarefied gas slows down, further increasing the static pressure.

[0033] The above describes one or more embodiments of the present invention in a relatively specific and detailed manner, but it should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.

Claims

1. A magnetic levitation booster fan for conveying low-pressure rarefied gas, characterized in that, include: The outer pipe includes an inlet pipe, a straight pipe and an outlet pipe connected in sequence. The inlet pipe is provided with an air inlet and the outlet pipe is provided with an air outlet. An electric motor includes a motor housing, a motor stator, and a motor rotor. The motor housing is disposed inside the outer tube and coaxial with the outer tube. The motor housing includes a tubular body with a front end cap at one end facing the inlet pipe and a rear end cap at the other end. The outer diameter of the tubular body is larger than the inner diameter of the air inlet. The motor stator is disposed on the inner wall of the tubular body. The motor rotor is rotatably connected to the tubular body via an electromagnetic bearing. The motor rotor also includes an output shaft. The centrifugal impeller includes a hub disposed on the output shaft and multiple blades disposed on the hub. The hub is conical, and the bottom surface of the hub with a larger area faces the front end cover. The flow channel connects the air inlet and the air outlet. The flow channel includes a centrifugal flow channel formed by the inlet pipe, the hub, and the motor housing, and a diffuser flow channel formed by the outlet pipe and the motor housing. The blade is disposed at the end of the centrifugal flow channel facing the air inlet. The diffuser flow channel has the largest cross-sectional area at the end facing the air outlet.

2. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The tubular body is connected to the straight pipe by a plurality of connecting plates, which extend along the axial direction of the straight pipe.

3. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The inlet pipe is also provided with a constricted section, which is the area between the air inlet and the hub. The inner diameter of the constricted section gradually decreases from the air inlet to the end of the constricted section facing the hub. The outer diameter of the tubular body is greater than the maximum inner diameter of the constricted section.

4. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The inner diameter of the inlet pipe gradually increases from the air inlet to the straight end of the inlet pipe, and the inner diameter of the outlet pipe gradually decreases from the straight end of the outlet pipe to the air outlet.

5. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 4, characterized in that, The outer diameter of the rear end cover gradually decreases from one end toward the air inlet to the other.

6. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The motor speed is at least 20,000 rpm.

7. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The electromagnetic bearing includes a first radial electromagnetic bearing and a second radial electromagnetic bearing respectively disposed at both ends of the motor stator, and a thrust electromagnetic bearing disposed on the side of the first radial electromagnetic bearing away from the motor stator.

8. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, Both the front and rear covers are provided with protective bearings between themselves and the motor rotor.

9. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The flow channel also includes a flat DC channel formed by the straight pipe and the motor housing, the cross-sectional area of ​​which remains constant from one end of the straight pipe to the other.

10. A magnetic levitation booster fan for conveying low-pressure rarefied gas according to claim 1, characterized in that, The straight pipe is also equipped with a lead pipe.

Images