JPS6038940B2 - Coolant inlet/output device for liquid-cooled rotor-type rotating electric machines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a liquid-cooled rotor-type rotating electric machine that circulates a coolant around a rotor to cool the rotor, and particularly to a coolant introduction/intake device thereof.

As is well known, in order to increase the capacity of a single rotating electric machine, the problem is how to suppress the temperature rise, that is, how to achieve effective cooling.

In other words, it is no exaggeration to say that the capacity of a rotating electrical machine is determined by its temperature rise, that is, its cooling performance. On the other hand, it is increasingly necessary to increase the single machine capacity of generators among rotating electric machines, especially turbine generators, from the viewpoint of improving the efficiency of power plant construction. By the way, a cooling method that circulates hydrogen gas has been used to cool turbine generators so far, and an increase in the capacity of a single unit has been achieved, but this has already reached its limit. A significant increase in capacity cannot be expected. Therefore, there is a strong desire to put another cooling method into practical use. To meet this demand,
It is conceivable to use a cooling fluid with good cooling efficiency, such as water, instead of hydrogen gas as the cooling medium.

Based on this idea, it has already been proposed and realized to cool the stator by circulating the coolant, but if we can develop this and successfully circulate the coolant to the rotor. , the cooling effect can be dramatically increased.・However, when taking a turbine generator as an example, the rotor usually rotates at a high speed of 3,600 revolutions per minute (60Hz), and it is difficult to introduce coolant into such a high-speed rotating body. Deriving this is the biggest problem in the market and has hindered the spread of liquid-cooled rotor-type rotating electric machines.

FIG. 1 is a diagram showing a conventionally considered coolant inlet/output device for a liquid-cooled rotor, and 1 is an inlet pipe to which coolant, such as pure water, is supplied via a feed pump (not shown). .

The reason why pure water is used as a cooling liquid is as follows. As described below, the coolant is circulated within each tube and rotor coil, so if water containing impurities is used as the coolant, the impurities may cause each tube and rotor coil to become damaged. Therefore, it is desirable to use pure water that does not contain any impurities. Reference numeral 2 denotes a circular inflow pipe which has a closing part 2a and receives the cooling liquid from the inlet pipe 1 through this closed part, and its hollow interior 2b serves as an inflow path for the cooling liquid.

Reference numeral 3 denotes a circular outflow pipe provided around the inflow pipe 2 with a predetermined gap therebetween, and the gap 3b between the inflow pipe 2 and the inflow pipe 2 serves as an outflow path for the coolant.

3a is an opening □ provided at one end of this outflow pipe 3;
Coolant is discharged through this opening.

Incidentally, the outflow pipe 3 and the inflow pipe 2 are integrally connected to form a supply/discharge pipe 4 as shown in FIG. That is, in FIG. 2, 2c is a plurality of protruding pieces (the figure shows a case of six pieces) formed integrally with the outer periphery of the inflow pipe 2, and these protruding pieces 2c are connected to the outflow pipe 3. It serves as a base for integrally connecting the inflow pipe 2 and the outflow pipe 3, and also serves as reinforcement for the exchangers 2 and 3. The inflow pipe 2 and the outflow pipe 3 having the protruding piece 2c are integrally connected more firmly by shrink fitting, for example, to form a supply/discharge pipe 4. 4a is a flange formed at the end of this supply pipe 4, and 5 is a flange 5a that is in close contact with this flange and is connected, for example, with a bolt (not shown).
This is a rotor shaft of a rotating electric machine having a rotor shaft, and needless to say, a rotor coil (not shown) is attached to this rotor shaft.

Further, as is clear from the figure, this rotor shaft 5 is provided with an inflow path 5b and an outflow path 5c that communicate with the inflow path 2b and outflow path 3b of the above-mentioned rock supply pipe 4, respectively. The supplied coolant circulates through the rotor coil and is then discharged to the outflow path 5c. Note that the arrows in the figure indicate the flow of the cooling liquid, and after the rotor coil is circulated and cooled as described above, it is discharged from the opening 3a of the outflow pipe 3 via the outflow passages 5c and 3b. . Reference numeral 61 denotes a first outlet chamber for receiving the liquid discharged from the closed portion 3a, and the chamber is always kept full of the cooling liquid to prevent the cooling liquid (pure water) from coming into contact with the atmosphere and being contaminated. It is configured as follows.

71 is a first outlet chamber for discharging the cooling liquid from this first outlet chamber.
As mentioned above, the coolant drawn out from this first outlet pipe does not come into contact with the atmosphere and is not contaminated, so it is cooled by a heat exchanger (not shown) or the like before being sent. It is fed back to the inlet pipe 1 via a feed pump (not shown) and subjected to recirculation.

Reference numeral 81 denotes a first labyrinth seal for suppressing leakage of cooling liquid from inside the inlet pipe 1 to the first outlet chamber 61, and it is impossible to completely eliminate leakage between the rotating part and the fixed part. Therefore, efforts are made to minimize leakage.

This leakage is not a big problem because it is circulated again via the first outlet pipe 71 as described above, but if the leakage amount is too large, the efficiency will deteriorate, so it goes without saying that it is better to have a smaller amount. Nor. 82 is the first exit chamber 61
A second labyrinth seal 62 is used to suppress leakage between the rotating supply and discharge pipe 4, and 62 is a second outlet chamber that receives liquid leakage from the first outlet chamber 61 that has passed through the second labyrinth seal. It is.

This second outlet chamber 62 is different from the first outlet chamber 61 described above and is not filled with cooling liquid, so there is a risk that the cooling liquid (pure water) will come into contact with the atmosphere and be contaminated. Reference numeral 9 denotes an air supply pipe for preventing this, and by constantly supplying a gas such as nitrogen or hydrogen to the second outlet chamber 62 through this air supply pipe, the second outlet chamber 62 The pressure is always kept slightly above atmospheric pressure to prevent atmospheric air from entering the second outlet chamber.

Therefore, since the liquid leaking from the second outlet chamber 62 does not come into contact with the atmosphere and is not contaminated, the coolant drawn out from the second outlet pipe 72 is similar to the coolant drawn out from the first outlet chamber 61. It is provided for recirculation via a heat exchanger and a feed pump (none of which are shown). 83 is a third labyrinth seal for suppressing leakage between the second outlet chamber 62 and the rotating supply/discharge pipe 4, and 63 is a seal from the second outlet chamber 62 that has passed through the third labyrinth seal. A third outlet chamber, 73, which receives leakage liquid, is a third outlet pipe adapted to fit into this outlet chamber.

The cooling liquid reaching the third outlet chamber 63 is connected to the two-stage seal 82,
Due to the effect of
Therefore, the coolant discharged from the third outlet pipe 73 is discarded without being recirculated. Of course, it is also possible to send the water to a reprocessing device, purify it, and recirculate it. The above device can achieve the intended purpose.

Incidentally, the rotor shaft 5 is supported by a bearing (not shown), but as is clear from the figure, the supply/discharge pipe 4 cannot be provided with a bearing due to the outlet chamber, so there is an overhang on the rotor shaft 5. It will be supported in form. For this reason, it is always exposed to the Z problem of axial runout of the supply/discharge pipe 4. Axial runout is undesirable because it impairs the sealing effect. This shaft runout is due to E pipe 4.
The longer this occurs, the more likely it is to occur, so a shorter length is better, but the conventional device described above has three outlet chambers, and the supply pipe 4 has to be made that much longer, increasing the risk of shaft vibration. become. Furthermore, in the conventional device described above, the exit chamber 6
1 is to be kept full of water, the casing of the outlet chamber 61 must be tightly sealed, and
Since the system is full of water, there is a problem in that there is a large power loss due to friction between the water and the supply/discharge pipe 4. In order to solve this problem, it is conceivable to have two outlet chambers as shown in FIG. 3 and not to fill either outlet chamber with water. That is, in Figure 3, 6
Reference numeral 12 denotes an outlet chamber formed by integrating the outlet chambers 61 and 62 in FIG. 1, and 712 an outlet pipe communicating with this outlet chamber, and the rest is the same as in FIG. 1. The idea behind this figure 3 is
In order to avoid filling the outlet chamber 612 with water and therefore avoid contact with the atmosphere, a gas such as nitrogen or hydrogen is supplied from the air supply pipe 9 to the outlet chamber 612 to lower the pressure inside the outlet chamber 612 below atmospheric pressure. The idea is to keep the value high to prevent air from entering. That is, the two outlet chambers 61 and 62 in FIG. 1 are combined into one, and the cooling liquid led out from the outlet pipe 712 is provided for recirculation as in FIG. 1. According to FIG. 3, one of the drawbacks of FIG. 1 can be avoided, but the following major problem remains. That problem is cavitation. In other words, the pressure in the outlet chamber 612 that receives the drained liquid from the closed part 3a of the outflow pipe 3 is not as high as when it is full of water, so the coolant is discharged without resistance). The pressure in the coolant pipe, such as the child coil (not shown), reaches the outlet chamber 61.
2 will be lower than when the water is full. The temperature of the coolant flowing through the coolant pipes such as the outflow passages 3b and 5c and the rotor coil (not shown) is high as a result of cooling the rotor coil, so when the pressure of the coolant becomes low, the temperature easily increases. Cavitation will occur, and the area will be eroded. In Fig. 1, the outlet chamber 61 that receives the drained liquid from the inflow pipe 3 is kept full of water in order to prevent the above-mentioned cavitation.Therefore, conventionally, it has been an essential condition to keep the outlet chamber full of water. Therefore, the various difficulties mentioned above were thought to be unavoidable. Now, by further developing the concept shown in FIG. 3 above, the device shown in FIG. 4 can be considered as a coolant lead-in/out device that can solve not only the various problems shown in FIG. 1 but also the problem of cavitation.

In FIG. 4, reference numeral 10 denotes a discharge ring having a small hole 10a, which is fixed to the inflow pipe by, for example, a rice bracing or the like so that the small hole 10a faces the entrance portion 3a. Therefore, the cooling liquid from the outlet pipe 3 is discharged into the outlet chamber 612 through the small hole 10a of the discharge ring 10. That is, the discharge ring 10 exhibits a so-called orifice action when discharging the coolant, and the pressure in the entrance portion 3a becomes higher than the pressure in the outlet chamber 612. For this reason, it is possible to reliably prevent cavitation, which became a problem in FIG. By eliminating the problem of cavitation, it is no longer necessary to keep the outlet chamber 612 full of water, and it is therefore possible to reduce the number of outlet chambers to two. Therefore, the length of the supply/discharge pipe 4 can be made shorter than that shown in Fig. 1, which reduces the risk of shaft vibration.Also, since it is not filled with water, it is easier to seal the casing of the outlet chamber 612. It is possible to obtain a coolant introducing/extracting device that can eliminate power loss due to friction with the exhaust pipe 4. However, since the release ring has a small hole, the stress in the small hole increases due to the notch effect, making it impossible to obtain a large competition fee.Furthermore, the release ring receives water pressure as internal pressure, so it is difficult to prevent dawn bracken. Easy to loosen.

This may cause the discharge ring to rotate and its small hole to be blocked by the outer peripheral surface of the protruding piece 2c shown in FIG. 2, thereby preventing the discharge of the coolant. The present invention has been made to solve the above-mentioned disadvantages, and it is an object of the present invention to provide a lead-in/out device which allows the coolant to be discharged from the small hole without any problem even if the discharge ring rotates. FIG. 5 is a diagram showing an embodiment of the lead-in/out device according to the present invention, and FIG. 6 is a diagram showing an example of the inflow pipe used in the present invention.

In FIGS. 5 and 6, the same reference numerals as in FIG. 4 are the same or equivalent parts, and 2d is located on the outer peripheral surface of the protruding piece 2c of the inflow pipe 2, facing each hole 10a of the discharge ring 10. It has two grooves cut into it. That is, the outflow passages 3b formed between the protruding pieces 2c of the inflow pipe 2 and the outflow pipe 3 are independent, but are joined by the groove 2d on the outer circumferential surface of the protruding piece 2c. As described above, according to the present invention, even if the discharge ring 10, which is supposed to be iron-fitted into the inflow pipe 2 so as not to rotate, rotates, the cooling liquid from the outlet passage 3b will always flow through the lotus groove 2d of the protruding piece 2c. Release ring 1
The small hole 10 of No. 0 is discharged without being blocked by the protruding piece 2c.

In addition, since each outlet passage 3b is passed through by the passage groove 2d, even if the pressure of the coolant immediately before entering the discharge ring is different due to uneven fluid resistance of the outlet passage 3b, this lotus can be closed. The pressure is equalized by the passage groove 2d. This prevents distortion of the rotor shaft 5 due to non-uniform jetting pressure of the coolant from the small holes 10a of the discharge ring 10, and also prevents lateral vibration of the rotor shaft 5 due to this distortion. It also has a preventive effect. In the above embodiment, two rows of the holes 10a of the release ring 10 are provided in the circumferential direction, and two rows of lotus grooves 2d are provided opposite to each row. Even when more than one row is provided, it is sufficient to provide one or three or more passage grooves 2d facing these rows, and it is also possible to provide one lotus passage groove 2d spanning each row of these 4 holes 10a. It has the same effect as the example.

Furthermore, although the above embodiment has been described as a coolant lead-in/out device for a turbine generator, it can also be applied to a coolant lead-in/out device for other rotor shafts such as a water turbine generator.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conventional coolant lead-in/out device, FIG. 2 is a sectional view taken along the Rolo line in FIG. The figure shows a lead-in/out device which is a further development of Figure 3 and which can be considered before reaching this invention. Figure 5 shows an embodiment of the lead-in/out device according to this invention. It is a figure which shows an example of the inflow pipe used. Note that the same reference numerals in each of the above figures indicate the same or equivalent parts, and 2 is an inlet pipe, 2 is an inflow pipe, 2a is its entrance, 2b is an inflow channel, 2c is a protruding piece, and 2d is a delivery groove. , 3 is the outflow pipe, 3a is its opening, 3b is the outflow path, 4 is the supply 8
In the E pipe, 4a is its flange, and 5 is the rotor shaft.
is its flange, 5b is an inflow path, 5c is an outflow path, 61,
62, 63, 612 are exit chambers, 71, 72, 73, 71
2 is an outlet pipe, 81, 82, 83, 84 are lapirin seals, 9 is an air supply pipe, 10 is a discharge ring, and 10a is a small hole thereof. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6

Claims (1)

[Claims] 1. A circular inflow pipe with one end connected to the rotor shaft and the other end open to introduce the cooling liquid; A circular outflow pipe having an opening for discharging the coolant at the end thereof, an outlet chamber formed around the outflow pipe from which the coolant is discharged, and an axial direction formed on the outer periphery of the inflow pipe. a plurality of protruding pieces formed on the inner peripheral surface of the outflow pipe to define the gap; and a plurality of small protruding pieces that cover the opening and are fitted into the inflow pipe and communicate with the opening and the outlet chamber. A liquid-cooled rotor type comprising a discharge ring in which a hole is formed, and a communication groove formed in the protruding piece along the circumference facing the small hole and communicating the gap defined by the protruding piece. Coolant inlet/output device for rotating electric machines.