JPH0474947B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting rotor, and particularly to a superconducting rotor having a rotating shaft, a torque tube, a superconducting field winding, a refrigerant reservoir, a refrigerant injection pipe, and the like.

A conventional example of a superconducting rotor is shown in FIG. As shown in the figure, superconducting field winding 1
is fixed on the torque tube 2, and the ends of the torque tube 2 are supported by rotating shafts, that is, shafts 3 and 4. The shafts 3 and 4 are provided with bearing journal parts 5 and 6, which serve as bearing support parts. A vacuum insulation layer is provided between the superconducting field winding 1 and the outer cylinder 7 at room temperature, and a radiation shield 8 is placed in between. The superconducting field winding 1 is cooled by liquid helium in a refrigerant reservoir, that is, a liquid helium reservoir 9 flowing through the winding portion 10 . In the liquid helium reservoir 9, the liquid helium evaporates due to heat entering from the outside, and the evaporated gas helium cools the end of the torque tube 2 and the power lead (not shown), and then cools down the end of the torque tube 2 and the power lead (not shown). The helium is discharged to the outside of the machine by a helium supply/exhaust device 12 as a gas flow 11. Liquid helium is supplied to the liquid helium reservoir 9 through a refrigerant injection pipe, that is, a liquid helium injection pipe 13, and the liquid helium injection pipe 13 is supplied with liquid helium from outside the machine by a helium supply/discharge device 12. The slip ring 14 supplies excitation current to the power lead from an external power source (not shown).

In the superconducting rotor 15 configured in this way,
As mentioned above, the radiation shield 8 is placed around the liquid helium reservoir 9 to reduce the amount of heat radiation (heat transfer) from the normal temperature part to the cryogenic part. If there is no such shield, the amount of heat radiated into the liquid helium injection tube 13 is calculated for a large superconducting rotor of the size shown in Fig. 2, for example, a superconducting rotor of a 1000MVA generator, as described below. As a result, the amount of heat radiated into the liquid helium injection pipe 13 is large.

The amount of radiation and penetrating heat Q between concentric cylinders is: Q=σπD ₁ L/1/ε ₁ +D ₁ /D ₂ (1/ε ₂ −1) T ⁴ ₂ {(T ₁ /T ₂ ) ⁴ −1} ... It is expressed as (1). Here, σ is the Stephan-Boltzmann constant, L is the length of the heat transfer surface, ε ₁ and ε ₂ are the emissivity of the small diameter side and the large diameter side, D ₁ and D ₂ are the diameters of the small diameter side and the large diameter side, T ₁ and T ₂ are the temperatures on the small diameter side and on the large diameter side. The emissivity ε ₁ and ε ₂ are both 0.2, and the temperatures T ₁ and T ₂ are the liquid helium injection tube 1 on the small diameter side.
The temperature _T1 of torque tube 3 is 4.2K over the entire length, and the temperature T2 of torque tube ₂ , which is the large diameter side, is distributed in a quadratic curve from 4.2K on the low temperature side to 300K at the connection to shaft 4, so it is 4.2K. It is assumed that the temperature distribution is quadratic from K to 300 K, and the temperature T ₂ of the shaft 4, which is also on the large diameter side, is 300 K over the entire length up to the tip of the superconducting rotor 15. In addition, as shown in the figure, the diameter D ₁ of the liquid helium injection tube ₁₃ on the small diameter side is 15 mm, and the large and small parts of the torque tube ₂ and shaft 4 on the large diameter side. The diameter D ₂ of the torque tube 2 and the shaft 4 are 600, 200, and 20 mm, respectively, and the length L of the heat transfer surface is 700, 1500, and 1500mm
shall be. And from the above equation (1), these D ₂ are 600mm
(L=700mm), 200mm (L=1500mm), 20mm (L=
The total amount of radiation and penetrating heat ΣQ is approximately 10W by calculating the amount of radiation and penetrating heat Q for each section (1500mm) and adding the obtained results. Of course, it is conceivable to provide a radiation heat shield around the refrigerant injection pipe. However, since complete shielding is impossible, the temperature of the cooling medium increases.

In this way, there is an amount of heat radiated into the liquid helium injection pipe 13, and therefore the liquid helium injection pipe 13
The disadvantage was that the heat loss was large.

The present invention has been made in view of the above points,
The purpose is to provide a superconducting rotor having a liquid helium injection tube with low heat loss.

That is, the present invention provides a shield cylinder that is a good thermal conductor around a refrigerant injection pipe, and is provided so that at least a part of the shield cylinder contacts the outer periphery of the shield cylinder, and that the helium gas evaporated in the refrigerant reservoir is diverted. The invention is characterized in that it is provided with a radiation heat shield formed from a diverter pipe.

The present invention will be explained below based on the illustrated embodiments. FIG. 3 shows one practical example of the invention. Note that parts that are the same as those in the conventional model are given the same reference numerals, and therefore their explanations will be omitted. In this embodiment, a radiation heat shield 16a is provided around the liquid helium injection pipe 13. A radiation heat shield 16a is provided with a shield cylinder 17 that is a good thermal conductor so that at least a part of the shield cylinder 17 contacts the outer periphery of the shield cylinder 17, and a diversion pipe 18 that divides the gas helium evaporated in the liquid helium reservoir 9. It was formed from. By doing this, the shield cylinder 17 is cooled by the diverted gas helium flowing through the diverted pipe 18, and its temperature is lowered, reducing the amount of heat radiated into the liquid helium injection pipe 13, and
The temperature of the refrigerant itself can also be lowered, and the heat loss of the liquid helium injection pipe 13 can be reduced. In this case, even if the refrigerant cools the windings, its temperature is very low compared to the outside temperature, and the helium in the liquid helium injection tube 13 can be kept at a low temperature.

Incidentally, if the temperature of the radiation heat shield 16a is 4.2K on the low temperature side and 300K on the high temperature side, and if the temperature distribution from the low temperature side to the high temperature side changes like a quadratic curve, then from equation (1), the liquid helium injection tube The amount of radiation and penetration heat ΣQ into the liquid helium injection pipe 13 is 1.2W, and the heat loss of the liquid helium injection pipe 13 can be significantly reduced compared to the conventional method.

If T ₁ = 4.2K in equation (1), then the amount of radiation and intrusion heat increases approximately in proportion to the fourth power of T ₂ (that is, the temperature of the radiation heat shield 16a), so if the overall temperature of the radiation heat shield 16a is lowered, the radiation intrusion The amount of heat can be significantly reduced. For example, if the temperature on the high temperature end side of the radiation heat shield 16a is 100K, and the temperature distribution in the axial direction is quadratic from 4.2K on the low temperature end side, then the radiation heat shield 1
The temperature of the entire 6a decreases, and the amount of radiation and penetration heat ΣQ becomes
It becomes very small at 0.014W.

Another embodiment of the invention is shown in FIG. In this embodiment, the radiation heat shield 16b is formed from a shield cylinder 17 and a branch pipe 18 that are good thermal conductors, and the high temperature end sides of the shield cylinder 17 and the branch pipe 18 in the axial direction are connected to the rotor structure 20.
and is supported via an insulator 19. That is, the high temperature end sides of the shield cylinder 17 and the branch pipe 18, which are good thermal conductors, were connected to the rotor structure 20 via the insulator 19, respectively. In this way, since the thermal resistance of the insulator 19 is very high, a large temperature difference is created between the radiation heat shield 16b and the rotor structure 20, lowering the temperature of the radiation heat shield 16b, and reducing the temperature required by the radiation heat shield 16b. A temperature distribution in a low temperature range can be obtained, and the amount of heat radiated into the liquid helium injection pipe 13 can be reduced compared to the case described above.

FIG. 5 shows yet another embodiment of the invention. In this embodiment, the radiation heat shield 16c is
A concentric shield cylinder 16c, which is a non-thermal conductor, is used to separate the gas helium evaporated in the liquid helium reservoir. Since the shunt gas helium is made to flow through the shield cylinder 16c, which is a non-thermal good conductor, the heat conduction of the shield cylinder 16c is deteriorated, and the amount of radiant heat transmitted through the radiation heat shield 16c can be reduced.

FIG. 6 shows yet another embodiment of the invention. In this embodiment, the radiation heat shield 16d is
The high temperature end side is connected to the rotor structure 20 and the insulator 1 respectively.
It is formed from a shield cylinder 17 with good thermal conductivity and a branch pipe 18 which are coupled through a tube 9, and insulators 19 are interposed at a plurality of locations in the axial direction of the shield cylinder 17 with good thermal conductivity. In this way, there is an insulator 1 on the high temperature end side.
The temperature of the entire radiation heat shield 16d can be lowered to a greater degree than when the shield 9 is interposed.
Note that in the figure, 21 is a magnetic fluid seal.

FIG. 7 shows yet another embodiment of the invention. The radiation heat shield 16e is formed from a shield cylinder 17 that is a good thermal conductor and a branch pipe 18, and an opening A that communicates with the gas helium flow path 11a inside the rotor structure 20 is provided near the axial end of the branch pipe 18. Established. In this way, the low-temperature diverted gas helium flowing through the diverter pipe 18 mixes through the opening A into the gas flow 11 indicated by the arrow in the figure after the torque tube has been cooled. The mixed branch gas helium cools the torque tube, and the gas helium that has become the gas flow 11 and has flowed through the gas flow path 11a is at room temperature because a large amount of the gas helium is almost at room temperature. Therefore, the diverted gas helium becomes room-temperature gas helium and is recovered by the helium supply/discharge device 12. Therefore, the magnetic fluid seal 21, which is a sealing mechanism between the rotating part and the stationary part, converts the diverted gas helium to the low-temperature diverted gas helium. magnetic fluid seal 21 without being exposed
It is possible to prevent the adverse effects of low-temperature shunt gas helium on the air.

As described above, the present invention is provided with a shield cylinder made of a good heat conductor around a refrigerant injection pipe so that at least a part of the shield cylinder is in contact with the outer periphery of the shield cylinder, and a gas helium evaporated in the refrigerant reservoir. A radiation heat shield formed from a shunt pipe that separates the refrigerant is installed, so radiation heat to the refrigerant injection pipe is shielded, and the temperature of the refrigerant itself in the injection pipe decreases, making it possible to use a refrigerant injection pipe with low heat loss. A superconducting rotor can be obtained.

[Brief explanation of the drawing]

Figure 1 is a vertical side view of a conventional superconducting rotor, Figure 2 is a vertical side view of the area around the refrigerant injection pipe for calculating the amount of heat radiation and penetration into the refrigerant injection pipe of a conventional superconducting rotor, and Figure 3 is a vertical side view of a conventional superconducting rotor. 7 are longitudinal sectional side views of the surroundings of the refrigerant injection pipes showing different embodiments of the superconducting rotor of the present invention. DESCRIPTION OF SYMBOLS 1... Superconducting field winding, 2... Torque tube, 3... Rotating shaft, 9... Refrigerant reservoir, 11a... Gas helium channel, 13... Refrigerant injection pipe, 16a,
16b, 16c, 16d, 16e... Radiation heat shield, 17... Shield cylinder of good thermal conductor, 18
... Diversion pipe, 19 ... Insulator, 20 ... Rotor structure.

Claims (1)

[Scope of Claims] 1. A rotating shaft, a torque tube connected to the rotating shaft, a superconducting field winding disposed on the outer periphery of the torque tube, and a superconducting field winding disposed within the torque tube and connected to the torque tube. In a superconducting rotor having a refrigerant reservoir storing a refrigerant for cooling the superconducting field windings and a refrigerant injection pipe supplying the refrigerant to the refrigerant reservoir, a shield of a good thermal conductor is provided around the refrigerant injection pipe. A radiant heat shield is provided, which is formed from a cylinder and a diversion pipe that is provided so that at least a portion thereof contacts the outer periphery of the shield cylinder, and that divides the gas helium evaporated in the refrigerant reservoir. A superconducting rotor featuring: 2. The superconducting rotor according to claim 1, wherein the radiation heat shield is formed of a concentric shield cylinder that is a non-thermal conductor and that divides the gas helium evaporated in the refrigerant reservoir between them. . 3. A patent in which the radiation heat shield is formed from the shield cylinder of the good thermal conductor and the branch pipe, and the high-temperature ends of the shield cylinder and the branch pipe are connected to the rotor structure through an insulator, respectively. A superconducting rotor according to claim 1. 4. The radiation heat shield is formed of the shield cylinder of the good thermal conductor and the branch pipe, each of which has a high-temperature end side connected to the rotor structure via an insulator, and the shield cylinder of the good thermal conductor comprises:
The superconducting rotor according to claim 1 or 3, wherein insulators are interposed at a plurality of locations in the axial direction. 5. The radiation heat shield is formed of the concentric and non-thermal conductive shield cylinder, and
The superconducting rotor according to claim 1 or 2, wherein a high temperature end side of the shield cylinder is connected to the rotor structure via an insulator. 6. The radiant heat shield is formed of the shield cylinder made of a good thermal conductor and the branch pipe or the concentric shield cylinder made of a non-thermal good conductor, and the rotating The superconducting rotor according to claim 1 or 2, wherein the superconducting rotor is provided with an opening that communicates with a gas helium flow path inside the child structure.