KR19980024652U - Impeller for Centrifugal Compressors - Google Patents

Abstract

The present invention relates to an impeller for a centrifugal compressor, according to the present invention, a rotating body and a plurality of blades formed radially on the main body, and the air flow path is formed in the braid to flow a portion of the jet flow to the wake impeller Reducing the velocity of the leaving jets not only reduces the partial diffusion velocity due to the strong velocity, but also reduces the internal flow loss of the impeller.

Description

Impeller for Centrifugal Compressors

The present invention relates to an impeller for a centrifugal compressor, and more particularly, to an impeller for a centrifugal compressor having improved flow loss of the impeller.

In general, a compressor for compressing a fluid includes various types of compressors, such as a reciprocating compressor, a swash plate compressor, and a centrifugal compressor using centrifugal force, depending on the compression method.

BACKGROUND OF THE INVENTION Centrifugal compressors are generally used in a gas turbine engine compressor, an air cooling machine (ACM), a turbocharger, a turbo-compressor, and the like.

1 schematically shows a portion of a gas turbine engine.

Referring to the drawings, when the gas turbine engine multi-stage compresses the air generated by the compressor 10 and supplies it to the combustion chamber 12, the gas turbine engine is generated by injecting fuel into the high-pressure air supplied to the combustion chamber 12 and burning it. It is an engine which sends a combustion gas of high temperature and high pressure to the turbine 14, and obtains an output. This gas turbine engine is advantageous in that its weight is less than that of an internal combustion engine, and the structure of the engine is simpler than that of a steam turbine engine.

2 shows an example of such a centrifugal compressor.

As shown, an impeller 20 having a plurality of braids 21 formed on the upper surface at predetermined intervals, a space portion 23a in which the impeller 20 is installed, and a suction port 23b in communication with the space portion 23a. And a discharge port 23c are formed, and includes a housing 23 on which a rotating shaft 24 for rotating the impeller 20 is supported. Here, the impeller 20 is provided with a braid 21 to have a predetermined curved surface on the upper surface of the conical body 22a, the longitudinal upper end of the braid 21 is close to the inner peripheral surface of the housing.

Conventional centrifugal compressors configured as described above are subjected to centrifugal force as the impeller 20 rotates at high speed while air flowing into the suction port 23b flows along a flow path formed between the braid 21 and the housing 23. It is discharged to the discharge port 23c.

3 is a view showing a flow loss phenomenon of the impeller of the conventional centrifugal compressor.

Referring to the drawings, due to the rotation of the impeller 20, the fluid passing through the braid 21 cannot withstand the back pressure at the end of the impeller 20, so the pressure side (PS) and the suction side (Suction Side: SS separation occurs. Here, the flow of the suction side SS is a wake loss, which causes the flow loss of the impeller 20.

The wake is present irrespective of radial blades, backward curved blades and forward curved blades.

4 and 5 show the distribution of the ratio of the relative speed W2 of the impeller internal fluid to the end speed U2 of the impeller 20 of FIG. 3 (where the horizontal axis is the pitch P of the braid and the vertical axis is the depth D of the braid D). ), The vertical axis represents the velocity ratio respectively) and the flow pattern respectively.

Referring to the drawings, while maintaining the average speed ratio of 0.6, the speed ratio rapidly decreases to 0.2 at 0.5 or more of the blade pitch and 0.5 or less of the depth, resulting in the wake 33b. In addition, as shown in FIG. 5, the suction side SS and the pressure side PS are clearly distinguished, and the suction side SS has a higher flow loss than the pressure side PS.

In the centrifugal compressor having the above configuration, the flow inside the impeller is separated into the pressure side and the suction side, and the separation of the flow appears severely at the upper part of the outlet of the braid. The loss due to the wake accounts for more than 3% of the unit efficiency.

The present invention has been made to solve the above problems, the object of the present invention is to provide an impeller for a centrifugal compressor that can reduce the flow loss.

1 is a schematic illustration of a portion of a gas turbine engine.

2 is a cross-sectional view of a conventional centrifugal compressor.

3 is a view showing a flow loss phenomenon of a conventional impeller.

Figure 4 is a view showing the distribution of the relative velocity ratio of the internal fluid in the conventional impeller.

5 is a view showing a flow pattern of a conventional impeller.

6 is a cross-sectional view of the centrifugal compressor according to the present invention.

7 is a perspective view of the impeller shown in FIG. 6.

FIG. 8 is a schematic projection view illustrating a cross-sectional view taken along the line VII-VII of FIG. 7;

9 is a perspective view showing an extract of the braid according to the present invention.

10 is a schematic view showing a cross section along the line VII-VII of FIG. 9;

11 is a view showing a flow pattern of the impeller according to the present invention.

Explanation of symbols for the main parts of the drawings

10. Compressor 14. Turbin

12. Combustion chamber Braid

23.61. Housing 24.62. Axis of rotation

20.60. Impeller 65. hall

65a. slot

In order to achieve the above object, the present invention is an impeller including a rotating body and a plurality of blades formed radially predetermined length in the body, the air outlet path for the flow of air between adjacent braids each of the braids Characterized in that formed. Here, the impeller body is preferably formed in a disc or truncated cone.

Hereinafter, a preferred embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

Centrifugal compressor according to the present invention is to give a pressure by the centrifugal force to the fluid, an embodiment is shown in FIG.

As shown, a truncated conical space portion 61a is formed in the housing 61 with a fluid inlet 61b and an outlet 61c formed therein, and the space 61a has a rotating shaft installed in the housing 61. An impeller 60 supported by 62 is provided. Here, the impeller 60 is provided with a braid 64 to have a predetermined curved surface on the upper surface of the conical body (63a), the longitudinal upper end of the braid 64 is close to the inner peripheral surface of the housing between the adjacent braid A hole 65 is formed as an air outlet path capable of flowing a portion of the airflow discharged by the braid to the adjacent braid side in order to reduce the imbalance of the flow loss.

FIG. 7 is a perspective view illustrating an impeller for a centrifugal compressor according to the present invention, and FIG. 8 is a schematic projection view illustrating a cross section cut along the line VII-VII of FIG. 7.

7 and 8, the impeller 60 for the centrifugal compressor according to the present invention is a truncated cone-shaped main body 63a and a braid 64 radially installed on the outer circumferential surface of the main body 63a and spaced apart from each other by a predetermined interval. ). The braid 54 is formed with a hole 65 of a predetermined size. In addition, the hole 65 of the braid 64 may have a predetermined angle (alpha: alpha) with respect to the longitudinal direction of the braid 64 so that a portion of the jet's strong flow rate may flow into the wake, that is, SS. It is preferable to maintain the.

Figure 9 is a perspective view showing another embodiment of the braid according to the present invention, Figure 10 is a schematic diagram showing a cross section along the line VII-VII of FIG.

9 and 10, the impeller for a centrifugal compressor according to the present invention includes a truncated cone body not shown and radially installed on the outer circumferential surface of the body and spaced apart from each other by a predetermined interval. The braid 64a is installed in the longitudinal direction so as to be close to the inner circumferential surface of the housing 61 (Fig. 6), which is the same as in the previous embodiment. However, in the present embodiment, each of the braids 64 is an air outlet, and slots 65a of a predetermined size are formed. In addition, the slot 65a of the braid 64a maintains a predetermined angle (beta: β) with respect to the longitudinal direction of the braid 64a so that a portion of the jet's strong flow rate may be sent to the wake, that is, SS. And it is preferable to be drawn in the upper end of the braid (64a).

In the compressor employing the impeller according to the present invention configured as described above, as the impeller 60 installed inside the housing 61 is rotated at a high speed, fluid is introduced from the inlet 61b so that the main body 63a of the impeller 60 is provided. Is flowed along the passage formed between the braids 64 formed in the crankshaft and the inner surface of the housing 61, and is discharged to the discharge port 61c at a predetermined speed by centrifugal force. Here, air flow passages or slots formed in the braids 64 respectively maintain a predetermined angle with respect to the longitudinal direction of the braids 64 to blur a portion of the airflow of the SS to the PS to minimize flow loss. 11 illustrates this flow pattern. As can be seen in the figure, the flow pattern between SS and PS shows almost the same level. That is, it can be seen that the flow pattern of the braid end is kept constant by the air outlet passages 65 and 65a.

As described above, the braid 64 of the impeller 60 sends a portion of the jet's strong flow rate to the wake, ie, SS, thereby reducing the loss at the diffusion inlet due to the jet's rapid flow rate and generating wake. By moving the point behind the impeller, the flow losses of the impeller can be minimized.

Although the present invention has been described with reference to one embodiment shown in the accompanying drawings, this is merely an example, and those skilled in the art may understand that various modifications and equivalent embodiments are possible therefrom. There will be. Therefore, the true scope of protection of the present invention should be defined only by the spirit of the appended claims.

Claims (4)

An impeller comprising a main body rotating and a plurality of braids formed radially predetermined length in the main body, An impeller for each of said braids for the flow of air between adjacent braids. The method of claim 1, The main body is an impeller, characterized in that formed in a disc or truncated cone. The method of claim 1, The air outlet path is an impeller, characterized in that the center line is a hole forming a predetermined angle with respect to the longitudinal direction of the braid. The method of claim 1, The air outlet path is an impeller, characterized in that the center line is a slot formed at a predetermined angle with respect to the longitudinal direction of the braid and inserted into the upper end of the braid.