JP2022102679A - Rotating machine cooling system, and cooling system for superconducting devices - Google Patents

Abstract

To provide a rotating machine cooling system having an excellent cooling performance while preventing occurrence of problems when the refrigerant leaks, and a cooling system for superconducting devices.SOLUTION: A rotating machine cooling system has a rotating part 4a including a superconducting circuit. The superconducting rotor 4 includes: a first tank capable of storing liquid nitrogen; and a nitrogen gas supply path 18 for supplying a nitrogen gas generated from liquid nitrogen to the superconducting circuit. The nitrogen gas generated from the liquid nitrogen stored in the first tank is supplied to the superconducting circuit of the rotating part 4a via the nitrogen gas supply path to cool the superconducting circuit. Thus, the nitrogen gas in a gaseous state is supplied as the refrigerant supplied to the rotating part.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a cooling system for rotating machinery and a cooling system for superconducting devices.

The electric resistance value of a conductor used in an electric circuit is one of the important physical properties that affect the performance of the electric circuit. As one of these types of conductors, superconductors are attracting attention as materials having extremely excellent conductivity because their electric resistance values are greatly reduced in an extremely low temperature environment. For example, high-temperature superconductors such as YBCO and BSCCO have a transition temperature from the normal conduction state to the superconducting state higher than the boiling point (77K) of liquid nitrogen at atmospheric pressure, and are easier to handle than liquid helium. Since liquid nitrogen, which is inexpensive, can realize a superconducting state, it is expected to be used for various purposes.

In order to realize a superconducting device, a cooling system for stably maintaining the superconducting state of the superconductor is required. As an example of this type of cooling system, Patent Document 1 proposes a cooling device capable of cooling using latent heat by evaporating a part of the liquid refrigerant stored in the liquid refrigerant tank.

Japanese Unexamined Patent Publication No. 2016-162893

By the way, in a rotating machine provided with a rotating portion that can rotate with respect to a stationary system, in a superconducting device in which at least a part of an electric circuit included in the rotating portion is composed of a superconducting circuit, the superconducting device rotates to cool the superconducting circuit. It is necessary to supply the refrigerant to the part. In this case, since the refrigerant supply path for supplying the refrigerant is provided from the stationary system to the rotating portion, if the refrigerant in a liquid state is supplied as in Patent Document 1, when the refrigerant leaks to the outside. Due to the vaporization, the volume expands significantly, which may lead to problems such as damage to the peripheral configuration.

At least one aspect of the present disclosure has been made in view of the above circumstances, and is used to cool a rotating machine cooling system and a superconducting device, which have excellent cooling performance while preventing the occurrence of problems when a refrigerant leaks. The purpose is to provide a system.

The rotary machine cooling system according to one aspect of the present disclosure is to solve the above problems.
A cooling system for rotating machinery that has a rotating part that includes a superconducting circuit.
The first tank that can store liquid nitrogen and
A nitrogen gas supply path for supplying nitrogen gas generated from the liquid nitrogen to the superconducting circuit,
To prepare for.

The cooling system for the superconducting device according to one aspect of the present disclosure is to solve the above problems.
A cooling system for superconducting devices, including superconducting circuits.
The first tank that can store liquid nitrogen and
A nitrogen gas supply path for supplying nitrogen gas generated from the liquid nitrogen to the superconducting circuit,
To prepare for.

According to at least one aspect of the present disclosure, it is possible to provide a cooling system for a rotating machine and a cooling system for a superconducting device, which have excellent cooling performance while preventing the occurrence of defects when a refrigerant leaks.

It is sectional drawing which shows schematic about the whole structure of the rotary machine which concerns on one Embodiment. It is sectional drawing along the central axis of the superconducting rotor of FIG. It is a perspective view which shows the cage-shaped conductor of FIG. 2 alone. It is an overall block diagram of the cooling system of the rotary machine which concerns on 1st Embodiment. It is an overall block diagram of the cooling system of the rotary machine which concerns on 2nd Embodiment. It is an overall block diagram of the cooling system of the rotary machine which concerns on 3rd Embodiment.

Hereinafter, some embodiments of the present disclosure will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, etc. of the components described as embodiments or shown in the drawings are not intended to limit the scope of the present disclosure to this, and are merely explanatory examples. do not have.
For example, expressions that represent relative or absolute arrangements such as "in one direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" are exact. Not only does it represent such an arrangement, but it also represents a tolerance or a state of relative displacement at an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "same", "equal", and "homogeneous" that indicate that things are in the same state not only represent exactly the same state, but also have tolerances or differences to the extent that the same function can be obtained. It shall also represent the existing state.
For example, an expression representing a shape such as a square shape or a cylindrical shape not only represents a shape such as a square shape or a cylindrical shape in a geometrically strict sense, but also an uneven portion or a chamfering within a range where the same effect can be obtained. It shall also represent the shape including the part and the like.
On the other hand, the expressions "to have", "to have", "to have", "to include", or "to have" one component are not exclusive expressions that exclude the existence of other components.

First, with reference to FIG. 1, the overall configuration of the rotary machine 1 to be cooled by the cooling system 100 will be described. FIG. 1 is a cross-sectional view schematically showing an overall configuration of a rotary machine 1 according to an embodiment. Although the superconducting motor will be described as an example of the rotary machine 1 in the present embodiment, the rotary machine 1 may be any device provided with a rotating portion that can rotate with respect to the stationary system.

The rotating machine 1 includes a stator 2 which is a stationary system, and a superconducting rotor 4 including a rotating portion 4a (see FIG. 2) which is rotatable with respect to the stator 2. The stator 2 and the superconducting rotor 4 are arranged in the motor casing 3 so as to face each other with a predetermined clearance. The superconducting rotor 4 is rotatable about a rotation shaft C and is supported by bearings 6a, 6b, 6c with respect to the motor casing 3 as described later with reference to FIG.

FIG. 2 is a cross-sectional structural view along the central axis C of the superconducting rotor 4 of FIG. 1, and FIG. 3 is a perspective view showing the cage-shaped conductor 13 of FIG. 2 as a single unit.

As shown in FIG. 2, the superconducting rotor 4 has a rotating portion 4a that is rotatable with respect to the central axis C, and a stationary portion 4b that is stationary with respect to the motor casing 4. The rotating portion 4a includes a rotor core 12 and a cage-shaped conductor 13 attached to the rotor core 12. The rotor core 12 is configured to include a magnetic material such as iron, and has a plurality of slots 12a configured to penetrate between the end faces perpendicular to the rotation axis C. The cage conductor 13 is supported with respect to the rotor core 12 by inserting the plurality of superconducting bars 14 included in the cage conductor 13 into the plurality of slots 12a.

The inner diameter of the plurality of slots 12a provided in the rotor core 12 is formed to be larger than the outer diameter of the plurality of superconducting bars 14. As a result, between the inner surface of the plurality of slots 12a and the outer surface of the plurality of superconducting bars 14, a flow path for cooling the plurality of superconducting bars 14 inserted in the plurality of slots 12a flows (described later). Refrigerant flow path 10c) is secured.

As shown in FIG. 3, the cage-shaped conductor 13 is an example of a superconducting circuit 8, and a plurality of superconducting bars 14 extending along a rotation axis C and both ends of the plurality of superconducting bars 14 are connected to each other. A pair of superconducting end rings 16a, 16b, and the like. The superconducting bar 14 and the pair of superconducting end rings 16a and 16b are configured, for example, by laminating superconducting tape wires obtained by molding a superconducting material into a long shape. A plurality of superconducting bars 14 among the cage-shaped conductors 13 flow in the plurality of slots 12a in a state of being inserted into the plurality of slots 12a formed in the rotor core 12 as described above with reference to FIG. It is cooled by the refrigerant. Further, although the pair of superconducting end rings 16a and 16b is not shown in FIG. 2, by being housed in the refrigerant flow paths 10b and 10d, the pair of superconducting end rings 16a and 16b are cooled by the refrigerant flowing through the refrigerant flow paths 10b and 10d.

Returning to FIG. 2, the rotor core 12 to which the cage conductor 13 is attached has an output shaft together with a rotor casing 23 constituting the outer shell of the superconducting rotor 4 via a torque tube 17 on both ends along the central axis C. It is linked to 19. The output shaft 19 and the rotor casing 23 are rotatably supported with respect to the motor casing 3 (see FIG. 1), which is a stationary system, via bearings 6a and 6b, respectively.

The superconducting rotor 4 has a cooling flow path 10 for cooling the superconducting circuit 8. The cooling flow path 10 is provided from the rotating portion 4a to the stationary portion 4b of the superconducting rotor 4, so that the refrigerant can be supplied from the outside to the rotating portion 4a including the superconducting circuit 8. Low-temperature nitrogen gas is supplied to the cooling flow path 10 as a refrigerant from the nitrogen gas supply path 18 provided in the stationary portion 4b. The superconducting circuit 8 is cooled to a superconducting transition temperature Tc or less by exchanging heat with the refrigerant flowing through the cooling flow path 10. The nitrogen gas whose temperature has risen due to heat exchange with the superconducting circuit 8 is discharged to the outside of the superconducting rotor 4 via the nitrogen gas discharge path 20.

The stationary portion 4b of the superconducting rotor 4 is fixed to the motor casing 3 arranged around the superconducting rotor 4, and includes a nitrogen gas supply path 18 and a nitrogen gas discharge path 20. The nitrogen gas supply path 18 extends from the nitrogen gas supply source outside the superconducting rotor 4 toward the rotor core 12 along the central axis C, and the tip thereof is opened so that the cooling flow provided in the rotor core 12 is provided. Communicate with road 10. The refrigerant discharged from the cooling flow path 10 is discharged to the outside of the superconducting rotor 4 via the nitrogen gas discharge path 20.

The nitrogen gas discharge passage 20 includes a first nitrogen gas discharge passage 20a provided along the central axis C (on the outer diameter side of the nitrogen gas supply passage 18) so as to surround the nitrogen gas supply passage 18, and a first nitrogen gas. The first inner casing 20b provided at the end of the discharge path 20a (the end opposite to the rotor core 12) and the first inner casing 20b extend perpendicularly to the central axis C and discharge external nitrogen. Includes a second nitrogen gas discharge path 20c communicating with the above (not shown). The first inner casing 20b is provided so as to surround the end of the first nitrogen gas discharge path 20a from the outside, and is to prevent nitrogen gas from leaking between the first inner casing 20b and the outer surface of the first nitrogen gas discharge path 20a. The first seal member 25a of the above is arranged.

Of the nitrogen gas discharge passages 20, the first nitrogen gas discharge passage 20a belongs to the rotating portion 4a, while the first inner casing 20b and the second nitrogen gas discharge passage 20c belong to the stationary portion 4b. Therefore, the first nitrogen gas discharge path 20a is rotatably supported with respect to the first inner casing 20b via the bearing 6c.

Further, on the outside of the first inner casing 20b, a second inner casing 27 is provided so as to surround the first inner casing 20b. The second inner casing 27 is rotatably connected to the rotor housing 23 included in the rotating portion 4a of the superconducting rotor 4 via the second seal member 25b. A vacuum heat insulating layer 22 is provided between the outer surface of the first inner casing 20b and the inner surface of the second inner casing 27. As will be described later, the vacuum heat insulating layer 22 continues to the rotating portion 4a side of the superconducting rotor 4, and heat invades the cooling flow path 10, the nitrogen gas supply path 18, and the nitrogen gas discharge path 20 by insulating them from the outside. It suppresses the amount of gas, enhances the cooling effect, and suppresses the consumption of refrigerant.

The stationary portion 4b has a decompression pipe 26 that leads to a decompression device (for example, a vacuum pump) arranged outside (for example, a vacuum pump). By communicating the pressure reducing pipe 26 with the second inner casing 27, the degree of vacuum of the vacuum heat insulating layer 22 is satisfactorily maintained by the pressure reducing device.

The layout of the cooling flow path 10 in the superconducting rotor 4 is designed corresponding to the shape of the superconducting circuit 8 included in the superconducting rotor 4. FIG. 1 shows a case where the cooling flow path 10 is configured to include the first flow path 10a to the fourth flow path 10d as an example of the layout. The first flow path 10a passes through the substantially central portion of the superconducting rotor 4 along the rotation axis C so as to continue to the downstream side of the nitrogen gas supply path 18 included in the stationary portion 4b, and is on the output shaft side of the rotor core 12. It is a flow path that extends to. The second flow path 10b is a manifold flow path connected to the downstream side of the first flow path 10a on the output shaft side of the rotor core 12 and having a plurality of branch paths extending along the radial direction. One of the superconducting end rings 16a is housed in the second flow path 10b, and the superconducting end ring 16a is cooled by the refrigerant flowing through the second flow path 10b. The third flow path 10c is a flow path defined by a plurality of slots 12a provided in the rotor core 12 as described above, and is connected to the downstream side of each of the plurality of branch paths of the second flow path 10b. It extends along the axial direction to the stationary portion 4b side of the rotor core 12. The superconducting bar 14 is housed in the third flow path 10c, and the superconducting bar 14 is cooled by the refrigerant flowing through the third flow path 10c. The fourth flow path 10d extends along the radial direction on the stationary portion 4b side of the rotor core 12 to join the downstream sides of each of the plurality of flow paths of the third flow path 10c and communicate with the nitrogen gas discharge path 20. Manifold flow path. The other superconducting end ring 16b is housed in the fourth flow path 10d, and the superconducting end ring 16b is cooled by the refrigerant flowing through the fourth flow path 10d.

As a result, in the cooling flow path 10 shown in FIG. 2, the nitrogen gas supplied from the nitrogen gas supply path 18 first flows radially inside the superconducting rotor 4 to one end side of the rotor core 12 by the first flow path 10a. It is branched by the second flow path 10b. The nitrogen gas branched in the second flow path 10b reaches the third flow path 10c while cooling one of the superconducting end rings 16a housed in the second flow path 10b. In the third flow path 10c, the nitrogen gas flows to the other end side of the rotor core 12 while cooling the superconducting bar 14 housed in the third flow path 10c, and reaches the fourth flow path 10d. In the fourth flow path 10d, the nitrogen gas reaches the nitrogen gas discharge path 20 while cooling the superconducting end ring 16b housed in the fourth flow path 10d.

Further, the rotating portion 4a of the superconducting rotor 4 has a vacuum heat insulating layer 22 continuing from the above-mentioned stationary portion 4b. In the rotating portion 4a, the vacuum heat insulating layer 22 is configured to surround at least a part of the cooling flow path 10. In the example of FIG. 1, the vacuum heat insulating layer 22 extends over a wide range inside the superconducting rotor 4, and in the rotating portion 4a, particularly in the cooling flow path 10, the first flow path 10a, the second flow path 10b, and the cooling flow path 10b. By surrounding the rotor core 12 in addition to the fourth flow path 10d, heat intrusion into the refrigerant flowing through these flow paths and the rotor core 12 is prevented. The vacuum heat insulating layer 22 may be configured to surround at least a part of these flow paths and the rotor core 12.

(First Embodiment)
Subsequently, the cooling system 100 for cooling the rotary machine 1 having the above configuration will be specifically described based on some embodiments. FIG. 4 is an overall configuration diagram of the cooling system 100A of the rotary machine 1 according to the first embodiment.

The cooling system 100A includes a first tank 102, a nitrogen gas supply path 18, and a nitrogen gas discharge path 20. The first tank 102 is a tank capable of storing liquid nitrogen LN, which is a refrigerant for cooling the superconducting circuit. The capacity of the first tank 102 is set sufficiently large so as to have a margin with respect to the maximum capacity of the liquid nitrogen LN stored in the first tank 102. A predetermined amount of liquid nitrogen LN is stored in the first tank 102, and the upper layer side thereof is filled with nitrogen gas GN generated by evaporation of a part of liquid nitrogen.

The first tank 102 has a first refrigerator 108 for cooling the liquid nitrogen LN stored therein. The operating state of the first refrigerator 108 is controlled by a controller (not shown), so that the temperature of the liquid nitrogen LN stored in the first tank 102 is adjusted to be lower than the preset first temperature T1. .. The first temperature T1 is, for example, 77K, which is the boiling point of nitrogen (N ₂ ) at atmospheric pressure.

The nitrogen gas supply path 18 supplies the nitrogen gas GN generated from the liquid nitrogen LN stored in the first tank 102 to the superconducting circuit 8. In the first embodiment, the nitrogen gas supply path 18 can introduce a nitrogen gas GN generated by evaporation of liquid nitrogen LNN inside the first tank 102 by communicating the upstream side with the upper part of the first tank 102. It is composed of. The downstream side of the nitrogen gas supply path 18 is connected to the cooling flow path 10 included in the superconducting rotor 4 as described above with reference to FIG. As a result, the nitrogen gas GN supplied by the nitrogen gas supply path 18 is introduced into the cooling flow path 10, and the superconducting circuit 8 is cooled to a temperature lower than the superconducting transition temperature Tc.

As described above, in the first embodiment, the nitrogen gas GN generated by the evaporation of the liquid nitrogen LN stored in the first tank 102 is passed through the nitrogen gas supply path 18 connected to the first tank 102. It can be supplied to the superconducting circuit 8 included in the superconducting rotor 4 which is a rotating portion. By supplying the nitrogen gas GN in a gaseous state as the refrigerant supplied to the superconducting rotor 4 in this way, even if the nitrogen gas GN leaks from the cooling flow path 10, there is a problem in the peripheral configuration. Can be effectively reduced.

When the refrigerant supplied to the cooling flow path 10 is liquid nitrogen LN, if leakage occurs, the volume rapidly increases, and a problem is likely to occur in the peripheral configuration. In the present embodiment, since the superconducting circuit 8 is at least partially surrounded by the vacuum heat insulating layer 22 as described above, when the liquid nitrogen LN leaks from the cooling flow path 10 to the vacuum heat insulating layer 22, the liquid nitrogen LN is generated. Due to rapid vaporization, the volume increases rapidly. This causes a problem in the peripheral configuration.

The nitrogen gas GN whose temperature has risen by cooling the superconducting circuit 8 in the superconducting rotor 4 is recovered in the first tank 102 via the nitrogen gas recovery path 106. A compressor 109 is provided in the nitrogen gas recovery path 106, and driving the compressor 109 promotes the discharge of nitrogen gas GN from the superconducting rotor 4. The downstream side of the nitrogen gas recovery path 106 is connected to the first tank 102, and the nitrogen gas GN discharged from the superconducting rotor 4 is recovered in the first tank 102 and cooled by the first refrigerator 108. It is liquefied. As a result, the nitrogen gas GN used for cooling the superconducting circuit 8 can be repeatedly used, and the system operating cost can be effectively reduced.

(Second Embodiment)
FIG. 5 is an overall configuration diagram of the cooling system 100B of the rotary machine 1 according to the second embodiment. In the following description, of the cooling system 100B of the second embodiment, the configuration corresponding to the above-described embodiment is indicated by a common reference numeral, and duplicated description will be omitted as appropriate.

The cooling system 100B includes a first tank 102, a decompression device 103, a nitrogen gas supply path 18, a gas-liquid separation device 105, and a liquid nitrogen recovery path 112. The decompression device 103 decompresses the liquid nitrogen LN stored in the first tank 102. The first tank 102 and the decompression device 103 are connected via a liquid nitrogen supply line 110. The upstream side of the liquid nitrogen supply line 110 communicates with a relatively lower portion of the first tank 102 so that the liquid nitrogen LN stored in the first tank 102 can be introduced into the decompression device 103.

The temperature of the liquid nitrogen LN introduced into the depressurizing device 103 is lowered by depressurizing the liquid nitrogen LN, and the liquid nitrogen LN becomes a two-phase state in which the liquid phase component and the gas phase component are mixed. The gas-liquid separator 105 (for example, a centrifuge, a tank with a demista, etc.) has nitrogen gas GN, which is a gas phase component, and liquid nitrogen, which is a liquid phase component, from the two-phase state generated by depressurizing in this way. Separate from LN. The low-temperature nitrogen gas GN separated by the gas-liquid separator 105 is supplied to the superconducting rotor 4 via the nitrogen gas supply path 18 and is used for cooling the superconducting circuit 8 of the superconducting rotor 4. ..

As described above, in the second embodiment, the low-temperature nitrogen gas GN generated by decompressing the liquid nitrogen LN stored in the first tank 102 by gas-liquid separation can be supplied to the superconducting circuit 8 as a refrigerant. .. As a result, the superconducting circuit 8 can be satisfactorily cooled by using a lower temperature nitrogen gas GN. Further, since the liquid nitrogen LNN used for generating the nitrogen gas GN can be stored in the first tank 102 in a liquid state, the first tank 102 is the first as compared with the case where the refrigerant is stored in the gas state (the state of the nitrogen gas GN). The capacity of the tank 102 can be reduced, and the cooling system 100B can be realized with a more compact configuration.

Further, the low-temperature liquid nitrogen LN separated by the gas-liquid separation device 105 is recovered in the first tank 102 via the liquid nitrogen recovery path 112. The liquid nitrogen recovery path 112 is provided with a pump 111 for adjusting the flow rate of the liquid nitrogen LN separated by the gas-liquid separation device 105.

The nitrogen gas GN whose temperature has risen by cooling the superconducting circuit 8 in the superconducting rotor 4 is recovered in the first tank 102 via the nitrogen gas recovery path 106. A compressor 109 is provided in the nitrogen gas recovery path 106, and driving the compressor 109 promotes the discharge of nitrogen gas GN from the superconducting rotor 4. The downstream side of the nitrogen gas recovery path 106 is connected to the first tank 102, and the nitrogen gas GN discharged from the superconducting rotor 4 is recovered in the first tank 102 and cooled by the first refrigerator 108. It is liquefied. As a result, the nitrogen gas GN used for cooling the superconducting circuit 8 can be repeatedly used, and the system operating cost can be effectively reduced.

(Third Embodiment)
FIG. 6 is an overall configuration diagram of the cooling system 100C of the rotary machine 1 according to the third embodiment. In the following description, of the cooling system 100C of the third embodiment, the configuration corresponding to the above-described embodiment is indicated by a common reference numeral, and duplicated description will be omitted as appropriate.

The cooling system 100C includes a first tank 102, a decompression device 103, a nitrogen gas supply path 18, a gas-liquid separation device 105, a liquid nitrogen supply path 114, a second tank 116, and a heat exchanger 118. Be prepared. The low-temperature nitrogen gas GN separated by the gas-liquid separator 105 is supplied to the superconducting rotor 4 via the nitrogen gas supply path 18 and is used for cooling the superconducting circuit 8 of the superconducting rotor 4. ..

The low-temperature liquid nitrogen LN separated by the gas-liquid separation device 105 is supplied to the second tank 116 via the liquid nitrogen supply path 114. The liquid nitrogen supply path 114 is provided with a pump device 124 for adjusting the supply amount of liquid nitrogen LN to the second tank 116 by the liquid nitrogen supply path 114. The second tank 116 is a tank capable of storing the liquid nitrogen LN separated by the gas-liquid separation device 105. The capacity of the second tank 116 is set sufficiently large so as to have a margin with respect to the maximum capacity of the liquid nitrogen LN stored in the second tank 116. Further, the second tank 116 has a second refrigerator 119 for cooling the liquid nitrogen LN stored therein. The operating state of the second refrigerator 119 is controlled by a controller (not shown), so that the temperature of the liquid nitrogen LN stored in the second tank 116 is adjusted to be lower than the preset second temperature T2. .. The second temperature T2 is set lower than the above-mentioned first temperature T1, and is, for example, about 70K.

The second tank 116 is provided with a nitrogen gas circulation path 120 for circulating the liquid nitrogen LN stored in the second tank 116. The nitrogen gas circulation path 120 is connected to a relatively lower portion of the second tank 116 so that the liquid nitrogen LN stored in the second tank 116 can be circulated. Further, the nitrogen gas circulation path 120 is provided with a pump device 122 for adjusting the circulation amount of liquid nitrogen LN in the nitrogen gas circulation path 120.

The heat exchanger 118 is configured to be able to exchange heat between the nitrogen gas GN flowing through the nitrogen gas discharge path 20 and the liquid nitrogen LN flowing through the nitrogen gas circulation path 120. As a result, the nitrogen gas GN flowing through the nitrogen gas discharge path 20 whose temperature has risen due to the cooling of the superconducting circuit 8 is cooled by the low-temperature liquid nitrogen LN flowing through the nitrogen gas circulation path 120.
The flow rate of the nitrogen gas flowing through the nitrogen gas discharge path 20 can be adjusted by the pump device 109 provided in the nitrogen gas discharge path 20 as in the above-described embodiment.

As described above, in the third embodiment, the nitrogen gas GN whose temperature has risen by cooling the superconducting circuit 8 exchanges heat with the low-temperature liquid nitrogen LN flowing through the nitrogen gas circulation path 120 in the heat exchanger 118. Be cooled. As a result, the nitrogen gas GN supplied to the superconducting circuit 8 can be repeatedly used for cooling the superconducting circuit 8 while keeping it in a low temperature state. As a result, the amount of refrigerant consumed in the cooling system 100C can be reduced, and the operating cost of the system can be effectively suppressed.

As described above, according to some of the above-described embodiments, the nitrogen gas GN generated from the liquid nitrogen LN stored in the first tank 102 is supplied to the superconducting circuit 8 via the nitrogen gas supply path 18. By doing so, the superconducting circuit 8 is cooled. By supplying the nitrogen gas GN in a gaseous state as a refrigerant to the superconducting circuit 8 in this way, even if the refrigerant leaks, the possibility of causing a problem in the peripheral configuration is effectively reduced, and the result is good. The superconducting circuit 8 can be cooled.

In the above-described embodiment, the case where the superconducting circuit 8 provided on the superconducting rotor 4 side, which is the rotating portion of the rotating machine 1, is targeted for cooling has been described, but the superconducting circuit provided on the stator 2 side is used. It may be a cooling target. Further, a superconducting device (for example, a superconducting cable or the like) that utilizes a superconducting circuit in a mode different from that of the rotating machine 1 may be a cooling target.

In addition, it is possible to replace the components in the above-described embodiment with well-known components as appropriate without departing from the spirit of the present disclosure, and the above-described embodiments may be combined as appropriate.

The contents described in each of the above embodiments are grasped as follows, for example.

(1) The cooling system for the rotating machine according to one aspect is
A cooling system (for example, the above embodiment) of a rotating machine (for example, the rotating machine 1 of the above embodiment) having a rotating portion (for example, the superconducting rotor 4 of the above embodiment) including a superconducting circuit (for example, the superconducting circuit 8 of the above embodiment). The cooling system of the form 100),
A first tank capable of storing liquid nitrogen (for example, the first tank 102 of the above embodiment) and
A nitrogen gas supply path for supplying nitrogen gas generated from the liquid nitrogen to the superconducting circuit (for example, the nitrogen gas supply path 18 of the above embodiment) and
To prepare for.

According to the aspect (1) above, the nitrogen gas generated from the liquid nitrogen stored in the first tank is supplied to the superconducting circuit of the rotating portion via the nitrogen gas supply path, so that the superconductivity is achieved. The circuit is cooled. As the refrigerant supplied to the rotating portion in this way, nitrogen gas in a gaseous state is supplied. Therefore, compared to the case of supplying liquid nitrogen in a liquid state, even if a leak occurs when supplying the refrigerant to the superconducting circuit included in the rotating part, the capacity change of the refrigerant is small, causing a problem in the peripheral configuration. Good cooling of superconducting circuits is possible while effectively reducing the possibility.

(2) In another aspect, in the above aspect (1),
The nitrogen gas supply path is connected to the first tank so that the nitrogen gas can be obtained from the upper layer side of the liquid nitrogen stored in the first tank.

According to the aspect (2) above, the nitrogen gas generated by the evaporation of the liquid nitrogen stored in the first tank is passed through the nitrogen gas supply path connected to the first tank to the rotating portion. Can be supplied to superconducting circuits.

(3) In another aspect, in the above aspect (1) or (2),
A nitrogen gas recovery path (for example, the nitrogen gas recovery path 106 of the above embodiment) for recovering the nitrogen gas after cooling the superconducting circuit is further provided in the first tank.

According to the aspect (3) above, the nitrogen gas whose temperature has risen by cooling the superconducting circuit is recovered in the first tank via the nitrogen gas recovery path. This makes it possible to repeatedly use the nitrogen gas used for cooling the superconducting circuit, and the system operating cost can be effectively reduced.

(4) In another aspect, in the above aspect (1),
A decompression device capable of depressurizing the liquid nitrogen stored in the first tank (for example, the decompression device 103 of the above embodiment) and
A gas-liquid separator capable of separating the liquid nitrogen decompressed by the decompression device (for example, the gas-liquid separation device 105 of the above embodiment) and the like.
Equipped with
The nitrogen gas supply path can supply the nitrogen gas separated by the gas-liquid separator to the superconducting circuit.

According to the aspect (4) above, the liquid nitrogen stored in the first tank is decompressed by the decompression device to generate a low temperature refrigerant. The gas-liquid separation device separates the low-temperature refrigerant thus generated into gas-liquid, so that low-temperature nitrogen gas, which is a gas phase component, is supplied to the superconducting circuit of the rotating part via the nitrogen gas supply path. To. As a result, a lower temperature nitrogen gas can be introduced into the rotating portion, so that the superconducting circuit can be cooled more effectively.
Further, since the liquid nitrogen in the first tank can be depressurized to generate nitrogen gas to be supplied to the rotating portion, the refrigerant can be stored in the first tank in a liquid state. Therefore, the capacity of the first tank can be reduced as compared with the case where the refrigerant is stored in the first tank in a gaseous state (nitrogen gas state), and a cooling system can be realized with a more compact configuration.

(5) In another aspect, in the above aspect (4),
A liquid nitrogen recovery path (for example, the liquid nitrogen recovery path 112 of the above embodiment) for recovering the liquid nitrogen separated by the gas-liquid separator is further provided in the first tank.

According to the above aspect (5), the liquid nitrogen generated when the low-temperature nitrogen gas to be supplied to the rotating body is separated by the gas-liquid separation device is recovered in the first tank via the liquid nitrogen recovery path. .. This makes it possible to repeatedly use the liquid nitrogen separated by the gas-liquid separator, and the system operating cost can be effectively reduced.

(6) In another aspect, in the above aspect (4) or (5),
A second tank capable of storing the liquid nitrogen separated by the gas-liquid separator (for example, the second tank 116 of the above embodiment) and the like.
A nitrogen gas circulation path (for example, the nitrogen gas circulation path 20 of the above embodiment) that connects the nitrogen gas after cooling the superconducting circuit to the nitrogen gas supply path.
A heat exchanger capable of exchanging heat between the nitrogen gas flowing through the nitrogen gas circulation path and the liquid nitrogen stored in the second tank (for example, the heat exchanger 118 of the above embodiment).
To prepare for.

According to the aspect (6) above, the low temperature liquid nitrogen separated by the gas-liquid separator is stored in the second tank. Then, the nitrogen gas whose temperature has risen by cooling the superconducting circuit in the rotating portion is cooled by exchanging heat with the low-temperature liquid nitrogen flowing through the nitrogen gas circulation path connected to the second tank in the heat exchanger. To. As a result, the nitrogen gas supplied to the superconducting circuit via the nitrogen gas supply path can be repeatedly used for cooling the superconducting circuit while keeping the nitrogen gas in a low temperature state. As a result, the consumption of liquid nitrogen in the cooling system can be reduced, and the operating cost of the system can be effectively suppressed.

(7) In another aspect, in the above aspect (6),
The liquid nitrogen stored in the second tank has a lower temperature than the liquid nitrogen stored in the first tank.

According to the configuration of (7) above, by lowering the temperature of liquid nitrogen flowing through the liquid nitrogen circulation path to a temperature lower than that of nitrogen gas after cooling the superconducting circuit, nitrogen gas repeatedly supplied to the superconducting circuit is preferably used. Can be cooled.

(8) In another aspect, in any one of the above (1) to (7),
The superconducting circuit is at least partially surrounded by a vacuum insulating layer (eg, the vacuum insulating layer 22 of the above embodiment).

According to the above aspect (8), the superconducting circuit to be cooled is at least partially surrounded by the vacuum heat insulating layer, so that heat intrusion into the superconducting circuit is suppressed and good cooling performance can be obtained. In this case, if liquid nitrogen is supplied as a refrigerant from the nitrogen gas supply path, when the refrigerant leaks to the vacuum heat insulating layer, the volume increases significantly due to expansion, which may cause problems such as damage to the peripheral configuration. There is. On the other hand, by supplying nitrogen gas as a refrigerant from the nitrogen gas supply path as described above, even if the refrigerant leaks to the vacuum heat insulating layer, the volume increase is small and there are problems such as damage to the peripheral configuration. It can be effectively suppressed from occurring.

(9) In another aspect, in any one of the above (1) to (8),
The rotating portion is a rotor of a superconducting motor that is rotatable with respect to a stator (for example, the stator 2 of the above embodiment) and is arranged to face the stator.

According to the aspect (9) above, the superconducting motor can rotate with respect to the stator, and the superconducting circuit included in the rotor arranged to face the stator can be suitably cooled.

(10) The cooling system for the superconducting device according to one aspect is
A cooling system for superconducting devices, including superconducting circuits.
The first tank that can store liquid nitrogen and
A nitrogen gas supply path for supplying nitrogen gas generated from the liquid nitrogen to the superconducting circuit,
To prepare for.

According to the above aspect (10), the nitrogen gas generated from the liquid nitrogen stored in the first tank is supplied to the superconducting circuit via the nitrogen gas supply path, so that the superconducting circuit is cooled. To. By using nitrogen gas in a gaseous state as the refrigerant in this way, the capacity change of the refrigerant is small even when a leak occurs when supplying the refrigerant to the superconducting circuit, as compared with the case where liquid nitrogen in a liquid state is used. , Other superconducting circuits (eg, superconducting circuits included on the stator side of superconducting motors, superconducting cables, etc.) that any superconducting device has, while effectively reducing the possibility of causing defects in the peripheral configuration. The device) can be cooled effectively.

1 Rotating machine 2 Stator 3 Motor casing 4 Superconducting rotor 6a, 6b, 6c Bearing 8 Superconducting circuit 10 Cooling flow path 12 Rotor core 12a Slot 13 Cage conductor 14 Superconducting bar 16a, 16b Superconducting end ring 17 Torque tube 18 Nitrogen Gas supply path 19 Output shaft 20 Nitrogen gas discharge path 20a First nitrogen gas discharge path 20b First inner casing 20c Second nitrogen gas discharge path 22 Vacuum heat insulating layer 25a First seal member 25b Second seal member 26 Pressure reducing pipe 27 Second Inner casing 100 Cooling system 102 First tank 103 Decompression device 105 Gas / liquid separation device 106 Nitrogen gas recovery path 108 First refrigerator 109 Compressor 110 Liquid nitrogen supply line 112 Liquid nitrogen recovery path 114 Liquid nitrogen supply path 116 Second tank 118 Heat Exchanger 119 No. 2 Refrigerator 120 Nitrogen gas circulation path

Claims (10)

A cooling system for rotating machinery that has a rotating part that includes a superconducting circuit.
The first tank that can store liquid nitrogen and
A nitrogen gas supply path for supplying nitrogen gas generated from the liquid nitrogen to the superconducting circuit,
A rotating machine cooling system. The cooling system for a rotary machine according to claim 1, wherein the nitrogen gas supply path is connected to the first tank so that the nitrogen gas can be obtained from the upper layer side of the liquid nitrogen stored in the first tank. The cooling system for a rotary machine according to claim 1 or 2, further comprising a nitrogen gas recovery path for recovering the nitrogen gas after cooling the superconducting circuit in the first tank. A decompression device capable of decompressing the liquid nitrogen stored in the first tank, and a decompression device.
A gas-liquid separator capable of separating the liquid nitrogen decompressed by the decompression device,
Equipped with
The cooling system for a rotating machine according to claim 1, wherein the nitrogen gas supply path can supply the nitrogen gas separated by the gas-liquid separator to the superconducting circuit. The cooling system for a rotary machine according to claim 4, further comprising a liquid nitrogen recovery path for recovering the liquid nitrogen separated by the gas-liquid separator in the first tank. A second tank capable of storing the liquid nitrogen separated by the gas-liquid separator, and
A nitrogen gas circulation path for connecting the nitrogen gas after cooling the superconducting circuit to the nitrogen gas supply path, and a nitrogen gas circulation path.
A heat exchanger capable of heat exchange between the nitrogen gas flowing through the nitrogen gas circulation path and the liquid nitrogen stored in the second tank.
The cooling system for a rotary machine according to claim 4 or 5. The cooling system for a rotary machine according to claim 6, wherein the liquid nitrogen stored in the second tank has a lower temperature than the liquid nitrogen stored in the first tank. The cooling system for a rotating machine according to any one of claims 1 to 7, wherein the superconducting circuit is at least partially surrounded by a vacuum insulation layer. The cooling system for a rotating machine according to any one of claims 1 to 8, wherein the rotating portion is rotatable with respect to the stator and is a rotor of a superconducting motor arranged to face the stator. A cooling system for superconducting devices, including superconducting circuits.
The first tank that can store liquid nitrogen and
A nitrogen gas supply path for supplying nitrogen gas generated from the liquid nitrogen to the superconducting circuit,
A cooling system for superconducting devices.

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