A wind-inducing structure of a main helium blower

Abstract

The present invention provides an induced draft structure for a main helium blower, and belongs to the field of main helium blowers. The cooled helium of the present invention flows from the upper ends of six ventilation slot steels to the lower ends, and enters the lower end of the drive motor cavity from the air inlet of the machine base. Through the guiding effect of the induced draft hood, the cooled helium is concentrated and directed to the lower auxiliary bearing to cool the lower auxiliary bearing. Then most of the helium flows through the axially inclined ventilation holes on the lower end cover to the outer side of the stator of the lower radial electromagnetic bearing, enters the drive motor cavity, and then flows out through the air outlet of the machine base, taking away the heat generated by the lower auxiliary bearing and the lower electromagnetic bearing. The induced draft structure of the main helium blower of the present invention protects the normal operation of the lower end electromagnetic bearing, thereby ensuring the reliable operation of the main helium blower equipment, avoiding leakage and heat transfer effects of the blower cavity, and avoiding the lower auxiliary bearing being unable to be cooled due to a short circuit in the cooling air path, resulting in excessive temperature of the lower auxiliary bearing, thermal expansion, and causing the lower auxiliary bearing to seize the shaft.

Description

Technical Field

[0001] The invention relates to an air induction structure of a main helium blower, belonging to the field of main helium blowers. Background Art

[0002] The demonstration project of high-temperature gas-cooled reactor nuclear power plant is one of the 16 major projects in my country's "Eleventh Five-Year Plan". The main helium blower is the core active equipment of the high-temperature gas-cooled reactor with completely independent intellectual property rights and the safety characteristics of the fourth-generation nuclear energy system. It is known as the "heart" of the high-temperature gas-cooled reactor. Its function is to provide sufficient flow of helium through the primary circuit system to take away the heat generated by the reactor core during the reactor startup, power operation and shutdown conditions. The main helium blower is a vertical, variable frequency, high-speed large blower with a covering structure, that is, the blower impeller is cantilevered and installed on the end of the drive motor shaft, coaxial with the drive motor, and the blower cavity (243℃) is connected to the drive motor cavity (67℃). The operating temperature difference between the two cavities is very large. The whole machine is installed in the primary circuit helium coolant medium pressure cavity of 7Mpa, and the cumulative environmental radioactive dose is ≤3.5×10 5 GY. The main helium blower has a single unit power of 4500kW, a speed range of 800r / min to 4200r / min, a service life of 40 years, and an unplanned shutdown frequency of less than 1 per year. There are no mature models for blowers of this power scale and speed at home and abroad. This is a domestic first and an international leader.

[0003] The main helium blower is divided into two chambers, the upper chamber is the drive motor chamber (67°C), and the lower chamber is the fan chamber (243°C). There are shaft penetration and heat shield devices between the two chambers to prevent the heat from the fan chamber from entering the drive motor chamber. A water cooler is installed at the upper end of the drive motor chamber, and the drive motor self-cooling fan is installed at the upper end of the fan shaft. The self-cooling fan flows the helium cooled by the water cooler in the drive motor chamber from top to bottom. The cooled helium takes away the heat generated by the drive motor and the electromagnetic bearing, and then returns to the upper end to exchange heat through the water cooler. Because the auxiliary electromagnetic bearing under the driving motor is close to the fan cavity, although insulation measures have been taken at the lower end of the base, there is still a small amount of leakage and heat transfer through the shaft penetration. In addition, the gap between the stator and rotor of the lower auxiliary electromagnetic bearing is very small, only 0.35mm. If the temperature at the lower auxiliary bearing is too high, thermal expansion will occur, the gap will be close to zero, and the stator and rotor will collide, which will cause the bearing to stick to the shaft and the main helium fan will not work. Therefore, in order to ensure the reliable operation of the electromagnetic bearing under the main helium fan, it is crucial to invent a main helium fan induced air structure. Summary of the invention

[0004] The purpose of the present invention is to avoid the above situation from occurring, which may cause the main helium blower to be unable to operate, and further provide an air induction structure for the main helium blower.

[0005] The objective of the present invention is achieved through the following technical solutions:

[0006] A main helium blower air induction structure, the main helium blower air induction structure comprising an air induction cover, a ventilation channel steel and a lower end cover of a driving motor,

[0007] The induced draft hood is installed at the upper end of the heat shield. The induced draft hood and the lower end cover of the drive motor form a cooling helium air path area space. The induced draft hood, the heat shield and the shaft pass through the three components to form a heat insulation cavity. The lower end cover of the drive motor and the drive motor base are fastened and connected by bolts. Ventilation channel steel is welded on the outer side of the wall plate of the drive motor base.

[0008] The self-cooling fan of the driving motor flows the helium cooled by the water cooler from the upper ends of the six ventilation slot steels on the machine base to the lower end, enters the lower end of the driving motor cavity from the air inlet, and is guided by the induced draft hood to the lower auxiliary bearing. A small part of the helium flows through the stator-rotor gap of the lower auxiliary bearing and the stator-rotor gap of the lower radial electromagnetic bearing, and most of the helium flows through the outer side of the stator of the lower auxiliary bearing, and then flows through the axially inclined ventilation holes on the lower end cover to the outer side of the stator of the lower radial electromagnetic bearing, taking away the heat generated by the lower auxiliary bearing and the lower radial electromagnetic bearing of the driving motor, and flows back to the upper water cooler through the air outlet of the machine base for heat exchange circulation cooling.

[0009] The present invention discloses an air induction structure of a main helium blower. The air induction hood comprises an air guide ring, an air guide plate, a rib plate, a baffle plate, a support plate, an air induction plate and a connecting plate. The air guide ring, the air guide plate, the baffle plate and the rib plate are welded to form an air guide area. The air induction hood has six air induction plates, and every two air induction plates are welded to form an acute-angle air outlet area, which are evenly distributed into three acute-angle air outlet areas. The acute-angle air outlet area is further divided into three evenly distributed air inlet areas by the connecting plate and the support plate. Air enters the air inlet area into the air induction hood, flows upward through the acute-angle air induction plates, and flows out of the air induction hood through the air outlet area.

[0010] The present invention provides an air induction structure of a main helium blower. When the air induction cover is installed, it is ensured that each air inlet of the driving motor corresponds to each air induction plate of the air induction cover, and the air inlet of the driving motor cannot correspond to the air inlet area of ​​the air induction cover.

[0011] The present invention provides an air induced draft structure of a main helium blower, wherein the cooling helium is guided to a lower auxiliary bearing via an air induced draft hood to form a centralized cooling air path area, and the lower auxiliary bearing is cooled. Then, the helium is guided from the lower end of the drive motor cavity to the stator surface of the lower radial electromagnetic bearing via 8 evenly distributed axially inclined ventilation holes arranged on the lower end cover of the drive motor, thereby achieving the purpose of cooling the lower auxiliary bearing and the lower radial electromagnetic bearing.

[0012] The present invention discloses an air induction structure for a main helium blower. Six air inlets are arranged on a drive motor base, and three air inlet areas and three air outlet areas are arranged in an air induction hood.

[0013] The present invention provides an air induction structure for a main helium fan. The air induction structure for the main helium fan protects the normal operation of the lower end electromagnetic bearing of the main helium fan driving motor, thereby ensuring the reliable operation of the main helium fan equipment, avoiding leakage and heat transfer influences of the fan cavity, and further avoiding the lower auxiliary bearing from being unable to be cooled due to a short circuit in the cooling air path, resulting in excessive temperature of the lower auxiliary bearing, generating thermal expansion, causing the lower auxiliary bearing to stick, and causing the main helium fan to fail to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the air induction structure of the main helium blower of the present invention.

[0015] Figure 2 It is the front view of the air hood in the present invention.

[0016] Figure 3 It is a top view of the air hood in the present invention.

[0017] Figure 4 This is a diagram of the air hood structure and air path guide in the present invention.

[0018] The reference numerals in the figure are: 1 is the lower end cover of the driving motor; 2 is the lower radial electromagnetic bearing; 3 is the driving motor base; 4 is the ventilation channel steel; 5 is the induced draft hood; 6 is the impeller; 7 is the shaft through-hole; 8 is the heat insulation screen; 9 is the lower auxiliary bearing; 10 is the air inlet; 11 is the air outlet; 12 is the driving motor cavity; 13 is the fan cavity; 14 is the heat insulation cavity; 15 is the air guide ring; 16 is the air guide plate; 17 is the rib plate; 18 is the baffle plate; 19 is the support plate; 20 is the induced draft plate; 21 is the connecting plate; 22 is the air outlet area; 23 is the air inlet area. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings: This embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation method is given, but the protection scope of the present invention is not limited to the following embodiments.

[0020] Embodiment 1: Figure 1-4As shown, the embodiment involves an induced draft structure of a main helium fan, in which the induced draft hood of the main helium fan is installed at the upper end of the heat insulation screen, and forms a cooling helium air path area space with the lower end cover of the drive motor, thereby achieving the purpose of cooling the auxiliary electromagnetic bearing and the lower radial electromagnetic bearing under the main helium fan. In addition, when the induced draft hood is installed, it is necessary to ensure that the air inlet of the drive motor corresponds to the induced draft plate area of ​​the induced draft hood, and cannot be opposite to the air inlet area of ​​the induced draft hood. Ventilation channel steel is welded on the outer side of the wall plate of the drive motor base. The self-cooling fan of the drive motor flows the helium cooled by the water cooler from the upper end of the ventilation channel steel to the lower end, and enters the lower end of the drive motor cavity from the air inlet of the base. After being guided by the induced draft hood, the helium flows to the lower auxiliary bearing. A small part of the helium flows through the stator-rotor gap of the lower auxiliary bearing and the stator-rotor gap of the lower radial electromagnetic bearing, and most of the helium flows through the outer side of the stator of the lower auxiliary bearing, and then flows to the outer side of the stator of the lower radial electromagnetic bearing through the 8 evenly distributed axial inclined ventilation holes on the lower end cover, taking away the heat generated by the lower auxiliary bearing and the lower radial electromagnetic bearing at the lower end of the drive motor, and then exiting through the base. The vent flows back to the upper water cooler for heat exchange circulation cooling; in addition, the induced draft hood is installed at the upper end of the heat insulation screen, and forms a heat insulation cavity with the three parts of the shaft through, which effectively prevents the leakage of high-temperature helium in the fan cavity to the drive motor cavity, and blocks the small amount of leakage and heat transfer of high-temperature helium in the fan cavity (243°C) due to the shaft through-hole, playing the role of a heat insulation screen. At the same time, the guiding effect of the induced draft hood directly guides the cooling helium to the surface of the lower auxiliary bearing, avoiding the direct outflow from the ventilation hole of the end cover due to the short circuit of the wind path, causing the lower auxiliary bearing to have high temperature and generate thermal expansion, and the stator and rotor collide to cause the shaft to stick, which ultimately affects the operation of the main helium fan. The main helium fan induced draft structure of the present invention protects the normal operation of the lower auxiliary bearing and the lower electromagnetic bearing of the main helium fan drive motor, avoids the high temperature of the fan cavity affecting the drive motor cavity, and thus ensures the reliable operation of the main helium fan equipment.

[0021] Embodiment 2: Figure 1 As shown, the induced draft structure of a main helium fan involved in this embodiment, the induced draft structure technology of the main helium fan has been applied to the main helium fan product. The main helium fan product has been tested on the test bench. Before the induced draft hood is installed, the temperature of the lower end bearing of the drive motor is too high during the test process. The lower auxiliary bearing is short-circuited due to the wind path. Most of the cooling helium flows directly from the ventilation hole of the lower end cover. The lower auxiliary bearing is not cooled, and thermal expansion occurs, causing the stator and rotor of the lower auxiliary bearing to almost collide. The surface temperature of the lower auxiliary bearing is as high as 176°C, and the stator temperature of the lower radial electromagnetic bearing is 78°C, resulting in the interruption of the test. After adding the induced draft hood, the test passed smoothly, and the surface temperature of the lower auxiliary bearing was measured to be 82°C, and the stator temperature of the lower radial electromagnetic bearing was 63.4°C. The test proves that after adding the induced draft hood, the surface temperature of the lower auxiliary bearing and the stator temperature of the lower radial electromagnetic bearing are significantly reduced, which meets the normal working requirements of the main helium fan and verifies the practicality of the induced draft structure of the main helium fan.

[0022] The above are only preferred specific embodiments of the present invention, which are all different implementations based on the overall concept of the present invention, and the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A main helium blower air induction structure, characterized in that: The air induced structure of the main helium blower comprises an air induced hood (5), a ventilation channel steel (4) and a lower end cover (1) of the driving motor. The air induced hood (5) is installed at the upper end of the heat insulation screen (8). The air induced hood (5) and the lower end cover (1) of the driving motor form a cooling helium air path area space. The air induced hood (5), the heat insulation screen (8) and the shaft through-hole (7) form a heat insulation cavity (14). The lower end cover (1) of the driving motor and the driving motor base (3) are fastened and connected by bolts. The ventilation channel steel (4) is welded to the outer side of the wall plate of the driving motor base (3). The self-cooling fan of the driving motor directs the helium cooled by the water cooler to flow from the upper ends of the six ventilation slot steels (4) on the machine base to the lower ends, and enters the lower end of the driving motor cavity (12) through the air inlet (10). The helium flows to the lower auxiliary bearing (9) under the guidance of the induced draft hood (5). A small portion of the helium flows through the stator-rotor gap of the lower auxiliary bearing (9) and the stator-rotor gap of the lower radial electromagnetic bearing (2), and most of the helium flows through the stator outer side of the lower auxiliary bearing (9), and then flows to the stator outer side of the lower radial electromagnetic bearing (2) through the axially inclined ventilation holes on the lower end cover (1), taking away the heat generated by the lower auxiliary bearing and the lower radial electromagnetic bearing of the driving motor, and flows back to the upper water cooler through the machine base air outlet (11) for heat exchange circulation cooling; The air induced hood (5) comprises an air guide ring (15), an air guide plate (16), a rib plate (17), a baffle plate (18), a support plate (19), an air induced plate (20) and a connecting plate (21). The air guide ring (15), the air guide plate (16), the baffle plate (18) and the rib plate (17) are welded to form an air guide area. The air induced hood (5) has six air induced plates (20). Every two air induced plates are welded to form an acute angle air outlet area (22). The air induced plates (20) are evenly distributed to form three acute angle air outlet areas (22). The acute angle air outlet areas (22) are further divided into three evenly distributed air inlet areas (23) by the connecting plate (21) and the support plate (19). The air enters the air induced hood (5) from the air inlet area (23), flows upward through the air induced plates (20), and flows out of the air induced hood (5) through the air outlet area (22).

2. The air induction structure of the main helium blower according to claim 1, characterized in that: When the air induced hood (5) is installed, it is necessary to ensure that each air inlet (10) of the driving motor corresponds to each air inlet plate (20) of the air induced hood (5), and the air inlet (10) of the driving motor cannot correspond to the air inlet area (23) of the air induced hood (5).

3. The air induction structure of the main helium blower according to claim 2, characterized in that: The cooling helium is led to the lower auxiliary bearing (9) through the induced draft hood (5) to form a concentrated cooling air path area for cooling the lower auxiliary bearing. Then, the helium is led from the lower end of the drive motor cavity (12) to the stator surface of the lower radial electromagnetic bearing (2) through 8 evenly distributed axial inclined ventilation holes provided on the lower end cover (1) of the drive motor.

4. The air induction structure of the main helium blower according to claim 2, characterized in that: Six base air inlets (10) are arranged on the drive motor base (3), and three air inlet areas (23) and three air outlet areas (22) are arranged in the air induced cover (5).

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