A high head centrifugal fan with backward leaning airfoil blades

Abstract

The application relates to the technical field of centrifugal fans, in particular to a high-pressure-head centrifugal fan with backward-inclined blade, which comprises a volute, an impeller and a flow collector, the impeller and the flow collector are arranged in the volute, and the flow collector is fixedly connected with the volute; the impeller comprises a front disc and a rear disc, a plurality of blades are arranged in an array on the rear disc, a suction port is arranged in the middle of the front disc, the blades are arranged in a single-plate straight structure, the blade comprises a leading edge, a trailing edge, a first side connected between the first end of the leading edge and the first end of the trailing edge, and a second side connected between the second end of the leading edge and the second end of the trailing edge, the first side is a side close to the suction port, and the second side is a side far away from the suction port; the leading edge comprises a leading edge arc segment close to the suction port and a leading edge straight segment far away from the suction port, the trailing edge is arranged in a straight segment structure, the leading edge straight segment and the trailing edge are arranged in parallel with the hub of the impeller, and the second side is arranged in perpendicular to the hub of the impeller. The high-pressure-head centrifugal fan has greater flow and higher pressure.

Description

Technical Field

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

[0002] In modern building design, kitchen exhaust ducts are particularly long, resulting in high system resistance. This necessitates a fan that can stably deliver large volumes of gas under high static pressure to effectively extract kitchen fumes. Currently, while traditional multi-blade forward-curved fan can generate high pressure and large flow rates, its power curve is prone to overload, and it also suffers from problems such as oil buildup, poor vibration resistance, and low fatigue life.

[0003] The flow rate and pressure of the high-pressure centrifugal fan need to be further improved, and issues such as oil adhesion, poor vibration resistance and fatigue life need to be further addressed. Summary of the Invention

[0004] The purpose of this invention is to provide a high-pressure centrifugal fan with backward-curved blades, which aims to solve the problems of existing high-pressure centrifugal fans, such as the need for further improvement in flow rate and pressure, oil adhesion, poor vibration resistance and fatigue life.

[0005] To achieve the above objectives, a high-pressure centrifugal fan with backward-curved blades includes a volute, an impeller, and a collector. Both the impeller and the collector are housed within the volute, and the collector is fixedly connected to the volute. The impeller includes a front plate and a rear plate, with multiple blades arranged in an array around the rear plate, and an air intake is located in the center of the front plate.

[0006] The blade is designed as a single-plate straight structure. The blade includes a leading edge, a trailing edge, 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.

[0007] The leading edge includes a leading edge arc section near the air inlet and a leading edge straight section away from the air inlet. The trailing edge is set as a straight section structure. Both the leading edge straight section and the trailing edge are set parallel to the impeller hub, and the second side is set perpendicular to the impeller hub.

[0008] The first side includes a single arc segment and multiple arc segments. The single arc segment is connected to the leading edge arc segment, and the multiple arc segments are connected to the trailing edge. The multiple arc segments are set as a continuous multi-segment arc structure, and the thickness of the blade remains unchanged from the leading edge to the trailing edge.

[0009] The exit angle ∠2 during blade installation is 49°-51°;

[0010] The number of leaves is 16.

[0011] Furthermore, the circumference diameter φ1 formed by the outermost ends of all the blades is 515mm, and the circumference diameter φ2 formed by the innermost ends of all the blades is 356.4mm-358mm.

[0012] On the unfolded diagram of the blade, the vertical distance L11 between the first end of the leading edge and the second end of the leading edge is 203mm-208mm, the vertical distance L12 between the first end of the leading edge and the first end of the trailing edge is 100mm-103mm, the radius R7 of the single arc segment on the first side is 103mm-105.5mm and the arc length is 30mm-32mm, and the length L7 of the second side is 128.5mm-131.5mm.

[0013] The thickness t of the blade is 2.4mm-2.6mm.

[0014] Furthermore, the diameter of the air intake φ3 is 364mm-366mm, the vertical distance L10 between the air intake and the rear plate is 212mm-217mm, and the circumference diameter φ4 formed by the intersection of the leading edge arc of all blades and the front plate is 380.8mm-383.2mm.

[0015] The front disc is designed with a single-arc structure;

[0016] The impeller is sectioned by a plane passing through its central axis. On the cross-section:

[0017] The radius of the arc of the front disc, R6, is 89mm-91mm and the arc length is 88.9mm-91.5mm. The radius of the leading edge arc segment, R5, is 412mm-416mm and the arc length is 102mm-105mm. The length of the straight section of the leading edge, L9, is 97.6mm-99.6mm. The length of the trailing edge, L8, is 163.5mm-166.5mm.

[0018] Furthermore, ∠2 is 50°, φ2 is 357.3mm, L11 is 205.5mm, L12 is 101.7mm, R7 is 104.3mm with an arc length of 31mm, L7 is 130mm, t is 2.5mm, φ3 is 365mm, L10 is 215mm, φ4 is 382mm, R6 is 90mm with an arc length of 90.2mm, R5 is 414.3mm with an arc length of 103.3mm, L9 is 98.6mm, and L8 is 165mm.

[0019] Furthermore, the collector includes a connecting part and a guide section. The collector is fixedly connected to the volute through the connecting part. The guide section includes a straight guide section connected to the connecting part and an arc guide section away from the connecting part. The connecting part is annular and has an air inlet formed on its inner circumference. The outlet of the guide section is annular and has an air inlet formed on its inner circumference.

[0020] 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.

[0021] 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.

[0022] Furthermore, the diameter of the air inlet φ5 is 498mm-502mm, the diameter of the air guide φ7 is 354.5mm-357.5mm, and the diameter of the narrowest part of the air guide arc φ6 is 318.7mm-321.3mm;

[0023] The collector is cut off by a plane passing through its central axis. In the cross section: the radius R8 of the air guide arc is 49mm-51mm and the arc length is 76mm-79mm; the length L13 of the air guide straight section is 117.5mm-120.5mm; and the included angle ∠3 formed between the air guide straight section and the connecting part is 48.3°-50.1°.

[0024] The length L1 of the collector extending into the front disc of the impeller is 4.8mm-5.2mm, and the radial clearance length L2 between the collector and the impeller is 5.3mm-5.9mm.

[0025] Furthermore, φ5 is 500mm, φ7 is 356mm, φ6 is 320mm, R8 is 50mm with an arc length of 77.7mm, L13 is 119mm, ∠3 is 49.2°, L1 is 5mm, and L2 is 5.6mm.

[0026] 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, 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, and the third arc section are not concentric.

[0027] A rectangular coordinate system is established with the center O of the impeller 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 (29.8, 29.8), the radius R2 is 330mm-332mm and the arc length is 531mm-536mm. The coordinates of the center O4 of the second arc section are (34, -34), the radius R3 is 393.5mm-396mm and the arc length is 619mm-624.5mm. The coordinates of the center O3 of the third arc section are (-38.4, -38.4), the radius R4 is 465mm-469mm and the arc length is 785.5mm-792mm. The first diffuser section and the second diffuser section are set in parallel.

[0028] Furthermore, the height L5 of the air outlet is 447mm-453mm, and the width L6 of the air outlet is 375.5mm-392.5mm;

[0029] The radius R1 of the volute tongue segment is 19.5mm-20.5mm and the arc length is 34.5mm-36mm. The length L3 of the first diffuser straight segment is 32mm-33mm, and the length L4 of the second diffuser straight segment is 307mm-311mm. A tangent line is drawn to the volute tongue segment through the point of tangency between the volute tongue segment and the first arc segment. The angle ∠1 between this tangent line and the first diffuser straight segment is 78°-80°.

[0030] Furthermore, it also includes an I-beam flange, a motor, and a base. The I-beam flange, the connecting part, and the volute are connected in sequence by fasteners. The motor is connected to the impeller via a drive shaft. Both the volute and the motor are fixedly mounted on the base.

[0031] Compared with the prior art, the high-pressure head centrifugal fan with backward-curved blades provided by the present invention has the following beneficial effects:

[0032] (1) Through the design of the blade, the blade is designed as a knife-shaped structure. After the airflow is guided from the collector to the impeller, it is divided into sections by the leading edge arc section (similar to a knife edge) and the leading edge straight section (similar to a knife body) and then introduced into the blade surface for transportation. In the long blade-shaped blade, the blade (leading edge arc section) faces the airflow inlet, which can better adapt to the changes in the airflow inside the fan, greatly reduce flow separation and eddy loss, increase the fan flow and pressure, reduce oil stain adhesion, and improve vibration resistance and fatigue life. The flow channel design of the backward-curved blade can make the inlet smooth and the gas accelerate smoothly, generate a high pressure head while avoiding surge, and widen the high-efficiency working range.

[0033] (2) The blades adopt a narrow-width-ratio plate-type large-angle backward structure, which improves the self-cleaning ability of oil stains adhering to the impeller before static solidification, and the oil stains are more likely to fall off by their own weight when the impeller is stationary, effectively improving the self-cleaning efficiency of the fan.

[0034] (3) Adapt to the overall performance of the fan. By adopting a conical horn-shaped collector structure, the convergence of the collector matches the impeller, which can make the airflow smooth and accelerate, and the pressure gradient change is gradual. This ensures that the fan can operate continuously and efficiently during the airflow delivery process, maintain the stability of the impeller's normal operation, and is conducive to the improvement of the fan's flow rate and pressure.

[0035] (4) The fan with a three-arc volute profile with an unequal side base can form a large flow channel that can accelerate the airflow smoothly and reduce the pressure gradient change. This reduces the impact force of the airflow in the volute and the friction loss, which is conducive to achieving large air volume delivery and increasing delivery pressure. Attached Figure Description

[0036] Figure 1 This is a schematic diagram of the structure of a high-pressure centrifugal fan with backward-curved blades according to the present invention;

[0037] Figure 2 This is a schematic diagram of the volute structure;

[0038] Figure 3 This is a side view of the volute.

[0039] Figure 4 This is a schematic diagram of the impeller structure;

[0040] Figure 5 This is a side sectional view of the impeller;

[0041] Figure 6 This is a schematic diagram of the blade's unfolded structure;

[0042] Figure 7 This is a schematic diagram of the three-dimensional structure of the impeller;

[0043] Figure 8 A three-dimensional structural diagram of the impeller without the front disc;

[0044] Figure 9 This is a side sectional view of the collector;

[0045] Figure 10 This is a performance curve diagram of the present invention;

[0046] Figure 11 This is a proportional performance curve.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1. Volute; 11. First diffuser straight section; 12. Volute tongue section; 13. First arc section; 14. Second arc section; 15. Third arc section; 16. Second diffuser straight section; 17. Air outlet;

[0049] Impeller 2; Blade 21; Leading edge 211; Leading edge arc segment 2111; Leading edge straight segment 2112; First side 212; First side single arc segment 2121; First side multi-arc segment 2122; Trailing edge 213; Second side 214; Front plate 22; Rear plate 23; Air inlet 24;

[0050] Collector 3; Connector 31; Air guide section 32; Straight air guide section 321; Arc air guide section 322; Air inlet 33; Air outlet 34;

[0051] 4. I-beam flange; 5. Motor; 6. Base. Detailed Implementation

[0052] The present invention will be described in detail below with reference to specific embodiments.

[0053] 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.

[0054] 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 500mm, it can be scaled by 0.1-30 times, etc.). Such reasonable proportional scaling also falls within the protection scope of this invention.

[0055] Please see Figure 1-11 A high-pressure centrifugal fan with backward-curved blades includes a volute 1, an impeller 2, and a collector 3. The impeller 2 and the collector 3 are both disposed inside the volute 1, and 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 inlet 24 is provided in the middle of the front plate 22.

[0056] The blade 21 is configured as a single-plate straight structure. The blade 21 includes a leading edge 211, a trailing edge 213, 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 intake 24, and the second side 214 is the side away from the air intake 24.

[0057] The leading edge 211 includes a leading edge arc segment 2111 near the air inlet 24 and a leading edge straight segment 2112 away from the air inlet 24. The trailing edge 213 is set as a straight segment structure. Both the leading edge straight segment 2112 and the trailing edge 213 are arranged parallel to the hub of the impeller 2. The second side 214 is arranged perpendicular to the hub of the impeller 2.

[0058] The first side 212 includes a first side single arc segment 2121 and a first side multi-arc segment 2122. The first side single arc segment 2121 is connected to the leading edge arc segment 2111, and the first side multi-arc segment 2122 is connected to the trailing edge 213. The first side multi-arc segment 2122 is set as a continuous multi-segment arc structure. The thickness of the blade 21 remains unchanged from the leading edge 211 to the trailing edge 213.

[0059] The exit angle ∠2 when blade 21 is installed is 49°-51°; preferably, ∠2 is 50°;

[0060] There are 16 leaves in leaf 21.

[0061] Through the above technical solution, the blade 21 is designed as a knife-shaped structure. After the airflow is guided from the collector 3 to the impeller 2, it is divided and guided onto the blade surface by the leading edge arc section 2111 (similar to a knife edge) and the leading edge straight section 2112 (similar to a knife body). In the long knife-shaped blade design, the blade 21 (leading edge arc section 2111) faces the airflow inlet, which can better adapt to the changes in airflow inside the fan, significantly reducing flow separation and eddy current losses, increasing the fan's flow rate and pressure, reducing oil adhesion, and improving vibration resistance and fatigue life. The flow channel design of the backward-curved blade 21 can ensure smooth inlet and smooth gas acceleration, generating a high-pressure head while avoiding surge, and widening the high-efficiency working range. It can meet the needs of modern kitchens with long flues and high-resistance fume extraction.

[0062] In this embodiment, the circumferential diameter φ1 formed by the outermost ends of all blades 21 is 515mm, and the circumferential diameter φ2 formed by the innermost ends of all blades 21 is 356.4mm-358mm; preferably, φ2 is 357.3mm.

[0063] In the unfolded view of blade 21, the vertical distance L11 between the first end of leading edge 211 and the second end of leading edge 211 is 203mm-208mm, the vertical distance L12 between the first end of leading edge 211 and the first end of trailing edge 213 is 100mm-103mm, the radius R7 of the first side single arc segment 2121 is 103mm-105.5mm and the arc length is 30mm-32mm, and the length L7 of the second side 214 is 128.5mm-131.5mm; preferably, L11 is 205.5mm, L12 is 101.7mm, R7 is 104.3mm and the arc length is 31mm, and L7 is 130mm;

[0064] The thickness t of blade 21 is 2.4mm-2.6mm. Preferably, t is 2.5mm.

[0065] Through the above technical solution, the blade 21 adopts a narrow-aspect-ratio plate-type large-angle backward structure, which improves the self-cleaning ability of oil stains adhering to the impeller 2 before solidification. Furthermore, when the impeller 2 is stationary, the oil stains are more easily detached by gravity, effectively improving the self-cleaning efficiency of the fan. More preferably, to improve the durability of the blade 2, the blade 2 is made of high-grade carbon steel, and undergoes sandblasting, spraying, and baking processes to ensure the service life of the fan.

[0066] In this embodiment, the diameter φ3 of the air intake 24 is 364mm-366mm, the vertical distance L10 between the air intake 24 and the rear plate 23 is 212mm-217mm, and the circumference diameter φ4 formed by the intersection of the leading edge arc segments 2111 of all blades 21 and the front plate 22 is 380.8mm-383.2mm; preferably, φ3 is 365mm, L10 is 215mm, and φ4 is 382mm.

[0067] The front disc 22 is designed with a single arc structure;

[0068] Take a section of impeller 2 with a plane passing through the central axis of impeller 2. On the cross-section:

[0069] The radius R6 of the front disc 22 is 89mm-91mm and the arc length is 88.9mm-91.5mm. The radius R5 of the leading edge arc segment 2111 is 412mm-416mm and the arc length is 102mm-105mm. The length L9 of the leading edge straight segment 2112 is 97.6mm-99.6mm. The length L8 of the trailing edge 213 is 163.5mm-166.5mm. Preferably, R6 is 90mm and the arc length is 90.2mm, R5 is 414.3mm and the arc length is 103.3mm, L9 is 98.6mm, and L8 is 165mm.

[0070] Through the above technical solution, the arc-shaped structure of the front plate 22 matches the structure of the blade 21, forming a straight tapering impeller 2 flow channel from the leading edge 211 to the trailing edge 213, which can make the inlet smooth and the gas accelerate smoothly, generate a high pressure head while avoiding surge, and widen the high-efficiency working range.

[0071] In this embodiment, the collector 3 includes a connecting part 31 and an air guide section 32. The collector 3 is fixedly connected to the volute 1 through the connecting part 31. 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.

[0072] 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.

[0073] 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.

[0074] Through the above technical solution, the overall performance of the fan is adapted. By adopting the conical horn-shaped collector 3 structure, the convergence of the collector 3 matches the impeller 2, which can make the airflow smooth and accelerate, and the pressure gradient change is gradual. This ensures that the fan can operate continuously and efficiently during the airflow delivery process, maintain the stability of the impeller 2's normal operation, and is conducive to improving the fan's flow rate and pressure.

[0075] In this embodiment, the diameter φ5 of the air inlet 33 is 498mm-502mm, the diameter φ7 of the air guide 34 is 354.5mm-357.5mm, and the diameter φ6 at the narrowest point of the air guide arc 322 is 318.7mm-321.3mm; preferably, φ5 is 500mm, φ7 is 356mm, and φ6 is 320mm.

[0076] The collector 3 is cut along a plane passing through its central axis. In the cross-section: the radius R8 of the air guide arc 322 is 49mm-51mm and the arc length is 76mm-79mm; the length L13 of the air guide straight section 321 is 117.5mm-120.5mm; and the included angle ∠3 formed between the air guide straight section 321 and the connecting part 31 is 48.3°-50.1°. Preferably, R8 is 50mm and the arc length is 77.7mm, L13 is 119mm, and ∠3 is 49.2°.

[0077] The collector 3 extends into the front disc 22 of the impeller 2 by a length L1 of 4.8mm-5.2mm, and the radial clearance length L2 between the collector 3 and the impeller 2 is 5.3mm-5.9mm. Preferably, L1 is 5mm and L2 is 5.6mm.

[0078] 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, and a second diffuser straight section 16 connected tangentially in sequence. The first diffuser straight section 11 and the second diffuser straight section 16 enclose and form an air outlet 17. The first arc section 13, the second arc section 14, and the third arc section 15 are not concentric.

[0079] 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 (29.8, 29.8), the radius R2 is 330mm-332mm and the arc length is 531mm-536mm. The coordinates of the center O4 of the second arc section 14 are (34, -34), the radius R3 is 393.5mm-396mm and the arc length is 619mm-624.5mm. The coordinates of the center O3 of the third arc section 15 are (-38.4, -38.4), the radius R4 is 465mm-469mm and the arc length is 785.5mm-792mm. The first diffuser section 11 and the second diffuser section 16 are set in parallel. Preferably, R2 is 330.9 mm with an arc length of 533.4 mm, R3 is 394.7 mm with an arc length of 621.8 mm, and R4 is 467.1 mm with an arc length of 788.5 mm.

[0080] Through the above technical solution, the fan's convergent structure with a three-arc section volute of unequal sides forms a large flow channel that enables the airflow to accelerate smoothly and the pressure gradient to change gently. This reduces the impact force and friction loss of the airflow within the volute, which is beneficial for achieving large-volume delivery and increasing delivery pressure.

[0081] In this embodiment, the height L5 of the air outlet 17 is 447mm-453mm, and the width L6 of the air outlet 17 is 375.5mm-392.5mm; preferably, L5 is 450mm and L6 is 390mm.

[0082] The radius R1 of the volute tongue segment 12 is 19.5mm-20.5mm and the arc length is 34.5mm-36mm. The length L3 of the first diffuser straight segment 11 is 32mm-33mm, and the length L4 of the second diffuser straight segment 16 is 307mm-311mm. A tangent is drawn to the volute tongue segment 12 through the point of tangency between the volute tongue segment 12 and the first arc segment 13. The angle ∠1 between this tangent and the first diffuser straight segment 11 is 78°-80°. Preferably, R1 is 20mm and the arc length is 35.2mm, L3 is 32.5mm, L4 is 309.2mm, and ∠1 is 79.3°.

[0083] In this embodiment, it also includes an I-beam flange 4, a motor 5, and a base 6. The I-beam flange 4, the connecting part 31, and the volute 1 are connected in sequence by fasteners. The motor 5 is connected to the impeller 2 via a drive shaft. The volute 1 and the motor 5 are both fixedly mounted on the base 6.

[0084] It should be noted that the essential components involved in this invention, such as the I-beam flange 4, the motor 5, and the base 6, 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.

[0085] To verify this embodiment, based on the preferred structural parameters provided in this embodiment, a high-pressure centrifugal fan with backward-curved blades was tested using an impeller 2 with a diameter of 500 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 was tested using an impeller 2 with a conventional blade diameter of 500 mm as a comparative example. The test results were converted to atmospheric pressure of 101325 Pa, atmospheric temperature of 20 ℃, fan speed of 1450 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 10 The performance curves shown are used to derive test data as shown in Table 2. Figure 11 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).

[0086] Table 1

[0087]

[0088] Table 2

[0089]

[0090] The test data and performance curves show that, compared to the test case, the comparative example performs worse in terms of volumetric flow rate, total pressure, and static pressure. In contrast:

[0091] (1) Under optimal fan efficiency: When the optimal fan efficiency of the test case is 78.736% at the third operating point, the volumetric flow rate is 7797.5 m³ / s. 3 / h, total pressure is 837.82 Pa, static pressure is 746.82 Pa; at the fourth operating point where the optimal fan efficiency is 78.956%, the volumetric flow rate is 6158.1 m³ / h. 3 / h, total pressure is 631.98Pa, static pressure is 550.96Pa; at the optimal fan efficiency, compared with the control group, the test case showed a 26.62% increase in volumetric flow rate, a 32.57% increase in total pressure, and a 35.55% increase in static pressure;

[0092] (2) Under the effective operating conditions of points 2-5: the volumetric flow rate of the test case is 6702.9 m³ / s. 3 / h-9955.6m 3 / h, total pressure ranges from 592.08 Pa to 942.14 Pa, static pressure ranges from 443.29 Pa to 874.96 Pa; the comparative volumetric flow rate ranges from 4276.7 m³ / h. 3 / h-7085.7m 3 / h, total pressure range is 516.21Pa-757.92Pa, static pressure range is 408.82Pa-718.90Pa;

[0093] In summary, the test cases generally have larger volumetric flow rates, higher total pressure, and higher static pressure compared to the comparative examples.

[0094] The results above show that the high-pressure centrifugal fan with backward-curved blades of the present invention has a larger flow rate and higher pressure.

[0095] Where there is no conflict, the above embodiments and features can be combined with each other.

[0096] 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-pressure centrifugal fan with backward-curved blades, comprising a volute, an impeller, and a collector, wherein the impeller and the collector are both disposed within the volute, and the collector is fixedly connected to the volute; the impeller comprises a front plate and a rear plate, wherein multiple blades are arranged in an array around the rear plate, and an air intake is disposed in the center of the front plate, characterized in that: The blade is designed as a single-plate straight structure. The blade includes a leading edge, a trailing edge, 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 includes a leading edge arc section near the air inlet and a leading edge straight section away from the air inlet. The trailing edge is set as a straight section structure. Both the leading edge straight section and the trailing edge are set parallel to the impeller hub, and the second side is set perpendicular to the impeller hub. The first side includes a single arc segment and multiple arc segments. The single arc segment is connected to the leading edge arc segment, and the multiple arc segments are connected to the trailing edge. The multiple arc segments are set as a continuous multi-segment arc structure, and the thickness of the blade remains unchanged from the leading edge to the trailing edge. The exit angle ∠2 during blade installation is 49°-51°; The number of leaves is 16.

2. A high-pressure centrifugal fan with backward-curved blades according to claim 1, characterized in that: The diameter of the circle formed by the outermost ends of all the blades, φ1, is 515 mm, and the diameter of the circle formed by the innermost ends of all the blades, φ2, is 356.4 mm to 358 mm. On the unfolded diagram of the blade, the vertical distance L11 between the first end of the leading edge and the second end of the leading edge is 203mm-208mm, the vertical distance L12 between the first end of the leading edge and the first end of the trailing edge is 100mm-103mm, the radius R7 of the single arc segment on the first side is 103mm-105.5mm and the arc length is 30mm-32mm, and the length L7 of the second side is 128.5mm-131.5mm. The thickness t of the blade is 2.4mm-2.6mm.

3. A high-pressure centrifugal fan with backward-curved blades according to claim 2, characterized in that: The diameter of the air inlet φ3 is 364mm-366mm, the vertical distance L10 between the air inlet and the rear plate is 212mm-217mm, and the circumference diameter φ4 formed by the intersection of the leading edge arc of all blades and the front plate is 380.8mm-383.2mm. The front disc is designed with a single-arc structure; The impeller is sectioned by a plane passing through its central axis. On the cross-section: The radius of the arc of the front disc, R6, is 89mm-91mm and the arc length is 88.9mm-91.5mm. The radius of the leading edge arc segment, R5, is 412mm-416mm and the arc length is 102mm-105mm. The length of the straight section of the leading edge, L9, is 97.6mm-99.6mm. The length of the trailing edge, L8, is 163.5mm-166.5mm.

4. A high-pressure centrifugal fan with backward-curved blades according to claim 3, characterized in that: ∠2 is 50°, φ2 is 357.3mm, L11 is 205.5mm, L12 is 101.7mm, R7 is 104.3mm with an arc length of 31mm, L7 is 130mm, t is 2.5mm, φ3 is 365mm, L10 is 215mm, φ4 is 382mm, R6 is 90mm with an arc length of 90.2mm, R5 is 414.3mm with an arc length of 103.3mm, L9 is 98.6mm, and L8 is 165mm.

5. A high-pressure centrifugal fan with backward-curved blades according to claim 4, characterized in that: The collector includes a connecting part and a guide section. The collector is fixedly connected to the volute through the connecting part. The guide section includes a straight guide section connected to the connecting part and an arc 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 outlet 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.

6. A high-pressure centrifugal fan with backward-curved blades according to claim 5, characterized in that: The diameter of the air inlet φ5 is 498mm-502mm, the diameter of the air guide φ7 is 354.5mm-357.5mm, and the diameter of the narrowest part of the air guide arc φ6 is 318.7mm-321.3mm. The collector is cut off by a plane passing through its central axis. In the cross section: the radius R8 of the air guide arc is 49mm-51mm and the arc length is 76mm-79mm; the length L13 of the air guide straight section is 117.5mm-120.5mm; and the included angle ∠3 formed between the air guide straight section and the connecting part is 48.3°-50.1°. The length L1 of the collector extending into the front disc of the impeller is 4.8mm-5.2mm, and the radial clearance length L2 between the collector and the impeller is 5.3mm-5.9mm.

7. A high-pressure head centrifugal fan with backward-curved blades according to claim 6, characterized in that: φ5 is 500mm, φ7 is 356mm, φ6 is 320mm, R8 is 50mm and the arc length is 77.7mm, L13 is 119mm, ∠3 is 49.2°, L1 is 5mm, and L2 is 5.6mm.

8. A high-pressure head centrifugal fan with backward-curved blades according to claim 7, 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, 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, and the third arc section are not concentric. A rectangular coordinate system is established with the center O of the impeller 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 (29.8, 29.8), the radius R2 is 330mm-332mm and the arc length is 531mm-536mm. The coordinates of the center O4 of the second arc section are (34, -34), the radius R3 is 393.5mm-396mm and the arc length is 619mm-624.5mm. The coordinates of the center O3 of the third arc section are (-38.4, -38.4), the radius R4 is 465mm-469mm and the arc length is 785.5mm-792mm. The first diffuser section and the second diffuser section are set in parallel.

9. A high-pressure centrifugal fan with backward-curved blades according to claim 8, characterized in that: The height of the air outlet, L5, is 447mm-453mm, and the width of the air outlet, L6, is 375.5mm-392.5mm. The radius R1 of the volute tongue segment is 19.5mm-20.5mm and the arc length is 34.5mm-36mm. The length L3 of the first diffuser straight segment is 32mm-33mm, and the length L4 of the second diffuser straight segment is 307mm-311mm. A tangent line is drawn to the volute tongue segment through the point of tangency between the volute tongue segment and the first arc segment. The angle ∠1 between this tangent line and the first diffuser straight segment is 78°-80°.

10. A high-pressure centrifugal fan with backward-curved blades according to claim 9, characterized in that: It also includes an I-beam flange, a motor, and a base. The I-beam flange, the connecting part, and the volute are connected in sequence by fasteners. The motor is connected to the impeller via a drive shaft. Both the volute and the motor are fixedly mounted on the base.

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