Centrifugal fan blade and embedded air conditioner

Abstract

The application provides a centrifugal fan blade and an embedded air conditioner. The centrifugal fan blade comprises a front cover, a blade and a rear cover, the blade is connected between the front cover and the rear cover, the blade comprises a first blade and a second blade, the first blade is connected with the front cover, the second blade is connected with the rear cover, a top surface of the second blade forms a bottom surface of the first blade, the top surface of the second blade is parallel to a bottom surface of the second blade, a cross section of the second blade is parallel to the bottom surface of the second blade, the cross section of the second blade comprises an inlet angle alpha, an outlet angle beta, an inlet diameter D1 and an outlet diameter D2, 30 DEG <= alpha + beta <= 70 DEG, alpha belongs to (0 DEG, 30 DEG ], beta belongs to [20 DEG, 50 DEG ], D1 belongs to [260 mm, 400 mm], and D2 belongs to [400 mm, 500 mm]. According to the centrifugal fan blade, the fan blade parameters can be optimized and designed, the fan blade aerodynamic performance is improved, the fan blade air volume and efficiency are improved, and the noise is reduced.

Description

Technical Field

[0001] This invention relates to the field of fan technology, and more specifically, to a centrifugal fan blade and an embedded air conditioner. Background Technology

[0002] As a general-purpose machine, fans are widely used in various industries. In the home appliance industry, fans are indispensable to meet various cooling and air supply requirements. Among them, centrifugal fans are the most widely used due to their characteristics of high pressure, small flow rate, and ability to change airflow direction. The fan blades are the core component of a centrifugal fan, and their performance directly affects the overall performance of the machine, and also has a significant impact on the noise level, which is the most intuitive aspect for consumers.

[0003] Ceiling-mounted or recessed air conditioners, also known as ceiling-mounted units, are increasingly favored by consumers due to their long air delivery distance, attractive appearance, and space-saving design. The fan has a significant impact on the performance of a ceiling-mounted unit.

[0004] The working principle of a joist is that the airflow is organized by the backward centrifugal fan blades, which rotate and work, then turn 90° before flowing out from the blade outlet. After passing through the heat exchanger, it is turned 90° again by the air outlet channel and blown out. Due to the air outlet method of the joist and the influence of internal damping components such as the heat exchanger and electric auxiliary heating, the internal flow is complex and contains many vortices, which affects the aerodynamic performance and noise of the joist.

[0005] The design of blade characteristic parameters has a great influence on the aerodynamic performance of the fan blades. How to optimize the design of fan blade parameters to obtain excellent aerodynamic performance is an urgent problem to be solved in current centrifugal fan research. Summary of the Invention

[0006] The main objective of this invention is to provide a centrifugal fan blade and an embedded air conditioner, which can optimize the design of fan blade parameters, improve the aerodynamic performance of the fan blade, increase the air volume and efficiency of the fan blade, and reduce noise.

[0007] To achieve the above objectives, according to one aspect of the present invention, a centrifugal fan blade is provided, comprising a front cover, blades, and a rear cover, wherein the blades are connected between the front cover and the rear cover, and the blades include a first blade and a second blade, wherein the first blade is connected to the front cover, and the second blade is connected to the rear cover, wherein the top surface of the second blade forms the bottom surface of the first blade, the top surface of the second blade is parallel to the bottom surface of the second blade, and the cross section of the second blade is parallel to the bottom surface of the second blade, wherein the cross section of the second blade includes an inlet angle α, an outlet angle β, an inlet diameter D1, and an outlet diameter D2, wherein 30°≤α+β≤70°, α∈(0°, 30°], β∈[20°, 50°], D1∈[260mm, 400mm], and D2∈[400mm, 500mm].

[0008] Furthermore, the bottom surface of the second blade forms a first cross section, and the top surface of the second blade forms a third cross section. The inlet angle of the first cross section is α1, the outlet angle is β1, the inlet diameter is D11, and the outlet diameter is D21. The inlet angle of the third cross section is α2, the outlet angle is β2, the inlet diameter is D12, and the outlet diameter is D22, where α1 < α2, β1 = β2, D11 < D12, and D21 = D22.

[0009] Furthermore, 30°≤α1+β1≤60°, α1∈(0°, 30°], β1∈[20°, 50°], D11∈[260mm, 350mm], D21∈[400mm, 500mm].

[0010] Furthermore, 45°≤α2+β2≤70°, α2∈[0°, 30°], β2∈[20°, 50°], D11∈[300mm, 400mm], D21∈[400mm, 500mm].

[0011] Furthermore, the bottom surface of the second blade forms a first cross section, and the top surface of the second blade forms a third cross section. The projections of the centerlines of the first and third cross sections onto the first cross section coincide.

[0012] Furthermore, the second blade includes a first segment and a second segment. The first segment is formed by extending a first cross section along a guide line to form a first sub-segment. The second segment is formed by extending a second cross section along a guide line to form a second sub-segment. The second cross section is parallel to the first cross section, and the projections of the midlines of the first and second cross sections onto the first cross section coincide. The first cross section is the same as the second cross section, and the area of ​​the third cross section is smaller than the area of ​​the second cross section.

[0013] Furthermore, taking the centerline endpoint of the blade inlet position of the first section as the starting point, the centerline length of the first section is Lz1, and in the second blade after the centerline length of (0~0.3)Lz1, the projections of the first section and the third section on the first section coincide.

[0014] Furthermore, the top surface of the first blade forms a fourth section. The centerlines of the first, second, third, and fourth sections are all arcs, and the centerline radius of each section is Rz. The intersection of the centerline on each section with the outlet circle of the centrifugal fan blade coincides with the projection point on the first section. The centerline length of the first section is Lz1, the centerline length of the second section is Lz2, the centerline length of the third section is Lz3, and the centerline length of the fourth section is Lz4. Lz1 = Lz2, Lz3 / Lz1 ∈ [0.6, 1], and Lz4 / Lz1 ∈ [0.3, 0.6].

[0015] Furthermore, the top surface of the first blade forms a fourth section. The height difference between the first and second sections in the axial direction of the centrifugal fan blade is Hy1, the height difference between the first and third sections in the axial direction of the centrifugal fan blade is Hy2, the height difference between the third and fourth sections in the axial direction of the centrifugal fan blade is Hy3, the height of the blade in the axial direction of the centrifugal fan blade is Hy, and the total height of the centrifugal fan blade in the axial direction of the centrifugal fan blade is H0, where Hy = Hy2 + Hy3, Hy2 / Hy ∈ [0.6, 0.9], Hy1 / Hy2 ∈ [0.1, 0.4], Hy / H0 ∈ [0.8, 1], Hy2 ∈ [90mm, 110mm], and Hy3 ∈ [20mm, 40mm].

[0016] Furthermore, the height difference between the first section and the second section in the axial direction of the centrifugal fan blade is Hy1, where Hy1 ∈ [10 mm, 50 mm].

[0017] Furthermore, the cross-sectional profile of the blade constitutes the blade profile at the cross-section, and the blade profile equation is:

[0018] x=f(τ=L z *τ 5 +b1*τ 4 *(1-τ)+c1*τ 3 *(1-τ) 2 +d1*τ 2 *(1-τ) 3 +e1*τ*(1-τ) 4 ,

[0019] y = f(τ) = 1.25 * τ 5 +b2*τ 4 *(1-τ)+c2*τ 3 *(1-τ) 2 +d2*τ 2 *(1-τ) 3 +e2*τ*(1-τ) 4 ,

[0020] Where x is the abscissa of the profile, y is the ordinate of the profile, Lz is the centerline length of the section, b1∈[474.2, 484.2], c1∈[552, 572], d1∈[190, 210], e1∈[22.5, 32.5], b2∈[9.5, 19.5], c2∈[25, 45], d2∈[130, 150], e2∈[30, 40], τ∈[0, 1].

[0021] Furthermore, the first blade is tilted relative to the second blade towards the side away from the suction surface.

[0022] Furthermore, the cross-sectional helix angle of the first blade relative to the second blade is θ, the height of the first blade along the axial direction of the centrifugal fan blade is Hy3, the bottom surface of the second blade forms the first cross-section, the top surface of the second blade forms the third cross-section, the top surface of the first blade forms the fourth cross-section, the centerline length of the first cross-section is Lz1, the centerline length of the third cross-section is Lz3, the centerline length of the fourth cross-section is Lz4, Hy3∈[20mm, 40mm], Lz3 / Lz1∈[0.6, 1], Lz4 / Lz1∈[0.3, 0.6].

[0023] Furthermore,

[0024] Where n∈[0.1, 0.4], m∈[0.45, 1.2].

[0025] Furthermore, the blade is hollow inside to form a cavity, which extends through the rear cover along the axial direction of the centrifugal fan blade, and the cross-sectional area of ​​the cavity gradually increases along the direction close to the rear cover.

[0026] Furthermore, the blade wall thickness Hb≥2.5mm, and on the cross-section of the blade, the two end sidewalls of the cavity are treated with rounded corners, with a rounded corner radius Rd≥1.5mm.

[0027] Furthermore, the top of the first blade also includes a patch that fills the gap between the front cover and the top of the first blade; and / or, the centrifugal fan blade is a one-piece molded structure.

[0028] Furthermore, the front cover includes a straight arm section and an arc wall section, the top of which is connected to the straight arm section, and the arc wall section has an outwardly expanding arc-shaped structure.

[0029] Furthermore, the arc wall segment includes a first arc segment and a second arc segment. The first arc segment is connected to the straight arm segment and is tangent to the straight arm segment at the connection point. The second arc segment is located at the end of the arc wall segment, and the end of the second arc segment is tangent to a plane perpendicular to the axis of the centrifugal fan blade.

[0030] Furthermore, the first and second arc segments are connected and tangent at the connection point. The inner diameter of the front cover is Dq0, the outer diameter is Dq2, and the height is Hq0, where Hq1 / Hq0∈[0.3, 0.6], Hq0∈[30mm, 50mm], and Hq1∈[10mm, 30mm].

[0031] Furthermore, the rear cover includes a wheel hub with sound-dampening holes.

[0032] Furthermore, the cavity noise of the centrifugal fan blades is obtained by the following formula:

[0033]

[0034] Where f is the target silencing frequency in Hz; C is the speed of sound in air in m / s; n is the number of silencing holes in units; L is the cavity depth of the hub in meters; t is the actual wall thickness of the hub at the location of the silencing hole in meters; r is the radius of the silencing hole in meters; and R is the cavity radius of the hub in meters.

[0035] Furthermore, r∈[0.0025m, 0.025m], L∈[0.050m, 0.150m], n∈[4, 8], R∈[0.050m, 0.180m].

[0036] According to another aspect of the present invention, an embedded air conditioner is provided, including a centrifugal fan blade, which is the centrifugal fan blade described above.

[0037] Applying the technical solution of this invention, the centrifugal fan blade includes a front cover, blades, and a rear cover. The blades are connected between the front cover and the rear cover. The blades include a first blade and a second blade. The first blade is connected to the front cover, and the second blade is connected to the rear cover. The top surface of the second blade forms the bottom surface of the first blade. The top surface and the bottom surface of the second blade are parallel. The cross-section of the second blade is parallel to the bottom surface of the second blade. The cross-section of the second blade includes an inlet angle α, an outlet angle β, an inlet diameter D1, and an outlet diameter D2, where 30°≤α+β≤70°, α∈(0°, 30°], β∈[20°, 50°], and D1∈[260mm, 400mm]. [D2∈[400mm, 500mm]]. The design of characteristic parameters of the second blade, which is the main working area of ​​the centrifugal fan, has a great influence on the aerodynamic performance of the fan. By limiting the parameter range of the inlet angle, outlet angle, inlet diameter, and outlet diameter of the second blade located below the first blade, the parameter design of the second blade, which is the main working area, is optimized. The various parameters cooperate with each other, so that the parameter characteristics of the designed second blade can promote the aerodynamic performance of the fan, improve the aerodynamic performance of the fan, thereby increasing the air volume and efficiency of the fan, reducing noise, and ultimately improving the overall performance of the machine. Attached Figure Description

[0038] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0039] Figure 1 A partial cross-sectional view of an embedded air conditioner according to an embodiment of the present invention is shown;

[0040] Figure 2 A three-dimensional structural schematic diagram of a centrifugal fan blade according to an embodiment of the present invention is shown;

[0041] Figure 3 A cross-sectional structural schematic diagram of a centrifugal fan blade according to an embodiment of the present invention is shown;

[0042] Figure 4 A bottom view of the centrifugal fan blade according to an embodiment of the present invention is shown;

[0043] Figure 5 A side view of the centrifugal fan blade according to an embodiment of the present invention is shown;

[0044] Figure 6 A top view of the centrifugal fan blade according to an embodiment of the present invention is shown;

[0045] Figure 7 It shows Figure 6 A schematic diagram of the AA-direction cross-section structure;

[0046] Figure 8 It shows Figure 7 A magnified structural diagram at point Q;

[0047] Figure 9 A partially enlarged structural schematic diagram of the centrifugal fan blade according to an embodiment of the present invention is shown;

[0048] Figure 10 A schematic diagram of the blade structure of a centrifugal fan blade according to an embodiment of the present invention is shown;

[0049] Figure 11 A schematic diagram of the blade size structure of a centrifugal fan blade according to an embodiment of the present invention is shown;

[0050] Figure 12 A schematic diagram showing the dimensions and structure of the first cross-section of a centrifugal fan blade according to an embodiment of the present invention is shown.

[0051] Figure 13 This invention illustrates a schematic diagram of the dimensions and structure of the third cross-section of a centrifugal fan blade according to an embodiment of the present invention.

[0052] Figure 14 A schematic diagram showing the dimensions and structure of the blade cross-section helix angle of a centrifugal fan blade according to an embodiment of the present invention is shown;

[0053] Figure 15 A schematic diagram of the rear cover structure of the centrifugal fan blade according to an embodiment of the present invention is shown;

[0054] Figure 16 A comparison diagram of the rotational speed and airflow of a centrifugal fan blade according to an embodiment of the present invention and a centrifugal fan blade of a related art is shown.

[0055] Figure 17 A comparison diagram of airflow and noise levels between centrifugal fan blades of an embodiment of the present invention and centrifugal fan blades of related technologies is shown; and

[0056] Figure 18A comparison diagram of airflow and power between the centrifugal fan blades of this invention and centrifugal fan blades of related technologies is shown.

[0057] The above figures include the following reference numerals:

[0058] 1. Front cover; 2. Rear cover; 3. First blade; 4. Second blade; 5. First section; 6. Second section; 7. Third section; 8. Fourth section; 9. First segment; 10. Second segment; 11. Cavity; 12. Patch; 13. Straight arm segment; 14. Arc wall segment; 15. First arc segment; 16. Second arc segment; 17. Wheel hub; 18. Muffler hole. Detailed Implementation

[0059] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0060] See Figures 1 to 18 As shown, according to an embodiment of the present invention, the centrifugal fan blade includes a front cover 1, blades and a rear cover 2. The blades are connected between the front cover 1 and the rear cover 2. The blades include a first blade 3 and a second blade 4. The first blade 3 is connected to the front cover 1, and the second blade 4 is connected to the rear cover 2. The top surface of the second blade 4 forms the bottom surface of the first blade 3. The top surface of the second blade 4 is parallel to the bottom surface of the second blade 4. The cross section of the second blade 4 is parallel to the bottom surface of the second blade 4. The cross section of the second blade 4 includes an inlet angle α, an outlet angle β, an inlet diameter D1 and an outlet diameter D2, where 30°≤α+β≤70°, α∈(0°, 30°], β∈[20°, 50°], D1∈[260mm, 400mm], and D2∈[400mm, 500mm].

[0061] In the fan blade flow channel composed of blades, front cover 1, and rear cover 2, the inlet angle, outlet angle, inlet radius, and outlet radius of the blades affect the inlet angle, inlet velocity, outlet angle, outlet velocity, and airflow state within the fan blade flow channel. This has a significant impact on the aerodynamic performance of the fan blade, such as air volume, noise, and efficiency. The blades are the main working structure of the fan blade, and the design of the blade characteristic parameters has a significant impact on the aerodynamic performance of the fan blade. The front cover 1 and rear cover 2 can prevent airflow leakage within the fan blade flow channel and guide the direction of airflow entering and exiting the blades.

[0062] The design of the characteristic parameters of the second blade 4, which is the main working area of ​​the centrifugal fan, has a great influence on the aerodynamic performance of the fan. By limiting the parameter range of the inlet angle, outlet angle, inlet diameter, and outlet diameter of the second blade 4 located below the first blade 3, the parameter design of the second blade 4, which is the main working area, is optimized. The various parameters cooperate with each other, so that the parameter characteristics of the designed second blade 4 can promote the aerodynamic performance of the fan, improve the aerodynamic performance of the fan, thereby increasing the air volume and efficiency of the fan, reducing noise, and ultimately improving the overall performance of the machine.

[0063] In one embodiment, the blade is divided into an upper first blade 3 and a lower second blade 4. The first blade 3 and the second blade 4 are integrally formed. The bottom surface of the first blade 3 and the top surface of the second blade 4 are coplanar. The first blade 3 is inclined, and the second blade 4 is a vertical blade. The blade shape of the first blade 3 and the second blade 4 is configured by multiple cross sections and guide lines, and is controlled by parameters such as inlet angle, outlet angle, inlet radius, outlet radius, centerline, thickness distribution, tilt angle, and cross section height to obtain the required blade structure. This allows the blade structure to achieve the expected effect, which can improve the air volume and efficiency of the fan blade and reduce noise.

[0064] In one embodiment, the first blade 3 is tilted away from the suction surface relative to the second blade 4, which can alleviate the impact of air intake and recirculation on the blade and reduce flow separation in the airflow channel.

[0065] The second blade 4 is a vertical blade, meaning that the projections of the centerlines of the second blade 4 at various heights on the horizontal plane coincide, i.e., there is no rotation or offset. Since the second blade 4 requires a draft angle, its thickness needs to decrease from bottom to top. To ensure consistent thickness of the second blade 4 at different heights along the same longitudinal direction, and to guarantee a good draft angle, the difference between the maximum and minimum thickness of the second blade 4 at different heights along the same longitudinal direction is less than or equal to 2 mm.

[0066] The cross-section of the centrifugal fan blades is as follows: Figure 11 As shown, each cross-section is composed of parameters such as blade inlet angle α, outlet angle β, inlet diameter D1, outlet diameter D2, centerline, and thickness distribution. The inlet diameter of the centrifugal fan blade is D1, and its radius is the shortest radial distance between the fan blade axis and the centerline. The outlet diameter of the centrifugal fan blade is D2, and its radius is the farthest radial distance between the fan blade axis and the centerline. The inlet angle α of the centrifugal fan blade is the angle between the two tangents drawn from the intersection of the centerline and the inlet circle. The outlet angle β of the centrifugal fan blade is the angle between the two tangents drawn from the intersection of the centerline and the outlet circle.

[0067] In this embodiment, the bottom surface of the second blade 4 is parallel to the horizontal plane. Therefore, the bottom surface of the second blade 4 can be used as a reference surface to define the parameter characteristics of each section of the second blade 4. The structural characteristics of the blade are defined by the relationship between the parameter characteristics of the bottom surface and the top surface of the second blade 4, so that the designed blade can meet the design requirements.

[0068] In one embodiment, the centerline of the centrifugal fan blade is an arc with a radius of Rz. A circle with a radius of RL is drawn with a point on the centerline as the center. This circle can be tangent to the blade profiles on both sides of the centerline and is called the base circle.

[0069] In one embodiment, the bottom surface of the second blade 4 forms a first cross section 5, and the top surface of the second blade 4 forms a third cross section 7. The inlet angle of the first cross section 5 is α1, the outlet angle is β1, the inlet diameter is D11, and the outlet diameter is D21. The inlet angle of the third cross section 7 is α2, the outlet angle is β2, the inlet diameter is D12, and the outlet diameter is D22, where α1 < α2, β1 = β2, D11 < D12, and D21 = D22.

[0070] In this embodiment, the inlet angle α1 of the first section 5 is set to be smaller than the inlet angle α2 of the third section 7, the inlet diameter D11 of the first section 5 is set to be smaller than the inlet diameter D12 of the third section 7, and the outlet angle β1 of the first section 5 is equal to the outlet angle β2 of the third section 7. The outlet diameter D21 of the first section 5 is equal to the outlet diameter D22 of the third section 7. This makes the pressure loss on the side of the third section 7 near the air inlet of the fan blade less than the pressure loss on the side of the first section 5 away from the air inlet of the fan blade. This balances the problem of inconsistent pressure loss caused by inconsistent distance from the air inlet of the fan blade, making the pressure loss deviation at various positions after flowing through the blade smaller. Since the outlet angle of the blade is basically the same at different positions in the entire axial direction, the air pressure entering the fan blade is basically the same, which can ensure that the air pressure distribution blown out of the air outlet is more balanced, thereby improving the consistency of the centrifugal fan blade outlet pressure, improving the outlet efficiency, and reducing the outlet noise.

[0071] In one embodiment, 30°≤α1+β1≤60°, α1∈(0°, 30°], β1∈[20°, 50°], D11∈[260mm, 350mm], D21∈[400mm, 500mm].

[0072] In one embodiment, 40°≤α1+β1≤60°, α1∈(0°, 15°], β1∈[30°, 50°], D11∈[260mm, 350mm], D21∈[400mm, 500mm].

[0073] In one embodiment, 45°≤α2+β2≤70°, α2∈[0°, 30°], β2∈[20°, 50°], D11∈[300mm, 400mm], D21∈[400mm, 500mm].

[0074] In one embodiment, 45°≤α2+β2≤65°, α1∈[5°, 20°], β1∈[30°, 50°], D11∈[300mm, 400mm], D21∈[400mm, 500mm].

[0075] In one embodiment, the bottom surface of the second blade 4 forms a first section 5, and the top surface of the second blade 4 forms a third section 7. The projections of the centerlines of the first section 5 and the third section 7 onto the first section 5 coincide.

[0076] Since the projections of the centerlines of the first section 5 and the third section 7 onto the first section 5 coincide, and the first section 5 is a horizontal plane, when the projections of the centerlines of each section located between the first section 5 and the third section 7 onto the first section 5 coincide with the centerline of the first section 5, it indicates that the centerline plane formed by the centerlines of each section of the second blade 4 is perpendicular to the horizontal plane, that is, the second blade 4 is a vertical blade.

[0077] The vertically arranged second blade 4, together with the inclined first blade 3, can both reduce the impact of air intake and return on the blades, reduce flow separation in the blade channel, and improve airflow efficiency, and ensure the working efficiency of the blades, increase the air volume and efficiency of the blades, and reduce the noise of the exhaust.

[0078] In one embodiment, the second blade 4 includes a first segment 9 and a second segment 10. The first segment 9 is formed by extending a first cross section 5 along a guide line to form a first segment. The second segment 10 is formed by extending a second cross section 6 along a guide line to form a second segment. The second cross section 6 is parallel to the first cross section 5, and the projections of the midlines of the first cross section 5 and the second cross section 6 onto the first cross section 5 coincide. The first cross section 5 is the same as the second cross section 6, and the area of ​​the third cross section 7 is smaller than the area of ​​the second cross section 6.

[0079] In one embodiment, the height difference between the first section 5 and the second section 6 in the axial direction of the centrifugal fan blade is Hy1, where Hy1 ∈ [10 mm, 50 mm].

[0080] The second section 6 is positioned within a preset height range, specifically within the height range [10mm, 50mm] from the bottom surface of the blade, i.e., the first section 5. This is because the closer to the blade bottom, the lower the axial velocity of the airflow within the blade, resulting in less airflow loss and a larger flow rate in the horizontal section of the blade channel. Conversely, the higher the section, the greater the axial velocity of the airflow within the blade channel, leading to greater airflow loss and a smaller flow rate. Based on this characteristic, the length of the blade bottom section is increased to enhance airflow while minimizing bottom flow loss; conversely, the length of the top section is reduced to decrease airflow and minimize flow loss. Within a certain height range at the blade bottom, flow loss is relatively low. Therefore, the first section 5 and the second section 6 are designed to be identical within this height range to maximize the benefits of this characteristic and improve blade performance.

[0081] In one embodiment, taking the centerline endpoint of the blade inlet position of the first section 5 as the starting point, the centerline length of the first section 5 is Lz1, and the second blade 4 after the centerline length of (0~0.3)Lz1, the projections of the first section 5 and the third section 7 on the first section 5 coincide.

[0082] In this embodiment, along the direction from the first section 5 to the third section 7, the centerline length of each section gradually decreases. Within the centerline length range of (0 to 0.3)Lz1, the area and size of different sections are different, belonging to the variation region of the blade. In the region after the centerline length of (0 to 0.3)Lz1, the structure of each section is the same, so that within the same longitudinal section perpendicular to the centerline of the section, the thickness of each section at different heights is the same. This makes the blade profile of the third section 7 of the centrifugal fan blade coincide with that of the first section 5 within a certain centerline length range on the horizontal projection plane. That is, the blade has the same thickness at different heights, resulting in greater work efficiency and effectively improving the aerodynamic performance of the fan blade.

[0083] In one embodiment, the top surface of the first blade 3 forms a fourth section 8. The centerlines of the first section 5, the second section 6, the third section 7, and the fourth section 8 are all arcs, and the centerline radius of each section is Rz. The intersection of the centerline of each section with the outlet circle of the centrifugal fan blade coincides with the projection point on the first section 5. The centerline length of the first section 5 is Lz1, the centerline length of the second section 6 is Lz2, the centerline length of the third section 7 is Lz3, and the centerline length of the fourth section 8 is Lz4. Lz1 = Lz2, Lz3 / Lz1 ∈ [0.6, 1], and Lz4 / Lz1 ∈ [0.3, 0.6].

[0084] The centerline serves as the reference for blade configuration, defining the position and length of the cross-section. Controlling the length, position, and shape of the centerline makes it easier to achieve the blade configuration and meet the requirements for one-piece blade molding.

[0085] In one embodiment, the top surface of the first blade 3 forms a fourth section 8, the structure of the first blade 3 is controlled by the third section 7 and the fourth section 8, the structure of the second blade 4 is controlled by the first section 5 and the second section 6, the height difference between the first section 5 and the second section 6 in the axial direction of the centrifugal fan blade is Hy1, the height difference between the first section 5 and the third section 7 in the axial direction of the centrifugal fan blade is Hy2, the height difference between the third section 7 and the fourth section 8 in the axial direction of the centrifugal fan blade is Hy, the height of the blade in the axial direction of the centrifugal fan blade is Hy, and the total height of the centrifugal fan blade in the axial direction of the centrifugal fan blade is H0, where Hy = Hy2 + Hy3, Hy2 / Hy ∈ [0.6, 0.9], Hy1 / Hy2 ∈ [0.1, 0.4], Hy / H0 ∈ [0.8, 1], Hy2 ∈ [90mm, 110mm], and Hy3 ∈ [20mm, 40mm].

[0086] By controlling the cross-section, the blade shape can be better constructed and meet the conditions for one-piece molding.

[0087] In one embodiment, the cross-sectional profile of the blade constitutes the blade profile at the cross-section, and the blade cross-sectional thickness distribution of the centrifugal fan blade is the perpendicular distance between the blade profile and the centerline. The shape of the blade profile is controlled by a polynomial parametric equation related to the centerline length, which is the blade profile equation as follows:

[0088] x=f(τ=L z *τ 5 +b1*τ 4 *(1-τ)+c1*τ 3 *(1-τ) 2 +d1*τ 2 *(1-τ) 3 +e1*τ*(1-τ) 4 ,

[0089] y = f(τ) = 1.25 * τ 5 +b2*τ 4 *(1-τ)+c2*τ 3 *(1-τ) 2 +d2*τ 2 *(1-τ) 3 +e2*τ*(1-τ) 4 ,

[0090] Where x is the abscissa of the profile, y is the ordinate of the profile, Lz is the centerline length of the section, b1∈[474.2, 484.2], c1∈[552, 572], d1∈[190, 210], e1∈[22.5, 32.5], b2∈[9.5, 19.5], c2∈[25, 45], d2∈[130, 150], e2∈[30, 40], τ∈[0, 1].

[0091] The blade cross-sectional profile controlled by polynomials can ensure that the distance from the centerline is equal on both sides of the centerline, and at the same time control the profiles of multiple cross-sections to be equidistant from the centerline. The blade cross-sectional profile controlled by polynomials is convex in front and concave in the back, which increases the blade inlet pressure, reduces the pressure gradient, reduces turbulent kinetic energy, and improves the blade efficiency.

[0092] In one embodiment, the cross-sectional helix angle of the first blade 3 relative to the second blade 4 is θ, the height of the first blade 3 along the axial direction of the centrifugal fan blade is Hy3, the bottom surface of the second blade 4 forms a first cross-section 5, the top surface of the second blade 4 forms a third cross-section 7, the top surface of the first blade 3 forms a fourth cross-section 8, the centerline length of the first cross-section 5 is Lz1, the centerline length of the third cross-section 7 is Lz3, the centerline length of the fourth cross-section 8 is Lz4, Hy3∈[20,40], Lz3 / Lz1∈[0.6,1], Lz4 / Lz1∈[0.3,0.6].

[0093] The first blade 3 has a certain tilt angle, which mainly reduces the axial impact of air entering through the guide ring and the backflow between the blade and the guide ring. The second blade 4 is the main working area of ​​the blade, and its cross-sectional length decreases from top to bottom. This is also to follow the law that the axial wind speed of the blade decreases from top to bottom, increase the effective work, and improve the efficiency of the fan.

[0094] In one embodiment,

[0095] Where n∈[0.1, 0.4], m∈[0.45, 1.2].

[0096] The cross-sectional helix angle θ tilts the first blade 3 at a certain angle, which can reduce the axial impact of air entering through the guide ring and the backflow from the gap between the blade and the guide ring. θ is designed based on the angle of axial impact, which can better reduce flow loss and improve the efficiency of the fan.

[0097] In this embodiment, the cross-sectional rotation angle θ of the centrifugal fan blade is the angle between the tangent line to the centerline drawn from the intersection of the centerlines of the third cross-section 7 and the fourth cross-section 8 and the outlet circle on the horizontal projection plane.

[0098] In one embodiment, the blade is hollow to form a cavity 11, which extends through the rear cover 2 along the axial direction of the centrifugal fan blade, and the cross-sectional area of ​​the cavity 11 gradually increases along the direction close to the rear cover 2.

[0099] The blade wall thickness Hb≥2.5mm. On the cross-section of the blade, the two end sidewalls of cavity 11 are rounded, with a radius Rd≥1.5mm.

[0100] The centrifugal fan blades are internally shelled and connected to the bottom of the blades. The blade wall thickness Hb ≥ 2.5 mm is required. The two ends of the shelled part are rounded with a radius Rd ≥ 1.5 mm. The blade wall thickness should be made as thin as possible to avoid inversion, so as to facilitate injection molding and reduce the weight of the fan blades and the amount of raw materials used.

[0101] In one embodiment, the top of the first blade 3 further includes a patch 12, which fills the gap between the front cover 1 and the top of the first blade 3.

[0102] In this embodiment, by adding a supplementary block 12 in the gap between the first blade 3 and the front cover 1, the supplementary block is located above the first blade 3 and below the front cover 1. The supplementary block 12 can fill the gap between the first blade 3 and the front cover 1, thereby avoiding the inverted phenomenon when the wind blade adopts an integrated molding structure, and ensuring that the wind blade can be smoothly demolded when it is integrally molded.

[0103] In one embodiment, the centrifugal fan blade adopts an integral molding structure, with the front cover 1, blades, and rear cover 2 being integrally injection molded. Through the above structural modification, the defect that the existing centrifugal fan blade cannot be integrally injection molded can be eliminated, enabling the integral injection molding of the centrifugal fan blade to be realized, allowing the overall structure to be demolded, and possessing better structural and aerodynamic performance.

[0104] In one embodiment, the front cover 1 includes a straight arm section 13 and an arc wall section 14, the top end of the arc wall section 14 being connected to the straight arm section 13, and the arc wall section 14 having an outwardly expanding arc-shaped structure.

[0105] The arc-shaped wall section 14 of the front cover 1 can reduce the flow loss of the centrifugal fan blades and reduce flow separation in the fan blade flow channel, thereby increasing air volume and reducing noise.

[0106] In one embodiment, the arc wall segment 14 includes a first arc segment 15 and a second arc segment 16. The first arc segment 15 is connected to the straight arm segment 13 and is tangent to the straight arm segment 13 at the connection position. The second arc segment 16 is located at the end of the arc wall segment 14, and the end of the second arc segment 16 is tangent to a plane perpendicular to the axis of the centrifugal fan blade.

[0107] Since the arc-shaped wall section 14 and the straight arm section 13 are tangent at the connection point, and the various arc segments constituting the arc-shaped wall section 14 are also tangent at the connection point, the smoothness of the airflow along the wall is increased, the flow resistance is reduced, and the airflow efficiency is improved. Furthermore, since the first arc segment 15 is tangent to the straight arm section 13, and the end of the second arc segment 16 is tangent to the horizontal direction, the tangent line of the first arc segment at the connection point with the straight arm section 13 is perpendicular to the tangent line of the end of the second arc segment 16. This allows for a 90° turn in the airflow direction. Due to the use of an arc structure, flow losses during the airflow turning process are reduced, ensuring the airflow efficiency.

[0108] In one embodiment, the first arc segment 15 and the second arc segment 16 are connected and tangent at the connection point. The inner diameter of the front cover 1 is Dq0, the outer diameter is Dq2, and the height is Hq0, where Hq1 / Hq0∈[0.3, 0.6], Hq0∈[30mm, 50mm], and Hq1∈[10mm, 30mm].

[0109] Since the fan blades are axially inlet and circumferentially outlet, the airflow direction changes more as the rotation radius increases. Designing the front cover as an arc structure can guide the change in airflow direction, reduce airflow separation and negative pressure zone under the front cover of the fan blades, reduce duct blockage, increase air volume and improve fan efficiency.

[0110] In one embodiment, the rear cover 2 includes a hub 17, on which a noise reduction hole 18 is provided.

[0111] The hub 17 in the rear cover 2 can guide the airflow before it enters the blade channel, and reduce the axial impact of the airflow on the rear cover 2, thus reducing energy loss. In addition, the hub 17 is designed with a sound-absorbing hole 18, which can prevent the formation of a cavity at the bottom of the hub 17 and cause cavity resonance, thereby playing a role in noise reduction.

[0112] In one embodiment, the cavity noise of the centrifugal fan blades is obtained by the following formula:

[0113]

[0114] Where f is the target silencing frequency in Hz; C is the speed of sound in air in m / s; n is the number of silencing holes in units; L is the cavity depth of hub 17 in m; t is the actual wall thickness of hub at the location of silencing hole 18 in m; r is the radius of silencing hole in m; and R is the cavity radius of hub 17 in m.

[0115] In one embodiment, r∈[0.0025m, 0.025m], L∈[0.05m, 0.15m], n∈[4, 8], R∈[0.05m, 0.18m].

[0116] By using the above formula and the data range defined by each parameter, the commutation noise frequency f can be kept between [100, 400] Hz when the motor speed of the centrifugal fan is below 1000 r / min, which effectively controls the working noise of the centrifugal fan and reduces noise pollution.

[0117] In one embodiment, the fan blade outlet has the same diameter at both the top and bottom, meaning the fan blade outlet diameter is the same at all height positions, and the outer diameter of the front cover 1 is equal to the outer diameter of the rear cover 2.

[0118] See also Figures 16 to 18 As shown, by comparing the centrifugal fan blades of the present invention embodiment with those of related technologies, it can be seen that after structural optimization, the centrifugal fan blade of the present invention has an air volume 100m higher than that of the centrifugal fan blades of related technologies at the same rotational speed. 3 / h; the noise level is reduced by 1.5dB compared to centrifugal fan blades in related technologies at the same air volume; the power consumption is reduced by 5W compared to centrifugal fan blades in related technologies at the same air volume, and the air output efficiency, air volume, noise and power are all effectively improved.

[0119] According to an embodiment of the present invention, the embedded air conditioner includes a centrifugal fan blade, which is the centrifugal fan blade described above.

[0120] Centrifugal fan blades Figure 1 As shown, its position is at the center of the whole machine. The air inlet end has a guide ring to guide the axial air intake. The air outlet end is equipped with heat exchange damping components such as PTC and evaporator. The air outlet duct of the whole machine guides the airflow to exit from all sides upwards. The air intake and air outlet directions of the whole machine have a 180° turn, and the centrifugal fan blades also have a 90° turn from axial to circumferential from air intake to air outlet.

[0121] Centrifugal fan blades Figure 2 As shown, it consists of a front cover 1, blades, and a rear cover 2. The front cover 1 is located at the air inlet of the fan blade. The inner diameter of the front cover 1 is the fan blade inlet diameter D0, and the outer diameter is the fan blade outlet diameter D2. The blades are located between the front cover 1 and the rear cover 2. Their outlet diameter is the fan blade outlet diameter D2, and their outlet height is the fan blade outlet height H1. The front cover 1 and the rear cover 2 form the blade flow channel, which is the main working structure of the fan blade. The airflow entering the blades is pressurized and accelerated through the blade flow channel before flowing out of the fan blades. The hub 17 in the rear cover 2 can play a guiding role. It guides the airflow entering the fan blades to change direction before entering the blade flow channel, and reduces the axial impact of the airflow entering the rear cover 2, thereby reducing energy loss. In addition, the hub 17 is designed with a sound-absorbing hole 18 to avoid the formation of a cavity at the bottom of the hub 17, which would cause cavity resonance and play a role in noise reduction.

[0122] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0123] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A centrifugal fan blade, characterized in that, Includes a front cover (1), blades, and a rear cover (2). The blades are connected between the front cover (1) and the rear cover (2). The blades include a first blade (3) and a second blade (4). The first blade (3) is connected to the front cover (1), and the second blade (4) is connected to the rear cover (2). The top surface of the second blade (4) forms the bottom surface of the first blade (3). The top surface of the second blade (4) is parallel to the bottom surface of the second blade (4). The cross-section of the second blade (4) is parallel to the bottom surface of the second blade (4). The cross-section of the second blade (4) includes an inlet angle α, an outlet angle β, an inlet diameter D1, and an outlet diameter D2, where 30°≤α+β≤70°, α∈(0°, 30°], β∈[20°, 50°], D1∈[260mm, 400mm], D2∈[400mm, 500mm]; The bottom surface of the second blade (4) forms the first section (5), and the top surface of the second blade (4) forms the third section (7). The inlet angle of the first section (5) is α1, the outlet angle is β1, the inlet diameter is D11, and the outlet diameter is D21. The inlet angle of the third section (7) is α2, the outlet angle is β2, the inlet diameter is D12, and the outlet diameter is D22. α1<α2, β1=β2, D11<D12, D21=D22; The projections of the centerlines of the first section (5) and the third section (7) onto the first section (5) coincide.

2. The centrifugal fan blade according to claim 1, characterized in that, 30°≤α1+β1≤60°, α1∈(0°, 30°], β1∈[20°, 50°], D11∈[260 mm, 350 mm], D21∈[400 mm, 500 mm].

3. The centrifugal fan blade according to claim 1, characterized in that, 45°≤α2+β2≤70°, α2∈[0°, 30°], β2∈[20°, 50°], D11∈[300 mm, 400 mm], D21∈[400 mm, 500 mm].

4. The centrifugal fan blade according to claim 1, characterized in that, The second blade (4) includes a first segment (9) and a second segment (10). The first segment (9) is formed by extending the first cross section (5) along the guide line to form a first segment. The second segment (10) is formed by extending the second cross section (6) along the guide line to form a second segment. The second cross section (6) is parallel to the first cross section (5), and the projections of the midlines of the first cross section (5) and the second cross section (6) on the first cross section (5) coincide. The first cross section (5) is the same as the second cross section (6). The area of ​​the third cross section (7) is smaller than the area of ​​the second cross section (6).

5. The centrifugal fan blade according to claim 4, characterized in that, Starting from the centerline endpoint of the blade inlet position of the first section (5), the centerline length of the first section (5) is Lz1. In the second blade (4) after the centerline length of (0~0.3)Lz1, the projection of the first section (5) and the third section (7) on the first section (5) coincides.

6. The centrifugal fan blade according to claim 4, characterized in that, The top surface of the first blade (3) forms a fourth section (8). The centerlines of the first section (5), the second section (6), the third section (7) and the fourth section (8) are all arcs, and the centerline radius of each section is Rz. The projection point of the intersection of the centerline of each section and the outlet circle of the centrifugal fan blade on the first section (5) coincides. The centerline length of the first section (5) is Lz1, the centerline length of the second section (6) is Lz2, the centerline length of the third section (7) is Lz3, and the centerline length of the fourth section (8) is Lz4. Lz1 = Lz2, Lz3 / Lz1 ∈ [0.6, 1], and Lz4 / Lz1 ∈ [0.3, 0.6].

7. The centrifugal fan blade according to claim 4, characterized in that, The top surface of the first blade (3) forms a fourth section (8). The height difference between the first section (5) and the second section (6) in the axial direction of the centrifugal fan blade is Hy1. The height difference between the first section (5) and the third section (7) in the axial direction of the centrifugal fan blade is Hy2. The height difference between the third section (7) and the fourth section (8) in the axial direction of the centrifugal fan blade is Hy3. The height of the blade in the axial direction of the centrifugal fan blade is Hy. The total height of the centrifugal fan blade in the axial direction of the centrifugal fan blade is H0. Where Hy = Hy2 + Hy3, Hy2 / Hy ∈ [0.6, 0.9], Hy1 / Hy2 ∈ [0.1, 0.4], Hy / H0 ∈ [0.8, 1], Hy2 ∈ [90mm, 110mm], Hy3 ∈ [20mm, 40mm].

8. The centrifugal fan blade according to claim 4, characterized in that, The height difference between the first section (5) and the second section (6) in the axial direction of the centrifugal fan blade is Hy1, where Hy1 ∈ [10 mm, 50 mm].

9. The centrifugal fan blade according to any one of claims 1 to 3, characterized in that, The cross-sectional profile of the blade constitutes the blade profile at the cross-section, and the blade profile equation is: x = f(τ) = L z t 5 + b1 t 4 (1-τ) + c1 t 3 (1-t) 2 + d1 t 2 (1-t) 3 + e1 t (1-t) 4 , y = f(τ) = 1.25 t 5 + b2 t 4 (1-τ)+ c2 t 3 (1-t) 2 + d2 t 2 (1-t) 3 + e2 t (1-t) 4 , Where x is the abscissa of the profile, y is the ordinate of the profile, Lz is the centerline length of the cross section, b1∈[474.2, 484.2], c1∈[552, 572], d1∈[190, 210], e1∈[22.5, 32.5], b2∈[9.5, 19.5], c2∈[25, 45], d2∈[130, 150], e2∈[30, 40], τ∈[0, 1].

10. The centrifugal fan blade according to any one of claims 1 to 3, characterized in that, The first blade (3) is tilted away from the suction surface relative to the second blade (4).

11. The centrifugal fan blade according to claim 10, characterized in that, The cross-sectional helix angle of the first blade (3) relative to the second blade (4) is θ, the height of the first blade (3) along the axial direction of the centrifugal fan blade is Hy3, the bottom surface of the second blade (4) forms a first cross-section (5), the top surface of the second blade (4) forms a third cross-section (7), the top surface of the first blade (3) forms a fourth cross-section (8), the centerline length of the first cross-section (5) is Lz1, the centerline length of the third cross-section (7) is Lz3, the centerline length of the fourth cross-section (8) is Lz4, Hy3∈[20mm, 40mm], Lz3 / Lz1∈[0.6, 1], Lz4 / Lz1∈[0.3, 0.6].

12. The centrifugal fan blade according to claim 11, characterized in that, ， Where n∈[0.1, 0.4], m∈[0.45, 1.2].

13. The centrifugal fan blade according to any one of claims 1 to 3, characterized in that, The blade is hollow to form a cavity (11), which penetrates the rear cover (2) along the axial direction of the centrifugal fan blade, and the cross-sectional area of ​​the cavity (11) gradually increases along the direction close to the rear cover (2).

14. The centrifugal fan blade according to claim 13, characterized in that, The blade wall thickness Hb≥2.5mm, and the two end sidewalls of the cavity (11) on the cross-section of the blade are rounded with a radius Rd≥1.5mm.

15. The centrifugal fan blade according to any one of claims 1 to 3, characterized in that, The top of the first blade (3) also includes a patch (12) that fills the gap between the front cover (1) and the top of the first blade (3); and / or, the centrifugal fan blade is an integrally formed structure.

16. The centrifugal fan blade according to any one of claims 1 to 3, characterized in that, The front cover (1) includes a straight arm section (13) and an arc wall section (14). The top end of the arc wall section (14) is connected to the straight arm section (13), and the arc wall section (14) has an outwardly expanding arc structure.

17. The centrifugal fan blade according to claim 16, characterized in that, The arc wall segment (14) includes a first arc segment (15) and a second arc segment (16). The first arc segment (15) is connected to the straight arm segment (13) and is tangent to the straight arm segment (13) at the connection position. The second arc segment (16) is located at the end of the arc wall segment (14), and the end of the second arc segment (16) is tangent to a plane perpendicular to the axis of the centrifugal fan blade.

18. The centrifugal fan blade according to claim 17, characterized in that, The first arc segment (15) and the second arc segment (16) are connected and tangent at the connection position. The inner diameter of the front cover (1) is Dq0, the outer diameter is Dq2, and the height is Hq0, where Hq1 / Hq0∈[0.3, 0.6], Hq0∈[30mm, 50mm], and Hq1∈[10mm, 30mm].

19. The centrifugal fan blade according to any one of claims 1 to 3, characterized in that, The rear cover (2) includes a hub (17) on which a noise reduction hole (18) is provided.

20. The centrifugal fan blade according to claim 19, characterized in that, The cavity noise of the centrifugal fan blades is the target noise reduction frequency. Target silencing frequency It can be obtained through the following formula: ， in , where is the target silencing frequency in Hz; C is the speed of sound in air in m / s; n is the number of silencing holes in units; L is the cavity depth of the hub (17) in m; t is the actual wall thickness of the hub at the location of the muffler hole (18), in meters; r is the radius of the muffler hole, in meters; R is the cavity radius of the hub (17), in meters.

21. The centrifugal fan blade according to claim 20, characterized in that, r∈[0.0025m, 0.025m], L∈[0.050m, 0.150m], n∈[4, 8], R∈[0.050m, 0.180m].

22. An embedded air conditioner, comprising centrifugal fan blades, characterized in that, The centrifugal fan blade is the centrifugal fan blade according to any one of claims 1 to 21.

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