A high-speed centrifugal fan with biomimetic backward-curved airfoil blades

Abstract

This invention relates to the centrifugal fan industry, and particularly to a high-speed centrifugal fan with biomimetic backward-curved airfoil blades. The fan includes a volute, an impeller, and a collector, with the volute and collector fixedly connected. Both the impeller and collector are housed within the volute. The impeller comprises a front plate and a rear plate. An air intake is located in the center of the front plate, and multiple blades are arranged in a circular array around the rear plate. The blades are biomimetic backward-curved airfoil sheet metal structures, each blade including a leading edge, a trailing edge, a first side connecting the first ends of the leading and trailing edges, and a second side connecting the second ends of the leading and trailing edges. The first side is closer to the air intake, and the second side is farther from the air intake. The leading edge includes a leading edge arc segment connected to the first side and a leading edge straight segment connected to the second side. The leading edge straight segment is parallel to the trailing edge. From the leading edge to the trailing edge, the blade thickness gradually increases and then gradually decreases. The centrifugal fan of this invention has higher fan efficiency and lower fan noise.

Description

Technical Field

[0001] This invention relates to the centrifugal fan industry, and in particular to a high-speed centrifugal fan with biomimetic backward-curved airfoil blades. Background Technology

[0002] Centrifugal fans are essential auxiliary equipment in industrial production, widely used in civilian and military fields such as thermal power generation, petrochemicals, coal mining, and shipbuilding. Their actual operating conditions directly affect the safety and economy of industrial production. The airflow inside the fan is a complex three-dimensional, viscous, surging, and unsteady flow. The impeller is the key component determining the fan's performance. The impeller's rotation generates energy to draw gas into the fan, where it is then guided by the volute casing to form a gas transport process. Therefore, a well-designed impeller will result in better fan performance, enabling centrifugal fans to achieve higher efficiency and lower noise.

[0003] For centrifugal fans, variations in the flow area, curvature, and volute profile within the impeller's blade passages all contribute to non-uniformity in the flow field parameters. Simultaneously, the continuous impact of the airflow from the blade passages on the volute interior, along with the viscosity and boundary layer on the blade surfaces, causes phenomena such as boundary layer separation, secondary flow, jets, and wakes. These all result in flow channel losses for the fan, primarily from friction, viscosity, separation, and impact losses on the blade surfaces, thus affecting the impeller's output efficiency.

[0004] Blades are a crucial component of the impeller, and their shape and structure directly affect the overall performance of the fan. To improve the performance of centrifugal fans, domestic and international R&D teams have conducted extensive research on the shape and structure of airfoil blades, combining biomimetic theories, including changing the blade shape to reduce drag. However, currently available backward-curved high-speed centrifugal fans still suffer from inefficiency and high noise levels.

[0005] Therefore, the performance of existing backward high-speed centrifugal fans needs further optimization. Summary of the Invention

[0006] The purpose of this invention is to provide a high-speed centrifugal fan with biomimetic backward-curved airfoil blades, aiming to solve the problems of low efficiency and high noise in existing backward-curved high-speed centrifugal fans.

[0007] To achieve the above objectives, the present invention provides a high-speed centrifugal fan with biomimetic backward-curved blades, including a volute, an impeller, and a collector. The volute and the collector are fixedly connected, and both the impeller and the collector are disposed inside the volute. The impeller includes a front plate and a rear plate. An air inlet is provided in the middle of the front plate, and multiple blades are arranged in an array around the rear plate.

[0008] The blade is a biomimetic backward-curved sheet metal structure. The blade includes a leading edge, a trailing edge, a first side connecting the first end of the leading edge and the trailing edge, and a second side connecting the second end of the leading edge and the trailing edge. The first side is the side closer to the air inlet, and the second side is the side farther away from the air inlet. The leading edge includes a leading edge arc segment connected to the first side and a leading edge straight segment connected to the second side. The leading edge straight segment is parallel to the trailing edge. From the leading edge to the trailing edge, the thickness of the blade gradually increases and then gradually decreases.

[0009] On the projection surface of the rear disc, the first side includes a first arc segment, a first straight segment, and a second straight segment arranged sequentially. A second transition connection is provided between the first arc segment and the second straight segment, and a first transition connection is provided between the first straight segment and the second straight segment.

[0010] The inlet angle ∠2 during blade installation is 18.5°-19.5°, and the outlet angle ∠3 during blade installation is 56°-58°.

[0011] The collector extends into the impeller, and a radial clearance is provided between the collector and the impeller;

[0012] There are 10 leaves.

[0013] Furthermore, with the impeller diameter φ4 being 510mm, on the projection surface of the rear disc:

[0014] The diameter φ8 of the circle formed by the intersection of the first arc segment of the side and the extension of the second straight segment of the side is 517.5mm-522.5mm; the diameter φ6 of the circle formed by the intersection of the first straight segment of the side and the extension of the second straight segment of the side is 291.5mm-294.5mm; and the diameter φ7 of the circle formed by the intersection of the first arc segment of the side and the first straight segment of the side is 419mm-423mm.

[0015] The radius R4 of the first arc segment on the side is 298mm-302mm and the arc length is 118.5mm-125mm. The length L5 of the first straight segment on the side is 62mm-64mm. The length L6 of the second straight segment on the side is 180mm-184mm. The radius R5 of the second transition connection is 2.4mm-2.6mm and the arc length is 7.0mm-7.4mm. The radius R6 of the first transition connection is 0.95mm-1.05mm and the arc length is 2.9mm-3.1mm.

[0016] Furthermore, the diameter of the air intake φ5 is 333.5mm-336.5mm, and the vertical distance L4 between the air intake and the rear plate is 228mm-232mm;

[0017] The impeller is sectioned by a plane passing through its central axis. On the cross-section:

[0018] From the leading edge to the trailing edge, the cross-section of the front plate includes the first straight section of the front plate, the arc section of the front plate, the second straight section of the front plate, and the outer edge flange arranged sequentially. The length L13 of the first straight section of the front plate is 5.5mm-5.9mm, the radius R3 of the arc section of the front plate is 68.8mm-71.2mm and the arc length is 96mm-99mm, the length L14 of the second straight section of the front plate is 23.7mm-24.7mm, and the included angle ∠5 between the second straight section of the front plate and the rear plate is 9.6°-10.4°.

[0019] The outer edge flange includes an outer edge flange straight section and an outer edge flange arc section connecting the outer edge flange straight section and the second straight section of the front plate. The outer edge flange arc section is tangent to both the outer edge flange straight section and the second straight section of the front plate. The outer edge straight section is parallel to the tail edge. The radius R12 of the outer edge flange arc section is 4.9mm-5.1mm and the arc length is 8.5mm-8.9mm. The length L15 of the outer edge flange straight section is 9.6mm-10.2mm.

[0020] The radius R2 of the leading edge arc segment is 54mm-56mm and the arc length is 55.1mm-57.1mm. The length L2 of the leading edge straight segment is 149.5mm-153mm, and the length L3 of the trailing edge is 149.5mm-153mm.

[0021] Furthermore, ∠2 is 19°, ∠3 is 57°, φ8 is 520mm, φ6 is 293mm, φ7 is 421mm, R4 is 300mm with an arc length of 121.6mm, L5 is 63mm, L6 is 182mm, R5 is 2.5mm with an arc length of 7.2mm, R6 is 1.0mm with an arc length of 3.0mm, φ5 is 335mm, L4 is 230mm, R3 is 70mm with an arc length of 97.7mm, L14 is 24.2mm, ∠5 is 10.0°, R12 is 5.0mm with an arc length of 8.7mm, L15 is 9.9mm, R2 is 55mm with an arc length of 56.1mm, L2 is 151mm, and L3 is 151mm.

[0022] Furthermore, the collector includes a connecting part and an air guide part. The collector is fixedly connected to the volute through the connecting part, and the air guide part extends into the front disc of the impeller. The connecting part is annular and has an air inlet formed on its inner circumference.

[0023] The air guide section includes a straight section connected to the connecting section and an arc section of the air guide section away from the connecting section. The outlet of the arc section of the air guide section forms a funnel-shaped air guide.

[0024] From the air inlet to the air guide, the diameter of the air guide gradually decreases and then gradually increases.

[0025] Furthermore, the collector is sectioned using a plane passing through its central axis. In the cross-section:

[0026] The diameter of the air inlet φ1 is 497mm-503mm, the diameter of the air guide φ3 is 323mm-327mm, the diameter of the narrowest part of the air guide φ2 is 308.6mm-311.5mm, the radius R1 of the arc section of the air guide is 54mm-56mm and the arc length is 86mm-90mm, and the length L1 of the straight section of the air guide is 70mm-71mm.

[0027] The included angle ∠1 formed between the straight segments of the air guide sections arranged opposite each other in the direction from the air inlet to the air outlet is 128°-130°.

[0028] The length L12 of the collector extending into the impeller is 5.9mm-6.3mm, and the radial clearance length L11 between the collector and the impeller is 3.6mm-3.8mm.

[0029] Furthermore, φ1 is 500mm, φ3 is 325mm, φ2 is 310mm, R1 is 55mm with an arc length of 88.05mm, L1 is 70.43mm, ∠1 is 129°, L12 is 6.1mm, and L11 is 3.7mm.

[0030] Furthermore, the profile of the volute includes a first diffuser straight segment, a volute tongue segment, a first arc segment, a second arc segment, a third arc segment, a fourth arc segment, and a second diffuser straight segment connected tangentially in sequence; the first diffuser straight segment and the second diffuser straight segment enclose and form an air outlet, and the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment are not concentric;

[0031] Establish a rectangular coordinate system with the impeller center O as the origin. When the first diffuser straight segment is located in the third quadrant, the coordinates of the center O2 of the first arc segment are (-27.5, 7.5), the radius R9 is 288mm-291mm, and the arc length is 166mm-169.5mm. The coordinates of the center O1 of the second arc segment are (47.5, 7.5), the radius R8 is 362mm-367mm, and the arc length is 569mm-5. The center O4 of the third arc segment is (47.5, -67.5), the radius R11 is 436.5mm-442.5mm, and the arc length is 686mm-695mm. The center O3 of the fourth arc segment is (-27.5, -67.5), the radius R10 is 511mm-518mm, and the arc length is 800mm-815mm. The first diffusion straight line segment is parallel to the second diffusion straight line segment.

[0032] Furthermore, the height L9 of the air outlet is 396mm-404mm, and the width L10 is 347mm-353mm;

[0033] The radius R7 of the volute tongue segment is 19mm-21mm and the arc length is 2.9mm-3.1mm. The length L7 of the first diffuser straight segment is 43mm-44mm, and the length L8 of the second diffuser straight segment is 300mm-305mm. A tangent line is drawn to the volute tongue segment with the tangent point between the volute tongue segment and the first arc segment as the tangent point. The angle ∠4 between this tangent line and the first diffuser straight segment is 55.2°-58.5°.

[0034] Furthermore, the center O2 of the first arc segment has coordinates of (-27.5, 7.5), radius R9 of 289.5 mm, and arc length of 167.8 mm; the center O1 of the second arc segment has coordinates of (47.5, 7.5), radius R8 of 364.5 mm, and arc length of 572.6 mm; the center O4 of the third arc segment has coordinates of (47.5, -67.5), radius R11 of 439.5 mm, and arc length of 690.4 mm; and the center O3 of the fourth arc segment has coordinates of (-27.5, -67.5), radius R10 of 514.5 mm, and arc length of 808.2 mm.

[0035] L9 is 400mm, L10 is 350mm, R7 is 20mm with an arc length of 3.0mm, L7 is 43.5mm, L8 is 302.5mm, and ∠4 is 56.8°.

[0036] This invention provides a high-speed centrifugal fan with biomimetic backward-curved airfoil blades:

[0037] (1) The backward-curved airfoil blades are designed with an unequal thickness from the leading edge to the trailing edge, so as to optimize the total pressure loss in the direction at the blade outlet, suppress the tip gap vortex and airflow disturbance at the blade root, improve the fan efficiency and reduce the fan noise.

[0038] (2) By designing the front plate of the impeller, the second straight section of the front plate and the rear plate are designed to be at a small angle, which can increase the speed of the outlet airflow of the impeller and thus increase the pressure of the outlet airflow; furthermore, by setting an outer edge flange on the front plate of the impeller, the backflow of the outlet airflow of the impeller to the inside of the volute can be effectively reduced, effectively suppressing the generation of vortices and further improving the efficiency of the fan.

[0039] (3) By rationally designing the radial clearance between the collector and the impeller front plate, and by adopting the internal expansion arc transition suppression technology for the collector, the airflow can enter the impeller more smoothly, effectively reducing and suppressing the vortex caused by the mutual impact loss of the internal airflow, further improving the fan efficiency and reducing the fan noise.

[0040] (4) The non-cocircular volute profile of the matching design enables the internal flow field of the fan to flow uniformly; by optimizing the ratio of the height and width of the outlet, a more reasonable outlet wind speed can be obtained, thereby effectively balancing the ratio of outlet dynamic pressure and inlet static pressure, and further improving the fan efficiency. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the structure of a high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to the present invention;

[0042] Figure 2 This is a schematic diagram of the profile of the volute.

[0043] Figure 3 This is a partially sectional side view of the volute.

[0044] Figure 4 This is a schematic diagram of the impeller structure;

[0045] Figure 5 This is a side view sectional diagram of the impeller.

[0046] Figure 6 This is a schematic diagram of the three-dimensional structure of the impeller;

[0047] Figure 7 This is a side sectional view of the collector;

[0048] Figure 8 This is a performance curve diagram of the present invention;

[0049] Figure 9 This is a performance curve graph with a proportional ratio.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Volute; 11. First diffuser straight section; 12. Volute tongue section; 13. First arc section; 14. Second arc section; 15. Third arc section; 16. Fourth arc section; 17. Second diffuser straight section; 18. Air outlet;

[0052] Impeller 2; Blade 21; Leading edge 211; Straight segment of leading edge 2111; Arc segment of leading edge 2112; Trailing edge 212; Front plate 22; First straight segment of front plate 221; Arc segment of front plate 222; Second straight segment of front plate 223; Arc segment of outer edge flange 224; Straight segment of outer edge flange 225; Rear plate 23; Air inlet 24; First arc segment of side 251; First straight segment of side 252; First transition connection 253; Second straight segment of side 254; Second transition connection 255;

[0053] Collector 3; Connector 31; Straight section of air guide 32; Arc section of air guide 33; Air inlet 34; Air outlet 35;

[0054] Motor 4. Detailed Implementation

[0055] The present invention will be described in detail below with reference to specific embodiments.

[0056] In this invention, unless otherwise explicitly specified and limited, terms such as "set in," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or a connection through one or more intermediate media. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. The directional terms appearing in this invention are for the purpose of better describing the characteristics of the features and the relationships between them. It should be understood that when the orientation of this invention changes, the orientation of the characteristics of the features and the relationships between them also changes accordingly. Therefore, directional terms do not constitute an absolute spatial limitation on the characteristics of the features and the relationships between them, but only a relative limitation.

[0057] The structural parameters used in this invention are only for illustrating the technical solution of this invention. That is, based on the basic structural parameters of this invention, reasonable proportional scaling can be performed in actual production (for example, when the diameter of the impeller is 500mm, it can be scaled by 0.1-30 times, etc.). Such reasonable proportional scaling also falls within the protection scope of this invention.

[0058] Please see Figure 1-9A high-speed centrifugal fan with biomimetic backward-curved blades includes a volute 1, an impeller 2, and a collector 3. The volute 1 and the collector 3 are fixedly connected, and both the impeller 2 and the collector 3 are disposed within the volute 1. The impeller 2 includes a front plate 22 and a rear plate 23. An air intake 24 is provided in the middle of the front plate 22, and multiple blades 21 are arranged in an array around the rear plate 23. The blades 21 are biomimetic backward-curved sheet metal structures, and each blade 21 includes a leading edge 211, a trailing edge 212, a first side connecting the first ends of the leading edge 211 and the trailing edge 212, and a second side connecting the second ends of the leading edge 211 and the trailing edge 212. The first side is the side closer to the air intake 24, and the second side is the side farther away from the air intake 24. The leading edge 211 includes a leading edge arc segment 2111 connected to the first side and a leading edge connected to the second side. The leading edge straight segment 2112 is parallel to the trailing edge 212. From the leading edge 211 to the trailing edge 212, the thickness of the blade 21 gradually increases and then gradually decreases. On the projection surface of the rear disc 23, the first side includes a first arc segment 251, a first straight segment 252, and a second straight segment 254 arranged sequentially. A second transition connection 255 is provided between the first arc segment 251 and the second straight segment 254, and a first transition connection 253 is provided between the first straight segment 252 and the second straight segment 254. The inlet angle ∠2 of the blade 21 during installation is 18.5°-19.5°, and the outlet angle ∠3 is 56°-58°. The collector extends into the impeller, and a radial gap is provided between the collector and the impeller. The number of blades is 10. Preferably, ∠2 is 19° and ∠3 is 57°.

[0059] Through the above technical solution, a backward-curved airfoil blade 21 is adopted. The blade 21 structure is designed with a thickness that gradually increases and then gradually decreases from the leading edge 211 to the trailing edge 212. This optimizes the total pressure loss in the direction at the blade 21 outlet, suppresses the tip gap vortex and airflow disturbance at the blade root, improves the fan efficiency, and reduces the fan noise. Furthermore, through the radial clearance between the collector 3 and the front disk 22 of the impeller 2 designed later, the airflow can enter the impeller 2 more smoothly, effectively reducing and suppressing the vortices that cause internal airflow to impact each other, further improving the fan efficiency and reducing the fan noise.

[0060] In this embodiment, with the impeller 2 having a diameter φ4 of 510mm, on the projection plane of the rear disc: the diameter φ8 of the circle formed by the intersection of the extension lines of the first side arc segment 251 and the second side straight segment 254 is 517.5mm-522.5mm; the diameter φ6 of the circle formed by the intersection of the extension lines of the first side straight segment 252 and the second side straight segment 254 is 291.5mm-294.5mm; and the diameter φ7 of the circle formed by the intersection of the first side arc segment 251 and the first side straight segment 252 is 419mm-423mm. The radius R4 of the first arc segment 251 on the side is 298mm-302mm and the arc length is 118.5mm-125mm; the length L5 of the first straight segment 252 on the side is 62mm-64mm; the length L6 of the second straight segment 254 on the side is 180mm-184mm; the radius R5 of the second transition connection 255 is 2.4mm-2.6mm and the arc length is 7.0mm-7.4mm; and the radius R6 of the first transition connection 253 is 0.95mm-1.05mm and the arc length is 2.9mm-3.1mm. Preferably, φ8 is 520mm, φ6 is 293mm, φ7 is 421mm, R4 is 300mm with an arc length of 121.6mm, L5 is 63mm, L6 is 182mm, R5 is 2.5mm with an arc length of 7.2mm, and R6 is 1.0mm with an arc length of 3.0mm.

[0061] In this embodiment, the diameter φ5 of the air intake 24 is 333.5mm-336.5mm, and the vertical distance L4 between the air intake 24 and the rear plate 23 is 228mm-232mm. Taking a plane passing through the central axis of the impeller 2, the impeller 2 is sectioned. In the cross-section: from the leading edge 211 to the trailing edge 212, the front plate 22 includes a first straight section 221, a circular arc section 222, a second straight section 223, and an outer flange arranged sequentially. The length L13 of the first straight section 221 is 5.5mm-5.9mm, the radius R3 of the circular arc section 222 is 68.8mm-71.2mm, and the arc length is 96mm-99mm. The length L14 of the second straight section 223 is 23.7mm-24.7mm, and the angle ∠5 between the second straight section 223 and the rear plate 23 is 9.6°. °-10.4°; the outer edge flange includes an outer edge flange straight section 225 and an outer edge flange arc section 224 connecting the outer edge flange straight section 225 and the front plate second straight section 223. The outer edge flange arc section 224 is tangent to both the outer edge flange straight section 225 and the front plate second straight section 223. The outer edge straight section 225 is parallel to the tail edge 212. The radius R12 of the outer edge flange arc section 224 is 4.9mm-5.1mm and... The arc length is 8.5mm-8.9mm, and the length L15 of the straight section 225 of the outer edge flange is 9.6mm-10.2mm; the radius R2 of the leading edge arc section 2111 is 54mm-56mm and the arc length is 55.1mm-57.1mm, the length L2 of the leading edge straight section 2112 is 149.5mm-153mm, and the length L3 of the trailing edge 212 is 149.5mm-153mm. Preferably, φ5 is 335mm, L4 is 230mm, R3 is 70mm and the arc length is 97.7mm, L14 is 24.2mm, ∠5 is 10.0°, R12 is 5.0mm and the arc length is 8.7mm, L15 is 9.9mm, R2 is 55mm and the arc length is 56.1mm, L2 is 151mm, and L3 is 151mm.

[0062] Through the above technical solution, by designing the front disc 22 of the impeller 2, the second straight section 223 of the front disc and the rear disc 23 are designed to have a small angle, which can increase the outlet airflow velocity of the impeller 2 and thus increase the outlet airflow pressure. Furthermore, by setting an outer edge flange on the front disc 22 of the impeller 2, the backflow of the outlet airflow of the impeller 2 into the volute 1 can be effectively reduced, effectively suppressing the generation of vortices and further improving the efficiency of the fan.

[0063] In this embodiment, the collector 3 includes a connecting part 31 and an air guide part. The collector 3 is fixedly connected to the volute 1 through the connecting part 31. The air guide part extends into the front disc 22 of the impeller 2. The connecting part 31 is annular and has an air inlet 34 formed on its inner circumference. The air guide part includes a straight section 32 connected to the connecting part 31 and an arc section 33 away from the connecting part 31. The outlet of the arc section 33 forms a trumpet-shaped air guide 35. From the air inlet 34 to the air guide 35, the diameter of the air guide part gradually decreases and then gradually increases.

[0064] In this embodiment, the collector 3 is cut along a plane passing through its central axis. In the cross-section: the diameter φ1 of the air inlet 34 is 497mm-503mm; the diameter φ3 of the air guide 35 is 323mm-327mm; the diameter φ2 at the narrowest point of the air guide is 308.6mm-311.5mm; the radius R1 of the arc segment 33 of the air guide is 54mm-56mm and the arc length is 86mm-90mm; the length L1 of the straight segment 32 of the air guide is 70mm-71mm; the included angle ∠1 formed between the relatively arranged straight segments 32 of the air guide from the air inlet 34 to the air guide 35 is 128°-130°; the length L12 of the collector 3 extending into the impeller 2 is 5.9mm-6.3mm; and the radial clearance length L11 between the collector 3 and the impeller 2 is 3.6mm-3.8mm. Preferably, φ1 is 500mm, φ3 is 325mm, φ2 is 310mm, R1 is 55mm with an arc length of 88.05mm, L1 is 70.43mm, ∠1 is 129°, L12 is 6.1mm, and L11 is 3.7mm.

[0065] Through the above technical solution, by rationally designing the radial clearance between the collector 3 and the front plate 22 of the impeller 2, and by adopting the internal expansion arc transition suppression technology for the collector 3, the airflow can enter the impeller 2 more smoothly, effectively reducing and suppressing the vortex caused by the mutual impact loss of the internal airflow, further improving the fan efficiency and reducing the fan noise.

[0066] In this embodiment, the profile of the volute 1 includes a first diffuser straight segment 11, a volute tongue segment 12, a first arc segment 13, a second arc segment 14, a third arc segment 15, a fourth arc segment 16, and a second diffuser straight segment 17 connected tangentially in sequence; the first diffuser straight segment 11 and the second diffuser straight segment 17 enclose and form an air outlet 18, and the first arc segment 13, the second arc segment 14, the third arc segment 15, and the fourth arc segment 16 are not concentric;

[0067] A rectangular coordinate system is established with the center O of impeller 2 as the origin. When the first diffuser straight segment 11 is located in the third quadrant, the coordinates of the center O2 of the first arc segment 13 are (-27.5, 7.5), the radius R9 is 288mm-291mm, and the arc length is 166mm-169.5mm. The coordinates of the center O1 of the second arc segment 14 are (47.5, 7.5), the radius R8 is 362mm-367mm, and the arc length is 569mm-5. The center O4 of the third arc segment 15 is (47.5, -67.5), the radius R11 is 436.5mm-442.5mm, and the arc length is 686mm-695mm. The center O3 of the fourth arc segment 16 is (-27.5, -67.5), the radius R10 is 511mm-518mm, and the arc length is 800mm-815mm. The first diffusion straight line segment 11 is parallel to the second diffusion straight line segment 17.

[0068] Preferably, the center O2 of the first arc segment 13 has coordinates of (-27.5, 7.5), radius R9 has a length of 289.5 mm and arc length of 167.8 mm; the center O1 of the second arc segment 14 has coordinates of (47.5, 7.5), radius R8 has a length of 364.5 mm and arc length of 572.6 mm; the center O4 of the third arc segment 15 has coordinates of (47.5, -67.5), radius R11 has a length of 439.5 mm and arc length of 690.4 mm; and the center O3 of the fourth arc segment 16 has coordinates of (-27.5, -67.5), radius R10 has a length of 514.5 mm and arc length of 808.2 mm.

[0069] In this embodiment, the height L9 of the air outlet 18 is 396mm-404mm, and the width L10 is 347mm-353mm; the radius R7 of the volute tongue segment 12 is 19mm-21mm and the arc length is 2.9mm-3.1mm; the length L7 of the first diffuser straight segment 11 is 43mm-44mm; the length L8 of the second diffuser straight segment 17 is 300mm-305mm; a tangent is drawn to the volute tongue segment 12 at the tangent point between the volute tongue segment 12 and the first arc segment 13, and the angle ∠4 between this tangent and the first diffuser straight segment 11 is 55.2°-58.5°. Preferably, L9 is 400mm, L10 is 350mm, R7 is 20mm and the arc length is 3.0mm, L7 is 43.5mm, L8 is 302.5mm, and ∠4 is 56.8°.

[0070] It should be noted that the high-speed centrifugal fan with biomimetic backward-curved blades of the present invention also includes a motor 4, which is connected to the impeller 2 via a motor shaft; the present invention also includes essential components such as a motor base. Since the above components are not improvements of the present invention and those skilled in the art know the structure and working principle of the basic components, they will not be described in detail.

[0071] Through the above technical solutions, the impeller 2 and collector 3 are improved, and the non-co-circular volute 1 profile is designed, so that the internal flow field of the fan can flow uniformly. By optimizing the ratio of the height and width of the outlet 18, a more reasonable outlet 18 wind speed can be obtained, thereby effectively balancing the ratio of outlet dynamic pressure and inlet static pressure, and further improving the fan efficiency.

[0072] To verify this embodiment, based on the preferred structural parameters provided in this embodiment, a high-speed centrifugal fan with biomimetic backward-curved blades, manufactured with an impeller 2 diameter of 500mm, was tested as a test example. Simultaneously, a conventional backward-curved centrifugal fan with a conventional impeller 2 diameter of 500mm and using ordinary backward-curved blades was tested as a comparative example. The test results were converted to atmospheric pressure of 101325Pa, atmospheric temperature of 20℃, fan speed of 2930r / min, and medium density of 1.2 kg / m³. 3 The test data under the test conditions are shown in Table 1. After performing dimensionless conversion on the test data, the dimensionless test data are shown in Table 2. Figure 8 The performance curves shown are used to obtain the test data shown in Table 3, and the dimensionless test data shown in Table 4 is obtained after performing dimensionless conversion on the test data. Figure 9 The performance curves shown have volumetric flow rate as the x-axis. In the performance curves, qvsglGu is the volumetric flow rate, LAGu is the A-weighted sound level, ηr is the fan efficiency, PrGu is the impeller power, pFGu is the total pressure, and psFGu is the static pressure.

[0073] Table 1

[0074]

[0075] Table 2

[0076]

[0077] Table 3

[0078]

[0079] Table 4

[0080]

[0081] The test data, dimensionless test data, and performance curves show that, compared to the test case, the comparative example is inferior to the test case in terms of fan efficiency, flow rate, total pressure, and specific A-weighted sound level. In contrast, the test case achieves its optimal fan efficiency of 82.446% at the fourth operating point, with a flow rate of 12808 m³ / h. 3The flow rate is 10608 m³ / h, with a total pressure of 3472.4 Pa, an A-weighted sound level of 92.219 dB, a flow coefficient of 0.23622, a total pressure coefficient of 0.48655, and a specific A-weighted sound level of 17.944 dB. In the comparative example, at the optimal fan efficiency of 76.093% at the third operating point, the flow rate is 10608 m³ / h. 3 The flow rate was 1000 m / h, the total pressure was 3171.7 Pa, the A-weighted sound level was 91.243 dB, the flow coefficient was 0.19565, the total pressure coefficient was 0.44501, and the specific A-weighted sound level was 18.573 dB. The test cases generally had higher flow rates, higher total pressures, and higher efficiency than the control group. Furthermore, even with increases in both flow rate and total pressure, the specific A-weighted sound level of the test cases generally decreased compared to the control group.

[0082] Meanwhile, during the stable operation of the fan in the test case, at operating points 2-5, the fan efficiency ranged from 78.438% to 82.446%, and the flow rate ranged from 9589.3 m³ / s. 3 / h-14117m 3 The total pressure range is 3134.9 Pa - 4015.9 Pa, the A-weighted sound level ranges from 90.879 dB to 92.901 dB, the flow coefficient ranges from 0.17686 to 0.26036, the total pressure coefficient ranges from 0.43976 to 0.56200, and the specific A-weighted sound level ranges from 16.598 dB to 19.091 dB. In the comparative example, during the stable operation of the fan at operating points 2-5, the fan efficiency ranges from 71.591% to 76.093%, and the flow rate ranges from 9343.6 m³ / h. 3 / h-13512m 3 / h, total pressure range is 2519.6Pa-3284.4Pa, A-weighted sound level range is 91.045dB-91.773dB, flow coefficient range is 0.17232-0.24920, total pressure coefficient range is 0.35423-0.46082, and specific A-weighted sound level range is 18.573dB-20.051dB.

[0083] Compared with the prior art, the high-speed centrifugal fan with biomimetic backward-curved blades of the present invention has higher fan efficiency and lower fan noise.

[0084] Where there is no conflict, the above embodiments and features can be combined with each other.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades, comprising a volute, an impeller, and a collector, wherein the volute and the collector are fixedly connected, and both the impeller and the collector are disposed within the volute; the impeller comprises a front plate and a rear plate, wherein an air inlet is disposed in the center of the front plate, and multiple blades are arranged in a circumferential array on the rear plate, characterized in that: The blade is a biomimetic backward-curved sheet metal structure. The blade includes a leading edge, a trailing edge, a first side connecting the first end of the leading edge and the trailing edge, and a second side connecting the second end of the leading edge and the trailing edge. The first side is the side closer to the air inlet, and the second side is the side farther away from the air inlet. The leading edge includes a leading edge arc segment connected to the first side and a leading edge straight segment connected to the second side. The leading edge straight segment is parallel to the trailing edge. From the leading edge to the trailing edge, the thickness of the blade gradually increases and then gradually decreases. On the projection surface of the rear disc, the first side includes a first arc segment, a first straight segment, and a second straight segment arranged sequentially. A second transition connection is provided between the first arc segment and the second straight segment, and a first transition connection is provided between the first straight segment and the second straight segment. The inlet angle ∠2 during blade installation is 18.5°-19.5°, and the outlet angle ∠3 during blade installation is 56°-58°. The collector extends into the impeller, and a radial clearance is provided between the collector and the impeller; There are 10 leaves.

2. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 1, characterized in that: With an impeller diameter of φ4 and a value of 510mm, projected onto the rear disc surface: The diameter φ8 of the circle formed by the intersection of the first arc segment of the side and the extension of the second straight segment of the side is 517.5mm-522.5mm; the diameter φ6 of the circle formed by the intersection of the first straight segment of the side and the extension of the second straight segment of the side is 291.5mm-294.5mm; and the diameter φ7 of the circle formed by the intersection of the first arc segment of the side and the first straight segment of the side is 419mm-423mm. The radius R4 of the first arc segment on the side is 298mm-302mm and the arc length is 118.5mm-125mm. The length L5 of the first straight segment on the side is 62mm-64mm. The length L6 of the second straight segment on the side is 180mm-184mm. The radius R5 of the second transition connection is 2.4mm-2.6mm and the arc length is 7.0mm-7.4mm. The radius R6 of the first transition connection is 0.95mm-1.05mm and the arc length is 2.9mm-3.1mm.

3. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 2, characterized in that: The diameter of the air intake φ5 is 333.5mm-336.5mm, and the vertical distance L4 between the air intake and the rear plate is 228mm-232mm. The impeller is sectioned by a plane passing through its central axis. On the cross-section: From the leading edge to the trailing edge, the cross-section of the front plate includes the first straight section of the front plate, the arc section of the front plate, the second straight section of the front plate, and the outer edge flange arranged sequentially. The length L13 of the first straight section of the front plate is 5.5mm-5.9mm, the radius R3 of the arc section of the front plate is 68.8mm-71.2mm and the arc length is 96mm-99mm, the length L14 of the second straight section of the front plate is 23.7mm-24.7mm, and the included angle ∠5 between the second straight section of the front plate and the rear plate is 9.6°-10.4°. The outer edge flange includes an outer edge flange straight section and an outer edge flange arc section connecting the outer edge flange straight section and the second straight section of the front plate. The outer edge flange arc section is tangent to both the outer edge flange straight section and the second straight section of the front plate. The outer edge straight section is parallel to the tail edge. The radius R12 of the outer edge flange arc section is 4.9mm-5.1mm and the arc length is 8.5mm-8.9mm. The length L15 of the outer edge flange straight section is 9.6mm-10.2mm. The radius R2 of the leading edge arc segment is 54mm-56mm and the arc length is 55.1mm-57.1mm. The length L2 of the leading edge straight segment is 149.5mm-153mm, and the length L3 of the trailing edge is 149.5mm-153mm.

4. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 3, characterized in that: ∠2 is 19°, ∠3 is 57°, φ8 is 520mm, φ6 is 293mm, φ7 is 421mm, R4 is 300mm with an arc length of 121.6mm, L5 is 63mm, L6 is 182mm, R5 is 2.5mm with an arc length of 7.2mm, R6 is 1.0mm with an arc length of 3.0mm, φ5 is 335mm, L4 is 230mm, L13 is 5.7mm, R3 is 70mm with an arc length of 97.7mm, L14 is 24.2mm, ∠5 is 10.0°, R12 is 5.0mm with an arc length of 8.7mm, L15 is 9.9mm, R2 is 55mm with an arc length of 56.1mm, L2 is 151mm, and L3 is 151mm.

5. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 4, characterized in that: The collector includes a connecting part and an air guide part. The collector is fixedly connected to the volute through the connecting part. The air guide part extends into the front plate of the impeller. The connecting part is annular and has an air inlet on its inner circumference. The air guide section includes a straight section connected to the connecting section and an arc section of the air guide section away from the connecting section. The outlet of the arc section of the air guide section forms a funnel-shaped air guide. From the air inlet to the air guide, the diameter of the air guide gradually decreases and then gradually increases.

6. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 5, characterized in that: The collector is cut off by a plane passing through its central axis. On the cross-section: The diameter of the air inlet φ1 is 497mm-503mm, the diameter of the air guide φ3 is 323mm-327mm, the diameter of the narrowest part of the air guide φ2 is 308.6mm-311.5mm, the radius R1 of the arc section of the air guide is 54mm-56mm and the arc length is 86mm-90mm, and the length L1 of the straight section of the air guide is 70mm-71mm. The included angle ∠1 formed between the straight segments of the air guide sections arranged opposite each other in the direction from the air inlet to the air outlet is 128°-130°. The length L12 of the collector extending into the impeller is 5.9mm-6.3mm, and the radial clearance length L11 between the collector and the impeller is 3.6mm-3.8mm.

7. A high speed centrifugal fan with bionic back-curved airfoil blades as claimed in claim 6, characterized in that: φ1 is 500mm, φ3 is 325mm, φ2 is 310mm, R1 is 55mm and the arc length is 88.05mm, L1 is 70.43mm, ∠1 is 129°, L12 is 6.1mm, and L11 is 3.7mm.

8. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 7, characterized in that: The profile of the volute includes a first diffuser straight segment, a volute tongue segment, a first arc segment, a second arc segment, a third arc segment, a fourth arc segment, and a second diffuser straight segment that are connected tangentially in sequence; the first diffuser straight segment and the second diffuser straight segment enclose and form an air outlet, and the first arc segment, the second arc segment, the third arc segment, and the fourth arc segment are not concentric; Establish a rectangular coordinate system with the impeller center O as the origin. When the first diffuser straight segment is located in the third quadrant, the coordinates of the center O2 of the first arc segment are (-27.5, 7.5), the radius R9 is 288mm-291mm, and the arc length is 166mm-169.5mm. The coordinates of the center O1 of the second arc segment are (47.5, 7.5), the radius R8 is 362mm-367mm, and the arc length is 569mm-5. The center O4 of the third arc segment is (47.5, -67.5), the radius R11 is 436.5mm-442.5mm, and the arc length is 686mm-695mm. The center O3 of the fourth arc segment is (-27.5, -67.5), the radius R10 is 511mm-518mm, and the arc length is 800mm-815mm. The first diffusion straight line segment is parallel to the second diffusion straight line segment.

9. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 8, characterized in that: The height of the air outlet L9 is 396mm-404mm, and the width L10 is 347mm-353mm; The radius R7 of the volute tongue segment is 19mm-21mm and the arc length is 2.9mm-3.1mm. The length L7 of the first diffuser straight segment is 43mm-44mm, and the length L8 of the second diffuser straight segment is 300mm-305mm. A tangent line is drawn to the volute tongue segment with the tangent point between the volute tongue segment and the first arc segment as the tangent point. The angle ∠4 between this tangent line and the first diffuser straight segment is 55.2°-58.5°.

10. A high-speed centrifugal fan with biomimetic backward-curved airfoil blades according to claim 9, characterized in that: The center O2 of the first arc segment has coordinates (-27.5, 7.5), radius R9 is 289.5mm and arc length is 167.8mm; the center O1 of the second arc segment has coordinates (47.5, 7.5), radius R8 is 364.5mm and arc length is 572.6mm; the center O4 of the third arc segment has coordinates (47.5, -67.5), radius R11 is 439.5mm and arc length is 690.4mm; and the center O3 of the fourth arc segment has coordinates (-27.5, -67.5), radius R10 is 514.5mm and arc length is 808.2mm. L9 is 400mm, L10 is 350mm, R7 is 20mm with an arc length of 3.0mm, L7 is 43.5mm, L8 is 302.5mm, and ∠4 is 56.8°.

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