Middle exhaust hole of CO2 scroll compressor and design method of middle exhaust hole

Abstract

The invention discloses a CO2 scroll compressor middle exhaust hole and a design method thereof, the CO2 scroll compressor middle exhaust hole comprises a first middle exhaust hole and a second middle exhaust hole, and the first middle exhaust hole and the second middle exhaust hole are symmetrically distributed about the center of a static scroll base circle; the circle center of the first middle exhaust hole is parallel to the tangent line of the base circle of the static vortex plate, and the circle center of the second middle exhaust hole is parallel to the tangent line of the base circle of the static vortex plate. On the premise of not increasing the invalid volume of the scroll compressor, the pressure consistency of the symmetrical working cavities can be ensured, and the energy efficiency ratio of operation of the scroll compressor is improved. And the non-uniformity of the pressure of the symmetrical working cavities of the scroll compressor during working is avoided, and the mechanical stress concentration and vibration caused by the non-uniform pressure are reduced, so that the operation stability of the CO2 scroll compressor is enhanced.

Description

Technical Field

[0001] The invention belongs to the field of fluid machinery and vehicle CO2 thermal management system, in particular to a middle exhaust hole of a CO2 scroll compressor and a design method thereof. Background Art

[0002] Scroll compressors have the characteristics of high efficiency, low noise, and smooth operation, and are widely used in various air-conditioning and heat pump systems. In particular, in automotive CO2 thermal management systems, scroll compressors are the preferred compressor solution. There are two symmetrical working chambers in the scroll compressor that compress the gas together, but factors such as changes in operating conditions and the design of the exhaust holes can cause inconsistent pressures in the two symmetrical working chambers. This pressure unevenness will have an adverse effect on the stable operation of the scroll compressor and increase the impact on the motor. In particular, for automotive CO2 thermal management systems, the refrigeration heat pump cycle often operates within the transcritical range, and its operating conditions are characterized by high operating pressure and large pressure difference for the scroll compressor. The pressure uniformity of the symmetrical working chambers of the scroll compressor is particularly important. Reasonable design of the intermediate exhaust hole is the key to ensuring stable and efficient operation of the CO2 scroll compressor.

[0003] At present, there are two main solutions to the problem of non-uniform pressure in the symmetrical working chambers of scroll compressors. One is to make a groove at the beginning of the vortex circle of the moving scroll or the static scroll so that the two working chambers are connected in advance; the other is to set up an intermediate exhaust hole so that the two working chambers can be exhausted simultaneously and in advance. Although the scroll compressor using the first solution can effectively reduce the non-uniformity of the symmetrical working chamber, it will increase the invalid volume of the scroll compressor, thereby reducing the efficiency of the scroll compressor. The existing scroll compressor using the second solution generally only focuses on the symmetrical distribution of the two intermediate exhaust holes about the center of the static scroll base circle. This design can only ensure that the two working chambers start to exhaust at the same time. In fact, the specific position of the intermediate exhaust hole also has a great influence on the uniformity of the pressure of the symmetrical working chamber. When the intermediate exhaust hole is completely blocked by the moving scroll before the beginning of the moving scroll and the static scroll are disengaged, the two working chambers cannot be exhausted through the intermediate exhaust hole. At this time, if one of the working chambers is connected to the main exhaust hole first, it will cause the pressure of the symmetrical working chamber to be non-uniform. Therefore, the reasonable design of the intermediate exhaust is of great significance to ensure the stable operation of the scroll compressor. Summary of the invention

[0004] The object of the present invention is to provide a middle exhaust hole of a CO2 scroll compressor and a design method thereof, so as to solve the problem of non-uniform pressure in the symmetrical working chamber of the scroll compressor in the prior art.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions:

[0006] A middle exhaust hole of a CO2 scroll compressor comprises a first middle exhaust hole and a second middle exhaust hole, wherein the first middle exhaust hole and the second middle exhaust hole are symmetrically distributed about the center of a static scroll base circle, and the tangent line between the center of the first middle exhaust hole and the static scroll base circle and the tangent line between the center of the second middle exhaust hole and the static scroll base circle are parallel.

[0007] Furthermore, the angle between the center of the first intermediate exhaust hole, the tangent line of the base circle of the static scroll and the x-axis of the static scroll is in the range of (-π, π).

[0008] Furthermore, the first intermediate exhaust hole is tangent to the involute on the inner side of the static vortex disk, and the center of the first intermediate exhaust hole is located on the generating line of the involute at the tangent point, and the generating line is tangent to the base circle of the static vortex disk.

[0009] Furthermore, the second intermediate exhaust hole is tangent to the involute of the outer side of the static vortex disk, and the center of the second intermediate exhaust hole is located on the generating line of the involute at the tangent point, and the generating line is tangent to the base circle of the static vortex disk.

[0010] A method for designing an intermediate exhaust hole of a CO2 scroll compressor, comprising:

[0011] According to the positional relationship between the static vortex base circle and the middle exhaust hole, the center and radius of the middle exhaust hole are determined;

[0012] The center position of the middle exhaust hole is corrected, and the position and size of the middle exhaust hole are determined according to the corrected center and radius.

[0013] Furthermore, for a stationary vortex with a fixed base circle, the coordinates of the center of the first intermediate exhaust hole are:

[0014]

[0015] Among them, x B and B denote the horizontal and vertical coordinates of the center of the first intermediate exhaust hole, a denotes the base circle radius, α denotes the starting angle of the involute, θ denotes the angle between the tangent line of the center of the first intermediate exhaust hole and the base circle of the static scroll and the x-axis of the static scroll, and r1 denotes the radius of the first intermediate exhaust hole;

[0016] The center coordinates of the second intermediate exhaust hole are:

[0017]

[0018] Among them, x F and F They respectively represent the horizontal and vertical coordinates of the center of the second middle exhaust hole, and r2 represents the radius of the second middle exhaust hole.

[0019] Furthermore, for a static vortex with a variable diameter base circle, the method for determining the center of the middle exhaust hole is:

[0020] According to the involute of the variable base circle radius, the base circle radius is determined, the curvature radius of the outer profile is obtained, and the outer profile equation is constructed;

[0021] According to the inner profile angle, the curvature radius of the inner profile is determined, and the inner profile equation is constructed;

[0022] The center coordinates of the first middle exhaust hole and the second middle exhaust hole are determined based on the outer profile equation and the inner profile equation.

[0023] Furthermore, the base circle radius is

[0024] a(φ)=a0+δ0φ k

[0025] Where a0 represents the initial radius of the base circle, δ0 represents the parameter for controlling the rate at which the base circle radius changes with the angle, φ represents the angle of expansion, and k represents the parameter for controlling the nonlinear effect of φ on the base circle radius;

[0026] The radius of curvature of the outer profile is

[0027]

[0028] Then the outer profile equation is:

[0029]

[0030] The inner profile angle is

[0031] φ in =φ+π-α in -α out

[0032] Among them, α in Indicates the starting angle of the inner involute, α out represents the starting angle of the outer involute;

[0033] The radius of curvature of the inner profile is

[0034]

[0035] Then the inside line equation is:

[0036]

[0037] Furthermore, the center coordinates of the first intermediate exhaust hole are:

[0038]

[0039] The center coordinates of the second intermediate exhaust hole are:

[0040]

[0041] Furthermore, the correction method includes symmetrical arc correction and symmetrical arc plus straight line correction. The corrected scroll compressor has a connecting arc correction angle, and the angle between the tangent of the center of the first intermediate exhaust hole and the base circle of the static scroll and the x-axis of the static scroll is smaller than the connecting arc correction angle.

[0042] Compared with the prior art, the present invention has the following beneficial effects:

[0043] The present invention provides a middle exhaust hole of a CO2 scroll compressor. For a scroll compressor of a vehicle CO2 thermal management system, the position of the middle exhaust hole is optimized and designed, and a first middle exhaust hole and a second middle exhaust hole are arranged to be symmetrically distributed about the center of the static scroll base circle. The center of the first middle exhaust hole is parallel to the tangent of the static scroll base circle, and the center of the second middle exhaust hole is parallel to the tangent of the static scroll base circle, so as to avoid the non-uniformity of the pressure of the symmetrical working chamber of the scroll compressor when the scroll compressor is working, and reduce the concentration of mechanical stress and vibration caused by uneven pressure. The symmetrical design of the present invention helps to ensure that the forces of various parts of the scroll compressor are balanced during operation, reduce mechanical wear and failure caused by uneven forces, thereby enhancing the stability of the operation of the scroll compressor, especially the CO2 scroll compressor. By maintaining the consistency of the symmetrical working chamber pressure, the internal fluid dynamic characteristics of the scroll compressor are optimized, which helps to reduce the energy loss in the compression process, improve the compression efficiency, make the gas flow in the scroll compressor smoother, reduce the energy consumption caused by flow resistance, and thus improve the overall performance of the scroll compressor. Compared with the prior art, the present invention can ensure the consistency of the symmetrical working chamber pressure without increasing the ineffective volume of the scroll compressor, thereby improving the energy efficiency ratio of the scroll compressor. Under the same input power, the scroll compressor can output more useful work, or consume less power when outputting the same useful work, which is of great significance for improving energy utilization efficiency and reducing operating costs. The present invention has wide applicability and potential market value for occasions requiring high stability and high efficiency, such as in the fields of new energy vehicles, cold chain logistics, etc., and can promote the development and progress of related industries. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0045] Figure 1 This is a geometric relationship diagram corresponding to the meshing point of the scroll compressor of the present invention using a symmetrical arc-corrected equal-wall thickness profile when the orbiting scroll and the static scroll start end are disengaged.

[0046] Figure 2 This is a geometric relationship diagram corresponding to the meshing point of the scroll compressor adopting a variable wall thickness profile with symmetrical arc correction of the present invention when the movable scroll and the static scroll start end are disengaged. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0048] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0050] In the description of the embodiments of the present invention, it should be noted that if the terms "upper", "lower", "horizontal", "inner", etc. indicate an orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the invention is usually placed when in use, it is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used to distinguish the description, and cannot be understood as indicating or implying relative importance.

[0051] In addition, if the term "horizontal" appears, it does not mean that the component must be absolutely horizontal, but can be slightly tilted. For example, "horizontal" only means that its direction is more horizontal than "vertical", which does not mean that the structure must be completely horizontal, but can be slightly tilted.

[0052] In the description of the embodiments of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] The present invention is further described in detail below in conjunction with the accompanying drawings:

[0054] The present invention provides a middle exhaust hole of a CO2 scroll compressor, comprising a first middle exhaust hole and a second middle exhaust hole. The first middle exhaust hole and the second middle exhaust hole are symmetrically distributed about the center of the static scroll base circle, and the center of the first middle exhaust hole and the tangent of the static scroll base circle are parallel to the center of the second middle exhaust hole and the tangent of the static scroll base circle. This design ensures that when the scroll compressor is working, the pressure distribution of each working chamber inside it is more uniform, which can effectively avoid the non-uniformity of the pressure of the symmetrical working chambers of the scroll compressor, and help reduce the mechanical stress concentration and vibration caused by uneven pressure.

[0055] The value range of the angle θ between the center of the first intermediate exhaust hole and the tangent line of the static scroll base circle and the x-axis of the static scroll is (-π, π), which is conducive to optimizing the gas flow path, improving exhaust efficiency, and reducing energy consumption and noise. The first intermediate exhaust hole is tangent to the involute on the inner side of the static scroll, and the center of the first intermediate exhaust hole is located on the generating line of the involute at the tangent point, and the generating line is tangent to the static scroll base circle. The second intermediate exhaust hole is tangent to the involute on the outer side of the static scroll, and the center of the second intermediate exhaust hole is located on the generating line of the involute at the tangent point, and the generating line is tangent to the static scroll base circle. The first intermediate exhaust hole and the second intermediate exhaust hole are tangent to the involute on the inner and outer sides of the static scroll respectively, which helps to reduce the flow resistance of the gas during the exhaust process, because the gas can flow out smoothly along the natural curve of the involute without generating excessive turbulence or pressure loss. By precisely controlling the center position of the exhaust hole and the tangent relationship with the involute, it can be ensured that the gas can be discharged from the scroll compressor quickly and effectively when needed. This helps to improve the exhaust efficiency of the overall equipment and reduce energy consumption. It also helps to disperse stress and reduce vibration and noise caused by gas exhaust, thereby enhancing the structural stability of the entire scroll compressor and extending the service life of the equipment.

[0056] The present invention also provides a method for designing an intermediate exhaust hole of a CO2 scroll compressor, comprising the following steps:

[0057] According to the positional relationship between the static vortex base circle and the middle exhaust hole, the center and radius of the middle exhaust hole are determined;

[0058] The center position of the middle exhaust hole is corrected, and the position and size of the middle exhaust hole are determined according to the corrected center and radius.

[0059] The design method of the present invention ensures the accuracy of the exhaust hole design by accurately determining the center and radius of the intermediate exhaust hole according to the positional relationship between the base circle of the static scroll and the intermediate exhaust hole. The method includes a correction of the center position of the intermediate exhaust hole, which helps to further optimize the position and size of the exhaust hole, thereby improving the compression efficiency and exhaust capacity of the scroll compressor. By accurately controlling the position and size of the exhaust hole, the energy loss in the compression process can be reduced and the overall efficiency can be improved.

[0060] Wherein, for a static vortex disk with a fixed base circle, the center coordinates of the first middle exhaust hole and the second middle exhaust hole are determined according to the involute of the circle;

[0061] This method is applicable not only to static vortex disks with fixed base circle, but also to static vortex disks with variable base circle. By constructing the equations of the outer and inner profiles, the coordinates of the center of the exhaust hole under different base circle radii can be accurately determined, thereby improving the versatility and flexibility of the design method.

[0062] For the static vortex with variable base circle, the base circle radius is determined according to the involute of the variable base circle radius, the curvature radius of the outer profile is obtained, and the outer profile equation is constructed;

[0063] According to the inner profile angle, the curvature radius of the inner profile is determined, and the inner profile equation is constructed;

[0064] The center coordinates of the first middle exhaust hole and the second middle exhaust hole are determined based on the outer profile equation and the inner profile equation.

[0065] Embodiment 1:

[0066] This embodiment provides a CO2 scroll compressor intermediate exhaust hole such as Figure 1 The figure shows a schematic diagram of a scroll compressor with a symmetrical arc correction and equal wall thickness profile. The first intermediate exhaust hole and the second intermediate exhaust hole are symmetrically distributed relative to the base circle of the static scroll, that is, the centers of the two intermediate exhaust holes are parallel to the tangent lines BC and DF of the base circle. This arrangement can ensure that the two intermediate exhaust holes are opened and closed at the same time, thereby ensuring the uniformity of the pressure in the symmetrical working chamber.

[0067] exist Figure 1 At the moment shown, the start of the orbiting scroll and the static scroll are before disengagement, that is, the two symmetrical working chambers are about to merge into the central chamber to form a new chamber. At this moment, the first intermediate exhaust hole and the inner contour of the static scroll are tangent at point A, and the second intermediate exhaust hole and the outer contour of the static scroll are tangent at point E. Points A and E are also the meshing points of the orbiting scroll and the static scroll.

[0068] In this embodiment, the design method of the middle exhaust hole of the CO2 scroll compressor is:

[0069] Determine that the angle between the center B of the first middle exhaust hole and the tangent BC of the static scroll base circle and the x-axis of the static scroll is θ, and the counterclockwise direction is the positive direction of θ, and the value range of θ is (-π, π).

[0070] The length of the involute of a circle can be determined based on the geometric parameters of the profile:

[0071] ρ=aφ

[0072] The first intermediate exhaust hole is tangent to the involute of the inner side of the static vortex disk at point A, the center B is located on the generating line of the involute at point A, its radius is r1, and the generating line is tangent to the base circle of the static vortex disk at point C. The second intermediate exhaust hole is tangent to the involute of the outer side of the static vortex disk at point E, the center F is located on the generating line of the involute at point E, its radius is r2, and the generating line is tangent to the base circle of the static vortex disk at point D.

[0073] According to the definition of the involute of a circle, the lengths of line AC and line DE are:

[0074]

[0075] Among them, a represents the base circle radius, and α represents the starting angle of the involute.

[0076] Then the coordinates of point B (x B ,y B ) and the coordinates of point F (x F ,y F )for:

[0077]

[0078] The use of equal wall thickness profile design can reduce the friction loss of the scroll compressor during operation and improve the compression efficiency. Through the involute correction of the circle, the contact position between the exhaust hole and the scroll disk can be accurately controlled to ensure that the exhaust hole is opened and closed at the right time to avoid gas leakage and energy loss. For equal wall thickness scroll compressors with symmetrical arc correction and symmetrical arc plus straight line correction, both have a connecting arc correction angle γ, and only when θ<γ, the first intermediate exhaust hole and the second intermediate exhaust hole can still be connected to the symmetrical working chamber for a period of time after the movable scroll and the static scroll are disengaged at the beginning, thereby ensuring the uniformity of the symmetrical working chamber pressure. Therefore, the design of the intermediate exhaust hole of the equal wall thickness scroll compressor using symmetrical arc plus straight line correction must also follow the rule of θ<γ.

[0079] It should be noted that for scroll compressors with equal wall thickness that use symmetrical arc correction and symmetrical arc plus straight line correction, the connection arc correction angle may be γ < 0. Therefore, the range of θ is specified to be (-π, π).

[0080] The material selection and processing accuracy of the scroll compressor have an important influence on the performance of the scroll compressor. In practical applications, it is necessary to verify the performance of the scroll compressor through experiments, and optimize the design based on the experimental results to improve the operating efficiency and stability of the scroll compressor.

[0081] Embodiment 2:

[0082] This embodiment provides a CO2 scroll compressor intermediate exhaust hole such as Figure 2 The first intermediate exhaust hole and the second intermediate exhaust hole are also symmetrically distributed relative to the base circle of the stationary scroll, that is, the centers of the two intermediate exhaust holes are parallel to the tangents B'C' and D'F' of the base circle.

[0083] exist Figure 2 At the moment shown, the start of the orbiting scroll and the static scroll are before disengagement, that is, the two symmetrical working chambers are about to merge into the central chamber to form a new chamber. At this moment, the first intermediate exhaust hole and the inner contour of the static scroll are tangent at point A', and the second intermediate exhaust hole and the outer contour of the static scroll are tangent at point E'. Points A' and E' are also the meshing points of the orbiting scroll and the static scroll.

[0084] The variable wall thickness profile can be designed more flexibly according to the working conditions and requirements of the scroll compressor, thereby optimizing the performance of the scroll compressor. In this embodiment, the design of the variable wall thickness profile enables the scroll disk to better adapt to the compression and expansion process of the gas during operation, thereby reducing energy loss. Based on the geometric characteristics of the variable diameter base circle involute, the design method of the middle exhaust hole of the CO2 scroll compressor is given as follows:

[0085] The angle between the center B' of the first intermediate exhaust hole and the tangent line B'C' of the static scroll base circle and the x-axis of the static scroll is specified to be θ, and the counterclockwise direction is the positive direction of θ, and the value range of θ is (-π, π).

[0086] For the involute with variable base circle radius, the base circle radius is:

[0087] a(φ)=a0+δ0φ k

[0088] Among them, a0 represents the initial radius of the base circle, δ0 represents the parameter for controlling the rate at which the base circle radius changes with the angle, φ represents the unfolding angle, and k represents the parameter for controlling the nonlinear effect of φ on the base circle radius.

[0089] The radius of curvature of the outer profile is:

[0090]

[0091] The outer profile equation is:

[0092]

[0093] Inner profile angle φ in for:

[0094] φ in =φ+π-α in -α out

[0095] Among them, αi n Indicates the starting angle of the inner involute, α out Indicates the starting angle of the outer involute.

[0096] The radius of curvature of the inner profile is:

[0097]

[0098] Then the inside line equation is:

[0099]

[0100] The first intermediate exhaust hole is tangent to the involute of the inner side of the static vortex at point A'. The center of the circle B' is located on the generating line of the involute at point A'. Its radius is r1. The generating line is tangent to the base circle of the static vortex at point C'. The center coordinates of the first intermediate exhaust hole (x B' ,y B' )for:

[0101]

[0102] The second middle exhaust hole is tangent to the involute of the outer side of the static vortex at point E'. The center F' is located on the generating line of the involute at point E'. Its radius is r2. The generating line is tangent to the base circle of the static vortex at point D'. The center coordinates of the second middle exhaust hole (x F' ,y F' )for:

[0103]

[0104] For the variable wall thickness scroll compressors with symmetrical arc correction and symmetrical arc plus straight line correction, both have a connection arc correction angle γ, and only when θ<γ, the first intermediate exhaust hole and the second intermediate exhaust hole can still be connected to the symmetrical working chamber for a period of time after the start of the orbiting scroll and the static scroll are disengaged, thereby ensuring the uniformity of the symmetrical working chamber pressure. Therefore, the design of the intermediate exhaust hole of the variable wall thickness scroll compressor with symmetrical arc plus straight line correction also needs to follow the rule of θ<γ.

[0105] It should be noted that for variable wall thickness scroll compressors that use symmetrical arc correction and symmetrical arc plus straight line correction, the connection arc correction angle γ>0, and the specified range of θ is still applicable as (-π,π). In practical applications, it is necessary to verify the performance of the scroll compressor through experiments and optimize the design based on the experimental results. For example, parameters such as the value range of the angle θ and the size of the connection arc correction angle can be adjusted to further improve the operating efficiency and stability of the scroll compressor. The design of the variable wall thickness profile enables the scroll disk to better adapt to the compression and expansion process of the gas during operation and reduce energy loss.

[0106] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A middle exhaust hole of a CO2 scroll compressor, characterized in that: It includes a first middle exhaust hole and a second middle exhaust hole, which are symmetrically distributed about the center of the static vortex base circle, and the center of the first middle exhaust hole and the tangent of the static vortex base circle are parallel.

2. The middle exhaust hole of a CO2 scroll compressor according to claim 1, characterized in that: The range of the angle between the center of the first intermediate exhaust hole, the tangent line of the base circle of the static scroll and the x-axis of the static scroll is (-π, π).

3. The middle exhaust hole of a CO2 scroll compressor according to claim 1, characterized in that: The first intermediate exhaust hole is tangent to the involute inside the static vortex disk, and the center of the first intermediate exhaust hole is located on the generating line of the involute at the tangent point, and the generating line is tangent to the base circle of the static vortex disk.

4. The middle exhaust hole of a CO2 scroll compressor according to claim 1, characterized in that: The second intermediate exhaust hole is tangent to the involute of the outer side of the static vortex disk, and the center of the second intermediate exhaust hole is located on the generating line of the involute at the tangent point, and the generating line is tangent to the base circle of the static vortex disk.

5. A method for designing a middle exhaust hole of a CO2 scroll compressor according to any one of claims 1 to 4, characterized in that: include: According to the positional relationship between the base circle of the static vortex disk and the middle exhaust hole, the center and radius of the middle exhaust hole are determined; The center position of the middle exhaust hole is corrected, and the position and size of the middle exhaust hole are determined according to the corrected center and radius.

6. The method for designing the intermediate exhaust hole of a CO2 scroll compressor according to claim 5, characterized in that: For a static vortex with a fixed base circle, the coordinates of the center of the first intermediate exhaust hole are: Among them, x B and B denote the horizontal and vertical coordinates of the center of the first intermediate exhaust hole, a denotes the base circle radius, α denotes the starting angle of the involute, θ denotes the angle between the tangent line of the center of the first intermediate exhaust hole and the base circle of the static scroll and the x-axis of the static scroll, and r1 denotes the radius of the first intermediate exhaust hole; The center coordinates of the second intermediate exhaust hole are: Among them, x F and F They respectively represent the horizontal and vertical coordinates of the center of the second middle exhaust hole, and r2 represents the radius of the second middle exhaust hole.

7. The method for designing the intermediate exhaust hole of a CO2 scroll compressor according to claim 5, characterized in that: For a static vortex with a variable diameter base circle, the method for determining the center of the middle exhaust hole is: According to the involute of the variable base circle radius, the base circle radius is determined, the curvature radius of the outer profile is obtained, and the outer profile equation is constructed; According to the inner profile angle, the curvature radius of the inner profile is determined, and the inner profile equation is constructed; The center coordinates of the first middle exhaust hole and the second middle exhaust hole are determined based on the outer profile equation and the inner profile equation.

8. The method for designing the intermediate exhaust hole of a CO2 scroll compressor according to claim 7, characterized in that: The base circle radius is a(φ)=a0+δ0φ k Where a0 represents the initial radius of the base circle, δ0 represents the parameter for controlling the rate at which the base circle radius changes with the angle, φ represents the angle of expansion, and k represents the parameter for controlling the nonlinear effect of φ on the base circle radius; The radius of curvature of the outer profile is Then the outer profile equation is: The inner profile angle is f in =φ+π-α in -a out Among them, αi n Indicates the starting angle of the inner involute, α out represents the starting angle of the outer involute; The radius of curvature of the inner profile is Then the inside line equation is:

9. The method for designing the intermediate exhaust hole of a CO2 scroll compressor according to claim 7, characterized in that: The center coordinates of the first intermediate exhaust hole are: The center coordinates of the second intermediate exhaust hole are:

10. The method for designing the intermediate exhaust hole of a CO2 scroll compressor according to claim 5, characterized in that: The correction method includes symmetrical arc correction and symmetrical arc plus straight line correction. The corrected scroll compressor has a connecting arc correction angle, and the angle between the tangent of the center of the first intermediate exhaust hole and the base circle of the static scroll and the x-axis of the static scroll is smaller than the connecting arc correction angle.

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