A backward high-pressure centrifugal fan with gray shark type blades

Abstract

The present application relates to centrifugal fan technical field, especially to a kind of backward high-pressure centrifugal fan with imitative grey mackerel shark type blade, including volute, impeller and current collector, impeller is arranged in volute, current collector partly extends into volute, another part extends outside volute, current collector is fixedly connected with volute;Impeller includes front disc and rear disc, and multiple blades are arrayed around on rear disc, and the middle part of front disc is provided with air inlet, and the leading edge and trailing edge are all set as arc structure in the direction from front disc to rear disc, and the windward surface and leeward surface are all set as arc structure in the direction from leading edge to trailing edge, first side includes first side arc segment and first side straight segment, second side is set as straight segment structure, the thickness of blade gradually increases first and then gradually decreases in the direction from leading edge to trailing edge, and the thickness of leading edge is greater than the thickness of trailing edge.The present application relates to a kind of backward high-pressure centrifugal fan with imitative grey mackerel shark type blade, which has higher pressure, higher efficiency and greater flow.

Description

Technical Field

[0001] This invention relates to the field of centrifugal fan technology, and in particular to a backward high-pressure centrifugal fan with mackerel-shaped blades. Background Technology

[0002] High-pressure centrifugal fans offer advantages such as low flow rate, high total pressure, high static pressure, and compact structure, making them widely used in high-pressure forced ventilation of smelting furnaces, industrial dust removal, and material conveying. However, they also suffer from problems such as large internal flow losses, low pressure, and low efficiency. With the continuous improvement of national energy strategies and industrial production demands, users are constantly raising new requirements for fan performance parameters. Traditional forward-curved single-arc uniform-thickness blade high-pressure centrifugal fans are struggling to meet customers' needs for larger flow rates, higher pressures, and higher efficiency.

[0003] The impeller is the core component of a high-pressure centrifugal fan, and the blades, as the core component of the impeller, play a crucial role in the overall performance of the high-pressure centrifugal fan due to their airfoil profile. For example, the blade profile significantly affects flow separation, secondary flow, and aerodynamic excitation within the impeller channel, which in turn influences the fan's efficiency. Therefore, improving the blade profile has become an important direction for enhancing the fan's flow rate, pressure, and efficiency.

[0004] With the development of biomimetic technology, its application can greatly improve the performance of wind turbines. Currently, the mako shark is one of the fastest swimming fish in the ocean, and its streamlined body and non-smooth surface have excellent hydrodynamic properties.

[0005] Whether the characteristic structure of the mackerel can be combined to improve the blade shape and thus the performance of the backward high-pressure centrifugal fan has become a technical problem to be solved. Summary of the Invention

[0006] The purpose of this invention is to provide a backward high-pressure centrifugal fan with mackerel-shaped blades, which aims to solve the problems of large flow loss, low pressure and low efficiency in the prior art of backward high-pressure centrifugal fans.

[0007] To achieve the above objectives, a backward high-pressure centrifugal fan with mackerel-shaped blades is provided, comprising a volute, an impeller, and a collector. The impeller is disposed inside the volute, and part of the collector extends into the volute and the other part extends out of the volute. The collector is fixedly connected to the volute. The impeller comprises a front plate and a rear plate. Multiple blades are arranged in an array around the rear plate, and an air intake is provided in the middle of the front plate.

[0008] The blade includes a leading edge, a trailing edge, a windward side, a leeward side, a first side connecting the first end of the leading edge and the first end of the trailing edge, and a second side connecting the second end of the leading edge and the second end of the trailing edge. The first side is the side closest to the air inlet, and the second side is the side furthest from the air inlet. The leading edge is inclined from the first side to the second side, and the inclination direction is gradually closer to the impeller hub.

[0009] Both the leading and trailing edges are set in an arc shape in the direction from the front disc to the rear disc. Both the windward and leeward sides are set in an arc shape in the direction from the leading edge to the trailing edge. The first side includes a first side arc segment and a first side straight segment. The second side is set in a straight segment structure. The thickness of the blade gradually increases and then gradually decreases in the direction from the leading edge to the trailing edge. The thickness of the leading edge is greater than the thickness of the trailing edge.

[0010] In the front view of the blade, the arc-shaped structure at the leading edge is concave to the blade, the arc-shaped structure at the trailing edge is concave to the blade, the straight section of the first side is parallel to the second side, the arc-shaped section of the first side is set as a continuous multi-segment arc-shaped structure, the arc surface of the first side is set as an inclined structure from the leeward side to the windward side, and the first side gradually moves closer to the second side from the leading edge to the trailing edge, and the inclination of the arc surface of the first side gradually decreases.

[0011] The inlet angle ∠2 during blade installation is 34.5°-35.5°, and the outlet angle ∠3 during blade installation is 47.2°-48.8°.

[0012] There are 12 leaves.

[0013] Furthermore, the circumference diameter φ4 formed by the outermost ends of all the blades is 705 mm, and the circumference diameter φ5 formed by the innermost ends of all the blades is 234.1 mm-235.9 mm.

[0014] In the front view of the blade, the radius of curvature R10 of the leading edge is 525mm-532mm and the arc length is 96mm-99mm; the radius of curvature R11 of the trailing edge is 194mm-196mm and the arc length is 56.5mm-58mm; the vertical distance L4 between the first end and the second end of the leading edge is 93.6mm-95.6mm; the vertical distance L5 between the first end and the second end of the trailing edge is 56.5mm-57.5mm; the vertical distance L6 between the first end and the first end of the trailing edge is 260mm-265mm; the length L7 of the straight section of the first side is 110mm-112mm; and the length L8 of the second side is 289mm-294mm.

[0015] On the projection surface of the rear disc, the radius of the arc on the windward side, R2, is 398mm-402mm and the arc length is 310mm-316mm; the radius of the arc on the leeward side, R3, is 547mm-553mm and the arc length is 303mm-308mm; the radius of the outer arc of the leading edge near the hub, R4, is 3.3mm-3.7mm and the arc length is 10mm-11mm; the radius of the inner arc of the leading edge away from the hub, R8, is 4.7mm-5.3mm and the arc length is 13.8mm-15.4mm; the radius of the outer arc of the trailing edge away from the hub, R5, is 1.9mm-2.1mm and the arc length is 8.5mm-9.5mm; and the radius of the inner arc of the trailing edge near the hub, R9, is 1.95mm-2.25mm and the arc length is 5.9mm-6.5mm.

[0016] Furthermore, multiple diamond-shaped grooves are arranged in an array at one end of the windward surface near the trailing edge, with the direction parallel to the rear disc as the lateral direction and the direction perpendicular to the rear disc as the longitudinal direction. The diamond-shaped grooves are arranged in 4 rows in the lateral direction and 3 columns in the longitudinal direction. One acute angle of the diamond-shaped groove faces the wheel hub and the other acute angle faces away from the wheel hub. One obtuse angle of the diamond-shaped groove faces the rear disc and the other obtuse angle faces away from the rear disc.

[0017] On the front view of the blade:

[0018] The side length L14 of the rhomboid groove is 39mm-41mm, and the acute angle ∠4 of the rhomboid groove is 59°-61°.

[0019] The distance L12 between the acute vertices of two adjacent rhomboid grooves in each row is 17.3mm-17.7mm, and the distance L13 between the obtuse vertices of two adjacent rhomboid grooves in each column is 21.5mm-22.5mm.

[0020] The vertical distance L11 between the acute angle vertex of the row of rhomboid grooves near the tail edge and the second end of the rear plate is 29.3mm-30.7mm. The distance between the obtuse angle vertex of the row of rhomboid grooves near the first straight section and the first straight section is L9. The distance between the obtuse angle vertex of the row of rhomboid grooves near the second side and the second side is L10. L9 and L10 are equal and both are 5.9mm-6.1mm.

[0021] Furthermore, the diameter of the air intake φ6 is 247mm-249mm, and the vertical distance L3 between the air intake and the rear plate is 109.8mm-112.2mm;

[0022] From the leading edge to the trailing edge, the front disc includes a first arc segment, a second arc segment, and a straight segment connected tangentially in sequence, with the straight segment of the front disc arranged parallel to the rear disc.

[0023] The impeller is sectioned by a plane passing through its central axis. On the cross-section:

[0024] The radius R6 of the first arc segment of the front disc is 62mm-64mm and the arc length is 57mm-60mm. The radius R7 of the second arc segment of the front disc is 280mm-287mm and the arc length is 88mm-91mm. The length L2 of the straight segment of the front disc is 104mm-107mm.

[0025] Furthermore, it also includes a front cover plate assembly, which includes a volute connecting part, a reinforcing part and a collector connecting part, wherein the collector connecting part is annular and the inner circumference forms a collector receiving part;

[0026] The front cover assembly is detachably connected to the collector via the collector connection part, and the collector is fixedly connected to the volute via the volute connection part.

[0027] Furthermore, the collector includes a connecting part and a guide section. The guide section includes a straight guide section connected to the connecting part and a curved guide section away from the connecting part. The connecting part is annular and has an air inlet on its inner circumference. The outlet of the guide section is annular and has an air inlet on its inner circumference.

[0028] From the air inlet to the air outlet, the straight section of the air guide and a part of the curved section of the air guide form a tapering section, and another part of the curved section of the air guide forms a widening section. The air guide section is designed to be a guide structure that first tapes out from the tapering section to the widening section and then widens out.

[0029] The air guide arc section extends into the front disc of the impeller, and a radial clearance is provided between the collector and the impeller.

[0030] Furthermore, the diameter of the air inlet φ1 is 279mm-281mm, the diameter of the air guide φ3 is 234.2mm-235.8mm, and the diameter of the narrowest part of the air guide arc φ2 is 231.3mm-232.7mm;

[0031] The collector is cut off by a plane passing through its central axis. In the cross section: the radius R1 of the air guide arc is 39.2mm-40.8mm and the arc length is 27mm-29.5mm; the length L1 of the air guide straight section is 49mm-51mm; and the included angle ∠1 formed between the air guide straight section and the connecting part is 65°-66.5°.

[0032] The length L19 of the collector extending into the front disc of the impeller is 6.6mm-7.4mm, and the radial clearance length L20 between the collector and the impeller is 5.7mm-6.3mm.

[0033] Furthermore, the profile of the volute includes a first diffuser straight section, a volute tongue section, a first arc section, a second arc section, a third arc section, a fourth arc section, and a second diffuser straight section that are connected tangentially in sequence. The first diffuser straight section and the second diffuser straight section enclose and form an air outlet. The first arc section, the second arc section, the third arc section, and the fourth arc section are not concentric.

[0034] A rectangular coordinate system is established with the impeller center O as the origin. When the first diffuser section is located in the third quadrant, the coordinates of the center O1 of the first arc section are (24, 24), the radius R12 is 383mm-389mm, and the arc length is 399mm-405mm. The coordinates of the center O2 of the second arc section are (-24, 24), the radius R13 is 430.8mm-437.2mm, and the arc length is 676mm-686mm. The coordinates of the center O3 of the third arc section are (-24, -24), the radius R14 is 477.5mm-484.5mm, and the arc length is 750mm-761mm. The coordinates of the center O4 of the fourth arc section are (24, -24), the radius R15 is 525mm-533mm, and the arc length is 824mm-836mm. The first diffuser section and the second diffuser section are set in parallel.

[0035] Furthermore, the height L17 of the air outlet is 200mm-204mm, and the width L18 of the air outlet is 144mm-146mm;

[0036] The radius R16 of the volute tongue segment is 21.5mm-22.5mm and the arc length is 56.5mm-58.5mm. The length L15 of the first diffuser straight segment is 181.5mm-184.5mm, and the length L16 of the second diffuser straight segment is 386mm-392mm. 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 ∠5 between this tangent line and the first diffuser straight segment is 30°-31°.

[0037] Furthermore, it also includes a motor and a base. The motor is connected to the impeller via a drive shaft, and both the volute and the motor are fixedly mounted on the base.

[0038] Compared with the prior art, the backward high-pressure centrifugal fan with mackerel-shaped blades provided by the present invention has the following beneficial effects:

[0039] (1) The shape of the leading and trailing edges of the backward high-pressure centrifugal fan blades is optimized by using bionics. The cross section of the leading edge of the blade adopts a semi-elliptical arc that resembles the head of a mako shark, which effectively reduces flow loss. At the same time, the trailing edge of the blade adopts a concave parabolic design of the tail fin of a mako shark, which effectively weakens the unsteady impact between the airflow at the trailing edge of the blade and the volute wall and volute tongue wall. The blade airfoil design of the backward imitation of a mako shark is adopted, and the windward and leeward sides are both set as arc-shaped airfoil structures, so that the backward bionic blade has a semi-elliptical, streamlined rotating body structure with the swimming posture of a mako shark. This can effectively suppress the flow separation and secondary flow in the blade passage, optimize the flow velocity distribution on the blade surface, reduce the vortex intensity, reduce aerodynamic excitation, improve the aerodynamic performance of the fan, and thus improve the fan pressure and fan efficiency.

[0040] (2) The rear half of the windward side of the blade is provided with non-smooth fish skin grooves, which can make the airflow tend to develop steadily, reduce the intensity of turbulent boundary layer pressure pulsation, effectively delay boundary layer separation, improve the flow state of turbulent boundary layer, reduce the periodic shedding of vortices at the tail of the blade and the formation of vortices, further improve the fan pressure and fan efficiency, and help reduce noise.

[0041] (3) The collector is designed by combining the air guide arc section and the air guide straight section. The air guide straight section and part of the air guide arc section form a tapering section, and the other part of the air guide arc section forms a widening section. The horn-shaped nozzle arc collector formed by stretching a certain arc and height is smoothly connected with the arc section of the front plate to form a gap fit transition dock, which reduces the mutual impact loss of airflow, reduces the impact of airflow after entering the impeller to generate vortices, and accelerates the airflow. It effectively ensures that the airflow enters the impeller smoothly, increases the fan air volume and air pressure, and significantly improves the performance efficiency.

[0042] (4) The logarithmic spiral volute profile structure is adopted. By improving the volute profile and width to suit the structure of the backward impeller with the imitation mackerel blade, the flow loss is reduced. It can effectively control the velocity distribution of all internal flow points, obtain the best flow state inside the fan, ensure the efficiency of fluid transport to reach the best, ensure the smooth flow of air in the volute space, and further improve the efficiency of the fan. Attached Figure Description

[0043] Figure 1 This is a schematic diagram of the structure of a backward high-pressure centrifugal fan with imitation mackerel-shaped blades according to the present invention;

[0044] Figure 2 This is a schematic diagram of the profile of the volute.

[0045] Figure 3 This is a schematic side sectional view of the volute.

[0046] Figure 4 This is a schematic diagram of the impeller structure;

[0047] Figure 5 This is a schematic diagram of the blade molding process;

[0048] Figure 6 This is a side sectional view of the impeller;

[0049] Figure 7 This is a schematic diagram of the front view structure of the blade;

[0050] Figure 8 for Figure 7 A magnified view of a section at point A in the middle;

[0051] Figure 9 A three-dimensional structural diagram of the impeller without the front disc;

[0052] Figure 10 This is a schematic diagram of the three-dimensional structure of the impeller;

[0053] Figure 11 This is a side sectional view of the collector;

[0054] Figure 12 This is a side sectional view of the front cover assembly;

[0055] Figure 13 This is a performance curve diagram of the present invention;

[0056] Figure 14 This is a proportional performance curve.

[0057] Explanation of reference numerals in the attached figures:

[0058] 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;

[0059] Impeller 2; Blade 21; Leading edge 211; First side 212; First side arc segment 2121; First side straight segment 2122; Trailing edge 213; Second side 214; Windward side 215; Leeward side 216; Leading edge outer arc 2171; Leading edge inner arc 2172; Trailing edge outer arc 2181; Trailing edge inner arc 2182; Diamond groove 219; Front plate 22; Front plate first arc segment 221; Front plate second arc segment 222; Front plate straight segment 223; Rear plate 23; Inlet 24;

[0060] Collector 3; Connector 31; Air guide section 32; Straight air guide section 321; Arc air guide section 322; Air inlet 33; Air outlet 34;

[0061] Front cover assembly 4; volute connecting part 41; collector connecting part 42; reinforcing part 43; collector housing part 44;

[0062] 5. Motor; 6. Base. Detailed Implementation

[0063] The present invention will be described in detail below with reference to specific embodiments.

[0064] 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.

[0065] 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 outer circumference circle formed by the outer ends of all the blades of the impeller is 705mm, it can be scaled by 0.1-30 times, etc.). Such reasonable proportional scaling also falls within the protection scope of this invention.

[0066] Please see Figure 1-14 A backward high-pressure centrifugal fan with mackerel-shaped blades includes a volute 1, an impeller 2, and a collector 3. The impeller 2 is disposed inside the volute 1, and part of the collector 3 extends into the volute 1 and the other part extends out of the volute 1. The collector 3 is fixedly connected to the volute 1. The impeller 2 includes a front plate 22 and a rear plate 23. Multiple blades 21 are arranged in a ring on the rear plate 23, and an air intake 24 is provided in the middle of the front plate 22.

[0067] The blade 21 includes a leading edge 211, a trailing edge 213, a windward surface 215, a leeward surface 216, a first side 212 connecting the first end of the leading edge 211 and the first end of the trailing edge 213, and a second side 214 connecting the second end of the leading edge 211 and the second end of the trailing edge 213. The first side 212 is the side closest to the air inlet 24, and the second side 214 is the side away from the air inlet 24. The leading edge 211 is inclined from the first side 212 to the second side 214, and the inclination direction is gradually closer to the hub of the impeller 2.

[0068] Both the leading edge 211 and the trailing edge 213 are set as arc-shaped structures in the direction from the front disc 22 to the rear disc 23. Both the windward side 215 and the leeward side 216 are set as arc-shaped structures in the direction from the leading edge 211 to the trailing edge 213. The first side 212 includes a first side arc segment 2121 and a first side straight segment 2122. The second side 214 is set as a straight segment structure. The thickness of the blade 21 gradually increases and then gradually decreases in the direction from the leading edge 211 to the trailing edge 213. The thickness of the leading edge 211 is greater than the thickness of the trailing edge 213.

[0069] In the front view of blade 21, the arc-shaped structure of the leading edge 211 is concave to blade 21, the arc-shaped structure of the trailing edge 213 is concave to blade 21, the first straight segment 2122 is parallel to the second side 214, the first arc segment 2121 is set as a continuous multi-segment arc structure, the arc surface of the first arc segment 2121 is set as an inclined structure from the leeward side 216 to the windward side 215, the first arc segment 2121 gradually approaches the second side 214 in the direction from the leading edge 211 to the trailing edge 213, and the inclination of the arc surface of the first arc segment 2121 gradually decreases;

[0070] The inlet angle ∠2 of blade 21 during installation is 34.5°-35.5°, and the outlet angle ∠3 of blade 21 during installation is 47.2°-48.8°; preferably, ∠2 is 35° and ∠3 is 48°.

[0071] There are 12 leaves in leaf 21.

[0072] Through the above technical solution, the shape of the leading edge 211 and trailing edge 213 of the backward high-pressure centrifugal fan blade 21 is optimized using bionics. The cross-section of the leading edge 211 of the blade 21 adopts a semi-elliptical arc that mimics the head of a mako shark, effectively reducing flow losses. At the same time, the trailing edge 213 of the blade 21 adopts a concave parabolic design of the tail fin of a mako shark, effectively weakening the unsteady impact between the airflow at the trailing edge 213 of the blade 21 and the wall of the volute 1 and the volute tongue wall. The blade 21 adopts a backward mako shark-inspired blade design, with both the windward side 215 and the leeward side 216 set as arc-shaped blade structures, giving the backward bionic blade 21 a semi-elliptical, streamlined rotating body structure with the swimming posture of a mako shark. This can effectively suppress undesirable flows such as flow separation and secondary flow in the blade passage, optimize the velocity distribution on the surface of the blade 21, reduce vortex intensity, reduce aerodynamic excitation, improve the aerodynamic performance of the fan, and thus improve the fan pressure and fan efficiency.

[0073] In this embodiment, the circumference diameter φ4 formed by the outermost ends of all blades is 705mm, and the circumference diameter φ5 formed by the innermost ends of all blades is 234.1mm-235.9mm; preferably, φ5 is 235mm.

[0074] In the front view of blade 21, the arc radius R10 of leading edge 211 is 525mm-532mm and the arc length is 96mm-99mm; the arc radius R11 of trailing edge 213 is 194mm-196mm and the arc length is 56.5mm-58mm; the vertical distance L4 between the first and second ends of leading edge 211 is 93.6mm-95.6mm; the vertical distance L5 between the first and second ends of trailing edge 213 is 56.5mm-57.5mm; the first... The vertical distance L6 between one end and the first end of the trailing edge 213 is 260mm-265mm, the length L7 of the first straight segment 2122 is 110mm-112mm, and the length L8 of the second side 214 is 289mm-294mm; preferably, R10 is 528.5mm and the arc length is 97.5mm, R11 is 195mm and the arc length is 57.2mm, L4 is 94.6mm, L5 is 57mm, L6 is 262.3mm, L7 is 111.1mm, and L8 is 291.6mm;

[0075] On the projection surface of the rear disc, the radius R2 of the arc on the windward side 215 is 398mm-402mm and the arc length is 310mm-316mm; the radius R3 of the arc on the leeward side 216 is 547mm-553mm and the arc length is 303mm-308mm; the radius R4 of the outer arc 2171 of the leading edge 211 near the wheel hub is 3.3mm-3.7mm and the arc length is 10mm-11mm; the radius R4 of the outer arc 2171 of the leading edge 211 away from the wheel hub is 3.3mm-3.7mm and the arc length is 10mm-11mm. The radius R8 of the inner arc 2172 at the leading edge of the hub is 4.7mm-5.3mm and the arc length is 13.8mm-15.4mm. The radius R5 of the outer arc 2181 at the trailing edge 213, which is away from the hub, is 1.9mm-2.1mm and the arc length is 8.5mm-9.5mm. The radius R9 of the inner arc 2182 at the trailing edge 213, which is close to the hub, is 1.95mm-2.25mm and the arc length is 5.9mm-6.5mm. Preferably, R2 is 400mm and the arc length is 313.1mm, R3 is 550mm and the arc length is 305.5mm, R4 is 3.5mm and the arc length is 10.6mm, R8 is 5mm and the arc length is 14.6mm, R5 is 2mm and the arc length is 9mm, and R9 is 2.1mm and the arc length is 6.2mm.

[0076] Through the above technical solution, the backward fish-shaped bionic blade 21 has a semi-elliptical, streamlined rotating body structure with the swimming posture of a mako shark, which can effectively suppress flow separation in the impeller 2 flow channel, optimize the flow velocity distribution on the surface of the blade 21, reduce vortex intensity, and improve the aerodynamic performance of the fan.

[0077] In this embodiment, a plurality of rhomboid grooves 219 are arranged in an array on one end of the windward surface 215 near the trailing edge 213. The direction parallel to the rear disc 23 is the lateral direction, and the direction perpendicular to the rear disc 23 is the longitudinal direction. The rhomboid grooves 219 are arranged in 4 rows in the lateral direction and 3 columns in the longitudinal direction. One acute angle of the rhomboid groove 219 faces the wheel hub and the other acute angle faces away from the wheel hub. One obtuse angle of the rhomboid groove 219 faces the rear disc 23 and the other obtuse angle faces away from the rear disc 23.

[0078] On the front view of blade 21:

[0079] The side length L14 of the rhomboid groove 219 is 39mm-41mm, and the acute angle ∠4 of the rhomboid groove 219 is 59°-61°; preferably, L14 is 40mm and ∠4 is 60°.

[0080] The distance L12 between the acute vertices of two adjacent rhomboid grooves 219 in each row is 17.3mm-17.7mm, and the distance L13 between the obtuse vertices of two adjacent rhomboid grooves 219 in each column is 21.5mm-22.5mm; preferably, L12 is 17.5mm and L13 is 22mm.

[0081] The vertical distance L11 between the acute angle vertex of a row of rhomboid grooves 219 near the trailing edge 213 and the second end of the rear plate 23 is 29.3mm-30.7mm. The distance between the obtuse angle vertex of a row of rhomboid grooves 219 near the first straight section 2122 and the first straight section 2122 is L9. The distance between the obtuse angle vertex of a row of rhomboid grooves 219 near the second side 214 and the second side 214 is L10. L9 and L10 are equal and both are 5.9mm-6.1mm. Preferably, L11 is 30mm, and L9 and L10 are equal and both are 6mm.

[0082] Through the above technical solution, the rear half of the windward surface 215 of the blade 21 is provided with non-smooth fish skin-like grooves, which can make the airflow tend to develop steadily, reduce the intensity of turbulent boundary layer pressure pulsation, effectively delay boundary layer separation, improve the flow state of turbulent boundary layer, reduce the periodic shedding of vortices at the tail of the blade 21 and the formation of vortices, further improve the fan pressure and fan efficiency, and help reduce noise.

[0083] In this embodiment, the diameter φ6 of the air intake 24 is 247mm-249mm, and the vertical distance L3 between the air intake 24 and the rear plate 23 is 109.8mm-112.2mm; preferably, φ6 is 248mm and L3 is 111mm.

[0084] In the direction from the leading edge 211 to the trailing edge 213, the front disc 22 includes a first arc segment 221, a second arc segment 222, and a straight segment 223 connected tangentially in sequence, with the straight segment 223 being arranged parallel to the rear disc 23.

[0085] Take a section of impeller 2 with a plane passing through the central axis of impeller 2. On the cross-section:

[0086] The radius R6 of the first arc segment 221 of the front disc is 62mm-64mm and the arc length is 57mm-60mm. The radius R7 of the second arc segment 222 of the front disc is 280mm-287mm and the arc length is 88mm-91mm. The length L2 of the straight segment 223 of the front disc is 104mm-107mm. Preferably, R6 is 63mm and the arc length is 58.5mm, R7 is 283.5mm and the arc length is 89.3mm, and L2 is 105.5mm.

[0087] Through the above technical solution, the design of the front plate 22, which transitions from an arc segment to a straight segment, can effectively guide the airflow into the impeller 2 flow channel and pressurize and throw the airflow out at high speed, further improving the fan pressure and efficiency.

[0088] In this embodiment, a front cover plate assembly 4 is also included. The front cover plate assembly 4 includes a volute connecting part 41, a reinforcing part 43 and a collector connecting part 42. The collector connecting part 42 is annular and has a collector receiving part 44 formed on its inner circumference.

[0089] The front cover plate assembly 4 is detachably connected to the collector 3 via the collector connection part 42, and the collector 3 is fixedly connected to the volute 1 via the volute connection part 41.

[0090] Through the above technical solution, the detachable and separate design of the front cover plate assembly 4 and the collector 3 provides a buffer space near the top of the front disc 22 of the impeller 2. Even if the height of the impeller 2 increases or the impeller 2 moves forward a certain distance, or if there are various errors such as processing errors, welding deformation, or manual assembly errors, it can effectively prevent the top of the front disc 22 of the impeller 2 and the front cover plate assembly 4 from rubbing against each other, thereby improving the operating efficiency and stability of the fan.

[0091] In this embodiment, the collector 3 includes a connecting part 31 and an air guide section 32. The air guide section 32 includes a straight air guide section 321 connected to the connecting part 31 and an arc-shaped air guide section 322 away from the connecting part 31. The connecting part 31 is annular and has an air inlet 33 formed on its inner circumference. The outlet of the air guide section 32 is annular and has an air guide outlet 34 formed on its inner circumference.

[0092] From the air inlet 33 to the air guide 34, the straight section 321 and part of the curved section 322 form a tapering section, and another part of the curved section 322 forms a widening section. The air guide section 32 is configured as an air guide structure that first tapes out from the tapering section to the widening section and then widens.

[0093] The air guide arc section 322 extends into the front disc 22 of the impeller 2, and a radial gap is provided between the collector 3 and the impeller 2.

[0094] Through the above technical solution, the collector 3, through the combined design of the air guide arc section 322 and the air guide straight section 321 of the air guide section 32, forms a tapering section with the air guide straight section 321 and part of the air guide arc section 322, and another part of the air guide arc section 322 forms a widening section. The funnel-shaped nozzle-type arc collector 3 formed by stretching a certain arc and height smoothly transitions with the arc section of the front plate 22 to form a gap fit transition dock, which reduces the mutual impact loss of airflow, reduces the impact of airflow entering the impeller 2 to generate vortices, and accelerates the airflow, effectively ensuring that the airflow smoothly enters the impeller 2, increasing the fan's air volume and air pressure, and significantly improving performance efficiency.

[0095] In this embodiment, the diameter φ1 of the air inlet 33 is 279mm-281mm, the diameter φ3 of the air guide 34 is 234.2mm-235.8mm, and the diameter φ2 at the narrowest point of the air guide arc 322 is 231.3mm-232.7mm; preferably, φ1 is 280mm, φ3 is 235mm, and φ2 is 232mm.

[0096] The collector 3 is cut along a plane passing through its central axis. In the cross-section: the radius R1 of the air guide arc 322 is 39.2mm-40.8mm and the arc length is 27mm-29.5mm; the length L1 of the air guide straight section 321 is 49mm-51mm; and the included angle ∠1 formed between the air guide straight section 321 and the connecting part 31 is 65°-66.5°. Preferably, R1 is 40mm and the arc length is 28.3mm, L1 is 49.8mm, and ∠1 is 65.7°.

[0097] The collector 3 extends into the front disc 22 of the impeller 2 by a length L19 of 6.6mm-7.4mm, and the radial clearance length L20 between the collector 3 and the impeller 2 is 5.7mm-6.3mm. Preferably, L19 is 7mm and L20 is 6mm.

[0098] Through the above technical solution, the collector 3 structure designed to match the impeller 2 and the volute 1 can efficiently and efficiently introduce airflow into the impeller, further improving the performance of the fan.

[0099] In this embodiment, the profile of the volute 1 includes a first diffuser straight section 11, a volute tongue section 12, a first arc section 13, a second arc section 14, a third arc section 15, a fourth arc section 16, and a second diffuser straight section 17 connected tangentially in sequence. The first diffuser straight section 11 and the second diffuser straight section 17 enclose and form an air outlet 18. The first arc section 13, the second arc section 14, the third arc section 15, and the fourth arc section 16 are not concentric.

[0100] A rectangular coordinate system is established with the center O of impeller 2 as the origin. When the first diffuser section 11 is located in the third quadrant, the coordinates of the center O1 of the first arc section 13 are (24, 24), the radius R12 is 383mm-389mm, and the arc length is 399mm-405mm. The coordinates of the center O2 of the second arc section 14 are (-24, 24), the radius R13 is 430.8mm-437.2mm, and the arc length is 676mm. The center O3 of the third arc segment 15 is (-24, -24), the radius R14 is 477.5mm-484.5mm, and the arc length is 750mm-761mm. The center O4 of the fourth arc segment 16 is (24, -24), the radius R15 is 525mm-533mm, and the arc length is 824mm-836mm. The first diffuser straight segment 11 and the second diffuser straight segment 17 are arranged in parallel. Preferably, R12 is 386mm and the arc length is 401.7mm, R13 is 434mm and the arc length is 681mm, R14 is 481mm and the arc length is 755.6mm, and R15 is 529mm and the arc length is 830.2mm.

[0101] Through the above technical solution, a logarithmic spiral volute 1 profile structure is adopted. By improving the profile and width of volute 1 to suit the structure of the backward impeller 2 with the imitation mako shark blade 21, flow loss is reduced, the velocity distribution of all internal flow points can be effectively controlled, the optimal flow state inside the fan is obtained, the efficiency of fluid transport is optimized, the airflow in the space inside volute 1 is ensured to be unobstructed, and the fan efficiency is further improved.

[0102] In this embodiment, the height L17 of the air outlet 18 is 200mm-204mm, and the width L18 of the air outlet 18 is 144mm-146mm; preferably, L17 is 202mm and L18 is 145mm.

[0103] The radius R16 of the volute tongue segment 12 is 21.5mm-22.5mm and the arc length is 56.5mm-58.5mm. The length L15 of the first diffuser straight segment 11 is 181.5mm-184.5mm, and the length L16 of the second diffuser straight segment 17 is 386mm-392mm. A tangent line is drawn to the volute tongue segment 12 with the tangent point between it and the first arc segment. The angle ∠5 between this tangent line and the first diffuser straight segment 11 is 30°-31°. Preferably, R16 is 22mm and the arc length is 57.5mm, L15 is 183mm, L16 is 389.3mm, and ∠5 is 30.4°.

[0104] By using the above technical solutions, matching the volute profile 1 of the impeller 2 and the collector 3 can reduce the impact of airflow and energy loss, thereby improving the efficiency of the fan.

[0105] In this embodiment, a motor 5 and a base 6 are also included. The motor 5 is connected to the impeller 2 via a transmission shaft, and both the volute 1 and the motor 5 are fixedly mounted on the base 6.

[0106] It should be noted that the essential components such as the motor 5 and the base 6 involved in this invention are not improvements of this invention, and those skilled in the art are familiar with the structure and working principle of the basic components, so they will not be described in detail here.

[0107] To verify this embodiment, based on the preferred structural parameters provided in this embodiment, a backward high-pressure centrifugal fan with imitation mackerel-shaped blades was tested using an impeller 2 with a diameter of 705 mm (i.e., the diameter of the outer circumference formed by the outer ends of all blades 21 of the impeller 2). Simultaneously, a conventional high-pressure centrifugal fan with an impeller 2 having a diameter of 705 mm and forward single-arc equal-thickness blades 21 was tested as a comparative example. The test results were converted to atmospheric pressure of 101325 Pa, atmospheric temperature of 20 ℃, fan speed of 2930 r / min, and medium density of 1.2 kg / m³. 3 Test data under test conditions, and test examples yielded the test data shown in Table 1. Figure 13 The performance curves shown are used to derive test data as shown in Table 2. Figure 14 The performance curves shown represent the volumetric flow rate (qvsglGu), A-weighted sound level (LAGu), fan efficiency (ηr), impeller power (PrGu), total pressure (pFGu), and static pressure (psFGu).

[0108] Table 1

[0109]

[0110] Table 2

[0111]

[0112] The test data and performance curves show that, compared to the test case, the comparative example is inferior in terms of fan efficiency, volumetric flow rate, and total pressure. In contrast, the optimal fan efficiency of the test case is 78.374%, while the optimal fan efficiency of the comparative example is 72.825%. Furthermore:

[0113] (1) Under the same or similar volumetric flow rate, such as the volumetric flow rate of the test case being 6026.8 m³ / s. 3 At the fourth operating point (per hour), the fan efficiency was 78.374%, and the total pressure was 9140.5 Pa; the comparative volumetric flow rate was 6047.6 m³ / h. 3 At the 7th operating point of / h, the fan efficiency is 60.172% and the total pressure is 7511.7Pa;

[0114] (2) Under the same or similar total pressure, such as the 7th operating point where the total pressure in the test case is 7902.1 Pa, the fan efficiency is 73.975% and the volumetric flow rate is 7922.7 m³ / s. 3 / h; at the sixth operating point with a total pressure of 7966.9 Pa (comparative example), the fan efficiency is 64.571% and the volumetric flow rate is 5668.1 m³ / h. 3 / h;

[0115] (3) Compared with the comparative example, the performance curve of the test example is broad and flat, making it easier to select the high-efficiency range when selecting the fan, and the reasonable working range is larger; and the static pressure performance curve of the backward impeller fan of the test example does not have a pressure instability hump region, so it will not surge when the flow rate is too small; while the static pressure performance curve of the forward impeller fan of the comparative example has a pressure instability hump region, and surge is likely to occur when the flow rate is too small, resulting in excessive fan vibration and noise, which may lead to failure to use normally or even damage and shutdown.

[0116] In summary, the test cases generally have larger volumetric flow rates, higher total pressure, and higher efficiency compared to the comparative examples.

[0117] The results above show that the backward high-pressure centrifugal fan with mackerel-shaped blades of the present invention has higher pressure, higher efficiency and greater flow rate.

[0118] Where there is no conflict, the above embodiments and features can be combined with each other.

[0119] 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 backward-facing high-pressure centrifugal fan with mackerel-shaped blades, comprising a volute, an impeller, and a collector, wherein the impeller is disposed within the volute, and a portion of the collector extends into the volute and another portion extends out of the volute, the collector being fixedly connected to the volute; the impeller comprises a front plate and a rear plate, the rear plate having a plurality of blades arranged in an array around it, and the front plate having an air intake at its center, characterized in that: The blade includes a leading edge, a trailing edge, a windward side, a leeward side, a first side connecting the first end of the leading edge and the first end of the trailing edge, and a second side connecting the second end of the leading edge and the second end of the trailing edge. The first side is the side closest to the air inlet, and the second side is the side furthest from the air inlet. The leading edge is inclined from the first side to the second side, and the inclination direction is gradually closer to the impeller hub. Both the leading and trailing edges are set in an arc shape in the direction from the front disc to the rear disc. Both the windward and leeward sides are set in an arc shape in the direction from the leading edge to the trailing edge. The first side includes a first side arc segment and a first side straight segment. The second side is set in a straight segment structure. The thickness of the blade gradually increases and then gradually decreases in the direction from the leading edge to the trailing edge. The thickness of the leading edge is greater than the thickness of the trailing edge. In the front view of the blade, the arc-shaped structure at the leading edge is concave to the blade, the arc-shaped structure at the trailing edge is concave to the blade, the straight section of the first side is parallel to the second side, the arc-shaped section of the first side is set as a continuous multi-segment arc-shaped structure, the arc surface of the first side is set as an inclined structure from the leeward side to the windward side, and the first side gradually moves closer to the second side from the leading edge to the trailing edge, and the inclination of the arc surface of the first side gradually decreases. The inlet angle ∠2 during blade installation is 34.5°-35.5°, and the outlet angle ∠3 during blade installation is 47.2°-48.8°. The number of leaves is 12; The diameter of the circle formed by the outermost ends of all the blades, φ4, is 705 mm, and the diameter of the circle formed by the innermost ends of all the blades, φ5, is 234.1 mm to 235.9 mm. In the front view of the blade, the radius of curvature R10 of the leading edge is 525mm-532mm and the arc length is 96mm-99mm; the radius of curvature R11 of the trailing edge is 194mm-196mm and the arc length is 56.5mm-58mm; the vertical distance L4 between the first end and the second end of the leading edge is 93.6mm-95.6mm; the vertical distance L5 between the first end and the second end of the trailing edge is 56.5mm-57.5mm; the vertical distance L6 between the first end and the first end of the trailing edge is 260mm-265mm; the length L7 of the straight section of the first side is 110mm-112mm; and the length L8 of the second side is 289mm-294mm. On the projection surface of the rear disc, the radius of the arc on the windward side, R2, is 398mm-402mm and the arc length is 310mm-316mm; the radius of the arc on the leeward side, R3, is 547mm-553mm and the arc length is 303mm-308mm; the radius of the outer arc of the leading edge near the hub, R4, is 3.3mm-3.7mm and the arc length is 10mm-11mm; the radius of the inner arc of the leading edge away from the hub, R8, is 4.7mm-5.3mm and the arc length is 13.8mm-15.4mm; the radius of the outer arc of the trailing edge away from the hub, R5, is 1.9mm-2.1mm and the arc length is 8.5mm-9.5mm; and the radius of the inner arc of the trailing edge near the hub, R9, is 1.95mm-2.25mm and the arc length is 5.9mm-6.5mm. On the windward side, near the tail edge, there are multiple diamond-shaped grooves arranged in an array. The direction parallel to the rear disc is the horizontal direction, and the direction perpendicular to the rear disc is the vertical direction. The diamond-shaped grooves are arranged in 4 rows in the horizontal direction and 3 columns in the vertical direction. One acute angle of the diamond-shaped groove faces the wheel hub and the other acute angle faces away from the wheel hub. One obtuse angle of the diamond-shaped groove faces the rear disc and the other obtuse angle faces away from the rear disc. On the front view of the blade: The side length L14 of the rhomboid groove is 39mm-41mm, and the acute angle ∠4 of the rhomboid groove is 59°-61°. The distance L12 between the acute vertices of two adjacent rhomboid grooves in each row is 17.3mm-17.7mm, and the distance L13 between the obtuse vertices of two adjacent rhomboid grooves in each column is 21.5mm-22.5mm. The vertical distance L11 between the acute angle vertex of the row of rhomboid grooves near the tail edge and the second end of the rear plate is 29.3mm-30.7mm. The distance between the obtuse angle vertex of the row of rhomboid grooves near the first straight section and the first straight section is L9. The distance between the obtuse angle vertex of the row of rhomboid grooves near the second side and the second side is L10. L9 and L10 are equal and both are 5.9mm-6.1mm.

2. A backward-facing high-pressure centrifugal fan with mackerel-shaped blades according to claim 1, characterized in that: The diameter of the air intake φ6 is 247mm-249mm, and the vertical distance L3 between the air intake and the rear plate is 109.8mm-112.2mm. From the leading edge to the trailing edge, the front disc includes a first arc segment, a second arc segment, and a straight segment connected tangentially in sequence, with the straight segment of the front disc arranged parallel to the rear disc. The impeller is sectioned by a plane passing through its central axis. On the cross-section: The radius R6 of the first arc segment of the front disc is 62mm-64mm and the arc length is 57mm-60mm. The radius R7 of the second arc segment of the front disc is 280mm-287mm and the arc length is 88mm-91mm. The length L2 of the straight segment of the front disc is 104mm-107mm.

3. A backward high-pressure centrifugal fan with mackerel-shaped blades according to claim 2, characterized in that: It also includes a front cover plate assembly, which includes a volute connecting part, a reinforcing part and a collector connecting part, wherein the collector connecting part is annular and the inner circumference forms a collector receiving part; The front cover assembly is detachably connected to the collector via the collector connection part, and the collector is fixedly connected to the volute via the volute connection part.

4. A backward high-pressure centrifugal fan with mackerel-shaped blades according to claim 3, characterized in that: The collector includes a connecting part and an air guide section. The air guide section includes a straight air guide section connected to the connecting part and an arc-shaped air guide section away from the connecting part. The connecting part is annular and has an air inlet formed on its inner circumference. The air guide section has an annular outlet and has an air guide outlet formed on its inner circumference. From the air inlet to the air outlet, the straight section of the air guide and a part of the curved section of the air guide form a tapering section, and another part of the curved section of the air guide forms a widening section. The air guide section is designed to be a guide structure that first tapes out from the tapering section to the widening section and then widens out. The air guide arc section extends into the front disc of the impeller, and a radial clearance is provided between the collector and the impeller.

5. A backward high-pressure centrifugal fan with mackerel-shaped blades according to claim 4, characterized in that: The diameter of the air inlet φ1 is 279mm-281mm, the diameter of the air guide φ3 is 234.2mm-235.8mm, and the diameter of the narrowest part of the air guide arc φ2 is 231.3mm-232.7mm. The collector is cut off by a plane passing through its central axis. In the cross section: the radius R1 of the air guide arc is 39.2mm-40.8mm and the arc length is 27mm-29.5mm; the length L1 of the air guide straight section is 49mm-51mm; and the included angle ∠1 formed between the air guide straight section and the connecting part is 65°-66.5°. The length L19 of the collector extending into the front disc of the impeller is 6.6mm-7.4mm, and the radial clearance length L20 between the collector and the impeller is 5.7mm-6.3mm.

6. A backward-facing high-pressure centrifugal fan with mackerel-shaped blades according to claim 5, characterized in that: The profile of the volute includes a first diffuser straight section, a volute tongue section, a first arc section, a second arc section, a third arc section, a fourth arc section, and a second diffuser straight section that are connected tangentially in sequence. The first diffuser straight section and the second diffuser straight section enclose and form an air outlet. The first arc section, the second arc section, the third arc section, and the fourth arc section are not concentric. A rectangular coordinate system is established with the impeller center O as the origin. When the first diffuser section is located in the third quadrant, the coordinates of the center O1 of the first arc section are (24, 24), the radius R12 is 383mm-389mm, and the arc length is 399mm-405mm. The coordinates of the center O2 of the second arc section are (-24, 24), the radius R13 is 430.8mm-437.2mm, and the arc length is 676mm-686mm. The coordinates of the center O3 of the third arc section are (-24, -24), the radius R14 is 477.5mm-484.5mm, and the arc length is 750mm-761mm. The coordinates of the center O4 of the fourth arc section are (24, -24), the radius R15 is 525mm-533mm, and the arc length is 824mm-836mm. The first diffuser section and the second diffuser section are set in parallel.

7. A backward-facing high-pressure centrifugal fan with mackerel-shaped blades according to claim 6, characterized in that: The height of the air outlet L17 is 200mm-204mm, and the width of the air outlet L18 is 144mm-146mm; The radius R16 of the volute tongue segment is 21.5mm-22.5mm and the arc length is 56.5mm-58.5mm. The length L15 of the first diffuser straight segment is 181.5mm-184.5mm, and the length L16 of the second diffuser straight segment is 386mm-392mm. 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 ∠5 between this tangent line and the first diffuser straight segment is 30°-31°.

8. A backward high-pressure centrifugal fan with mackerel-shaped blades according to claim 7, characterized in that: It also includes a motor and a base. The motor is connected to the impeller via a drive shaft, and both the volute and the motor are fixedly mounted on the base.

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