Sawtooth-shaped impeller blade

Abstract

A refrigerant compressor includes an impeller including vanes having a trailing edge with one or more serrations.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Application No. 63 / 358,294, filed on July 5, 2022. Background Art

[0003] A refrigerant compressor is used to circulate refrigerant in a cooler through a refrigerant circuit. A known refrigerant circuit includes a compressor, a condenser, an expansion device, and an evaporator. The compressor compresses a fluid, which then flows to a condenser, which in turn cools and condenses the fluid. The refrigerant then enters an expansion device, which reduces the pressure of the fluid, and enters an evaporator, where the fluid evaporates, completing the refrigeration cycle.

[0004] Many refrigerant compressors are centrifugal compressors and have an electric motor that drives at least one impeller to compress the refrigerant. The fluid flows into the impeller in an axial direction and is discharged radially from the impeller. Summary of the invention

[0005] A refrigerant compressor according to an example of the present disclosure includes an impeller including a blade having a trailing edge with one or more serrations.

[0006] In another example of the foregoing, the impeller includes a plurality of main blades and first and second splitter blades between adjacent main blades. Each of the main blades and the first and second splitter blades includes a trailing edge having one or more serrations.

[0007] In another example of any of the foregoing, the first splitter blade extends a first length between its leading edge and trailing edge, and the second splitter blade extends a second length between its leading edge and trailing edge. The first length is greater than the second length. Each main blade extends a third length between its leading edge and trailing edge, and the third length is greater than the first and second lengths.

[0008] In another example of any of the foregoing, the leading edges of the first splitter blade, the second splitter blade, and each main blade are staggered relative to each other. The trailing edges of the first splitter blade, the second splitter blade, and each main blade are aligned relative to each other and are disposed at a common radial distance from the rotational axis of the impeller and are coextensive with the outlet of the impeller.

[0009] In another example of any of the foregoing, the one or more serrations are arcuate serrations.

[0010] In another example of any of the foregoing, the one or more serrations each include first and second curved surfaces converging to a sharpened tip.

[0011] In another example of any of the foregoing, the first and second curved surfaces are convex.

[0012] In another example of any of the foregoing, the one or more serrations include a plurality of serrations, and the first and second curved surfaces of adjacent serrations of the plurality of serrations intersect at points radially inward of the sharp tip and form a space axially between the adjacent serrations.

[0013] In another example of any of the foregoing, the impeller includes a plurality of blades, and every other blade of the plurality of blades includes a trailing edge having one or more serrations, and the plurality of blades other than the every other blade do not include serrations.

[0014] In another example of any of the foregoing, the blade comprises three teeth.

[0015] A refrigerant system according to an example of the present disclosure includes a primary refrigerant circuit including a compressor, a condenser, an evaporator, and an expansion device. The compressor includes an impeller including a blade having a trailing edge with one or more serrations.

[0016] In another example of the foregoing, the impeller includes a plurality of main blades and first and second splitter blades between adjacent main blades, and each of the main blades and the first and second splitter blades includes a trailing edge having one or more serrations.

[0017] In another example of any of the foregoing, the first splitter blade extends a first length between its leading edge and trailing edge. The second splitter blade extends a second length between its leading edge and trailing edge. The first length is greater than the second length. Each main blade extends a third length between its leading edge and trailing edge, and the third length is greater than the first and second lengths.

[0018] In another example of any of the foregoing, the leading edges of the first splitter blade, the second splitter blade, and each main blade are staggered relative to each other. The trailing edges of the first splitter blade, the second splitter blade, and each main blade are aligned relative to each other and are disposed at a common radial distance from the axis of rotation of the impeller and are coextensive with the outlet of the impeller.

[0019] In another example of any of the foregoing, the one or more serrations are arcuate serrations.

[0020] In another example of any of the foregoing, the one or more serrations each include first and second curved surfaces converging to a sharpened tip.

[0021] In another example of any of the foregoing, the first and second curved surfaces are convex.

[0022] In another example of any of the foregoing, the one or more serrations include a plurality of serrations, and the first and second curved surfaces of adjacent serrations of the plurality of serrations intersect at points radially inward of the sharp tip and form a space axially between adjacent serrations.

[0023] In another example of any of the foregoing, the impeller includes a plurality of blades, and every other blade of the plurality of blades includes a trailing edge having one or more serrations, and the plurality of blades other than every other blade do not include serrations.

[0024] A refrigerant compressor according to an example of the present disclosure includes an impeller including a plurality of main blades and first and second flow divider blades located between adjacent main blades. Each main blade and the first and second flow divider blades include a trailing edge having a plurality of saw teeth. The first flow divider blade extends a first length between its leading edge and trailing edge. The second flow divider blade extends a second length between its leading edge and trailing edge. The first length is greater than the second length. Each main blade extends a third length between its leading edge and trailing edge. The third length is greater than the first and second lengths. The leading edges of the first flow divider blade, the second flow divider blade, and each main blade are staggered relative to each other. The trailing edges of the first flow divider blade, the second flow divider blade, and each main blade are aligned relative to each other and are arranged at a common radial distance from the rotation axis of the impeller and extend together with the outlet of the impeller. The plurality of saw teeth each include a first and second convex surface converging to a sharp tip, and the first and second convex surfaces of adjacent saw teeth in the plurality of saw teeth intersect at a point radially inward of the sharp tip, and a space is formed axially between adjacent saw teeth.

[0025] These and other features can be best understood from the following specification and drawings, the following of which is a brief description. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 A refrigerant system is shown schematically.

[0027] Figure 2 is a schematic partial cross-sectional view of a compressor.

[0028] Figure 3 is an axial end view of an example impeller.

[0029] Figure 4 is a cross-sectional view of a portion of an impeller and particularly illustrates an exemplary blade arrangement including a main blade, a first splitter blade, and a second splitter blade.

[0030] Figure 5 A radial view of the impeller is shown.

[0031] Figure 6The vortex from either trailing edge of an example impeller is schematically shown.

[0032] Figure 7 Another example impeller is shown.

[0033] Figure 8 Schematically shows the Figure 7 Example of vortex at either trailing edge of an impeller.

[0034] Fig. 9 Another example trailing edge is schematically shown.

[0035] Fig.10 A portion of another example impeller is shown.

[0036] Fig.11 Another example impeller is shown. DETAILED DESCRIPTION

[0037] The present invention relates generally to refrigerant compressors and, more particularly, to impeller blades for refrigerant compressors. It has been discovered that the systems and methods disclosed herein reduce the noise output of a refrigerant compressor.

[0038] Figure 1 A refrigerant system 10 is shown. The refrigerant system 10 includes a main refrigerant cycle or loop 12 in communication with a compressor 14, a condenser 16, an evaporator 18, and an expansion device 20. For example, the refrigerant system 10 can be used in a chiller. In this example, a cooling tower can be in fluid communication with the condenser 16. Although a specific example of the refrigerant system 10 is shown, the application can be extended to other refrigerant system configurations, including configurations without a chiller. For example, the main refrigerant loop 12 can include an economizer downstream of the condenser 16 and upstream of the expansion device 20.

[0039] Figure 2 A portion of the compressor 14 is shown in cross-section. The compressor 14 includes a motor 22 having a stator 24 disposed radially outwardly of a rotor 26. The rotor 26 is connected to a shaft 28 that rotates to drive at least one compression stage 30 of the compressor 14, which in this example includes at least one impeller 32. The compressor 14 may include a plurality of compression stages.

[0040] The shaft 28 and impeller 32 are rotatable about axis A by the motor 22 to compress the refrigerant F. The terms axial, radial, and circumferential in this disclosure are used relative to the axis A. The shaft 28 may be rotatably supported by a plurality of bearing assemblies, which in some examples are magnetic bearing assemblies.

[0041] During operation of the compressor 14, the refrigerant F flows axially toward the impeller 32 and is discharged radially outward to the diffuser 34 downstream of the impeller 32. The diffuser 34 is radially disposed between the outlet of the impeller 32 and the volute 40. The volute 40 may be in fluid communication with the condenser 16 or another compression stage of the compressor 14.

[0042] Figure 3 is an axial end view of an exemplary impeller 32 along axis A. In this example, the impeller 32 is configured to rotate in a counterclockwise direction. In this example, the impeller 32 is not covered. However, the impeller 32 may also be covered.

[0043] The impeller 32 includes a plurality of blades protruding radially outward from a hub 42. In particular, the impeller 32 includes a plurality of main blades 44 circumferentially spaced apart from each other about the axis A. Figure 3 Two main blades in the main blade 44 are marked. Figure 3 In the example of FIG. 4 , the impeller 32 includes a total of seven main blades 44 . The present disclosure also extends to impellers including other numbers of main blades 44 .

[0044] Reference Figure 4 and Figure 5 The main blades 44 extend from a leading edge 46 near the inlet to the impeller 32 to a trailing edge 48 near the outlet of the impeller 32. The main blades 44 are configured to receive a fluid flow flowing in an axial direction and turn the fluid flow so that the fluid flow is discharged radially from the impeller 32.

[0045] In this example, between each adjacent main blade 44, the impeller 32 includes first and second splitter blades 50, 52. The arrangement of the main blades 44, the first splitter blades 50, and the second splitter blades 52 continues and repeats about the axis A.

[0046] The first splitter vane 50 extends between a leading edge 54 and a trailing edge 56. Likewise, the second splitter vane 52 extends between a leading edge 58 and a trailing edge 60.

[0047] The first and second splitter blades 50, 52 are shorter than the main blade 44. Specifically, the length of the first and second splitter blades 50, 52 between the respective leading and trailing edges is less than the length of the main blade 44. In addition, the second splitter blade 52 is shorter than the first splitter blade 50.

[0048] The main blades 44 and the first and second splitter blades 50, 52 are staggered relative to each other along the impeller 32. Specifically, refer to Figure 5, leading edges 46, 54, 58 are spaced apart from one another, while trailing edges 48, 56, 60 are aligned. In particular, trailing edges 48, 56, 60 are disposed at a common distance, i.e., a common radial distance, away from axis A. In this example, trailing edges 48, 56, 60 are coextensive with the outlet of impeller 32. Other impeller configurations, including those with or without splitter blades, will benefit from the present disclosure.

[0049] Figure 6 The vortices from any one of the trailing edges 48, 56, 60 are schematically shown. In the case of a straight trailing edge, the applicant has recognised that the vortices created in the flow are in the same direction, persist and take a long time to dissipate, which results in the generation of noise in the fluid flowing over the impeller blades.

[0050] Figure 7 Another example impeller 132 is shown. It should be understood that like reference numerals indicate corresponding or similar elements throughout the several drawings. In some examples, impeller 132 is substantially similar to impeller 32, except that trailing edges 148, 156, 160 include one or more serrations 162. In the example shown, all trailing edges 148, 156, 160 include one or more serrations 162. In other examples, one or more trailing edges 148, 156, 160 may not be serrated and, for example, may have a straight edge. In some examples, such as Fig.11 In the example impeller 432, every other edge includes one or more serrations 462, while other edges do not include serrations. In some examples, some other selected number or pattern of edges include one or more serrations 162. Although three serrations 162 are shown on the example edge, more or fewer serrations may be used in some examples.

[0051] The serrations 162 may be implemented at any blade trailing edge in a centrifugal refrigerant compressor. At any of these locations, the geometry will change the velocity and trajectory of the flow, which will reduce its turbulence level. In some examples, a number of serrations may be provided at any or each blade trailing edge. With these serrations in place, the vortices generated by the straight trailing edge of the blade may be mitigated, thereby reducing the acoustic level of the fluid flow passing through the blade, as will be discussed further below. Although an example impeller 132 is shown, other configurations of the impeller, including those with or without splitter blades, will benefit from the present disclosure.

[0052] Figure 8Vortices from any one of the trailing edges 148, 156, 160 are schematically illustrated. The example serrations 162 are arcuate serrations, but other shapes and profiles may be used. Each example serration 162 includes a first curved surface 164 and a second curved surface 166 that converge to a sharp tip 168. In some examples, as shown, the surfaces 164, 166 are convex. Other curvatures are also contemplated. In some examples, as shown, the curved surfaces 164, 166 of adjacent serrations 162 intersect at a point 170 located radially inward of the tip 168 and form a space 172 axially between adjacent serrations. In some examples, the surfaces 164, 166 may be straight rather than curved. In the example shown, each of the three serrations 162 is an arcuate serration. In other examples, as shown, Fig. 9 As schematically shown, an edge may include two or more teeth 262 of different geometric shapes. Fig.10 As shown, the first edge of the impeller 332 may include serrations 362A of a first shape, number and / or pattern, and the second edge of the impeller 332 may include serrations 362B of a different shape, number and / or pattern. In other words, the shape, number and / or pattern of the serrations may vary on the blade edge of the same impeller.

[0053] As schematically shown, the serrated edges 148, 156, 160 reduce the sound level of a given centrifugal refrigerant compressor system by reducing the number and size of vortices generated by turbulence at the trailing edge of the impeller blades. Figure 6 As shown in FIG. 1 , when compared to a straight trailing edge on a blade, a serrated edge can reduce noise levels by vortex shedding. This is because the serrations, such as those of a circular arc, reduce the number and size of vortices formed at the trailing edge of the impeller blade. Vortices are formed in opposite directions at the serrated trailing edge and begin to cancel each other out. This vortex shedding Figure 8 The design utilizes its flow geometry to reduce the number and size of vortices at the trailing edge of the impeller blades, thereby reducing the noise level generated by the impeller 132.

[0054] The example serrated edges 148, 156, 160 implement a trailing edge geometry on an impeller of a centrifugal refrigerant compressor. The disclosed examples modify the flow characteristics at the trailing edge of the blade to reduce the number and size of vortices generated in the flow.

[0055] The foregoing description should be interpreted as illustrative. It will be appreciated by those skilled in the art that certain modifications may fall within the scope of the present disclosure. Various examples of the present disclosure have been described. Any combination of the described systems, operations, or functions is contemplated. Some components or features in any example may be used in combination with features or components in any other example.

[0056] Although the various examples are shown with specific components, the examples of the present disclosure are not limited to these specific combinations.Some components or features in any embodiment may be used in combination with features or components in any other embodiment.

[0057] The foregoing description should be interpreted as illustrative, rather than restrictive. It will be appreciated by those skilled in the art that certain modifications may fall within the scope of the present disclosure. For these reasons, the following claims should be studied to determine the true scope and content of the present disclosure.

Claims

1. A refrigerant compressor, comprising: An impeller includes a blade having a trailing edge with one or more serrations.

2. The compressor according to claim 1, wherein The impeller includes a plurality of main blades and a first splitter blade and a second splitter blade located between adjacent main blades, and Each of the main blade and the first and second splitter blades includes a trailing edge having one or more serrations.

3. The compressor according to claim 2, wherein The first splitter blade extends a first length between a leading edge and a trailing edge thereof, the second splitter blade extending a second length between its leading edge and trailing edge, The first length is greater than the second length, each main blade extends a third length between its leading edge and trailing edge, and The third length is greater than the first length and the second length.

4. The compressor according to claim 3, wherein The leading edges of the first splitter blade, the second splitter blade and each main blade are staggered relative to each other, and The trailing edges of the first splitter blade, the second splitter blade and each main blade are aligned relative to each other and are disposed at a common radial distance from the axis of rotation of the impeller and are coextensive with an outlet of the impeller.

5. The compressor according to claim 1, wherein: The one or more saw teeth are saw teeth of circular arc.

6. The compressor according to claim 5, wherein: The one or more serrations each include a first curved surface and a second curved surface that converge to a sharpened tip.

7. The compressor according to claim 6, wherein: The first curved surface and the second curved surface are convex surfaces.

8. The compressor according to claim 6, wherein: The one or more serrations include a plurality of serrations, and the first curved surface and the second curved surface of adjacent serrations of the plurality of serrations intersect at a point radially inward of the sharp tip and form a space axially between the adjacent serrations.

9. The compressor according to claim 1, wherein: The impeller includes a plurality of blades, and every other blade of the plurality of blades includes a trailing edge having one or more serrations, and the plurality of blades other than the every other blade do not include serrations.

10. The compressor according to claim 1, wherein The blade includes three teeth.

11. A refrigerant system comprising: A primary refrigerant circuit includes a compressor, a condenser, an evaporator, and an expansion device, wherein the compressor includes an impeller including blades having a trailing edge with one or more serrations.

12. The system according to claim 11, wherein The impeller includes a plurality of main blades and a first splitter blade and a second splitter blade located between adjacent main blades, and Each of the main blade and the first and second splitter blades includes a trailing edge having one or more serrations.

13. The system of claim 12, wherein The first splitter blade extends a first length between a leading edge and a trailing edge thereof, the second splitter blade extending a second length between its leading edge and trailing edge, The first length is greater than the second length, each main blade extends a third length between its leading edge and trailing edge, and The third length is greater than the first length and the second length.

14. The system of claim 13, wherein The leading edges of the first splitter blade, the second splitter blade and each main blade are staggered relative to each other, and The trailing edges of the first splitter blade, the second splitter blade and each main blade are aligned relative to each other and are disposed at a common radial distance from the axis of rotation of the impeller and are coextensive with an outlet of the impeller.

15. The system according to claim 11, wherein: The one or more saw teeth are saw teeth of circular arc.

16. The system of claim 15, wherein: The one or more serrations each include a first curved surface and a second curved surface that converge to a sharpened tip.

17. The system of claim 16, wherein: The first curved surface and the second curved surface are convex surfaces.

18. The system of claim 16, wherein: The one or more serrations include a plurality of serrations, and the first curved surface and the second curved surface of adjacent serrations of the plurality of serrations intersect at a point radially inward of the sharp tip and form a space axially between the adjacent serrations.

19. The system of claim 11, wherein the impeller comprises a plurality of blades, and every other blade of the plurality of blades comprises a trailing edge having one or more serrations, and the plurality of blades other than the every other blade do not comprise serrations.

20. A refrigerant compressor comprising: An impeller comprising a plurality of main blades and a first splitter blade and a second splitter blade located between adjacent main blades, wherein each of the main blades and the first splitter blade and the second splitter blade comprises a trailing edge having a plurality of serrations, wherein The first splitter blade extends a first length between a leading edge and a trailing edge thereof, the second splitter blade extending a second length between its leading edge and trailing edge, The first length is greater than the second length, each main blade extends a third length between its leading edge and trailing edge, The third length is greater than the first length and the second length, the leading edges of the first splitter blade, the second splitter blade and each main blade are staggered relative to each other, The trailing edges of the first splitter blade, the second splitter blade and each main blade are aligned relative to each other and are disposed at a common radial distance from the axis of rotation of the impeller and are coextensive with the outlet of the impeller, and Each of the plurality of saw teeth includes a first convex surface and a second convex surface converging to a sharp tip, and the first and second convex surfaces of adjacent saw teeth among the plurality of saw teeth intersect at a point radially inward of the sharp tip and form a space axially between the adjacent saw teeth.

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