JPH0447149B2 - - Google Patents

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]

Figure 6 is a cross-sectional view of a conventional bearing cooling device using a rotary shaft heat pipe for a horizontal shaft water turbine generator.
In FIG. 6, the rotating shaft 4 is directly connected to the runner 6.
is horizontally supported by the journal bearing 1 and the thrust bearing 3 outside the casing 15, the journal bearing 1 and the thrust bearing 3 are used as the heat generating part inside the rotating shaft 4, and the runner 6 exposed to the water channel in the suction pipe 18 is used as the condensing part. A rotating shaft heat pipe 7 is formed. The thrust collar 22 is supported in the axial direction by the thrust collar 3, and the journal bearing 1 and the thrust bearing 3 are housed in the bearing stand 2 and are filled with lubricating oil 5. 8 is a vapor space of the rotating shaft heat pipe, 16 is a speed ring, 17 is a guide vane, 20 is a working fluid of the rotating shaft heat pipe, and 23 is the ground.

In the conventional bearing cooling system, the thrust collar 22
Most of the heat generated flows into the rotating shaft heat pipe 7, but in this case, the heat conduction distance from the heat generating part of the thrust collar to the steam space 8 of the rotating shaft heat pipe is long.

Heat conduction within the thrust collar 22 and heat flux at the heat pipe evaporation surface are large.

Since the thrust collar 22 usually has a uniform wall thickness, the heat conduction area becomes smaller from the surface of the thrust collar that generates heat due to friction toward the center of rotation, and the area of the evaporation surface also becomes smaller.

For the above reasons, the temperature difference increases due to the increase in thermal resistance from the heat generating part to the heat pipe and the increase in thermal resistance due to the increase in heat flux at the heat pipe evaporation surface, so the temperature of the bearing part becomes higher than the allowable value. Therefore, it was difficult to apply it to the bearing cooling system of a horizontal shaft turbine generator with an output of approximately 500 kW or more.

Methods for keeping the temperature of the bearing part below the allowable value include reducing the temperature difference from the heat generating part to the heat pipe condensing part, increasing the heat transfer area in the cooling part and thinning the liquid film to increase the heat transfer coefficient. There is a way to increase the temperature and reduce the temperature difference.

[Purpose of the invention]

The present invention aims to increase the heat transfer area of the thrust bearing of a horizontal shaft water turbine generator, reduce the thermal resistance in the rotating shaft heat pipe condensing section, and reduce the bearing temperature.

[Key points of the invention]

According to the present invention, the above-mentioned object is provided to a thrust collar of a thrust bearing of a horizontal shaft water turbine generator in which a rotary shaft heat pipe is formed inside a rotary shaft that is horizontally supported by a journal bearing and a thrust bearing and is directly connected to a runner. By providing a hollow part, communicating the hollow part with the vapor space of the heat generating part of the rotating shaft heat pipe, and providing a plurality of concave and convex parts on the surface of the hollow part, which are arranged concentrically with respect to the rotating shaft. achieved.

[Embodiments of the invention]

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. 4 is a detailed view showing a thrust collar of a bearing cooling device according to another embodiment of the present invention, and FIG. 5 is a sectional view taken along B-B in FIG. 4. This will be explained below based on the drawings.

In FIG. 1, a rotating shaft 4 directly connected to a runner 6 passes through the casing, and the rotating shaft 4 is supported horizontally by a journal bearing 1 and a thrust bearing 3 housed in a bearing stand 2, and the other end of the rotating shaft is is coupled to a generator (not shown). The bearing stand 2 is filled with lubricating oil 5. In Fig. 1, 15 is a casing, 16 is a speed ring,
17 is a guide vane, and 18 is a suction pipe. In a rotary shaft heat pipe 7 in which the rotary shaft 4 is hollow and contains a working fluid 20, the journal bearing 1 and the thrust bearing 3 are used as heat generating parts, and the runner 6 exposed to the waterway is used as a condensing part, the thrust collar 22 of the thrust bearing 3 is heated. A hollow portion 9 is provided, and this hollow portion 9 is communicated with the steam space of the rotating shaft heat pipe, and a plurality of uneven portions are provided on the surface of the hollow portion.

In FIGS. 2 and 3, the hollow portion 9 of the thrust collar 22 has a donut-shaped cross section as shown in FIG. It communicates with the steam space 8 through 19, and 24 is a lid for sealing the hollow space. A plurality of uneven portions 21 are provided on the surface of the hollow portion 9 of the thrust collar 22 concentrically with respect to the rotating shaft 4.

In FIGS. 4 and 5, the same parts as in FIGS. 2 and 3 are given the same numbers, and the thrust collar 22 has a cylindrical hollow part 9 radially extending 8.
The thrust collar 22 is connected to the steam space 8 of the rotary shaft heat pipe through a cylindrical working fluid passage 19, and a plurality of annular uneven portions 21 are provided on the surface of the hollow portion 9 of the thrust collar 22.

The heat generated by frictional resistance when the thrust bearing 3 and the thrust collar 22 configured as described above receive thrust force is transmitted to the uneven portion 21 on the surface of the hollow portion 22 by heat conduction inside the thrust collar 22. When the working fluid is heated and evaporated in these uneven parts,
This steam flows from the hollow part 9 through the working fluid passage 19 to the steam space 8 of the heat generating part where the pressure is low, 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. This liquid is returned to the thrust collar side by centrifugal force, and the working liquid is vacuum-sealed in an amount that always fills the hollow part of the thrust collar. The heat of the fixed portion of the thrust bearing 3 is transmitted to the lubricating oil 5 and further to the surface of the rotating shaft heat pipe 7, where the heat is radiated to the runner side, and the heat is radiated from the outer surface of the bearing stand 2 to the atmosphere. The uneven portions 21 on the surface of the hollow portion 9 of the thrust collar 22 function as fins.

〔Effect of the invention〕

According to this invention, the heat generated in the thrust collar 22 of the horizontal-shaft turbine generator is conducted through the thickness of the thrust collar, and is further conducted through the hollow portion with a large heat transfer area, and the heat is transferred through the uneven portions on the surface of the hollow portion. Since the heat transfer area can be increased to 2 to 4 times that of a flat surface, the heat flux can be reduced and the thermal resistance of the evaporation section can be significantly reduced. This makes it possible to reduce the temperature difference in the thrust collar, making it possible to cool the thrust bearings of horizontal-shaft water turbine generators or horizontal-shaft pumps with an output of 500 kW or more, and improve cooling performance.

[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. A cross-sectional view of the thrust collar in the A-A direction,
FIG. 4 is a detailed view showing a thrust collar of a bearing cooling device according to another embodiment of the present invention, FIG. 5 is a sectional view of the thrust collar shown in FIG. 4 in the direction B-B, and FIG. 6 is a horizontal axis according to a conventional example. FIG. 2 is a sectional view of a bearing cooling device for a water turbine generator. 1... Journal bearing, 3... Thrust bearing,
4... Rotating shaft, 6... Runner, 7... Rotating shaft heat pipe, 8... Steam space, 9... Hollow part, 2
1... Uneven portion, 22... Thrust collar.

Claims (1)

[Claims] 1. A rotating shaft directly connected to the runner is horizontally supported by a journal bearing and a thrust bearing outside the casing, the journal bearing and thrust bearing are inside the rotating shaft as a heat generating part, and the runner exposed to the waterway is a condensing part. In a horizontal shaft water turbine generator forming a rotary shaft heat pipe, the thrust collar of the thrust bearing has a hollow portion, the hollow portion is communicated with the steam space of the heat generating portion of the rotary shaft heat pipe, and the surface of the hollow portion is A bearing cooling device for a horizontal shaft water turbine generator, characterized in that a plurality of uneven portions are provided concentrically with respect to the rotating shaft.