JPS6038941B2 - 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, increasing the capacity of a rotating electric machine depends on how to suppress 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, in the case of a turbine generator, the rotor normally rotates at a high speed of 3.60 revolutions per minute (60Hz), and it is difficult to introduce coolant into such a high-speed rotating body. Deriving this is the biggest problem for realization,
This 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 rotor, in which a coolant such as pure water is supplied in the direction of arrow A via a feed pump (not shown). This is the inlet pipe.

The reason why pure water is used as a cooling liquid is as follows. Since the coolant is circulated within each tube and rotor coil as described below, if such coolant contains impurities, each tube and rotor coil will corrode. Therefore, it is desirable to use pure water that does not contain 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 this 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 closure.

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 Figure 2,
Numeral 2c denotes 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 2 serve as a spacer between the inflow pipe 3 and the inflow pipe. It connects the pipe 2 and the outflow pipe 3 together 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 firmly connected together by, for example, solid fit, and constitute a supply/discharge pipe 4. 4a is a flange formed at the end of this supply/discharge pipe 4; 5 is a rotor shaft of a rotating electric machine having a flange 5a that is in close contact with this flange and is connected, for example, by bolts (not shown); Needless to say, a rotor coil (not shown) is attached to this rotor shaft.

Further, as is clear from the figure, the rotor shaft 5 is provided with an inflow passage 5b and an outflow passage 5c which communicate with the inflow passage 2b and the outflow passage 3b of the supply/discharge pipe 4, respectively, and the supply and discharge pipes are fed from the inflow passage 5b. After the coolant is circulated through the rotor coil, it is discharged into the outflow passage 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 closed part 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 entrance 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 after lowering the temperature using a heat exchanger (not shown), etc. 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
and the rotating feed pipe E pipe 4 to prevent leakage.
The labyrinth seal 62 is a second outlet chamber that receives leakage from the first outlet chamber 61 that has passed through the second labyrinth seal.

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 internal pressure is always kept slightly higher than atmospheric pressure to prevent atmospheric air from entering the second outlet chamber.

Therefore, since the source liquid in the second outlet chamber 62 is not in 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 subjected to 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. 3rd place to accept leakage
outlet chamber, 73 is a third outlet pipe adapted to this third outlet chamber.

The cooling liquid reaching the third outlet chamber 63 is connected to the two-stage seal 82,
Since the amount is small due to the effect of 83, it is not evacuated to the atmosphere, and therefore the coolant discharged from the third outlet pipe 73 is discarded as it is without being subjected to recirculation. 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, etc., so it is in the form of an overhang on the rotor shaft 5. It will be supported by For this reason, the supply 9E pipe 4 is always
subject to shaft runout problems. Axial runout is undesirable because it impairs the sealing effect. This axial runout is caused by the feed 8E tube 4.
The longer this happens, the more likely it is to occur, so it is better to keep it short, but in the conventional device mentioned above, there are three outlet chambers, and the feed pipe 4 has to be made that much longer, increasing the risk of shaft runout. It turns out. In addition, in the above-mentioned subordinate device, the outlet chamber 61 is kept full of water, so the outlet chamber 61 is kept full of water.
The problem was that the casing 1 had to be tightly sealed, and since it was full of water, there was 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 FIG. 3, 612 is an outlet chamber formed by integrating the outlet chambers 61 and 62 in FIG. 1, and 712 is an outlet pipe that is passed through the outlet chamber, and the other parts are the same as in FIG. The idea of FIG. 3 is that the outlet chamber 612 is not filled with water and therefore nitrogen is supplied from the air supply pipe 9 to the outlet chamber 612 to avoid contact with the atmosphere.
The idea is to supply a gas such as hydrogen and maintain the pressure inside the outlet chamber 612 at a value higher than atmospheric pressure to prevent atmospheric intrusion. That is, the two outlet chambers 61 in FIG.
62 are combined into one, and the cooling liquid led out from the outlet pipe 712 is provided for recirculation as in FIG. According to FIG. 3, the drawbacks of FIG. 1 can be avoided to some extent, but the following major problems remain.
That problem is cavitation. That is, the outflow pipe 3
Since the pressure in the outlet chamber 612 that receives the liquid scales from the closed part 3a of the cooling liquid is not as high as when it is full of water, the cooling liquid is discharged without resistance. The pressure in the coolant pipes, such as 1), is lower than when the outlet chamber 612 is full of water. Outflow paths 3b, 5c,
The temperature of the coolant flowing through the coolant pipes such as the rotor coil (not shown) is high due to the cooling of the rotor coil, so cavitation easily occurs in the coolant when the pressure decreases. This will corrode the coolant pipes in that area. In FIG. 1, the reason why the outlet chamber 61 that receives the discharged liquid from the outflow pipe 3 is kept full is to maintain the pressure inside the outlet chamber 61 high and prevent cavitation. It was considered that keeping the tank full of water was an indispensable condition, and as a result, there were various difficulties as mentioned above, and there was no solution. Now, by further developing the concept shown in FIG. 3 above, the device shown in FIG. 4 can be considered as a coolant introduction/intake device that can solve not only the various problems shown in FIG. 1 but also the problem of cavitation.
In FIG. 4, 101 is a discharge ring having a small hole 10a, with the small hole 10a facing the entrance part 3a.
For example, it is fixed to the inflow pipe by shrink fitting or the like. Therefore, the cooling liquid from the outflow pipe 3 flows through the hole 10a of the discharge ring 10.
It will be discharged into the outlet chamber 612 via the. That is, the discharge ring 10 exhibits a so-called orifice action when discharging the coolant, and the pressure in the opening 3a becomes higher than the pressure in the outlet chamber 612. Therefore, it is possible to reliably prevent cavitation, which became a problem in FIG. Having solved the problem of cavitation, it is no longer necessary to keep the outlet chamber 612 full of water, thus making it possible to reduce the number of outlet chambers to two. Therefore, the length of the supply pipe 9E can be made shorter than that shown in Fig. 1, reducing the risk of shaft vibration, and since it is not filled with water, the casing of the outlet chamber 612 can be easily sealed.
It is possible to obtain a coolant introducing/discharging device that can eliminate power loss due to friction with the supply/discharge pipe 4. However, in the above-mentioned conventional cooling liquid introduction/input device, the cooling liquid circulates and cools the rotor coil, and then is injected from the small hole 10a of the discharge ring 10 through the opening 3a of the inflow pipe 3 via the outflow passages 5c and 3b. is discharged into the outlet chamber 612.

The discharged coolant has a velocity that is a vector combination of the jetting velocity jetted radially outward from the small hole 10a of the discharge ring 10 and the circumferential velocity of the outer periphery of the supply pipe 4. In this way, the coolant was discharged at a considerable speed and collided with the inner wall of the outlet chamber 612, making the collision sound very loud.
Moreover, the inner circumferential wall of the outlet chamber 612 may become corroded due to the collision of the coolant over many years of use. Furthermore, the sealing performance of the outlet chamber 612 was also deteriorated. This invention was made in view of the above-mentioned drawbacks, and it is possible to reduce the flow velocity of the cooling liquid discharged from the supply pipe 9E between the discharge part of the supply pipe and the outlet chamber in the radial direction outward. The present invention provides a coolant inlet/output device for a liquid-cooled rotor-type rotating electrical machine that achieves high reliability.

An embodiment of the present invention will be described below with reference to FIGS. 5 and 6.

FIG. 5 is an enlarged view of the main part of the coolant discharge part, and FIG. 6 is a sectional view taken along the line W1 in FIG. Outflow pipe 31b
is an outflow path, and these constitute a supply/discharge pipe 41.
Reference numeral 11 denotes a discharge trench having an L-shaped cross section and coaxially connected to the inflow pipe 21 by means such as shrink fitting. A discharge path 12 is formed.

The storage part 11a temporarily stores the coolant, and the discharge path 12 is provided between the outer circumferential surface of the inflow pipe 21 and the back diagonally with respect to the rotation direction S of the rotor, as shown in FIG. A plurality of them are formed around the entire circumference parallel to the line of gravity of the supply/discharge pipe 41.
The dimensions and number of the discharge passages 12 are appropriately set with the aim of preventing cavitation from occurring.
In this invention configured as described above, the outflow pipe 3
The cooling liquid discharged from the outflow path 31b of the outflow pipe 31 is temporarily accommodated in the housing part 11a of the discharge ring 11 provided in the discharge ring 11, and the coolant is discharged between the discharge ring 11 and the inflow pipe 21 in the counter-rotation direction. From the plurality of discharge passages 12 formed to
I am trying to discharge it in 2 steps.

In this way, the cooling liquid led out from the outflow path 31b of the outflow pipe 31 is temporarily accommodated in the storage portion 11a of the discharge ring 11, and the cooling liquid is transferred from the discharge path 12 to the outlet chamber 612 in an axial direction in the opposite direction of rotation. Since the cooling liquid is discharged, the flow rate of the cooling liquid outward in the radial direction is significantly reduced compared to the conventional method. That is, since the coolant is discharged from the discharge passage 12 in all directions of the axis, its initial velocity outward in the radial direction is extremely small, and since it is discharged in the counter-rotational direction, the circumferential speed is also reduced. As described above, according to the present invention, the flow velocity of the cooling liquid outward in the radial direction is significantly reduced compared to the conventional method. Therefore, the energy that collides with the inner circumferential wall of the outlet chamber 612 is extremely small compared to the subordinate one, which can reduce the collision noise, prevent erosion of the inner circumferential wall of the outlet chamber 612, and improve the sealing performance. It is now possible to do so. Further, since the discharge ring 11 of the present invention is replaceable, there is also an effect of ease of maintenance. In addition, in the above embodiment, the discharge path 1
2 describes the case in which the cooling liquid is provided in the outlet chamber 612 so as to be discharged parallel to the axial direction and in the opposite rotational direction, but the present invention is not limited to this, and the discharge path 12 may be provided parallel to the vertical direction,
It is also possible to make the space between the discharge ring 11 and the inflow pipe 21 completely open, that is, to make the plurality of discharge passages 12 integrally pass through each other. Although the effect is reduced by that amount, it is still effective enough to overcome the drawbacks of the conventional method. Further, in the above embodiment, a case is shown in which pure water is used as the coolant, but it goes without saying that other liquids than pure water may be used as long as the liquid does not corrode the tubes and the rotor coil.

Further, in the above embodiments, the present invention has been described as being applied to a generator, particularly a turbine generator, but it goes without saying that it can be applied to other generators such as a water turbine generator, as well as various rotating electric machines such as electric motors, if necessary. .

Further, in the above embodiment, a labyrinth seal is used as a seal for suppressing leakage of the coolant, but it goes without saying that other seals such as a mechanical seal may be used.

As explained above, in this invention, the cooling liquid led out from the outflow pipe is temporarily stored in the discharge ring provided in the outflow pipe, and the coolant is transferred to the outlet chamber from the discharge path provided between the discharge ring and the inflow pipe. By discharging the coolant so as to reduce its radial outward flow velocity, the energy of the coolant colliding with the outlet chamber can be extremely reduced, significantly improving the soundproofing effect and the corrosion resistance and sealing performance of the outlet chamber. This makes it possible to obtain a highly reliable coolant inlet/output device.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional liquid-cooled rotor-type rotating electric machine coolant inlet/output device, Fig. 2 is a cross-sectional view taken along the Rolo line in Fig. 1, and Fig. 3 is a derivation considered before reaching this invention. FIG. 4 is a diagram showing a lead-in/out device which is a development of FIG. 3 and is considered before reaching this invention. FIG. 5 is a diagram showing a liquid-cooled rotor according to an embodiment of the present invention. FIG. 6 is an enlarged view of a main part showing a coolant inlet/output device for a rotating electric machine, and FIG. 6 is a sectional view taken along the line W- in FIG. 5. In addition, the same reference numerals in each figure indicate the same or equivalent parts, 21 is an inflow pipe, 31 is an outflow pipe, 41 is a supply pipe E,
612 is an outlet chamber, 11 is a discharge ring, and 12 is a discharge path. Figure 1 Figure 2 Figure 3 Figure 6 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. A supply/discharge pipe consisting of an inflow pipe in which an inflow path along the central axis is formed and an outflow pipe coaxially arranged outside the inflow pipe and forming an outflow path between the inflow pipe and the inflow pipe. A liquid-cooled rotor type that is coaxially connected to the rotor shaft and in which the coolant that circulates and cools the rotor is held at a pressure higher than atmospheric pressure by a shielding gas and is discharged to an outlet chamber that communicates with the outflow path. A coolant lead-in/out device for a rotating electric machine, comprising: a discharge ring coaxially fixed to the inflow pipe and having an L-shaped cross section; a housing portion communicating with the discharge passage and formed inside the discharge ring; and the housing portion. and a plurality of discharge passages formed in the discharge ring and parallel to the axis of the supply/discharge pipe, communicating with the outlet chamber. Device. 2. A coolant lead-in/out device for a liquid-cooled rotor-type rotating electric machine according to claim 1, wherein the discharge passage is formed so that the coolant is discharged into the outlet chamber in a direction opposite to the rotational direction of the rotor.