JPH03164532A - Two-shaft type emergency gas turbine - Google Patents

Abstract

PURPOSE:To enable the efficient cooling of a ball hearing by forming a lubricating oil feed passage, for feeding lubricating oil to the ball bearing for supporting a power turbine shaft rotatably, on a cylindrical housing covering the power turbine shaft. CONSTITUTION:A two-shaft type emergency gas turbine is provided with a power turbine rotor 12 driven by high-temperature high-pressure combustion gas, generated in a gas generator, flowing in an annular gas passage 19, and one end of a power turbine shaft 15 is connected to the downstream side in the combustion gas flowing direction of the rotor 12. The power turbine shaft 15 is rotatably supported by a ball bearing 22 fitted at a cylindrical housing 21 covering the power turbine shaft 15. In this case, a lubricating oil feed passage 33 for feeding lubricating oil to the ball bearing 22 is formed at the housing 21. This lubricating oil feed passage 33 is formed of a horizontal part 33a provided along the axial direction of a housing body 24, an annular part 33b, plural vertical parts 33c and plural nozzle parts 33d.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a two-shaft emergency gas turbine.

(Prior Art) In a two-shaft gas turbine, a power turbine rotor for extracting power is placed downstream of a turbine rotor that rotates an impeller of a compressor. It is connected to one end of a power turbine shaft located downstream in the gas flow direction. In the case of a two-shaft emergency gas turbine, one end of the power turbine shaft is supported by a ball bearing, since it is necessary to start up quickly even when lubricating oil is not sufficiently supplied. In the conventional two-shaft emergency gas turbine,
A lubricating oil supply passage was formed in the housing of the power turbine shaft, and lubricating oil was supplied to the ball bearing from the side opposite to the power turbine rotor side.

(Problem to be Solved by the Invention) Since the power turbine rotor is connected to one end of the power turbine shaft, the ball bearing must be placed as close to the power turbine rotor as possible in order to prevent a dangerous reduction in rotational speed due to resonance. It is desirable to place the However, the power turbine rotor becomes hot because its blades are exposed to hot combustion gases, and that heat is transferred to the ball bearings. In the conventional structure in which lubricating oil is supplied to the ball bearings from the side opposite to the power turbine rotor side, the ball bearings are not cooled sufficiently, resulting in severe deterioration of the ball bearings due to thermal effects.

(Means for Solving the Problems) In order to solve the above problems, the two-shaft emergency gas turbine of the present invention includes a power turbine rotor that is rotationally driven by combustion gas flowing through a gas passage having an annular cross-sectional shape; A power turbine shaft having one end connected to the downstream side of the combustion gas flow direction of the power turbine rotor, a cylindrical housing 11 located on the inner peripheral side of the gas passage and covering the power turbine shaft, and a housing attached to the housing. and a ball bearing that rotatably supports one end of the power turbine shaft, the lubricating oil being supplied to the housing from the power turbine rotor side to the ball bearing. A supply passage is formed.

(Function) Since lubricating oil is supplied to the ball bearing from the high-temperature power turbine rotor side, the ball bearing is cooled well. Furthermore, the portion of the housing closer to the power turbine rotor than the ball bearing is also well cooled by the lubricating oil.

(Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 and 2.

FIG. 2 is a schematic longitudinal sectional front view of a two-shaft emergency gas turbine according to an embodiment of the present invention. On the platform 1, which also serves as an oil pan for storing lubricating oil, air is sucked in and is placed under high temperature and high pressure. a gas generator 2 that generates combustion gas, and an output turbine 3 that extracts rotational power from the combustion gas generated by the gas generator 2.
and a reducer 4 that reduces the rotational power taken out by the output turbine 3 to a predetermined rotational speed are arranged in this order from left to right. Attached to the left side of the gas generator 2 is an auxiliary machine gearbox 5 that accommodates bearings, gears, etc. of various auxiliary machines.

The gas generator 2 includes an impeller 7 that constitutes the rotor part of a centrifugal compressor that compresses air, and a combustor 8 that creates high-temperature, high-pressure combustion gas by mixing and combusting compressed air and fuel. , a high-pressure turbine rotor 9 that is rotationally driven by combustion gas to rotate the impeller 7, and a low-pressure turbine rotor 10 that is located downstream of the high-pressure turbine rotor 9 and operates in the same manner as the high-pressure turbine rotor 9. . The output turbine 3 includes a power turbine rotor 12 located downstream of the low-pressure turbine rotor 10 and rotated by combustion gas, and a power turbine rotor 12 that is located downstream of the low-pressure turbine rotor 10 and rotates the combustion gas, that is, the exhaust gas after driving the power turbine rotor 12, without generating a vortex. It includes an exhaust differential user 13 for deceleration, an exhaust duct 14 for releasing exhaust gas, a power turbine shaft 15 that rotates integrally with the power turbine rotor 12, and the like. The reducer 4 includes an output shaft 17 and a plurality of gears that reduce the rotational power of the power turbine shaft 15 to a predetermined rotational speed and transmit it to the output shaft 17.

The power turbine shaft 15 is located downstream of the power turbine rotor 12 in the combustion gas flow direction (on the right side in the drawing) and on the inner circumferential side of the gas passage 19 having a substantially annular cross-sectional shape. is connected to one end of the power turbine shaft 15 by a bolt 20. The outer periphery of the power turbine shaft 15 is covered by a substantially cylindrical housing 21, and the housing 21 includes a ball bearing 22 that supports one end of the power turbine shaft 15 rotatably around the axis, and a ball bearing 22 that supports one end of the power turbine shaft 15 rotatably around the axis. A pair of roller bearings 23a and 23b are attached to support the other end of the roller bearing 15 rotatably about the axis. Ball bearing 22 and roller bearings 23a, 23
Lubricating oil is supplied to the gap between the outer periphery of the outer ring of b and the housing 21, and a floating system is adopted in which the power turbine shaft 15 is hydraulically supported when it rotates to prevent a dangerous rotational speed from decreasing. There is.

FIG. 1 is an enlarged vertical sectional front view of the main parts of a two-shaft emergency gas turbine according to an embodiment of the present invention.
A substantially cylindrical housing body 24 that loosely fits around the outer periphery of the power turbine shaft 15 at a predetermined interval, and a housing body 2
4, an annular bearing holder 26 attached to one end of the bearing holder 26 with a plurality of bolts 25, and an annular coupling holder 28 attached to one end of the bearing holder 26 with a plurality of bolts 27.
It exists. Two annular couplings that connect the power turbine rotor 12 and the power turbine shaft 15 are attached to the inner circumference of the coupling holder 28, and two couplings and a ball bearing are attached to the outer circumference of one end of the power turbine shaft 15. An annular spacer 30 is attached between the two parts 22 and 22. Between one end surface of the housing main body 24 and the bearing holder 26, a heat separator 32 in the shape of an annular plate made of carbon, for example, is provided.
A lubricating oil supply passage 33 for supplying lubricating oil to the ball bearing 22 is formed in the housing 21 . The lubricating oil supply passage 33 includes one horizontal portion 33a formed along the axial direction of the housing body 24, an annular annular portion 33b formed on the end surface of the bearing presser 26,
A plurality of vertical portions 33c are formed radially inward from the inner circumference of the annular portion 33b at appropriate intervals in the circumferential direction, and a plurality of small diameter nozzles are formed from the tip of the vertical portion 33C toward the ball bearing 22. 33d.

Note that the horizontal portion 33a passes through the thermal separator 32. Further, the bearing retainer 26 is connected to the inner cylinder 3 that forms the gas passage 19.
It is fixed to the flange portion 35a of No.5.

Next, the operation will be explained. When a two-shaft emergency gas turbine is operated, the power turbine rotor 1 is damaged by high-temperature combustion gas.
2 becomes hot, and the heat is transferred to the ball bearing 22 via the power turbine shaft 15.

Furthermore, the inner cylinder 35 becomes high in temperature due to the high temperature combustion gas, and the heat is transmitted to the ball bearing 22 via the bearing presser 26 and the housing body 24. These heats are transferred to the ball bearing 22 from the power turbine rotor 12 side (the left side in the figure), so the portion of the ball bearing 22 that is closer to the power turbine rotor 12 has a higher temperature than the portion that is farther from the power turbine rotor 12. Become.

On the other hand, lubricating oil discharged from a lubricating oil pump (not shown) passes through a predetermined path to the horizontal part 33a of the lubricating oil supply passage 33, and connects the horizontal part 33a, the annular part 33b, the vertical part 33c, and the nozzle part 33d. and is injected into the ball bearing 22. As a result, the ball bearing 22 is lubricated and cooled.

In this way, since lubricating oil is supplied to the ball bearing 22 from the high-temperature power turbine rotor 12 side, the ball bearing 22 can be cooled efficiently and well. Moreover, the annular portion 33b and the vertical portion 33
The lubricating oil passing through the nozzle portion 33d and the bearing retainer 26
Since the ball bearing 22 can be cooled, the heat transferred to the ball bearing 22 via the bearing presser 26 can be reduced, and the temperature rise of the ball bearing 22 can be effectively suppressed. Therefore, by reducing the distance between the power turbine rotor 12 and the ball bearing 22, it is possible to prevent resonance (dangerous reduction in rotational speed), reduce the temperature rise of the ball bearing 22, and extend the life of the ball bearing 22. Also, as in this embodiment, the housing body 24
If a thermal separator 32 is provided between the bearing retainer 26 and the bearing retainer 26,
Heat transfer from the bearing presser 26 to the housing main body 24 can be favorably reduced, and the temperature rise of the ball bearing 22 can be further favorably suppressed.

(Another Embodiment) In the above embodiment, the horizontal portion 3 is provided in the housing body 24.
3a, the present invention is not limited to such a configuration, and may be configured such that, for example, a vibrator or the like is used instead of the horizontal portion 33a to supply lubricating oil to the annular portion 33b.

(Effects of the Invention) As described above, according to the present invention, since lubricating oil is supplied to the ball bearing from the high temperature power turbine rotor side, the ball bearing can be efficiently and favorably cooled.

Moreover, since the one end of the housing can be cooled by the lubricating oil passing through the one end of the housing, the heat transferred to the ball bearing via the housing can be reduced, and the temperature rise of the ball bearing can be effectively suppressed. Therefore, the distance between the power turbine rotor and the ball bearing can be brought closer to prevent a dangerous reduction in rotational speed due to resonance, while the temperature rise of the ball bearing can be favorably reduced, and the life of the ball bearing can be extended.

[Brief explanation of the drawing]

FIG. 1 is an enlarged longitudinal sectional front view of essential parts of a two-shaft emergency gas turbine according to an embodiment of the present invention, and FIG. 2 is a schematic longitudinal sectional front view of the same two-shaft emergency gas turbine.

Claims (1)

[Claims] 1. A power turbine rotor rotationally driven by combustion gas flowing through a gas passage having an annular cross-sectional shape, a power turbine shaft having one end connected to the downstream side of the power turbine rotor in the combustion gas flow direction, and a cylindrical housing located on the circumferential side and covering the power turbine shaft;
In a two-shaft emergency gas turbine having a ball bearing attached to the housing and rotatably supporting one end of the power turbine shaft, lubricating oil is applied to the housing from the power turbine rotor side to the ball bearing. A two-shaft emergency gas turbine characterized in that a lubricating oil supply passage is formed to supply lubricating oil.