Blade structure, impeller, fan system and range hood

Abstract

The present invention discloses a blade structure, an impeller, a fan system and a range hood. The blade structure 1 includes a main blade, the main blade has an inlet, an outlet, a suction surface and a pressure surface, a notch is provided on the main blade, and the notch extends from the inlet to the outlet; the blade structure also includes an auxiliary blade, the auxiliary blade is arranged at the notch and matches the notch, the auxiliary blade is rotatably connected to the main blade and can rotate in the direction of the suction surface, and the rotation axis of the auxiliary blade is consistent with the length direction of the main blade, so that the rotation of the auxiliary blade changes the inlet angle of the blade structure. Compared with the prior art, the advantages of the present invention are: 1. increasing the airflow inlet angle, which is conducive to increasing the total pressure under severe working conditions; 2. utilizing the gap flow effect to transform the large vortex separated by the boundary layer caused by the curvature change into a small vortex, increasing the energy exchange near the boundary layer near the suction surface, preventing the generation of large local backflow, thereby improving efficiency and reducing noise.

Description

Technical Field

[0001] The invention relates to a power device, in particular to a blade structure, an impeller using the blade structure, a fan system using the impeller, and a range hood using the fan system. Background Art

[0002] Multi-blade centrifugal fans have the characteristics of high pressure and low noise. Therefore, the current society generally uses multi-blade centrifugal fan systems as power sources, using high-speed rotating impellers to complete the two functions of work and filtering in the volute. For example, it is often used in range hoods, and the multi-blade centrifugal fan installed inside the range hood absorbs and exhausts oil smoke. The multi-blade centrifugal fan includes a volute, an impeller installed in the volute, and a motor that drives the impeller to rotate. When the impeller rotates, negative pressure suction is generated in the center of the fan, sucking the oil smoke under the range hood into the fan, and after being accelerated by the fan, it is collected by the volute and guided to be discharged outdoors.

[0003] The existing range hoods generally use a multi-blade centrifugal fan as the power device, and the impeller blades 100' of the fan are mainly single arc blades, see Figure 7 This type of blade, on the one hand, has different intake states at different circumferential positions, and the intake state also changes greatly with the working conditions and speed changes. The suction surface of the blade near the inlet side (the back side of the work) is prone to large local reflux due to the negative pressure difference, see Figure 8 , is the blade path under low speed and smooth working conditions, Fig. 9 The figure shows the blade path under high-speed congestion conditions, where the arrows indicate the airflow path. It can be seen that as the operating conditions worsen, the suction surface vortex (the space surrounded by the triangle in the figure) increases, which will reduce efficiency and increase noise. On the other hand, the uneven air intake along the axial direction can easily cause the vortex on the suction surface to flow further laterally, generating secondary flow along the axis, further reducing the overall aerodynamic efficiency and increasing noise. Summary of the invention

[0004] The first technical problem to be solved by the present invention is to provide a blade structure to reduce energy loss, improve work efficiency and reduce noise in view of the deficiencies in the above-mentioned prior art.

[0005] The second technical problem to be solved by the present invention is to provide an impeller having the above blade structure.

[0006] The third technical problem to be solved by the present invention is to provide a fan system using the above-mentioned impeller.

[0007] The fourth technical problem to be solved by the present invention is to provide a range hood using the above-mentioned fan system.

[0008] The technical solution adopted by the present invention to solve the above-mentioned first technical problem is: a blade structure, including a main blade, the main blade having an inlet, an outlet, a suction surface and a pressure surface, characterized in that: a notch is opened on the main blade, and the notch extends from the inlet to the outlet;

[0009] The blade structure also includes an auxiliary blade, which is arranged at the notch and matches the notch. The auxiliary blade is rotatably connected to the main blade and can rotate toward the suction surface. The rotation axis of the auxiliary blade is consistent with the length direction of the main blade, so that the rotation of the auxiliary blade changes the inlet angle of the blade structure.

[0010] Through the above-mentioned composite blade scheme, ① the airflow inlet angle can be increased, which is beneficial to increase the total pressure under severe working conditions; ② the large vortex of boundary layer separation caused by curvature change is transformed into a small vortex by utilizing the gap flow effect - the curvature between the shorter auxiliary blade in front and the main blade at the back undergoes a large reverse change, and the airflow separates near the blade boundary to form a local vortex, but it is quickly dissipated into a small vortex under the action of the gap flow. The generation of such small vortices can increase the energy exchange near the boundary layer near the suction surface of the main blade at the back, prevent large local reflux from occurring on the suction surface at the later stage, thereby improving efficiency and reducing noise.

[0011] Preferably, in order to facilitate the rotational connection between the auxiliary blade and the main blade, the auxiliary blade is rotationally connected to the main blade via a rotating shaft, and the rotating shaft is arranged on a side of the auxiliary blade away from the inlet.

[0012] Furthermore, in order to make the state of the auxiliary blade automatically adapt to different working conditions, a torsion spring is arranged on the rotating shaft, and the torsion spring makes the auxiliary blade maintain a tendency to be placed in the notch.

[0013] Further, according to one aspect of the present invention, there are at least two auxiliary blades arranged at intervals along the length direction of the main blade, and the elastic forces of the torsion springs of the auxiliary blades are not completely the same, thereby avoiding the generation of secondary flow along the axial direction, further improving the overall aerodynamic efficiency, and reducing the noise problem.

[0014] Furthermore, since the inflow angle of the blade structure changes, a chamfer is formed at a corner of the auxiliary blade that is away from the rotating shaft and adjacent to the main blade, thereby reducing airflow impact and turbulence.

[0015] Preferably, a middle plate buckle is formed on the main blade, and the auxiliary blades have at least two and are distributed on both sides of the middle plate buckle along the length direction of the main blade.

[0016] In order to avoid affecting the work done by the middle disk area corresponding to the middle disk buckle, the length of the main blade is L, the distance between the auxiliary blade closest to the middle disk buckle and the middle disk buckle is L1, and the range of L1 / L is [0.1-0.35].

[0017] Further, according to another aspect of the present invention, along the length direction of the main blade, the width of the auxiliary blade gradually widens from the position close to the buckle of the middle plate to both sides, and the width of the auxiliary blade refers to the dimension along the inlet to the outlet of the main blade. This can avoid the generation of secondary flow along the axial direction, further improve the overall aerodynamic efficiency, and reduce noise.

[0018] Preferably, the notch profile is an arc, and the center angle ∠A∈[5°,30°] of the notch 13. If it is too small, the adjustment range will be weak, and the vortex suppression in the suction surface generation area will be weakened. If it is too large, the vortex will be generated in advance and the work effect of the main blade will be reduced.

[0019] Preferably, the rotation angle of the auxiliary blade is ∠B:∈[0,20], so as to avoid the angle being too large to hinder the main flow from passing through the blade channel and reduce efficiency.

[0020] The technical solution adopted by the present invention to solve the second technical problem is: an impeller, characterized in that: the blade structure as described above is applied, and the length direction of the main blade is the axial direction of the impeller. .

[0021] The technical solution adopted by the present invention to solve the third technical problem is: a fan system, which is a multi-blade centrifugal fan, characterized in that: an impeller as described above is applied.

[0022] The technical solution adopted by the present invention to solve the fourth technical problem is: a range hood, characterized in that: the fan system as described above is applied.

[0023] Compared with the prior art, the advantages of the present invention are: by adopting the composite blade solution, ① the airflow inlet angle can be increased, which is beneficial to increase the total pressure under severe working conditions; ② the large vortex of boundary layer separation caused by curvature change is transformed into a small vortex by utilizing the gap flow effect - the curvature between the shorter auxiliary blade in front and the main blade at the back undergoes a large reverse change, and the airflow separates near the blade boundary to form a local vortex, but it is quickly dissipated into a small vortex under the action of the gap flow. The generation of such small vortices can increase the energy exchange near the boundary layer near the suction surface of the main blade at the back, prevent large local reflux from occurring on the suction surface at the later stage, thereby improving efficiency and reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic diagram of the blade structure of an impeller according to a first embodiment of the present invention;

[0025] Figure 2 for Figure 1 A schematic diagram of the partial enlargement of Ⅰ;

[0026] Figure 3A side view of the blade structure of the impeller of the first embodiment of the present invention;

[0027] Figure 4 Schematic diagram of the impeller blade path of the first embodiment of the present invention (low speed normal working condition);

[0028] Figure 5 Schematic diagram of the impeller blade path of the first embodiment of the present invention (high speed congestion condition);

[0029] Figure 6 is a schematic diagram of the blade structure of an impeller according to a second embodiment of the present invention;

[0030] Figure 7 is a schematic diagram of an impeller of the prior art;

[0031] Figure 8 A schematic diagram of the impeller blade path of the prior art (low speed normal working condition);

[0032] Fig. 9 It is a schematic diagram of the blade path of the impeller of the prior art (high speed congestion condition). DETAILED DESCRIPTION

[0033] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals represent the same or similar elements or elements having the same or similar functions.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate the orientation or position relationship based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Since the embodiments disclosed in the present invention can be set in different directions, these terms indicating directions are only for illustration and should not be regarded as limitations. For example, "up" and "down" are not necessarily limited to directions opposite to or consistent with the direction of gravity. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of such features.

[0035] Embodiment 1

[0036] See also Figure 1 to Figure 3 , a blade structure of an impeller, the impeller is used in a fan system, the fan system is a multi-blade centrifugal fan, which can be mainly used in range hoods, and can also be used in other occasions requiring similar power devices.

[0037] The blade structure 100 includes a main blade 1 and an auxiliary blade 2, forming a composite blade, wherein the main blade 1 can be the same as an existing blade, such as a blade with a single arc profile. The main blade 1 has an inlet 11 (leading edge) and an outlet 12 (trailing edge). The airflow enters from the inlet 11, flows along the blade channel Q formed between two adjacent blade structures 100, and then flows out from the outlet 12. The inlet 11 is closer to the radial inner side of the impeller relative to the outlet 12. A notch 13 is provided on the main blade 1, and the notch 13 extends from the inlet 11 to the outlet 12. The auxiliary blade 2 is arranged at the notch 13. The profile of the notch 13 is consistent with that of the main blade 1. The position of the auxiliary blade 2 is recorded as the inlet section of the main blade 1.

[0038] The auxiliary blade 2 matches the notch 13 in shape and size. In this embodiment, the auxiliary blade 2 is approximately rectangular (with a certain curvature), and chamfers 21 are formed at the two corners facing the inlet 11. The auxiliary blade 2 is rotatably connected to the main blade 1 through a rotating shaft 22. The rotating shaft 22 is arranged on the side of the auxiliary blade 2 away from the inlet 11. The extension direction of the rotating shaft 22 is consistent with the length direction of the main blade 1 (i.e., the axial direction of the impeller), that is, the rotation axis of the auxiliary blade 2 is consistent with the length direction of the main blade 1. A torsion spring 23 is arranged on the rotating shaft 22. One end of the torsion spring 23 can abut against the main blade 1, and the other end of the torsion spring 23 can abut against the auxiliary blade 2. The torsion spring 23 makes the auxiliary blade 2 tend to be placed in the notch 13. The above-mentioned chamfer 21 is formed on the side of the auxiliary blade 2 away from the rotating shaft 22 and at the corner adjacent to the main blade 1.

[0039] In this embodiment, an impeller applied to a double-inlet air is taken as an example. The impeller with a double-inlet air is a prior art, as disclosed in the prior application of the present applicant, such as the Chinese patent application No. 201120024842.2. A middle disk buckle 14 is formed on the main blade 1, and the position of the middle disk buckle 14 corresponds to the position of the middle disk of the double-inlet air impeller. The above-mentioned auxiliary blades 2 may have at least two, which are distributed on both sides of the middle disk buckle 14 at intervals along the length direction of the main blade 1. Since the vicinity of the middle disk is the main working area, the auxiliary blades 2 are not set in the middle disk area. Let the length of the main blade 1 be L, and the distance between the auxiliary blade 2 closest to the middle disk buckle 14 and the middle disk buckle 14 be L1, and the preferred range of L1 / L is [0.1-0.35].

[0040] Alternatively, it can also be used for a single-inlet impeller, in which case the auxiliary blades 2 are not provided at the connection between the main blades 1 and the rear disc.

[0041] See also Figure 4 , a blade channel Q is formed between two adjacent blade structures 100. Under the condition of low speed and large flow rate with good working conditions, the auxiliary blade 2 does not unfold under the action of the torsion spring 23 and centrifugal force, and works normally. Figure 5When the working condition deteriorates and the speed increases, the centrifugal effect is enhanced, and the auxiliary blade 2 overcomes the elastic force of the torsion spring 23 and rotates in the direction of the suction surface 15 to rebalance. At this time, the auxiliary blade 2 is unfolded like a flap. This can play the following two roles: ① Increasing the airflow inlet angle is conducive to increasing the total pressure under severe working conditions of the fan; ② The curvature between the shorter auxiliary blade 2 in front and the main blade 1 behind changes greatly in the opposite direction, and the airflow separates near the blade boundary to form a local vortex, but it quickly dissipates into a small vortex under the action of the gap flow Q1. The generation of such small vortices can increase the exchange near the energy boundary layer of the suction surface 15 near the rear main blade 1, preventing large local reflux from occurring on the suction surface in the later stage, thereby improving efficiency and reducing noise. Figure 4 and Figure 5 The arrows in the figure show the airflow path. Figure 5 The circle near the gap flow Q1 is a small vortex.

[0042] The above-mentioned gap flow Q1 is caused by the suction surface 15 of the main blade 1 being a low-pressure area and the pressure surface 16 being a high-pressure area, which causes the airflow to pass through the gap at the connection between the auxiliary blade 2 and the main blade 1 and flow from the pressure surface 16 side to the suction surface 15 side.

[0043] The center angle of the notch 13 (the adjustable wrap angle position of the inlet section of the main blade 1) ∠A∈[5°,30°], if it is too small, the adjustment range will be weak, and the vortex suppression in the suction surface 15 generation area will become weak. If it is too large, it will cause the vortex to be generated prematurely and reduce the work effect of the main blade 1.

[0044] The rotation angle of the auxiliary blade 2 (i.e., the adjustable angle of the inlet section of the main blade 1 relative to the original arc blade inlet angle) ∠B: ∈[0,20]. When this angle is 0, the auxiliary blade 2 is tangentially fitted to the main blade 1. Because under high resistance conditions, the total pressure and efficiency first increase and then decrease with the change of angle. If the angle is too large, it will hinder the mainstream from passing through the blade channel Q and reduce the efficiency.

[0045] Alternatively, the curvatures of the auxiliary blade 2 and the main blade 1 can be different, such as other curvature arcs, straight line segment inlets, etc., which are similar to blades that combine straight line + arc profiles. Under certain working conditions, this may be beneficial to improving the efficiency of the front airflow entry.

[0046] See also Figure 3Taking into account the uneven air intake along the impeller axis, which can easily cause the vortex on the suction surface 15 to further flow laterally, generating secondary flow along the axial direction, further reducing the overall aerodynamic efficiency and increasing noise, the same impeller considers different axial air intake conditions and changes the inlet at different angles. Therefore, the elastic force of the torsion spring 23 of each auxiliary blade 2 can be set to be different, so that after the same speed is balanced, the unfolding angle of each auxiliary blade 2 is different, and even multiple groups can be set, changing along the axial direction. The opening angle close to the middle disk is small (the middle disk is the main flow area with few vortices), and the opening angle close to the impeller end ring can be large (the vortex is more serious and requires a larger angle change).

[0047] Embodiment 2

[0048] See also Figure 6 In this embodiment, the difference from the above-mentioned embodiment 1 is that along the length direction of the main blade 1, the width of the auxiliary blade 2 gradually widens from the position close to the middle plate buckle 14 to both sides (replacing the different elastic forces of the torsion spring 23), and accordingly, the size of the notch 13 on the main blade 1 also changes in width accordingly. Here, the width of the auxiliary blade 2 refers to the size along the direction from the inlet 11 to the outlet 12 of the main blade 1.

Claims

1. A blade structure, comprising a main blade (1), wherein the main blade (1) has an inlet (11), an outlet (12), a suction surface (15) and a pressure surface (16), characterized in that: The main blade (1) is provided with a notch (13), and the notch (13) extends from the inlet (11) toward the outlet (12); The blade structure further comprises an auxiliary blade (2), the auxiliary blade (2) being arranged at the notch (13) and matching the notch (13), the auxiliary blade (2) being rotatably connected to the main blade (1) and being able to rotate in the direction of the suction surface (15), the rotation axis of the auxiliary blade (2) being consistent with the length direction of the main blade (1), so that the rotation of the auxiliary blade (2) changes the inlet angle of the blade structure; The auxiliary blade (2) is rotatably connected to the main blade (1) via a rotating shaft (22). The rotating shaft (22) is arranged on a side of the auxiliary blade (2) away from the inlet (11). A torsion spring (23) is arranged on the rotating shaft (22). The torsion spring (23) enables the auxiliary blade (2) to maintain a tendency to be placed in the notch (13). The auxiliary blade (2) has at least two and is arranged at intervals along the length direction of the main blade (1). The elastic forces of the torsion springs (23) of the auxiliary blades (2) are not completely the same.

2. The blade structure according to claim 1, characterized in that: A chamfer (21) is formed at a corner of the auxiliary blade (2) which is away from the rotating shaft (22) and adjacent to the main blade (1).

3. The blade structure according to claim 1, characterized in that: A middle plate buckle (14) is formed on the main blade (1), and the auxiliary blades (2) have at least two and are distributed on both sides of the middle plate buckle (14) along the length direction of the main blade (1).

4. The blade structure according to claim 3, characterized in that: The length of the main blade (1) is L, the distance between the auxiliary blade (2) closest to the center plate buckle (14) and the center plate buckle (14) is L1, and the range of L1 / L is [0.1-0.35].

5. The blade structure according to claim 3, characterized in that: Along the length direction of the main blade (1), the width of the auxiliary blade (2) gradually widens from the vicinity of the center plate buckle (14) to both sides, and the width of the auxiliary blade (2) refers to the dimension along the direction from the inlet (11) to the outlet (12) of the main blade (1).

6. The blade structure according to claim 1 or 2, characterized in that: The profile of the notch (13) is an arc, and the center angle ∠A∈[5°, 30°] of the notch (13).

7. The blade structure according to claim 1 or 2, characterized in that: The rotation angle ∠B of the auxiliary blade (2) is: ∈[0,20].

8. An impeller, characterized in that: A blade structure as claimed in any one of claims 1 to 7 is applied, wherein the length direction of the main blade (1) is the axial direction of the impeller.

9. A fan system, which is a multi-blade centrifugal fan, characterized in that: An impeller as claimed in claim 8 is used.

10. A range hood, characterized in that: A fan system as claimed in claim 9 is used.

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