JPH05296190A - Turbo machinery - Google Patents

Abstract

(57) [Summary] [Objective] To provide a power recovery device with improved performance and efficiency of a fluid machine. A device constituted by a seal labyrinth 1, a rotary shaft 2, and blades 4 (blade row 4 ') formed on the rotary shaft. [Effect] By installing a plurality of simple blades on the rotary shaft of a turbo fluid machine, the leakage of fluid from the high pressure part can be used to
The performance and efficiency of fluid machinery can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to, for example, a centrifugal compressor,
The present invention relates to turbo fluid machines such as blowers, pumps and turbines.

[0002]

2. Description of the Related Art Generally, in a turbo type fluid machine, in order to prevent a fluid in a high pressure portion from leaking to a low pressure portion, for example, a leakage preventing shaft sealing device as shown in FIG. Have That is, since the fluid 3 in the high-pressure portion is connected to the fluid 3 ′ in the low-pressure portion via the shaft sealing device composed of the seal labyrinth 1 having a plurality of protrusions and the rotary shaft 2, the pressure difference between them is large. Even in the case of occurrence of the above, due to the seal labyrinth structure having the above-described shape, the fluid in the high pressure portion does not easily flow out to the low pressure portion, and the leakage amount can be suppressed to a relatively small amount (Mechanical Engineering Handbook B5). -Example of labyrinth seal described on fluid machine page 118).

[0003]

Even in the fluid machine having the shaft sealing device as described above, a certain amount of fluid leaks from the high pressure portion to the low pressure portion, and the amount of the fluid leaks from the high pressure portion and the low pressure portion. The larger the pressure difference, the more.

Generally, the amount of fluid that leaks is not so large that it has to be taken into consideration in comparison with the amount of fluid that the fluid machine handles, but in high-pressure CO ₂ compressors, the amount of fluid that leaks is high. May amount to several% of the total handling flow rate, resulting in large energy loss due to high-pressure fluid leakage,
Therefore, the fluid performance of the turbo fluid machine is deteriorated.

An object of the present invention is to provide a shaft sealing mechanism when energy loss due to leakage of high pressure fluid cannot be ignored.
It is to provide a turbo fluid machine that exhibits good fluid performance.

[0006]

In order to solve the above-described problem of energy loss due to leakage, the present invention provides a plurality of blades on the rotary shaft on the low pressure side of a conventional shaft sealing device. Thus, the kinetic energy of the leak flow from the shaft seal portion is recovered and used as the rotation energy of the rotating shaft.

[0007]

That is, in the power recovery device according to the present invention, the power recovery device consisting of a plurality of blades is installed in a part of the rotary shaft in advance to cope with the leakage of the fluid from the shaft seal portion. It is possible to absorb and utilize a part of the energy loss due to the rotational energy of the turbomachine.

With this device, the design of a turbo type fluid machine having better fluid performance and efficiency than ever before can be achieved.
It is possible to manufacture relatively easily.

[0009]

Embodiment An embodiment of the present invention will be described with reference to FIG.
FIG. 1A is an explanatory diagram of a power recovery device according to an embodiment of the present invention.

As shown in FIG. 1 (b), the blades 4 are each formed by machining on the rotary shaft 2 by machining. The blade may be processed on the sleeve and shrink fitted to the rotating shaft. FIG. 1A is a cross-sectional view of a turbomachine near the seal labyrinth structure, and FIG.
It is the figure which expanded and showed the surface of a rotating shaft in planar form.

As shown in FIG. 2 (a), the fluid flow in the vicinity of the shaft seal portion having such a structure has a circumferential component along the rotation direction of the rotary shaft and a labyrinth perpendicular to the longitudinal direction of the rotary shaft. It consists of an axial component toward the low pressure side.

Now, as shown in FIG. 2 (a), the blade row 4'is arranged on the rotating shaft in the vicinity of the shaft sealing structure in which such a flow exists. By rotating the flow direction of the shaft sealing portion as shown in FIG. 2 (a), this blade row 4'receives work from the fluid in the rotational direction. This is the energy recovered as the rotational energy of the rotary shaft, and the velocity components at the inlet and outlet of the blade row are represented as shown in FIGS. 2 (b) and 2 (c).

L = ρ · Q · (u ₁ cu ₁ −u ₁ cu ₂ ) (kW) where ρ: density of fluid (kgS ² / m ⁴ ) Q: amount of leakage per unit time (m ³ / s) When the above device is installed in the shaft seal portion, energy loss due to leakage can be minimized without impairing the original characteristics of the fluid machine, which contributes to energy saving.

[0014]

According to the present invention, the design and manufacture are relatively easy, and the performance and efficiency can be improved without impairing the characteristics of the equipped fluid machine itself.

Further, even if the machining accuracy of the labyrinth portion, which generally requires a high degree of precision, is lowered to some extent, the performance and efficiency of the machine are not sacrificed, so that the economy can be improved by simplifying the machining. ..

Further, even if the labyrinth tip portion comes into contact with the rotating shaft due to unexpected vibration or the like during operation of the turbofluid machine and the labyrinth tip portion is damaged, fluid leakage caused by the labyrinth damage occurs. The energy loss with increasing quantity can be recovered in the form of rotational energy.

[Brief description of drawings]

FIG. 1 is a central vertical cross-sectional view showing the entire structure of a labyrinth structure and a power recovery device showing an embodiment of the present invention.

FIG. 2 is an explanatory view (a) and a developed view (b) showing a main part of a rotary shaft.

FIG. 3 is an explanatory diagram of a conventional shaft sealing device for a turbo fluid machine.

[Explanation of symbols]

1 ... Seal labyrinth, 2 ... Rotary shaft, 3 ... High pressure part, 3 '
... Low pressure part, 4 ... wing, 4 '... wing part.

Claims (1)

[Claims] 1. A turbo machine characterized in that in a turbo fluid machine, kinetic energy of a fluid leaking from a high pressure portion is recovered by a blade row installed on a rotary shaft and utilized as rotational energy.