Impeller of a compressor and compressor

Abstract

This application discloses a compressor impeller and a compressor. The compressor impeller includes an impeller body, and the outer meridional profile of the impeller body includes a straight section, a first curved section, and a second curved section. The straight section is located on the impeller inlet side, and the curved section includes the first curved section and the second curved section. The slope of the tangent at various positions of the first curved section gradually increases, while the slope of the tangent at various positions of the second curved section gradually decreases. The first curved section forms a concave structure, which can suppress gas backflow and improve surge. The second curved section forms a convex structure, which increases the length of the profile near the impeller outlet, helps to decelerate the gas at the impeller cover, and at the same time increases the width of the impeller flow channel along the direction perpendicular to the impeller axis, increasing the blade area near the outlet. The linear velocity of the impeller near the outlet is higher, which can improve the impeller's work capacity. At the same time, the airflow distribution is more uniform, which helps to suppress the secondary flow of airflow from the bottom to the top of the impeller outlet and reduce the gap flow.

Description

Technical Field

[0001] This application relates to the field of compressor technology, and in particular to an impeller and compressor. Background Technology

[0002] In related technologies, such as Figure 1 and Figure 2 As shown, the outer meridional profile 01 of the impeller includes a straight segment 011 and a curved segment 012, or only a curved segment. Local optimization can be achieved by independently controlling the geometric parameters of the straight segment 011 and the curved segment 012.

[0003] However, the degree of freedom of the compressor impeller's outer meridional profile is limited, making it impossible to make localized adjustments to optimize the design, which prevents further improvement in pressure ratio and efficiency.

[0004] Therefore, how to improve the pressure ratio and efficiency of the compressor has become a technical problem that urgently needs to be solved by those skilled in the art. Utility Model Content

[0005] This application proposes an impeller for a compressor to improve the compressor's pressure ratio and efficiency. This application also proposes a compressor having the aforementioned impeller.

[0006] To achieve the above objectives, this application provides a compressor impeller, including an impeller body. The outer meridional profile of the impeller body includes a straight segment, a first curved segment, and a second curved segment. From the inlet to the outlet of the impeller body, the slope of the tangent at each position of the first curved segment gradually increases to suppress airflow backflow, and the slope of the tangent at each position of the second curved segment gradually decreases to suppress secondary flow from the bottom to the top at the outlet of the impeller body. The curvature between the end point of the first curved segment and the beginning point of the second curved segment is continuous.

[0007] Optionally, in the impeller of the above-mentioned compressor, the intersection point of the straight segment and the first curved segment is located at 10% to 50% of the length L of the outer meridian; the intersection point of the first curved segment and the second curved segment is located at 60% to 90% of the length L of the outer meridian; the length of the outer meridian is the distance between the starting end of the straight segment and the ending end of the second curved segment along the axial direction of the impeller body.

[0008] Optionally, in the impeller of the compressor described above, the length of the first curved segment is greater than the length of the second curved segment; the length of the second curved segment is greater than the length of the straight segment.

[0009] Optionally, in the impeller of the compressor described above, the angle between the tangent at the initial end of the second curved segment and the axis of the impeller body is θ, where 50° < θ < 80°.

[0010] Optionally, in the impeller of the compressor described above, the angle between the tangent at the end of the second curved segment and the axis of the impeller body is α, where α < θ and 45° < α < 75°.

[0011] Optionally, in the impeller of the above-mentioned compressor, the outlet side of the impeller body is at least one of a plane and a curved surface.

[0012] Optionally, in the impeller of the above-mentioned compressor, the height of the apex on the outlet side of the impeller body is higher than the height of the bottom point on the outlet side of the impeller body; the angle between the connecting line between the apex and the bottom point and the axis of the impeller body does not exceed 20°.

[0013] Optionally, in the impeller of the compressor described above, the first curve segment is a circular arc curve segment, an elliptical curve segment, or a third-order Bézier curve; the second curve segment is a circular arc curve segment, an elliptical curve segment, or a third-order Bézier curve; the first curve segment and the second curve segment may be the same or different.

[0014] Optionally, in the impeller of the above-mentioned compressor, the impeller body is formed by milling or casting.

[0015] In a second aspect, a compressor includes an impeller and a diffuser; the impeller is the impeller disclosed in any of the above embodiments; the profile of the diffuser is adapted to the outer meridional profile of the impeller.

[0016] This application discloses a compressor impeller, including an impeller body, the outer meridional profile of which includes a straight section, a first curved section and a second curved section. The straight section is located on the inlet side of the impeller body, and it forms a small angle with the axis of the impeller body, ensuring stable axial flow of fluid. The arc-shaped section includes a first curved section and a second curved section. The slope of the tangent at each position of the first curved section gradually increases, while the slope of the tangent at each position of the second curved section gradually decreases. The first curved section extends to the upper right, forming a concave structure. The airflow is in the turning stage in the first curved section, forming a larger pressure gradient, avoiding airflow blockage due to insufficient expansion force or boundary layer separation due to excessive expansion, thus suppressing gas backflow and improving surge. The second curved section extends to the lower right, forming a convex structure, which increases the length of the profile near the outlet of the impeller body, helping to decelerate the gas at the impeller cover. At the same time, the width of the impeller flow channel increases along the direction perpendicular to the impeller axis, increasing the blade area near the outlet. The linear velocity of the impeller near the outlet is higher, which can improve the impeller's work capacity. Meanwhile, the airflow distribution is more uniform, which helps to suppress secondary flow of airflow from the bottom to the top of the impeller outlet and reduce gap flow.

[0017] This application also discloses a compressor, including an impeller and a diffuser, wherein the impeller is the impeller described in any of the above embodiments, and the profile of the diffuser is adapted to the outer meridional profile of the impeller. Since the impeller has the aforementioned technical effects, the compressor having this impeller also has the same technical effects, which will not be elaborated further here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some examples or embodiments of this application. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort, and this application can be applied to other similar scenarios based on the provided drawings. Unless obvious from the linguistic context or otherwise specified, the same reference numerals in the drawings represent the same structures or operations.

[0019] Figure 1 This is a schematic diagram of the blade structure of an impeller provided by existing technology;

[0020] Figure 2 It is a projection diagram of the impeller blades in the meridional plane provided by existing technology;

[0021] Figure 3 This is a projection of the blades of an impeller in the meridional plane according to one embodiment of this application;

[0022] Figure 4This is a projection of the impeller blades in the meridional plane according to another embodiment of this application.

[0023] The attached diagram is described below:

[0024] 01-Outer Meridian Line; 011-Straight Line Segment; 012-Curved Line Segment;

[0025] 1-Outer meridian; 11-Straight line segment; 12-First curve segment; 13-Second curve segment; 2-Exit side. Detailed Implementation

[0026] The present application will now be described in further detail with reference to the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are merely illustrative of the application and not intended to limit it. The described embodiments are only a part of the embodiments of the present application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present application without inventive effort are within the scope of protection of the present application.

[0027] It should be noted that, for ease of description, only the parts relevant to the application are shown in the accompanying drawings. Unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined, provided that the combined technical features are not contradictory. All feasible combinations of features are the technical content explicitly described herein. Any one of the multiple sub-features contained in the same statement can be applied independently, without necessarily being applied together with other sub-features.

[0028] A compressor is a device that compresses gas from a low-pressure state to a high-pressure state. The compressor does work on the gas by rotating an impeller, and combined with the energy conversion of the diffuser, it achieves gas pressurization.

[0029] A compressor consists of an impeller and a diffuser. The high-speed rotating impeller applies centrifugal force or lift to the gas, accelerating it and increasing its kinetic energy. A diffuser is installed at the outlet of the impeller, which slows down the high-speed airflow at the impeller outlet and converts kinetic energy into pressure energy.

[0030] The meridional profile of an impeller is the projected contour of the impeller onto the meridional plane, which is a plane passing through the rotation axis of the compressor. The meridional profile includes the outer meridional profile and the inner meridional profile. The outer meridional profile is the contour of the outer boundary of the impeller onto the meridional plane, and the inner meridional profile is the contour of the inner boundary of the impeller (closer to the rotation axis) onto the meridional plane.

[0031] In related technologies, such as Figure 1 and Figure 2 As shown, the outer meridional profile 01 of the impeller includes a straight segment 011 and a curved segment 012. Local optimization can be achieved by independently controlling the geometric parameters of the straight segment 011 and the curved segment 012.

[0032] Curve segment 012 can be a circular arc segment, an involute curve segment, or a third-order Bézier curve, etc. Taking curve segment 012 as a third-order Bézier curve as an example, a third-order Bézier curve is uniquely determined by four control points: a start point, an end point, and two control vertices. One control vertex controls the curve's trajectory near the start point, and the other control vertex controls the curve's trajectory near the end point. In related technologies, the number of adjustable control points for curve segments is limited, preventing the compressor's pressure ratio and efficiency from reaching their maximum performance potential.

[0033] In a first aspect, this application discloses an impeller for a compressor, including an impeller body, such as... Figure 3 and Figure 4 As shown, the outer meridional profile 1 of the impeller body includes a straight segment 11, a first curved segment 12, and a second curved segment 13.

[0034] The straight section 11 is located on the inlet side of the impeller. The straight section 11 is at a small angle to the axis of the impeller to ensure that the fluid flows in stably along the axial direction.

[0035] The length of the straight section 11 controls the rate of change of the cross-sectional area of ​​the inlet section of the flow channel, ensuring uniform velocity and pressure distribution of the fluid and laying the foundation for subsequent energy conversion. The inclination angle of the straight section 11 can be designed according to the direction of the fluid velocity at the impeller inlet, ensuring stable fluid entry into the impeller flow channel and avoiding flow separation or eddies caused by sudden bending of the profile. The impeller flow channel is the aerodynamic passage inside the impeller, composed of blades and the inner and outer boundaries of the channel. The inner and outer boundaries of the impeller flow channel are the channels formed by the blades, the impeller disc (or hub), and the impeller cover (or casing).

[0036] The function of the arc segment is to change the flow direction of the fluid. Through the continuously changing curvature, the axially flowing fluid is converted into radially flowing fluid.

[0037] The arc segment of this scheme includes the first curve segment 12 and the second curve segment 13. For example... Figure 3 As shown, from the inlet of the impeller body to the outlet of the impeller body, the slope of the tangent at each position of the first curve segment 12 gradually increases, while the slope of the tangent at each position of the second curve segment 13 gradually decreases. That is, the bending directions of the first curve segment 12 and the second curve segment 13 are opposite. The first curve segment 12 extends to the upper right to form a concave structure, while the second curve segment 13 extends to the lower right to form a convex structure.

[0038] It should be noted that the curvature of the first curve segment 12 and the second curve segment 13 are opposite. The connection between the first curve segment 12 and the second curve segment 13 is required to be a smooth transition. That is, the curvature between the end point of the first curve segment 12 and the beginning point of the second curve segment 13 is continuous. The fluid can flow smoothly along the outer meridian profile 1, avoiding eddies and separation phenomena, reducing flow losses, improving the energy conversion efficiency of the impeller, and at the same time avoiding stress concentration and reducing the impact on the service life of the impeller.

[0039] The outer meridional profile 1 of the compressor impeller body disclosed in this scheme includes two curve segments: a first curve segment 12 and a second curve segment 13. The first curve segment 12 has control points to change the curve shape of the first curve segment 12, and the second curve segment 13 has control points to change the curve shape of the second curve segment 13. The total number of control points of the entire curve segment is the sum of the number of control points of the first curve segment 12 and the number of control points of the second curve segment 13. That is, this scheme increases the number of adjustable control points of the outer meridional profile 1, making the adjustment of the outer meridional profile 1 more flexible and helping to obtain an outer meridional profile 1 that can maximize the pressure ratio and efficiency of the compressor.

[0040] like Figure 3 As shown, the first curved segment 12 is located between the straight segment 11 and the second curved segment 13. The first curved segment 12 is closer to the impeller inlet than the second curved segment 13, while the second curved segment 13 is closer to the impeller outlet. The first curved segment 12 and the second curved segment 13 have different functions.

[0041] The slope of the tangent at various positions in the first curved segment 12 of the concave structure gradually increases, as does the curvature of the first curved segment 12. During the turning phase of the airflow in the first curved segment 12, the expansion angle of the impeller channel increases with the radius, creating a larger pressure gradient. This prevents airflow blockage due to insufficient expansion force or boundary layer separation due to excessive expansion, thus suppressing gas backflow and improving surge. The rate of increase in the slope of the tangent at various positions from the beginning to the end of the first curved segment 12 can be the same or different.

[0042] The slope of the tangent at various positions of the second curved segment 13 of the convex structure gradually decreases, increasing the length of the profile near the impeller outlet. This helps to decelerate the gas at the impeller cover. Simultaneously, the width of the impeller flow channel increases along the direction perpendicular to the impeller axis (i.e., the distance between the bottom and top of the impeller body increases along the direction perpendicular to the impeller axis). This increases the blade area near the outlet, resulting in a higher linear velocity of the impeller near the outlet, which improves the impeller's work capacity. Furthermore, the more uniform airflow distribution helps suppress secondary flow from the bottom to the top of the impeller outlet, reducing gap flow. Additionally, the increased distance between the bottom and top of the impeller body along the direction perpendicular to the impeller axis reduces the axial dimension ratio of the gap, contributing to improved impeller efficiency and pressure ratio. The rate of increase in the slope of the tangent at various positions from the beginning to the end of the second curved segment 13 can be the same or different.

[0043] In some embodiments, the intersection point of the straight segment 11 and the first curved segment 12 is located at 10% to 50% of the length L of the outer meridian line 1; the intersection point of the first curved segment 12 and the second curved segment 13 is located at 60% to 90% of the length L of the outer meridian line 1; the length L of the outer meridian line 1 is the distance between the starting end of the straight segment 11 and the ending end of the second curved segment 13 along the axial direction of the impeller.

[0044] Optionally, the length of the first curved segment 12 along the impeller axis is greater than the length of the second curved segment 13, and the length of the second curved segment 13 is greater than the length of the straight segment 11. This helps to ensure the efficiency and pressure ratio near the compressor surge, while also ensuring the compressor efficiency.

[0045] In some embodiments, the intersection point of the straight line segment 11 and the first curved segment 12 is located at 10% of the length L of the outer meridian line 1, and the intersection point of the first curved segment 12 and the second curved segment 13 is located at 60% of the length L of the outer meridian line 1. That is, the two endpoints of the first curved segment 12 are located at 10% and 60% of the length L of the outer meridian line 1, respectively. The straight line segment 11 is 0% to 10% of the length L of the outer meridian line 1, and the second curved segment 13 is 60% to 100% of the length L of the outer meridian line 1.

[0046] Optionally, the length of the first curved segment 12 along the axis of the impeller is greater than the length of the second curved segment 13, and the length of the straight segment 11 is greater than or equal to the length of the second curved segment 13.

[0047] In some embodiments, the intersection point of the straight line segment 11 and the first curved segment 12 is located at 30% of the length L of the outer meridian line 1, and the intersection point of the first curved segment 12 and the second curved segment 13 is located at 75% of the length L of the outer meridian line 1. That is, the two endpoints of the first curved segment 12 are located at 30% and 75% of the length L of the outer meridian line 1, respectively. The straight line segment 11 is 0% to 30% of the length L of the outer meridian line 1, and the second curved segment 13 is 75% to 100% of the length L of the outer meridian line 1.

[0048] In other embodiments, the intersection point of the straight line segment 11 and the first curved segment 12 is located at 10% of the length L of the outer meridian line 1, and the intersection point of the first curved segment 12 and the second curved segment 13 is located at 90% of the length L of the outer meridian line 1. That is, the two endpoints of the first curved segment 12 are located at 10% and 90% of the length L of the outer meridian line 1, respectively. The straight line segment 11 is 0% to 10% of the length L of the outer meridian line 1, and the second curved segment 13 is 90% to 100% of the length L of the outer meridian line 1.

[0049] Optionally, the length of the straight segment 11 along the axis of the impeller is greater than the length of the first curved segment 12, and the length of the first curved segment 12 is greater than the length of the second curved segment 13.

[0050] In some embodiments, the intersection point of the straight line segment 11 and the first curved segment 12 is located at 50% of the length L of the outer meridian line 1, and the intersection point of the first curved segment 12 and the second curved segment 13 is located at 90% of the length L of the outer meridian line 1. That is, the two endpoints of the first curved segment 12 are located at 50% and 90% of the length L of the outer meridian line 1, respectively. The straight line segment 11 is 0% to 50% of the length L of the outer meridian line 1, and the second curved segment 13 is 90% to 100% of the length L of the outer meridian line 1.

[0051] The length division of the first curve segment 12, the second curve segment 13, and the straight line segment 11 is not limited to the above embodiment, and may also be other proportions. The specific proportions can be selected by those skilled in the art according to actual needs, and no specific limitation is made here.

[0052] The tangent at the starting end of the first curve segment 12 is parallel to the extension direction of the straight line segment 11.

[0053] The angle between the tangent at the beginning of the second curve segment 13 and the axis of the impeller is θ, and the angle between the tangent at the end of the first curve segment 12 and the axis of the impeller is also θ, where 50° < θ < 80°.

[0054] The angle between the tangent at the end of the second curve segment 13 and the axis of the impeller is α, where α < θ and 45° < α < 75°.

[0055] The angle between the tangent at the beginning of the second curve segment 13 and the axis of the impeller is θ, and the angle between the tangent at the end of the second curve segment 13 and the axis of the impeller is α.

[0056] In some embodiments, θ = 50°, α = 45°;

[0057] In other embodiments, θ = 80°, α = 75°;

[0058] In other embodiments, θ = 80°, α = 45°;

[0059] In other embodiments, θ = 60° and α = 55°.

[0060] θ and α are not limited to the above embodiments, and can be other angles. The specific selection should be made by those skilled in the art according to actual needs, and no specific limitation is made here.

[0061] The angle change between the tangent at the beginning of the second curve segment 13 and the tangent at the end of the second curve segment 13 is less than the angle change between the tangent at the beginning of the first curve segment 12 and the tangent at the end of the first curve segment 12. The curvature of the first curve segment 12 and the second curve segment 13 is affected by the length distribution of the first curve segment 12 and the second curve segment 13. Optionally, in embodiments where the length of the second curve segment 13 is less than or equal to the length of the first curve segment 12, the curvature of the second curve segment 13 is greater than the curvature of the first curve segment 12.

[0062] The outlet side 2 of the impeller body is at least one of a plane and a curved surface.

[0063] like Figure 3 The image shows an embodiment where the outlet of the impeller body is planar.

[0064] like Figure 4 As shown, this is an embodiment where the outlet of the impeller body is curved. The curve near the top is an outward convex curve, which increases the length of the impeller trailing edge structure near the top to reduce the gas velocity in this part. The curve near the bottom is an inward concave curve, which shortens the length of the impeller trailing edge structure closer to the bottom, thereby increasing the airflow velocity closer to the bottom of the impeller.

[0065] For ease of subsequent description, the intersection of the outlet plane of the impeller body and the outer meridian profile 1 will be named the vertex, and the intersection of the outlet plane of the impeller body and the inner meridian profile will be named the vertex.

[0066] like Figure 3As shown, the angle between the connecting line between the apex and the bottom point and the axis of the impeller is 0°-20°, or in other words, the angle between the connecting line between the apex and the bottom point and the axis of the impeller does not exceed 20°, so as to form a deceleration slope on the outlet side 2 of the impeller body, which, together with the second curve segment 13, helps to distribute the airflow more evenly.

[0067] Alternatively, the impeller body may be milled or cast using a cutting tool.

[0068] Optionally, the first curve segment 12 is a circular arc segment, an elliptical curve segment, or a third-order Bézier curve.

[0069] Optionally, the second curve segment 13 is a circular arc segment, an elliptical curve segment, or a third-order Bézier curve.

[0070] The first curve segment 12 and the second curve segment 13 are not limited to the curve segments of the above types, but can also be parabolas, involutes, or logarithmic spirals, etc.

[0071] The first curve segment 12 and the second curve segment 13 can be of the same type or different types. In embodiments where the first curve segment 12 and the second curve segment 13 are of the same type, the first curve segment 12 is a circular arc curve, and the second curve segment 13 is a circular arc curve; the first curve segment 12 is an elliptical curve, and the second curve segment 13 is an elliptical curve; the first curve segment 12 is a third-order Bézier curve, and the second curve segment 13 is a third-order Bézier curve. In embodiments where the first curve segment 12 and the second curve segment 13 are of different types, the first curve segment 12 is a circular arc curve, and the second curve segment 13 is an elliptical curve or a third-order Bézier curve; the first curve segment 12 is an elliptical curve, and the second curve segment 13 is a circular arc curve or a third-order Bézier curve; the first curve segment 12 is a third-order Bézier curve, and the second curve segment 13 is a circular arc curve or an elliptical curve.

[0072] Secondly, this application also discloses a compressor, including an impeller and a diffuser, wherein the impeller is the impeller described in any of the above embodiments, and the profile of the diffuser is adapted to the outer meridional profile 1 of the impeller.

[0073] Since the impeller has the above-mentioned technical effects, the compressor with the impeller also has the same technical effects, which will not be elaborated here.

[0074] The above description is merely a preferred embodiment of this application and an explanation of the technical principles employed, and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. The scope of this application is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described application concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this application.

Claims

1. An impeller of a compressor, characterized by, Includes an impeller body, wherein the outer meridional profile (1) of the impeller body includes a straight segment (11), a first curved segment (12), and a second curved segment (13); From the inlet of the impeller body to the outlet of the impeller body, the slope of the tangent at each position of the first curve segment (12) gradually increases to suppress airflow backflow, and the slope of the tangent at each position of the second curve segment (13) gradually decreases to suppress secondary flow from the bottom to the top at the outlet of the impeller body. The curvature is continuous between the end point of the first curve segment (12) and the beginning point of the second curve segment (13).

2. The impeller of claim 1, wherein The intersection of the straight line segment (11) and the first curved segment (12) is located at 10% to 50% of the length L of the outer meridian line (1); The intersection of the first curve segment (12) and the second curve segment (13) is located at 60% to 90% of the length L of the outer meridian line (1); The length of the outer meridian line (1) is the distance between the starting end of the straight segment (11) along the axial direction of the impeller body and the ending end of the second curved segment (13).

3. The impeller of a compressor according to claim 1 or 2, characterized in that The length of the first curve segment (12) is greater than the length of the second curve segment (13); The length of the second curve segment (13) is greater than the length of the straight line segment (11).

4. The impeller of a compressor according to claim 1 or 2, characterized in that The angle between the tangent at the initial end of the second curve segment (13) and the axis of the impeller body is θ, where 50° < θ < 80°.

5. The impeller of claim 4, wherein The angle between the tangent at the end of the second curve segment (13) and the axis of the impeller body is α, where α < θ and 45° < α < 75°.

6. The impeller of the compressor according to claim 1, characterized in that The outlet side (2) of the impeller body is at least one of a plane and a curved surface.

7. The impeller of the compressor according to claim 1, characterized in that The height of the apex of the outlet side (2) of the impeller body is higher than the height of the bottom point of the outlet side (2) of the impeller body; The angle between the line connecting the vertex and the bottom point and the axis of the impeller body does not exceed 20°.

8. The impeller of the compressor according to claim 1, characterized in that The first curve segment (12) is a circular arc curve segment, an elliptical curve segment, or a third-order Bézier curve; The second curve segment (13) is a circular arc segment, an elliptical curve segment, or a third-order Bézier curve; The first curve segment (12) may be the same as or different from the second curve segment (13).

9. The impeller of the compressor of claim 1, wherein The impeller body is formed by milling or casting.

10. A compressor characterized by, Includes impeller and diffuser; The impeller is the impeller according to any one of claims 1-9; The profile of the diffuser is adapted to the outer meridional profile (1) of the impeller.

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