A centrifugal impeller and compressor

Abstract

This invention provides a centrifugal impeller comprising: a hub; multiple blades disposed on the hub and distributed circumferentially along the hub; each blade having a root and a tip; from the inlet to the outlet direction of the flow channel, the mid-arc installation angle of the blade root first increases and then decreases; the mid-arc installation angle of the blade tip first increases and then decreases, and the mid-arc installation angle of the blade root at the flow channel inlet is greater than the mid-arc installation angle of the blade tip, while the mid-arc installation angle of the blade root at the flow channel outlet is equal to the mid-arc installation angle of the blade tip. Through the design of the blade root and tip profiles, the inlet velocity of the centrifugal impeller is maintained at a low level, and the outlet installation angle of the impeller is increased, thus maintaining a high isentropic efficiency at the operating point and reducing the power consumption of the centrifugal impeller.

Description

Technical Field

[0001] This invention relates to the field of air compressor technology, and more specifically to a centrifugal impeller. Background Technology

[0002] In an aircraft air cycle system, the compressor is the direct source of air intake for the turbine. The working fluid at the compressor outlet is cooled and dehydrated before entering the turbine, driving the turbine to expand and do work. The airflow expands and does work inside the turbine to drive the compressor and other rotor components.

[0003] As an upstream component of the turbine, the compressor decelerates and pressurizes the incoming low-pressure air, driving the high-pressure air further into the turbine to complete the expansion and work process. Therefore, the compressor's pressurization level directly affects the turbine's work capacity, and consequently, the performance of the air circulation system. The compressor impeller rotor is the component in the compressor that directly affects the total gas pressure rise; its aerodynamic characteristics determine the turbine inlet boundary conditions.

[0004] Because the internal flow of a centrifugal compressor impeller is complex, the air velocity is high at the impeller inlet blade tip. When flowing in the flow channel, it is subjected to blade force, centrifugal force, and Coriolis force. There is also a loss of low-energy airflow due to leakage at the blade tip. Summary of the Invention

[0005] The technical solution disclosed in this invention proposes a centrifugal impeller, characterized by including a rim, a hub, and multiple blades circumferentially distributed between the rim and the hub;

[0006] A flow channel is formed between each pair of adjacent blades;

[0007] The blade has a leaf root, a leaf tip, and a leaf-shaped portion connecting the leaf root and the leaf tip. The leaf-shaped portion has a pressure surface and a suction surface.

[0008] Along the inlet to outlet direction of the flow channel, as the relative flow position Ф increases, the installation angle β1 of the blade root mid-arc line formed by the blade root mid-arc line and the hub axis first increases and then decreases.

[0009] Along the inlet to outlet direction of the flow channel, as the relative flow position Ф increases, the installation angle β2 of the blade tip mid-arc line formed by the blade tip mid-arc line and the hub axis first increases and then decreases.

[0010] Before the flow channel reaches the outlet, i.e., at any relative flow direction position where Ф < 100%, β1 is greater than β2, and the difference between β1 and β2 first increases and then decreases as the relative flow direction position Ф increases.

[0011] Furthermore, in some optional embodiments, at the position where the flow channel Ф = 40% to 60%, β1 reaches its maximum value, β2 reaches its maximum value, and the difference between β1 and β2 reaches its maximum value;

[0012] Furthermore, in some optional embodiments, when Ф=50%, β1 reaches its maximum value, β2 reaches its maximum value, and the difference between β1 and β2 reaches its maximum value.

[0013] Furthermore, in some alternative embodiments, β1 equals β2 at the outlet position of the flow channel, i.e., when Ф = 100%.

[0014] Furthermore, in some optional embodiments, at the outlet position where the flow channel Ф = 100%, β1 and β2 satisfy the following relationship:

[0015] β1=β2=arccos(0.2×Z0.7)2, where Z is the number of blades.

[0016] Furthermore, in some optional embodiments, the number of blades Z is 15 to 19, and at the outlet position of the flow channel Ф = 100%, both β1 and β2 are in the range of -63.7° to -51.9°.

[0017] Furthermore, in some optional embodiments, at the inlet position of the flow channel Ф=0, β1 is -56° to -57° and β2 is -38.5° to -39.5°.

[0018] Furthermore, in some optional embodiments, the blade root includes a front section, a middle section, and a rear section in the direction from the inlet to the outlet of the flow channel.

[0019] The relative flow direction position Ф corresponding to the front section of the leaf root has a value of 0 to 30%;

[0020] The relative flow direction position Ф corresponding to the middle section of the leaf root has a value of 30-70%;

[0021] The relative flow direction position Ф value corresponding to the rear section of the leaf root is 70-100%;

[0022] In the anterior segment of the leaf root, β1 gradually increases from -39° to 0°; in the middle segment of the leaf root, β1 gradually increases from 0° to +2.7°, and then gradually decreases from +2.7° to 0°; in the posterior segment of the leaf root, β1 gradually decreases from 0° to -58°.

[0023] Furthermore, in some optional embodiments, from the inlet to the outlet direction of the flow channel, the thickness of the blade root first increases and then decreases as the relative flow direction position Ф value increases;

[0024] From the inlet to the outlet of the flow channel, as the relative flow direction position Ф value increases, the thickness of the blade tip first increases and then decreases, wherein the thickness of the blade tip is less than the thickness of the blade root.

[0025] Furthermore, in some optional embodiments, the blade root thickness at the inlet of the flow channel is equal to the blade root thickness at the outlet of the flow channel.

[0026] The blade tip thickness at the inlet of the flow channel is equal to the blade tip thickness at the outlet of the flow channel.

[0027] Furthermore, in some optional embodiments, from the inlet to the outlet of the flow channel, the thickness of the front section of the blade root gradually increases, the thickness change of the middle section of the blade root approaches zero, and the thickness of the rear section of the blade root gradually decreases.

[0028] From the inlet to the outlet of the flow channel, the thickness of the front section of the blade tip gradually increases, the thickness change of the middle section of the blade tip approaches zero, and the thickness of the rear section of the blade tip gradually decreases.

[0029] Furthermore, in some optional embodiments, from the inlet to the outlet direction of the flow channel, the thickness of the middle section of the blade root is 1.3 mm, the thickness of the front section of the blade root gradually increases from 0.9 mm to 1.3 mm, and the thickness of the rear section of the blade root gradually decreases from 1.3 mm to 0.9 mm.

[0030] Furthermore, in some optional embodiments, the thickness of the blade at the hub position of the flow channel inlet and outlet is 0.85mm to 0.95mm; the thickness is maximum, 1.2mm to 1.4mm, within the 30%-70% relative flow direction range; the thickness of the blade at the rim position of the flow channel inlet and outlet is 0.55mm to 0.65mm; the thickness is maximum, 0.85mm to 0.95mm, within the 30%-70% relative flow direction range.

[0031] Furthermore, in some optional embodiments, the difference between the blade inlet installation angle and the blade airflow angle is 5.5° to 6.5°, wherein at the flow channel inlet, the angle difference is 5.5° to 6.5°, and the difference gradually decreases as the spanwise height increases.

[0032] Furthermore, in some optional embodiments, β1 at the flow channel inlet is -39 degrees; when Ф reaches the 50% flow direction position, the hub profile angle is 2.7 degrees, and when it reaches the 100% flow direction position, i.e., the impeller outlet, β1 reaches -58 degrees.

[0033] The β2 at the rotor inlet is -56.6 degrees; when Ф reaches the 47% flow direction position, the flange profile angle reaches its maximum of 23.2 degrees; when it reaches the 100% flow direction position, i.e., the impeller outlet, β2 reaches -58 degrees.

[0034] Furthermore, in some optional embodiments, from the inlet to the outlet direction of the flow channel, the blade tip includes a front section, a middle section, and a rear section.

[0035] The relative flow direction position Ф corresponding to the front section of the blade tip has a value of 0 to 40%;

[0036] The relative flow direction position Ф corresponding to the middle section of the blade tip has a value of 40-65%;

[0037] The relative flow direction position Ф value corresponding to the rear section of the blade tip is 65-100%;

[0038] In the front section of the leaf tip, β2 gradually increases from -56.6° to 0°; in the middle section of the leaf tip, β2 gradually increases from 0° to -23.2°; and in the rear section of the leaf tip, β2 gradually decreases from -23.2° to -58°.

[0039] Furthermore, in some optional embodiments, when β2 increases to -23.2 degrees, the corresponding relative flow direction position Ф value is 47%.

[0040] This invention also provides another design method embodiment, which is a method for designing the centrifugal impeller described in any of the above claims, the method comprising:

[0041] Determine the inlet gas state parameters and simultaneously specify the rotor hub radius value;

[0042] The impeller inlet flow velocity Cm1 is selected as the iteration parameter, and the preferred initial value of Cm1 can be selected as 0.28-0.32 times the inlet Mach number;

[0043] The rotor inlet area and rotor inlet rim radius are calculated based on the basic gas dynamics equations.

[0044] Calculate the relative velocity W1s at the rim position;

[0045] Return to step 2, change the value of Cm1, continue the calculation to obtain different W1s values, until the minimum value appears among all the obtained W1s values, exit the calculation loop, and select the rim radius value corresponding to the minimum value of W1s as the optimal rim radius corresponding to the hub radius.

[0046] The present invention also provides another embodiment of an air compressor, which is provided with the centrifugal impeller described in any of the above claims. Preferably, the air compressor includes a wheel cover, the wheel cover and the hub of the centrifugal impeller are fitted together, and a plurality of blades are disposed between the rim of the wheel cover and the hub.

[0047] The present invention provides the following advantages compared with the prior art:

[0048] By designing the blade root and tip profiles, the inlet velocity of the centrifugal impeller is kept at a low level, which can increase the impeller outlet installation angle, enabling it to maintain a high isentropic efficiency at the operating point and reducing the power consumption of the centrifugal impeller. Attached Figure Description

[0049] To more clearly illustrate the technical solution of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0050] Figure 1 This is a schematic diagram of the three-dimensional structure of a centrifugal impeller provided in an embodiment of the present invention;

[0051] Figure 2a This is a front view of a centrifugal impeller provided in an embodiment of the present invention;

[0052] Figure 2b A side view of a centrifugal impeller provided in an embodiment of the present invention;

[0053] Figure 3 A schematic diagram showing the distribution of flow direction positions (relative flow direction positions) along the flow channel, provided for an embodiment of the present invention;

[0054] Figure 4 A schematic diagram of the distribution of blade thickness along the flow channel (relative flow direction) provided in an embodiment of the present invention;

[0055] Figure 5 The rotor inlet mounting angle and airflow angle provided in the embodiments of the present invention are distributed along the spanwise direction;

[0056] Figure 6 Provided for embodiments of the present invention Figure 5 Schematic diagram of impeller streamline distribution at mid-span height;

[0057] Figure 7 The blade load distribution with relative spanwise height provided in the embodiments of the present invention;

[0058] Figure 8a This is a schematic diagram of the wheel cover structure of an air compressor embodiment provided by the present invention;

[0059] Figure 8b This is a schematic diagram of the blade structure of an air compressor embodiment provided by the present invention;

[0060] Figure 8c This is a schematic diagram of the hub structure of an air compressor embodiment provided by the present invention;

[0061] Figure 9This is a schematic diagram of the overall assembly of an air compressor embodiment provided in this invention. Detailed Implementation

[0062] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0063] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” used in the embodiments of this invention and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. “Multiple” generally includes at least two, but does not exclude the inclusion of at least one.

[0064] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.

[0065] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes said element.

[0066] The compressor is a crucial component in aircraft air conditioning air circulation systems. It pressurizes incoming air and sends it to the turbine for expansion and work, thus maintaining the normal operation of the entire rotor system. Its pressurization effect directly impacts the turbine's work capacity, and consequently, the performance of the air circulation system. The compressor impeller rotor directly affects the total gas pressure rise within the compressor, and its performance directly influences turbine performance. Due to the complex internal flow of a centrifugal compressor impeller, air velocity is high at the impeller inlet blade tip. During flow within the flow channel, it is subjected to blade forces, centrifugal forces, and Coriolis forces, and there is also low-energy airflow loss due to blade tip leakage. This invention proposes a centrifugal compressor with a large backbend angle to improve internal compressor flow and enhance compressor rotor performance.

[0067] Example 1

[0068] Figures 2a-2b Front and side views of the centrifugal impeller with the wheel cover removed. Figure 9 This is a side view of an embodiment of an air compressor having the centrifugal impeller. Figures 8a-8c This is a schematic diagram of the hub, blades, and wheel cover of the air compressor embodiment provided by the present invention, further combined with... Figures 1 to 3 8a-8c Figure 9 The centrifugal impeller embodiment of the present invention includes: a hub 1; a rim 3; and a plurality of blades 2, which are disposed between the rim and the hub and distributed along the circumference of the hub, with adjacent blades spaced apart to form a flow channel; the blades 2 have a blade root 21, a blade tip 22, and an air-shaped portion connecting the blade root and the blade tip, the air-shaped portion being the working part of the blade, which forms a pressure surface and a suction surface, both of which are curved surfaces 23, wherein the blade root 21 is connected to the hub 1, and the blade tip and the rim form a dynamic and static fit clearance; the blade root 21 forms the hub line, and the blade tip 22 forms the rim line.

[0069] Through a large amount of experimental data, such as Figure 3-7 As shown, surprisingly, the following optimized structural dimensions can significantly improve the internal flow of the compressor and enhance compressor rotor performance:

[0070] Along the inlet to outlet direction of the flow channel, as the relative flow position Ф increases, the installation angle β1 of the blade root mid-arc line formed by the blade root mid-arc line and the hub axis first increases and then decreases.

[0071] Along the inlet to outlet direction of the flow channel, as the relative flow position Ф increases, the installation angle β2 of the blade tip mid-arc line formed by the blade tip mid-arc line and the hub axis first increases and then decreases.

[0072] Before the flow channel reaches the outlet, i.e., at any relative flow direction position where Ф < 100%, β1 is greater than β2, and the difference between β1 and β2 first increases and then decreases as the relative flow direction position Ф increases.

[0073] It should be noted that:

[0074] In this application, the angle formed by the mid-arc line of the blade root and the hub axis is defined as the blade root mid-arc line installation angle β1, and the angle formed by the mid-arc line of the blade tip and the hub axis is defined as the blade tip mid-arc line installation angle β2.

[0075] The signs of the blade root mid-curve installation angle β1 and the blade tip mid-curve installation angle β2 are as follows: The inlet installation angle at the flow channel inlet is referenced to the axial direction; the angle forming a clockwise angle with the axial direction is defined as a negative angle, and the angle forming a counterclockwise angle with the axial direction is defined as a positive angle. The outlet installation angle at the flow channel outlet is referenced to the radial direction; the angle forming a clockwise angle with the radial direction is defined as a negative angle, and the angle forming a counterclockwise angle with the radial direction is defined as a positive angle. While the inlet and outlet installation angles are usually fixed values, the values ​​of the blade root mid-curve installation angle β1 and the blade tip mid-curve installation angle β2 vary within a range at different positions along the flow direction. They are relatively flexible and not fixed values ​​(for example, -23.2 degrees; this value has a certain range of variation, and the impeller performance changes with this value).

[0076] In this application, Ф is used to represent the relative flow direction position, with the hub axis as the reference, and is the ratio of the axial distance from the flow channel inlet to a certain position in the flow channel to the total axial distance from the flow channel inlet to the outlet.

[0077] As a preferred embodiment of this application, in some embodiments, such as Figure 3-9 As shown: At the inlet position where the flow channel Ф = 0, β1 is preferably -56° to -57°, and β2 is preferably -38.5° to -39.5°. At the inlet position where the flow channel Ф = 40% to 60%, β1 and β2 reach their maximum values, and the difference between β1 and β2 reaches its maximum value. Preferably, at Ф = 50%, β1 reaches its maximum value, β2 reaches its maximum value, and the difference between β1 and β2 reaches its maximum value. At the outlet position where the flow channel Ф = 100%, β1 is preferably equal to β2. β1 and β2 satisfy the following relationship: β1 = β2 = arccos(0.2 × Z) 0.7 ) 2 Z represents the number of blades. The number of blades Z is preferably 15 to 19, and at the outlet position where the flow channel Ф = 100%, both β1 and β2 are in the range of -63.7° to -51.9°.

[0078] As a preferred embodiment of this application, in some embodiments, such as Figure 3-9 As shown: From the inlet to the outlet direction of the flow channel, the blade root includes a front section, a middle section, and a rear section; the relative flow direction position Ф corresponding to the front section of the blade root has a value of 0-30%; the relative flow direction position Ф corresponding to the middle section of the blade root has a value of 30-70%; and the relative flow direction position Ф corresponding to the rear section of the blade root has a value of 70-100%. As a further preferred embodiment of this application, the β1 at the flow channel inlet (Ф value of 0) is -39 degrees; when Ф reaches 50% flow direction position, β1 is 2.7 degrees; and when it reaches 100% flow direction position, i.e., the impeller outlet, β1 reaches -58 degrees; as... Figure 3-7As shown: Along the flow channel from inlet to outlet, the optimal relationship between β1 and Ф is as follows: In the front section of the blade root, β1 gradually increases from -39° to 0°; in the middle section of the blade root, β1 gradually increases from 0° to +2.7°, and then gradually decreases from +2.7° to 0°; in the rear section of the blade root, β1 gradually decreases from 0° to -58°.

[0079] As a preferred embodiment of this application, in some embodiments, such as Figure 3-6 As shown:

[0080] From the inlet to the outlet of the flow channel, the thickness of the front section of the blade root gradually increases, the thickness of the middle section of the blade root changes to near zero, and the thickness of the rear section of the blade root gradually decreases.

[0081] From the inlet to the outlet direction of the flow channel, the blade tip includes a front section, a middle section, and a rear section.

[0082] The relative flow direction position Ф corresponding to the front section of the blade tip has a value of 0 to 40%;

[0083] The relative flow direction position Ф corresponding to the middle section of the blade tip has a value of 40-65%;

[0084] The relative flow direction position Ф value corresponding to the rear section of the blade tip is 65-100%;

[0085] The β2 at the rotor inlet is -56.6 degrees; β2 reaches its maximum at an angle of 23.2 degrees when Ф reaches 47% of the flow direction, and reaches 100% of the flow direction.

[0086] That is, at the impeller outlet, β2 reaches -58 degrees. More preferably, from the inlet to the outlet direction of the flow channel, in the leading section of the blade tip, β2 gradually increases from -56.6° to 0°; in the middle section of the blade tip, β2 gradually increases from 0° to -23.2°; and in the trailing section of the blade tip, β2 gradually decreases from -23.2° to -58°.

[0087] As a preferred embodiment of this application, in some embodiments, from the inlet to the outlet of the flow channel, the blade root thickness at the inlet of the flow channel is preferably equal to the blade root thickness at the outlet of the flow channel. The thickness of the leading section of the blade tip gradually increases, the thickness change of the middle section of the blade tip approaches zero, and the thickness of the trailing section of the blade tip gradually decreases. Preferably, the blade tip thickness at the inlet of the flow channel is equal to the blade tip thickness at the outlet of the flow channel. Specifically, preferably, the blade thickness at the hub position of the flow channel inlet and outlet is 0.85mm to 0.95mm, preferably 0.9mm; the thickness is maximum in the 30%-70% relative flow direction range, 1.2mm to 1.4mm, more preferably 1.3mm; the blade thickness at the rim position of the flow channel inlet and outlet is 0.55mm to 0.65mm, more preferably 0.6mm; the thickness is maximum in the 30%-70% relative flow direction range, 0.85mm to 0.95mm, more preferably 0.9mm.

[0088] Specifically, from the inlet to the outlet of the flow channel: the thickness of the front section of the blade root gradually increases from 0.9 mm to 1.3 mm, the thickness of the middle section of the blade root remains basically unchanged at 1.3 mm, and the thickness of the rear section of the blade root gradually decreases from 1.3 mm to 0.9 mm.

[0089] As a further preferred embodiment of this application,

[0090] From the inlet to the outlet direction of the flow channel, the blade tip includes a front section, a middle section, and a rear section.

[0091] The relative flow direction position Ф corresponding to the front section of the blade tip has a value of 0 to 40%;

[0092] The relative flow direction position Ф corresponding to the middle section of the blade tip has a value of 40-65%;

[0093] The relative flow direction position Ф value corresponding to the rear section of the blade tip is 65-100%;

[0094] The β2 at the rotor inlet is -56.6 degrees; β2 reaches its maximum at 23.2 degrees when Ф reaches 47% of the flow direction, and reaches -58 degrees when Ф reaches 100% of the flow direction, i.e., the impeller outlet; from the inlet to the outlet of the flow channel, in the leading section of the blade tip, β2 gradually increases from -56.6° to 0°; in the middle section of the blade tip, β2 gradually increases from 0° to -23.2°; and in the trailing section of the blade tip, β2 gradually decreases from -23.2° to -58°.

[0095] As a further preferred embodiment of this application, such as Figure 5As shown, to ensure stable airflow at the rotor inlet, this application designs the rotor inlet mounting angle and rotor inlet airflow angle to gradually increase with increasing spanwise relative height, while maintaining the difference between the rotor inlet mounting angle and the airflow angle within a small range. Preferably, at the rotor inlet, the angle difference is 5.5 degrees to 6.5 degrees, preferably around 6 degrees, and the difference gradually decreases with increasing blade spanwise height. Combined with... Figure 7 From the perspective of streamline distribution, the rotor inlet maintains a good flow state, and no suction surface separation occurs at the rotor inlet.

[0096] Figure 7 The impeller rotor surface load state under design conditions is such that the main pressure difference between the blade pressure surface and suction surface is concentrated at a position of 0.5 relative flow direction, after which the impeller load exhibits an afterloading state.

[0097] The table below shows the calculation results of the impeller aerodynamic parameters and efficiency under working conditions. The impeller aerodynamic efficiency reached 87%, which reduced the relative flow velocity at the compressor inlet tip, improved the impeller load distribution, formed the backloading characteristics, reduced the impact loss at the compressor rotor inlet, and improved the compressor rotor aerodynamic efficiency.

[0098] Table 1. Impeller aerodynamic parameters under full machine operating conditions

[0099]

[0100] Example 2

[0101] like Figures 1-9 The present invention proposes an embodiment of a centrifugal impeller design method, which can be applied to the centrifugal impeller design of the air compressor shown in Embodiment 1, including:

[0102] Determine the inlet gas state parameters and simultaneously specify the rotor hub radius value;

[0103] The impeller inlet flow velocity Cml is selected as the iteration parameter, and the preferred initial value of Cml can be selected as 0.28-0.32 times the inlet Mach number;

[0104] The rotor inlet area and rotor inlet rim radius are calculated based on the basic gas dynamics equations.

[0105] Calculate the relative velocity W1s at the rim position;

[0106] Return to step 2, change the Cml value, continue the calculation to obtain different W1s values, until the minimum value appears among all the obtained W1s values, exit the calculation loop, and select the rim radius value corresponding to the minimum value of W1s as the optimal rim radius corresponding to the hub radius.

[0107] After one-dimensional and three-dimensional calculations, the optimal number of impeller blades is 17, and the blades are evenly distributed around the rotation axis; Figure 2 also shows the relevant definitions of (β) and flow direction position (M). The blade outlet installation angle (β) provided by this invention reaches -58 degrees.

[0108] The centrifugal impeller of this invention completes the compressor inlet design through one-dimensional design calculations, obtaining its optimal tip radius. The relative flow velocity at the centrifugal compressor inlet tip position is maintained at a low level; furthermore, by applying higher-order Bezier curves to adjust and optimize the blade installation angle along the flow direction, the impeller outlet backbend angle is increased. This maintains a high isentropic efficiency at the operating point, reducing the power consumption of the compressor impeller. Simultaneously, the compressor impeller load is mainly distributed in the 0.5-1.0 relative flow direction position, with the entire impeller load in a back-loaded state.

[0109] In summary, the embodiments provided in this application solve the following technical problems:

[0110] 1. Reduced the relative flow velocity at the compressor inlet blade tip;

[0111] 2. Improve impeller load distribution to create backload characteristics;

[0112] 3. Reduced impact loss at the compressor rotor inlet;

[0113] 4. Improved the aerodynamic efficiency of the compressor rotor.

[0114] Any obvious modifications made to this invention without departing from its essential content will constitute an infringement of the patent rights of this invention and will incur corresponding legal liability.

[0115] The above are merely preferred embodiments of one or more embodiments of this disclosure and are not intended to limit the scope of one or more embodiments of this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of this disclosure should be included within the scope of protection of one or more embodiments of this disclosure.

Claims

1. A centrifugal impeller, characterized in that, Includes a hub and multiple blades circumferentially distributed on the hub; A flow channel is formed between each pair of adjacent blades; The blade has a leaf root, a leaf tip, and a leaf-shaped portion connecting the leaf root and the leaf tip. The leaf-shaped portion has a pressure surface and a suction surface. Along the inlet to outlet direction of the flow channel, as the relative flow position Ф increases, the installation angle β1 of the blade root mid-arc line formed by the blade root mid-arc line and the hub axis first increases and then decreases. Along the inlet to outlet direction of the flow channel, as the relative flow position Ф increases, the installation angle β2 of the blade tip mid-arc line formed by the blade tip mid-arc line and the hub axis first increases and then decreases. Before the flow channel reaches the outlet, i.e., at any relative flow direction position where Ф < 100%, β1 is greater than β2, and the difference between β1 and β2 first increases and then decreases as the relative flow direction position Ф increases.

2. The centrifugal impeller according to claim 1, characterized in that, At the position where the flow channel Ф = 40% to 60%: β1 reaches its maximum value, β2 reaches its maximum value, and the difference between β1 and β2 reaches its maximum value.

3. The centrifugal impeller according to claim 2, characterized in that, When Ф = 50%, β1 reaches its maximum value, β2 reaches its maximum value, and the difference between β1 and β2 reaches its maximum value.

4. The centrifugal impeller according to claim 1, characterized in that, At the outlet position of the flow channel, i.e., when Ф = 100%, β1 = β2.

5. The centrifugal impeller according to claim 4, characterized in that, At the outlet position where the flow channel Ф = 100%, β1 and β2 satisfy the following relationship: β1=β2=arccos(0.2×Z 0.7 ) 2 , where Z is the number of blades.

6. The centrifugal impeller according to claim 5, characterized in that, The number of blades Z is 15 to 19, and at the outlet position of the flow channel Ф=100%, both β1 and β2 are in the range of -63.7° to -51.9°.

7. The centrifugal impeller according to claim 1, characterized in that, At the inlet position of the flow channel Ф=0, β1 is -56°~-57° and β2 is -38.5°~-39.5°.

8. The centrifugal impeller according to claim 1, characterized in that, From the inlet to the outlet of the flow channel, as the relative flow direction position Ф value increases, the thickness of the blade root first increases and then decreases; From the inlet to the outlet of the flow channel, as the relative flow direction position Ф value increases, the thickness of the blade tip first increases and then decreases, wherein the thickness of the blade tip is less than the thickness of the blade root.

9. The centrifugal impeller according to any one of claims 1-8, characterized in that, From the inlet to the outlet direction of the flow channel, the blade root includes a front section, a middle section, and a rear section. The relative flow direction position Ф corresponding to the front section of the leaf root has a value of 0 to 30%; The relative flow direction position Ф corresponding to the middle section of the leaf root has a value of 30-70%; The relative flow direction position Ф value corresponding to the rear section of the leaf root is 70-100%; In the anterior segment of the leaf root, β1 gradually increases from -39° to 0°; in the middle segment of the leaf root, β1 gradually increases from 0° to +2.7°, and then gradually decreases from +2.7° to 0°; in the posterior segment of the leaf root, β1 gradually decreases from 0° to -58°.

10. The centrifugal impeller according to claim 9, characterized in that, The blade root thickness at the inlet of the flow channel is equal to the blade root thickness at the outlet of the flow channel. The blade tip thickness at the inlet of the flow channel is equal to the blade tip thickness at the outlet of the flow channel.

11. The centrifugal impeller according to claim 9, characterized in that, From the inlet to the outlet of the flow channel, the thickness of the front section of the blade root gradually increases, the thickness of the middle section of the blade root changes to near zero, and the thickness of the rear section of the blade root gradually decreases. From the inlet to the outlet of the flow channel, the thickness of the front section of the blade tip gradually increases, the thickness change of the middle section of the blade tip approaches zero, and the thickness of the rear section of the blade tip gradually decreases.

12. The centrifugal impeller according to claim 11, characterized in that, From the inlet to the outlet of the flow channel, the thickness of the middle section of the blade root is 1.3 mm, the thickness of the front section of the blade root gradually increases from 0.9 mm to 1.3 mm, and the thickness of the rear section of the blade root gradually decreases from 1.3 mm to 0.9 mm.

13. The centrifugal impeller according to any one of claims 1-8, characterized in that, The thickness of the blades at the hub position of the flow channel inlet and outlet is 0.85mm to 0.95mm; the thickness is greatest in the 30%-70% relative flow direction range, ranging from 1.2mm to 1.4mm; the thickness of the blades at the rim position of the flow channel inlet and outlet is 0.55mm to 0.65mm; the thickness is greatest in the 30%-70% relative flow direction range, ranging from 0.85mm to 0.95mm.

14. The centrifugal impeller according to any one of claims 1-8, characterized in that, The angle difference between β1 and the airflow from the blade is 5.5° to 6.5°. At the inlet of the flow channel, the angle difference is 5.5° to 6.5°. As the spanwise height increases, the difference between the two gradually decreases.

15. The centrifugal impeller according to claim 1, characterized in that, The β1 at the flow channel inlet is -39 degrees; when Ф reaches 50% flow direction, β1 is 2.7 degrees; and when it reaches 100% flow direction, i.e., the impeller outlet, β1 reaches -58 degrees. The β2 at the rotor inlet is -56.6 degrees; when Ф reaches 47% of the flow direction, β2 reaches its maximum at an angle of 23.2 degrees, and when it reaches 100% of the flow direction, i.e., the impeller outlet, β2 reaches -58 degrees.

16. The centrifugal impeller according to claim 1, characterized in that, From the inlet to the outlet direction of the flow channel, the blade tip includes a front section, a middle section, and a rear section. The relative flow direction position Ф corresponding to the front section of the blade tip has a value of 0 to 40%; The relative flow direction position Ф corresponding to the middle section of the blade tip has a value of 40-65%; The relative flow direction position Ф value corresponding to the rear section of the blade tip is 65-100%; From the inlet to the outlet of the flow channel, in the forward section of the blade tip, β2 gradually increases from -56.6° to 0°; in the middle section of the blade tip, β2 gradually increases from 0° to -23.2°; and in the rear section of the blade tip, β2 gradually decreases from -23.2° to -58°.

17. A method for designing a centrifugal impeller according to any one of claims 1-16, characterized in that, Determine the inlet gas state parameters and simultaneously specify the rotor hub radius value; Choose the impeller inlet flow velocity Cm1 as the iteration parameter; The rotor inlet area and rotor inlet rim radius are calculated based on the basic gas dynamics equations. Calculate the relative velocity W1 s at the rim position; Return to step 2, change the value of Cm1, and continue the calculation to obtain different W1s values ​​until the minimum value appears among all the obtained W1s values. Then, exit the calculation loop and select the rim radius value corresponding to the minimum value of W1s as the optimal rim radius corresponding to the hub radius.

18. The method for a centrifugal impeller as described in claim 17, characterized in that, The initial value of Cm1 is 0.28-0.32 times the entrance Mach number.

19. A compressor comprising a wheel cover and a centrifugal impeller as described in any one of claims 1-16, wherein the wheel cover and the hub of the centrifugal impeller are fitted together, and the plurality of blades are disposed between the rim of the wheel cover and the hub.

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