Compressor impeller with interconnected blades for a radial compressor

Abstract

Compressor impeller (1) with connections of the blades (2, 3) to each other for a radial compressor, having on a hub - first blades (2) with a first blade foot (2b), wherein the first blades (2) are connected to the hub by means of the first blade foot (2b), - second blades (3) differing from the first blades (2) and having a second blade base (3b), wherein the second blades (3) are connected to the hub by means of the second blade base (3b), - a first blade band (5) by means of which the first blades (2) and / or the second blades (3) are connected to each other, and - a second blade band (6) by means of which the first blades (2) and / or the second blades (3) are connected to each other, wherein the first blade band (5) and the second blade band (6) are arranged coaxially to each other.

Description

Technical field

[0001] The present invention relates to a compressor impeller with connections between the blades for a radial compressor. State of the art

[0002] Compressors are used to compress gases. Besides piston, screw, and other compressor types, turbo compressors are also known, which house a rotatably mounted and driven compressor impeller within a compressor casing. Depending on the flow deflection of the compressed gas, a distinction is made between axial, radial, and semi-axial compressors.

[0003] Radial compressors are particularly well-suited for use in reciprocating engines, often in combination with exhaust gas turbines as turbochargers for forced induction. Due to centrifugal force, these radial compressors can achieve higher pressures than axial compressors at a sufficient flow rate. This makes them especially suitable for use in reciprocating engines. However, radial compressors are also used in conveying systems, cooling systems, and heating systems.

[0004] To improve the efficiency of radial compressors, particular emphasis is placed on the design of the blades of the impeller, which is shaped like a paddle wheel. Specifically, efforts are made to shift the surge line and the choke line, thereby widening the compressor operating range and increasing efficiency in both the surge and choke regions to achieve a broader usable compressor operating range. To ensure optimal energy transfer from the impeller to the gas flow, crossflow must be avoided both within and between individual blade gaps.

[0005] Depending on the application of the radial compressor, reducing the acoustic emissions of the compressor impeller is also a key focus in the design of the impeller blades. This reduction can be achieved, for example, by minimizing the vibrations of the impeller blades that occur during operation.

[0006] Utility model CN ​​202370865 U discloses a double-air-duct internal fan in which an impeller with multiple blades is provided. The blades comprise radially inner blades, which are connected to each other by means of a shroud band, and radially outer blades, which are arranged on the shroud band of the inner blades and are further connected to each other by means of a separate shroud band. This creates parallel flow paths.

[0007] Patent EP 3 073 123 B1 relates to a centrifugal blower in which several blades arranged along a circumferential direction are arranged in two rows in a radial direction of a hub and are each connected to each other by means of a separate cover band.

[0008] From the patent application JP 2021-156266 A, a turbine runner is known in which the individual blades are connected to each other by means of a connecting element designed as a band, wherein the connecting element is arranged in the area of ​​the blade surfaces.

[0009] From German patent application DE 10 2018 103 722 A1, a compressor impeller is known in which flow separation is reduced in the low-flow range. For this purpose, the compressor impeller has main blades and splinter blades on a hub, wherein the main blades extend only partially along the flow passages from the compressor inlet, and the splinter blades extend only partially along the flow passages to the compressor outlet. At least one of the main blades and at least one of the splinter blades partially overlap in the circumferential direction of the compressor impeller.

[0010] Patent DE 10 2019 120 816 B3 discloses a compressor impeller for a radial compressor, which extends the compressor's operating range. This is achieved by dividing the main blades into two distinct main blade sections. The first and second main blade sections have different blade angles. Furthermore, a blade band is provided, which is arranged in the division between the first and second main blade sections. This band ensures the structural stability of the compressor impeller and divides the flow volume passing through the impeller.

[0011] Patent DE 195 39 162 C2 discloses a pump impeller assembly comprising a front and a rear impeller plate and a series of blades in between. An inner edge of a first blade of two adjacent blades in the series is inclined upwards from its inner corner to its outer corner. An inner edge of a second blade of the two adjacent blades is inclined downwards from its outer corner to its inner corner. The first and second blades are integrally connected to the front and rear impeller plates, such that the inner edge of the first blade and the inner edge of the second blade intersect each other on a mean fluid flow line.

[0012] Patent DE 21 14 702 C discloses a radial compressor stage with a multi-flow impeller. The impeller comprises a hub, first blades, each connected to the hub by means of a first blade root, a first blade band connecting the first blades to each other, second blades, each connected to the first blade band by means of a second blade root, and a second blade band, designed as a cover band, connecting the second blades to each other. The two blade bands are arranged coaxially with each other, forming a twin-flow impeller.

[0013] Patent AT 504 368 B1 discloses an exhaust gas turbocharger with a multi-flow compressor impeller. The flows of the compressor impeller are formed by means of a belt of blades that connects the blades to each other.

[0014] From the patent application EP 3 690 254 A1, a multi-flow impeller of a radial turbomachine is known, wherein the flows are formed by means of a blade band connecting the blades.

[0015] From patent application JP 2007-192 129 A, an exhaust gas turbocharger with a multi-flow turbine impeller is known. The flow channels of the turbine impeller are formed by means of a blade strip that connects the blades. Object of the invention

[0016] The object of the invention is to provide a compressor impeller with connections between the blades for a radial compressor, which is improved in terms of efficiency and acoustic emissions. Solution to the task

[0017] The problem is solved by a compressor impeller with interconnected blades for a radial compressor according to the features of claim 1. Advantageous further developments are described in the dependent claims and the exemplary embodiment. Description of the invention

[0018] The invention provides a compressor impeller with connections between the blades for a radial compressor, which is advantageous according to the invention and has improved efficiency and acoustic emissions.

[0019] The compressor impeller has several blades distributed around its circumference on a hub. At least two first blades, each with a first leading edge, a first root, a first outer edge, and a first trailing edge, are distinguished from at least two second blades, each with a second leading edge, a second root, a second outer edge, and a second trailing edge. The first leading edges define the compressor inlet plane, and the second trailing edges define the compressor outlet plane. The leading and trailing edges are those edges of the blades that define the blades in the direction of flow.The flow enters the blade at its leading edge and exits it at its trailing edge. The blade root and outer edge define the blade height, while the leading and trailing edges define the blade length. In a radial compressor, the inlet and outlet planes are inclined relative to each other. This deflects the flow radially outward from the axis of rotation of the compressor wheel. The blades are connected to the hub of the compressor wheel via the blade root.

[0020] The first and second blades are arranged such that a periodically repeating arrangement of first and second blades is formed around the circumference of the compressor impeller. The first and second blades form flow passages extending from the compressor inlet to the compressor outlet. In a particularly advantageous embodiment according to the invention, the first and / or second blades extend only partially along the flow passage. The blade lengths of the first and second blades are either the same or different. The blade heights of the first and second blades are either the same or different. In a particularly advantageous embodiment according to the invention, at least two adjacent blades partially overlap when viewed in the circumferential direction of the compressor impeller.The term "coverage" refers to the area that overlaps when the blades are projected around the axis of rotation of the compressor impeller.

[0021] Advantageously, according to the invention, the compressor impeller has at least two blade bands by means of which the first and / or second blades are connected to one another. Blade bands are understood to be flat connecting elements between the blades that extend along the flow path and are also curved along the flow path. Accordingly, the blade bands each have a shape that can be understood as a circular conical surface with a concavely curved generatrix and small thickness, wherein the blade band extending over the circumference of the compressor impeller is formed from several individual segments between each pair of blades.

[0022] The at least two blade bands are arranged coaxially with respect to an axis of rotation of the compressor impeller and with respect to each other, wherein a first blade band, with first blade surfaces delimited by a first blade leading edge and a first blade trailing edge, is arranged radially inside a second blade band, with respect to the axis of rotation of the compressor impeller, with respect to a second blade band, with second blade surfaces delimited by a second blade leading edge and a second blade trailing edge. The blade spacing is defined by the mean distance of the blade leading edge and the blade trailing edge from the axis of rotation of the compressor impeller, and the blade length is defined by the distance between the blade leading edge and the blade trailing edge along the respective blade band.

[0023] Starting from the axis of rotation of the compressor impeller, the at least two blade bands are arranged coaxially, with the first blade band spacing of the first blade band being smaller than the second blade band spacing of the second blade band. This creates several radially spaced flow passages distributed around the circumference, with the first blade band connecting the first blades and / or the second blades, and the second blade band connecting the first blades and / or the second blades.

[0024] In a particularly advantageous manner according to the invention, the first blade band and / or the second blade band extend only partially along the flow path. A first leading edge of the first blade band can be located in the inlet area and a second trailing edge of the second blade band in the outlet area. Alternatively, a second leading edge of the second blade band can be located in the inlet area and a first trailing edge of the first blade band in the outlet area. Accordingly, the first blade band and / or the second blade band can extend from a compressor inlet. Furthermore, the first blade band and / or the second blade band can extend towards a compressor outlet. The length of the first blade band and the length of the second blade band can be the same or different.

[0025] In a particularly advantageous manner according to the invention, at least one of the at least two blade bands is at least partially configured as a cover band. A cover band is understood to be a blade band that connects the blades in the region of the outer edges of the blades. Accordingly, the blade band configured as a cover band forms a radially outer boundary of the compressor impeller.

[0026] In a particularly advantageous manner according to the invention, the blade band length differs from the blade length of the blades connected by this blade band, wherein the blade band length is smaller or larger than the blade length of the blade connected by the blade band.

[0027] The arrangement of the blades and blade bands creates several flow passages arranged side by side in the radial and circumferential direction of the compressor impeller. Example 1

[0028] An advantageous embodiment of the compressor impeller according to the invention, with interconnected blades, is shown here as an example for a radial compressor. The accompanying figure shows: Fig. 1 a schematic representation of the compressor impeller 1 with connections of the blades 2, 3 to each other for a radial compressor.

[0029] The advantageous embodiment of the compressor impeller 1 according to the invention with connections of the blades 2, 3 to each other for a radial compressor, illustrated in Fig. 1, has on a hub first blades 2, each with first blade surfaces 2e delimited by a first blade leading edge 2a, a first blade root 2b, a first blade outer edge 2c, and a first blade trailing edge 2d, and second blades 3, each with second blade surfaces 3e delimited by a second blade leading edge 3a, a second blade root 3b, a second blade outer edge 3c, and a second blade trailing edge 3d. The first blade leading edges 2a define a compressor inlet 1a as the inlet plane, and the second blade trailing edges 3d define a compressor outlet 1b as the outlet plane.

[0030] The first blades 2 and the second blades 3 are arranged sequentially and periodically around the circumference of the compressor impeller 1. Thus, separate flow passages are formed by the first blades 2 and second blades 3, and by the second blades 3 and first blades 2. The first blades 2 overlap with the second blades 3.

[0031] Furthermore, a first blade band 5 and a second blade band 6 are provided, wherein the blade bands 5 and 6 are arranged coaxially to each other, with the first blade band 5 radially inside and the second blade band 6 radially outside. Accordingly, the blade bands 5 and 6 have different spacings.

[0032] The first blade band 5 connects the first blades 2 to each other, with the first blade band 5 extending from the first blade leading edge 2a to the first blade trailing edge 2d. The first blade band 5 is connected to the first blade surfaces 2e.

[0033] The first blades 2 and the second blades 3 are connected to each other by means of the second blade band 6, which extends from the first blade leading edge 2a to the second blade trailing edge 3d. The first blade band 5 is designed as a cover band and is connected to the first blade outer edges 2c and the second blade outer edges 3c.

[0034] The arrangement of the blades 2, 3 and the blade bands 5, 6 forms several flow passages arranged next to each other in the radial and circumferential direction of the compressor impeller 1. Example 2

[0035] An exemplary further advantageous embodiment of the compressor impeller according to the invention, with interconnected blades, is shown here for a radial compressor. The accompanying figure illustrates: Fig. 2 a schematic representation of the compressor impeller 1 with connections of the blades 2, 3, 4 to each other for a radial compressor.

[0036] The advantageous embodiment of the compressor impeller 1 according to the invention with connections of the blades 2, 3, 4 to each other for a radial compressor, illustrated in Fig.2, has on a hub first blades 2, each with first blade surfaces 2e delimited by a first blade leading edge 2a, a first blade root 2b, a first blade outer edge 2c, and a first blade trailing edge 2d; second blades 3, each with second blade surfaces 3e delimited by a second blade leading edge 3a, a second blade root 3b, a second blade outer edge 3c, and a second blade trailing edge 3d; and third blades 4, each with third blade surfaces 4e delimited by a third blade leading edge 4a, a third blade root 4b, a third blade outer edge 4c, and a third blade trailing edge 4d. The first blade leading edges 2a define a compressor inlet 1a as the inlet plane, and the third blade trailing edges 4d define a compressor outlet 1b as the outlet plane.

[0037] The first blades 2, the second blades 3, and the third blades 4 are arranged sequentially and periodically around the circumference of the compressor impeller 1. Thus, separate flow paths are formed by the first blades 2 and second blades 3, by the second blades 3 and third blades 4, and by the third blades 4 and first blades 2. The first blades 2 do not overlap with the second blades 3 or the third blades 4. The second blades 3 and the third blades 4 overlap.

[0038] Furthermore, a first blade band 5, a second blade band 6, and a third blade band 7 are provided, wherein the blade bands 5, 6, 7 are arranged coaxially to each other, with the first blade band 5 radially inward, the third blade band 7 radially outward, and the second blade band 6 arranged between the first blade band 5 and the third blade band 7. Accordingly, the blade bands 5, 6, 7 have different spacings.

[0039] The first blade band 5 connects the first blades 2 and the second blades 3, with the first blade band 5 extending from the first blade leading edge 2a to the second blade trailing edge 3d. The first blade band 5 is connected to the first blade surfaces 2e and the second blade surfaces 3e.

[0040] The second blade band 6 connects the second blades 3 and the third blades 4 to each other, with the second blade band 6 extending from the second blade leading edge 3a to the center of the third blade surface 4e. In the area of ​​the second blades 3, the second blade band 6 is designed as a cover band and is connected to the second blade outer edges 3c and the third blade surfaces 4e.

[0041] The third blade band 7 connects the third blades 4 to each other, with the third blade band 7 extending partially over the area of ​​the second blades 3 to the trailing edge 4d of the third blade. In the area of ​​the third blades 4, the third blade band 7 is designed as a cover band and connected to the outer edges 4c of the third blades.

[0042] The arrangement of the blades 2, 3, 4 and the blade bands 5, 6, 7 forms several flow passages arranged next to each other in the radial and circumferential direction of the compressor impeller 1. List of reference symbols used 1 compressor impeller 1a Compressor inlet 1b Compressor outlet 2 first shovels 2a first shovel leading edge 2b first shovel foot 2c first outer edge of the shovel 2d first blade trailing edge 2e first blade surfaces 3 second shovels 3a second shovel leading edge 3b second shovel foot 3c second outer edge of the shovel 3D second blade trailing edge 3e second blade surfaces 4 third shovels 4a third shovel leading edge 4b third shovel foot 4c third outer edge of the shovel 4d third blade trailing edge 4e third blade surfaces 5 first shovel belt 6 second shovel belt 7 third shovel band

Claims

[1] Compressor impeller (1) with connections of the blades (2, 3) to each other for a radial compressor, having on a hub - first blades (2) with a first blade foot (2b), wherein the first blades (2) are connected to the hub by means of the first blade foot (2b), - second blades (3) differing from the first blades (2) and having a second blade base (3b), wherein the second blades (3) are connected to the hub by means of the second blade base (3b), - a first blade band (5) by means of which the first blades (2) and / or the second blades (3) are connected to each other, and - a second blade band (6) by means of which the first blades (2) and / or the second blades (3) are connected to each other, wherein the first blade band (5) and the second blade band (6) are arranged coaxially to each other. [2] Compressor impeller (1) according to claim 1, characterized by, that the first blade band (5) and / or the second blade band (6) are designed as a cover band. [3] Compressor impeller (1) according to one of the preceding claims, characterized by , that the first blades (2) and the second blades (3) overlap at least partially in the circumferential direction of the compressor impeller (1). [4] Compressor impeller (1) according to one of the preceding claims, characterized by , that the first blade band (5) and / or the second blade band (6) extends from a compressor inlet (1a). [5] Compressor impeller (1) according to one of the preceding claims, characterized by , that the first blade band (5) and / or the second blade band (6) extends towards a compressor outlet (1b).

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