JPH0191635A - Bearing cooling system for horizontal water-turbine generator - Google Patents

Abstract

PURPOSE:To heighten the cooling effect of a thrust bearing and to lower the temperature of said bearing to an allowance value and less, by providing a hollow part and a radially extending collar passage within a thrust collar and by causing said parts to communicate with the steam space of the heating unit of a rotating shaft heat pipe. CONSTITUTION:In a generator provided with a rotating shaft heat pipe 7 using a journal bearing 1 and a thrust bearing 3 as a heating unit and a runner 6 as a cooling unit, a hollow part 9 is formed in the inner part of a thrust collar 22 of the thrust bearing 3, and said hollow part 9 is caused to communicate with the steam space 8 of said heat pipe 7. Further, a collar passage extending radially within the thrust collar 22 is formed between the hollow part 9 and a thrust collar sliding surface. Then, each collar passage is caused to communicate with the hollow part 9. Consequently, the heating surface area of the thrust bearing 3 grows larger and the distance of heat conduction shortens to enable heightening the cooling effect of said bearing.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention relates to cooling of a thrust bearing of a horizontal-shaft water turbine generator.

[Prior art and its problems]

Fig. 4 shows a bearing cooling device using a rotary shaft heat pipe of a horizontal shaft water turbine generator according to conventional example E, in which the rotary shaft 4 is made hollow to enclose an operating Fukada, and the bearing side is used as a heat generating part, and a runner 6 is used. The journal bearing 1 and the thrust bearing 3 are housed in a bearing stand 2 and are filled with lubricating oil 5. 16 is a speed ring, 17 is a guide vane, and the wing is the ground.

In the conventional bearing cooling device, most of the heat generated in the journal bearing 1 and the thrust bearing 3 flows into the rotating shaft heat pipe 7, but in this case, the thrust bearing 3 is The heat conduction distance to the steam space 8 is long.

■The heat conduction inside the thrust collar n and the heat flux (W, 4”) at the heat pipe evaporation surface are large.

■Since the inside of the thrust collar has a normal wall thickness, the heat conduction area decreases from the surface of the thrust collar, which generates heat from the friction guard, toward the center of rotation.
The area of the evaporation surface also becomes smaller.

■The heat conduction distance from the heat generating surface inside the thrust collar to the hydraulic fluid is long.

As a result, the temperature increases due to an increase in thermal resistance from the heat generating part of the thrust collar to the heat pipe surface (increasing the temperature difference) and an increase in thermal resistance due to an increase in heat flux at the evaporation surface of the heat pipe. Since the temperature of the bearing portion exceeds an allowable value, it has been difficult to apply the method to cooling the bearings of a horizontal-shaft water turbine generator with an output of approximately 500 kW or more.

In order to keep the temperature of the bearing part below the allowable value, it is necessary to reduce the temperature difference from the heat generating part to the heat pipe condensing part, and to increase the heat transfer coefficient by increasing the heat transfer area and thinning the liquid film in the cooling part. There is a way to increase the temperature and reduce the temperature difference.

The object of the present invention is to increase the heat transfer area of the thrust bearing of a horizontal shaft water turbine generator and shorten the heat transfer distance to reduce the thermal resistance and keep the bearing temperature below a permissible value.

[Means for solving problems]

The present invention provides a hollow shaft in the thrust collar of the thrust bearing of a horizontal shaft water turbine generator in which a rotary shaft heat pipe is formed inside the rotary shaft which is horizontally supported by a journal bearing and a thrust l-4 (iJ bearing and is directly connected to a runner). a plurality of collar portions extending radially within the thrust collar between the hollow portion and the thrust collar sliding surface; A passage is provided so that each of the collar passages communicates with the hollow part.

The heat generated is transferred over a short distance within the thickness of the thrust collar, and is further transferred to the collar passageway in the thrust collar, which has a large heat transfer area, where it evaporates the working fluid in the heat generating section of the heat pipe.

[Embodiments of the invention]

1 is a sectional view of a bearing cooling device for a horizontal shaft water turbine generator according to Embodiment 1 of the present invention, FIG. 2 is a detailed view showing the thrust collar of the bearing cooling device of FIG. 1, and FIG. It is a sectional view taken along the line AA in the figure. This will be explained below based on the drawings. In FIG. 1, the rotating shaft 4 directly connected to the runner 6 is connected to the casing 1.
The rotary shaft 4 is horizontally supported by a journal bearing 1 and a thrust bearing 3 housed in a bearing scund 2, and a generator (not shown) is connected to the other end of the rotary shaft. The bearing stand 2 is filled with lubricating oil 5. In Figure 1, 15 is a casing, 16 is a speed ring, 17 is a guide vane, and 18 is a suction pipe.

The rotary shaft 4 is made hollow and a hydraulic fluid is sealed in it, and the journal bearing 1
A rotating shaft heat vibe 7 is formed in which the thrust bearing 3 is used as a heat generating part, the runner 6 exposed to the waterway and the water sealing part of the runner side rotating shaft are used as condensing parts, and a hollow part 9 is formed in the thrust collar B of the thrust bearing 3. The hollow portion 9 is connected to the steam space of the rotary shaft heat vibrator through a plurality of working fluid passages 19, and a plurality of collar portions are provided which run radially within the thrust collar between the hollow portion 9 and the thrust collar sliding surface. A passage 21 is provided, and the collar passage 21 is communicated with the hollow portion 9.

In FIGS. 2 and 3, the hollow portion 9 of the thrust collar n has a donut-shaped cross section as shown in FIG. It communicates with the steam space 8 by. Note that the lid is for sealing the inner wall.

Inside the thrust collar n, a plurality of collar passages 21 are provided that run radially between the hollow portion 9 and the thrust collar F moving surface. The collar passage 21 may be provided only on the thrust receiving side of the thrust collar B, or may be provided on both sides of the thrust collar N as shown in FIG.

Further, the collar passage 21 is configured such that the inner and outer ends of the collar passage 21 communicate with the hollow portion 9 of the thrust collar as shown in FIG. It is sufficient to communicate only the inner diameter side end portion with the hollow portion 9 of the thrust collar.

Thrust bearing 3 configured in this way and thrust collar ρ
When the thrust force is applied to the thrust collar, the heat generated on the sliding surface due to frictional resistance during sliding first heats the working fluid within the collar portion passage 21 over a short distance by heat conduction within the thrust collar n, and evaporates. This steam flows from the inner end of the collar passageway through the hollow portion 9 and further through the working fluid passageway 19 into the steam space of the cooling section where the pressure is low n and further moves to the runner side where the pressure is low. The steam that has moved to the runner side comes into contact with the wall surface (liquid film) of the cooling section and condenses to become liquid. Further, when the heat flux is large in the collar passage 21, the working fluid in the hollow portion 9 is heated and a part of the working fluid is evaporated. The vapor in the hollow part 9 mixes with the steam in the collar passage 21 and flows into the working fluid passage 1 as described above.
9 into the vapor space of the cooling section.

The hydraulic fluid is vacuum-sealed so that the hollow part 9 of the thrust collar is always filled, and is returned to the thrust collar side by centrifugal force. The heat of the fixed part of the thrust bearing 3 is not transmitted to the lubricating oil 5.
Further, the heat is transmitted to the surface of the rotating shaft heat vibrator 7 and radiated to the runner side, and the heat is radiated from the outer surface of the bearing stand 2 to the atmosphere.

〔Effect of the invention〕

According to this invention, the hollow part of the thrust collar of the thrust bearing is communicated with the steam space of the heat generating part of the rotating shaft heat pipe, and at this time, a plurality of collar part passages are provided between the hollow part and the sliding surface of the thrust collar. In the crotch, each collar passageway is communicated with the hollow part, so the heat conduction distance from the thrust collar, which is the heat generating part, to the hollow part, which is the vapor space, can be reduced to about % to 1 compared to the conventional one. By increasing the heat transfer area of the thrust collar, it is possible to reduce the temperature difference between the sliding surface, which is the heat generating part, and the steam space, which improves cooling performance and is suitable for thrust bearings such as horizontal shaft water turbine generators with an output of 1000 kW or more. Applicable to

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a bearing cooling device for a horizontal shaft water turbine generator according to an embodiment of the present invention, FIG. 2 is a detailed view showing the thrust collar of the bearing cooling device of FIG. 1, and FIG. FIG. 4 is a sectional view of the thrust collar in the direction AA, and FIG. 4 is a sectional view of a bearing cooling system +q of a horizontal shaft water turbine generator according to a conventional example t. 1: Journal bearing, 3 Nilus thrust bearing, 4: Rotating shaft,
6: Runner, 7: Rotating shaft heat vibrator, 8: Steam space, 9: Hollow part, 19: Working fluid passage, 21: Collar passage, 22 Nilast collar. ,・,'r゛..., Agent Iwao Yamaguchi: ゛, Koni. Vlz diagram

Claims (1)

[Claims] 1) A rotating shaft directly connected to the runner is supported horizontally by a journal bearing and a thrust bearing outside the casing,
A horizontal shaft water turbine generator in which a rotary shaft heat pipe is formed inside the rotary shaft using the journal bearing and the thrust bearing as a heat generating part and a runner exposed to a waterway as a condensing part, wherein a hollow part is provided in the thrust collar of the thrust bearing. , the hollow part communicates with the vapor space of the heat generating part of the rotary shaft heat pipe, and at this time, a plurality of collar part passages running radially within the thrust collar are provided between the hollow part and the thrust collar sliding surface. 1. A bearing cooling device for a horizontal-shaft water turbine generator, characterized in that a bearing cooling device for a horizontal-shaft water turbine generator is provided, and each of the collar passages communicates with the hollow part. 2) A bearing cooling device for a horizontal shaft water turbine generator as set forth in claim 1, characterized in that the inner diameter side end of each collar passage is communicated with the hollow part of the thrust collar. Bearing cooling system for shaft turbine generator. 3) In the bearing cooling device for a horizontal shaft water turbine generator according to claim 1, the inner diameter side end and the outer diameter side end of each collar passage are communicated with the hollow part of the thrust collar. A bearing cooling device for a horizontal shaft water turbine generator, characterized by: