JP5915147B2 - Centrifugal compressor impeller - Google Patents

Description

  The present invention relates to an impeller, particularly an impeller of a centrifugal compressor.

  Conventionally, for example, as disclosed in Japanese Patent Application Laid-Open No. 9-42194, an impeller having a plurality of main wings and an auxiliary wing smaller than the main wing between the main wings has been proposed.

  By the way, in the conventional impeller as described in Patent Document 1, there is a problem that a loud sound is generated by the rotation of the impeller. For example, the centrifugal compressor includes an impeller, but if a loud sound is generated by the rotation of the impeller, the use of the centrifugal compressor is limited due to the noise.

  Accordingly, an object of the present invention is to provide an impeller for a centrifugal compressor capable of reducing sound generated during rotation.

  As a result of research, the inventor of the present invention has found that noise is generated when fluid sucked and discharged by impeller rotation collides with a stationary structure such as a casing around the impeller. Since they are arranged at equal intervals, the timing of fluid discharge from the impeller has periodicity, and when the fluid colliding with the stationary structure has periodicity, a louder sound is generated than when there is no periodicity or weakness I found out.

In view of the above knowledge, an impeller according to a first aspect of the present invention is an impeller of a centrifugal compressor, and includes a hub, a plurality of main wings provided on a surface of the hub, and a plurality of auxiliary wings. The auxiliary wings are respectively provided on the surface of the hub between two adjacent main wings, and are smaller than the main wings. The main wing and the auxiliary wing are arranged so as to intersect with a circle around the center of rotation of the hub in plan view. The intervals between adjacent wings on the circle are all equal. The distance between the at least one auxiliary wing and the main wing located next to the hub in the direction of rotation of the hub is a circle distance between the other auxiliary wing and the main wing located next to the hub in the direction of rotation of the hub. Different. Each of the auxiliary wings facing each other across the center of rotation of the hub has the same circular spacing with the main wing located next to the rear in the direction of rotation of the hub.

  In the impeller according to the first aspect of the present invention, the main wings are arranged at equal intervals, and the auxiliary wings are arranged at non-uniform intervals. Thereby, the periodicity of the timing of the fluid discharge from the impeller can be weakened. Therefore, it is possible to reduce the sound generated by the rotation of the impeller.

  Moreover, in this impeller, the space | interval of the auxiliary blade which opposes on both sides of a rotation center is the same. This makes it possible to achieve a suitable rotational balance.

  The impeller according to the second aspect of the present invention is the impeller according to the first aspect, and is arranged such that two or more auxiliary wings having the same interval do not continue in the rotation direction across the main wing. The interval is the interval on the circle between the auxiliary wing and the main wing located next to the hub in the rotational direction of the hub.

  In the impeller according to the second aspect of the present invention, the auxiliary wings having the same interval are arranged so as not to continue two or more in the rotation direction across the main wing, so that the arrangement of the auxiliary wings is not biased as much as possible. can do. Therefore, even if the arrangement intervals of the auxiliary blades are not uniform, it is possible to achieve a suitable rotational balance.

Impeller according to the third aspect of the present invention is the impeller according to the first aspect or the second aspect, the ailerons are located near the periphery of the hub.

In the impeller according to the third aspect of the present invention, the auxiliary wings are arranged in the vicinity of the peripheral edge of the hub where the separation vortex is likely to occur. This makes it possible to improve the ability to suppress the growth of the separation vortex.

With the impeller according to the first aspect of the present invention, it is possible to reduce the sound generated by the rotation of the impeller. It is also possible to achieve a suitable rotational balance.

The impeller according to the second aspect of the present invention, it is possible to take a suitable rotational balance.

In the impeller according to the third aspect of the present invention, it is possible to improve the ability to suppress the growth of the separation vortex.

1 is a schematic configuration diagram of a refrigeration apparatus in which a centrifugal compressor according to the present invention is employed. The schematic sectional drawing of a single stage centrifugal compressor. The top view which looked at the impeller from the front (for the wing, the cut figure in the base).

  Hereinafter, an embodiment of a heat pump apparatus employing a centrifugal compressor provided with an impeller according to the present invention will be described with reference to the drawings.

(1) Overall Configuration of Heat Pump Device 1 FIG. 1 is a schematic configuration diagram of a heat pump device 1 employing a single-stage centrifugal compressor 2 which is an example of a centrifugal compressor according to the present invention.

  The heat pump device 1 is a device that generates air conditioning and cold / hot water by a vapor compression refrigeration cycle. The heat pump apparatus 1 mainly has a single-stage centrifugal compressor 2, a four-way switching valve 15, a heat source side heat exchanger 3, an expansion mechanism 4, and a use side heat exchanger 5, and these devices are connected. As a result, a refrigerant circuit is configured. Here, carbon dioxide is used as the refrigerant.

  The single-stage centrifugal compressor 2 is connected to a suction pipe 6 that guides the refrigerant flowing out from the use side heat exchanger 5 to the suction side, and a discharge pipe 7 that extends from the discharge side to the inlet of the heat source side heat exchanger 3. The centrifugal compressor discharges the high-pressure refrigerant to the discharge pipe 7 after sucking and compressing the low-pressure refrigerant from the suction pipe 6.

  The four-way switching valve 15 is provided on the opposite side of the discharge pipe 7 from the single-stage centrifugal compressor 2 side, and switches between cooling operation and heating operation by switching the refrigerant flow in the refrigerant circuit. During the cooling operation, the heat-source-side heat exchanger 3 functions as a refrigerant radiator, and the user-side heat exchanger 5 functions as a refrigerant evaporator. During the heating operation, the heat source side heat exchanger 3 is caused to function as a refrigerant evaporator while the use side heat exchanger 5 is allowed to function as a refrigerant radiator. In addition, when the heat source side heat exchanger 3 and the use side heat exchanger 5 function as refrigerant radiators, they heat the air in the air-conditioning target space and / or heat a fluid such as water. In addition, when the heat source side heat exchanger 3 and the use side heat exchanger 5 function as a refrigerant evaporator, the air in the air-conditioning target space is cooled and / or the fluid such as water is cooled.

  The expansion mechanism 4 is a mechanism that lowers the pressure of the refrigerant that passes therethrough.

  Thus, the heat pump apparatus 1 is an apparatus that generates air conditioning and cold / hot water by a vapor compression refrigeration cycle that uses carbon dioxide as a refrigerant, and uses a single-stage centrifugal compressor 2 as a compressor. .

(2) Configuration of Single-stage Centrifugal Compressor FIG. 2 is a schematic cross-sectional view of the single-stage centrifugal compressor 2. FIG. 3 is a plan view of the impeller as viewed from the front (intake space side). In FIG. 3, the main wing 121 and the auxiliary wing 122 attached to the surface of the hub 120 are cut at the base.

  Here, the rotation axis of the impeller and the rotation shaft 52 is OO, and the direction along the rotation axis OO is the axial direction or the front-rear direction. The direction in which the rotational axis approaches the OO is defined as the radially inner side (inner side of the rotational radius), and the direction away from the OO is defined as the radially outer side (outer side of the rotational radius).

  The single stage centrifugal compressor 2 mainly includes a motor 50 and a compression mechanism 10.

(2-1) Motor 50
The motor 50 is a motor that drives the compression mechanism 10, and mainly includes a motor casing 51, a rotating shaft 52, a rotor 53, and a stator 54.

  Inside the motor casing 51, a space for accommodating the rotating shaft 52, the rotor 53, and the stator 54 is formed.

  The rotary shaft 52 is rotatably supported by a first radial bearing 55 and a second radial bearing 56 that are fixed to the motor casing 51. One axial end (left end in FIG. 2) of the rotation shaft 52 protrudes toward the compression mechanism 10 side. The other axial end of the rotating shaft 52 (the right end in FIG. 2) is slidably supported by a thrust bearing 57 fixed to the motor casing 51.

  The rotor 53 is pivotally supported on the rotary shaft 52 so as to rotate integrally with the rotary shaft 52 between the first radial bearing 55 and the second radial bearing 56 in the axial direction.

  The stator 54 is provided so as to surround the outer periphery of the rotor 53 and is supported by the motor casing 51 so as not to rotate.

(2-2) Compression mechanism 10
The compression mechanism 10 is a single-stage centrifugal compression mechanism.

  The compression mechanism 10 mainly has a compression mechanism casing 11 and an impeller 12.

(2-2-1) Compression mechanism casing 11
In the compression mechanism casing 11, a suction port 11a, a discharge port 11b, an infuser 11d, a shroud housing 11c, a diffuser 11e, and a scroll chamber 11f are mainly formed.

  The suction port 11 a is open toward one axial end (left end in FIG. 2) of the compression mechanism casing 11 and is connected to the suction pipe 6.

  The discharge port 11 b opens toward the outer circumferential end (the upper end in FIG. 2) of the compression mechanism casing 11 and is connected to the discharge pipe 7.

  As shown in FIG. 2, the shroud housing 11c is a space formed downstream of the suction port 11a, and accommodates the impeller 12 rotatably. A space between the suction port 11a and the shroud housing 11c is a suction side space of the impeller 12 called an infuser 11d.

  The space on the discharge side of the impeller 12 is a space called a diffuser 11e, where the velocity energy of the refrigerant discharged in a state where the flow velocity is increased is converted into pressure energy. A scroll chamber 11f for rectifying the refrigerant is provided at the tip of the diffuser 11e.

(2-2-2) Impeller 12
As shown in FIG. 3, the impeller 12 mainly includes a hub 120 and a plurality of blades 121 and 122 arranged on the front side of the hub 120 and radially outside, and extends in the front-rear direction of the hub 120. The rotating shaft 52 rotates around the axis.

  The hub 120 has a substantially conical shape whose diameter increases from the front toward the rear, and is supported by the rotary shaft 52 so as to rotate integrally with the rotary shaft 52. In addition, it is preferable that this hub 120 is hollow inside except a shaft peripheral part and an outer edge part from a viewpoint of weight reduction.

  On the front surface of the hub 120, main wings 121 and auxiliary wings 122 smaller than the main wings are provided alternately in the circumferential direction. As shown in FIG. 2, the main wing 121 and the auxiliary wing 122 are both three-dimensionally from the front surface of the hub 120 to the vicinity of the wing-facing wall 22b of the shroud housing 11c (see FIG. 1 of JP2011-80411). It is growing. Both the main wing 121 and the auxiliary wing 122 extend spirally so as to be left-handed when viewed from the front. That is, as shown in FIG. 3, the main wing 121 and the auxiliary wing 122 extend so as to turn to the left while expanding in the radial direction from the rotation center O of the hub 120 toward the periphery of the hub 120.

  Furthermore, the main wing 121 and the auxiliary wing 122 are formed so as to turn counterclockwise from the rotation center O of the hub 120 toward the periphery of the hub 120 in a front view.

  Each main wing 121 extends from the rotation center O of the hub 120 to the periphery of the hub 120.

  On the other hand, each auxiliary wing 122 is arranged between each main wing 121 and extends from a middle position between the rotation center O of the hub 120 and the periphery of the hub 120 to the periphery of the hub 120.

  When the motor 50 is driven, the impeller 12 rotates counterclockwise as viewed from the front, so that the refrigerant is sucked from the suction port 11a, compressed to a high pressure, and then discharged toward the discharge port 11b.

  At this time, the radially outer portion of each main wing 121 and auxiliary wing 122 moves along the vicinity of the inside of the blade facing wall 22b of the shroud housing 11c as the impeller 12 rotates. Thereby, it discharges in the state which the flow rate of the refrigerant | coolant increased, and becomes high-pressure refrigerant | coolant by converting speed energy into the energy of pressure in the diffuser 11e.

(3) Arrangement of Blades of Impeller 12 Next, the interval between the arrangement of the main wing 121 and the auxiliary wing 122 of the impeller 12 will be described in detail with reference to FIG.

  First, in defining the interval between the arrangement of the main wing 121 and the auxiliary wing 122, for the sake of convenience, it is assumed that there is a circle C on the front surface of the hub 120 with the rotation center O of the hub 120 as the center. Circle C intersects with the bases of all main wings 121 and auxiliary wings 122. Therefore, hereinafter, the interval between the main wing 121 and the auxiliary wing 122 refers to the interval on the circle C. The distance dimension may be the length of a straight line connecting the intersections of the main wing 121 and the auxiliary wing 122 and the circle C, or the arc length or center angle of the circle C sandwiched between the intersections. .

  The impeller 12 shown in FIG. 3 has six main wings 121 and six auxiliary wings 122. One auxiliary wing 122 is disposed between each two of the main wings 121. The main wings 121 of the impeller 12 are arranged at equal intervals. That is, the interval between each main wing 121 and the main wing 121 adjacent to the main wing 121 is the same. Specifically, as shown in FIG. 3, intervals I1, I2, I3, I4, I5, and I6 between adjacent main wings 121 on a circle C are all equal.

  On the other hand, the auxiliary blades 122 included in the impeller 12 are not arranged at equal intervals, and the intervals are not uniform. Specifically, the distance on the circle C between the at least one auxiliary wing 122 and the main wing 121 positioned next to the hub 120 in the rotational direction Y of the hub 120 is based on the rotational direction Y of the other auxiliary wing 122 and the hub 120. This is different from the interval on the circle C with the main wing 121 located on the rear side. In FIG. 3, the intervals on the circle C between the auxiliary wings 122 and the main wings 121 located on the rear side in the rotation direction Y of the hub 120 are indicated as α, β, and γ, respectively. The distances on the circle C between each auxiliary wing 122 and the main wing 121 positioned adjacent to the front in the rotation direction Y of the hub 120 are α ′, β ′, and γ ′. As shown in FIG. 3, α is larger than β, and β is an interval larger than γ. On the other hand, α ′ is smaller than β ′, and β ′ is an interval smaller than γ ′. Therefore, the auxiliary wings 122 are not arranged at equal intervals. Note that the intervals I1, I2, I3, I4, I5, I6 between the main wings 121 shown in FIG. 3 and the intervals α, β, γ, α ′, β ′, γ ′ between the main wing 121 and the auxiliary wing 122 are shown. Are proportional to the distance between the main wings 121 on the circle C and the distance between the main wing 121 and the auxiliary wing 122, respectively.

  Further, the auxiliary wings 122 are arranged so as to rotate with a good balance. Specifically, as shown in FIG. 3, two or more auxiliary wings 122 having the same distance from the next main wing 121 to the rotation direction Y do not continue in the rotation direction Y across the main wing 121. It is like that. For example, in FIG. 3, the distance between each auxiliary wing 122 and the adjacent main wing 121 in the rotation direction Y is α, β, γ, α, β, γ in order in the rotation direction Y, and is continuous. Absent. Further, the distance between each of the auxiliary blades 122 facing each other across the rotation center O of the hub 120 with respect to the rotation direction Y is the same. That is, the distance between the auxiliary wing 122 whose distance from the rear adjacent main wing 121 is α and the rear adjacent main wing 121 opposite to the rotation center O of the hub 120 is α. The distance between the auxiliary wing 121 whose distance between the rear adjacent main wing 121 is β and the rear adjacent main wing 121 opposed to the auxiliary wing 122 across the rotation center O of the hub 120 is β. The distance between the auxiliary wing 122 whose distance from the rear adjacent main wing 121 is γ and the rear adjacent main wing 121 facing the rotation center O of the hub 120 is γ. Thereby, the rotation balance of the impeller 12 can be taken.

  Even if the number of the auxiliary wings 122 is an odd number, it is preferable that the auxiliary wings 122 are not arranged as biased as possible. If the balance cannot be achieved only by the arrangement of the auxiliary wings 122, the center of gravity of the hub 120 may be adjusted so that the rotational balance can be achieved.

  In addition, as shown in FIG. 3, the auxiliary wing 122 is disposed in the vicinity of the peripheral edge of the hub 120. The vicinity of the peripheral edge of the hub 120 is a part where the sucked refrigerant is easily separated from the main wing 121 and forms a vortex (separation vortex). By providing the auxiliary wing 122 near the peripheral edge, the growth of the separation vortex is suppressed. I can do it.

(4) Features (4-1)
In the above embodiment, the main wings 121 are arranged at equal intervals, but the auxiliary wings 122 are not arranged at equal intervals. That is, the distance between the main wings can be designed mainly considering the performance, and the reduction of sound is taken into consideration when designing the distance between the auxiliary wings. Thereby, in the said embodiment, the periodicity of the timing of the discharge of the refrigerant | coolant from the impeller 12 can be weakened without sacrificing the performance of the impeller 12. FIG. As a result, it is possible to reduce the sound generated by the rotation of the impeller 12.

(4-2)
Moreover, in the said embodiment, the auxiliary wing | blade 122 is arrange | positioned so that it may rotate with sufficient balance. That is, two or more auxiliary wings 122 having the same distance from the main wing 121 on the rear side with respect to the rotation direction Y do not continue in the rotation direction Y across the main wing 121. That is, the arrangement of the auxiliary wings 122 can be minimized. Thereby, even if the arrangement | positioning space | interval of the auxiliary blade 122 is non-uniform | heterogenous, it is possible to take the suitable rotational balance of the impeller 12. FIG.

(4-3)
Moreover, in the said embodiment, the auxiliary wing | blade 122 is arrange | positioned so that it may rotate with sufficient balance. In other words, the distance between each of the auxiliary wings 122 facing each other across the rotation center O of the hub 120 with respect to the rotation direction Y is the same as the main blade 121 adjacent to the rear side. Thereby, even if the arrangement | positioning space | interval of the auxiliary blade 122 is non-uniform | heterogenous, it is possible to take the suitable rotational balance of the impeller 12. FIG.

(4-4)
Moreover, in the said embodiment, the auxiliary blade 122 is arrange | positioned in the peripheral vicinity of the hub 120 which a peeling vortex tends to generate | occur | produce. This makes it possible to improve the ability to suppress the growth of separation vortices.

  The impeller according to the present invention is particularly useful in a centrifugal compressor of a refrigeration apparatus.

1 Refrigeration equipment 2 Single stage centrifugal compressor (centrifugal compressor)
12 Impeller 120 Hub 121 Main wing 122 Auxiliary wing C Circle O Rotation center

Japanese Patent Laid-Open No. 9-42194

Claims (3)

An impeller (12) of a centrifugal compressor (2),
A hub (120);
A plurality of main wings (121) provided on the surface of the hub;
A plurality of auxiliary wings (122) each provided on the surface of the hub between two adjacent main wings and smaller than the main wings;
With
The main wing and the auxiliary wing are arranged so as to intersect with a circle (C) centering on the rotation center (O) of the hub in a plan view,
The intervals (I1, I2, I3, I4, I5, I6) between adjacent main wings on the circle are all equal,
A distance (α, β, γ) on the circle between at least one of the auxiliary wings and a main wing located next to the hub in the rotation direction of the hub is a rear of the other auxiliary wing and the hub in the rotation direction. intervals on the circle of the wing which is located next (alpha, beta, gamma) and varies,
Each of the auxiliary wings opposed across the center of rotation of the hub has the same spacing on the circle with the main wing located next to the hub in the direction of rotation of the hub.
Impeller (12). The auxiliary wings having the same distance on the circle with the main wing located next to the hub in the rotation direction of the hub are arranged so as not to be continuous in two or more in the rotation direction across the main wing.
The impeller (12) according to claim 1. The auxiliary wing is disposed near the periphery of the hub,
Impeller (12) according to claim 1 or 2 .

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