Blades of a fan impeller, impeller and fan

Abstract

Blade (2) of an impeller (1) of a fan, wherein the blade (2) has a leading edge (6) on the upstream side and a trailing edge (3) on the downstream side and wherein the leading edge (6) is slotted at least over a region of a span, wherein the slots (7) are continuous, i.e. open, from a suction side to a pressure side.

Description

[0001] The invention relates to the impeller blade of a fan. The fan can be an axial, radial, or diagonal fan. The blade has a leading edge on the upstream side and a trailing edge on the downstream side. For the generic prior art, reference is made by way of example to DE 10 2014 215 817 A1.

[0002] CN 1 11 677 692 A describes an axial fan with fan blades. These blades are arranged between the hub and an outer ring. Flow-guiding grooves are also formed on the fan blades.

[0003] DE 32 34 011 A1 describes an axial fan for a hairdryer with blades that have teeth on the leading edge.

[0004] There are many different quality criteria for fans. One of these quality criteria is the emitted sound power, which is one of the most important selling points nowadays.

[0005] Regarding the reduction of sound power, numerous approaches already exist for optimizing the wing trailing edge and the wingtip. Furthermore, it has also been recognized that optimizing the wing leading edge influences sound power. For example, corrugated wing leading edges are known from practical experience, used to increase airspeed.

[0006] The present invention is based on the objective of providing a blade of the impeller of a fan, an impeller with corresponding blades and a fan with a corresponding impeller, in which a further reduction of the emitted sound power is achieved.

[0007] According to the invention, it has been found that this is possible by modifying the wing's leading edge, with this modification being implemented at least over a portion of the wingspan. Specifically, the leading edge is slotted, i.e., provided with slots that extend from the leading edge into the wing. Tests have shown that slotting the wing's leading edge reduces the radiated sound power by up to 2 dB(A).

[0008] Advantageously, the slots extend essentially across the entire free area of ​​the wingspan. This means that the entire available area across the wingspan is slotted, taking care to ensure that the slotting does not mechanically weaken the leading edge of the wing. The slotting effectively gives the leading edge a comb-like structure.

[0009] Advantageously, the slots run parallel to each other and can be straight, curved, swung, twisted, or twisted. Overall, the slots can have an inclined path, regardless of their individual design.

[0010] In a further advantageous way, the slots run essentially concentrically to the axis of rotation of the impeller. One could also say that the slots run parallel to the impeller edge (wingtip) between the leading and trailing edges.

[0011] It should be noted that the slots can vary in length depending on the specific geometry of the wing. Adjusting the length and width of the slots allows for further optimization tailored to the specific wing and, consequently, the specific impeller.

[0012] In a further aspect of the invention, the slots extend continuously from the suction side towards the pressure side, i.e., they are open. Preferably, in the rear closed area, the slots can be provided with a radius so that flow separation due to sharp edges is avoided.

[0013] In an alternative embodiment, the slots on the leading edge are preferably completely closed, meaning the leading edge itself is free of slots. The leading edge is thus formed with a kind of nose, which affects both the airflow and the stability of the wing.

[0014] It is also conceivable that, with the leading edge closed, the slots in the front area of ​​the leading edge, i.e. near the nose, are also or alternatively equipped with a radius, analogous to the rear radius.

[0015] The slots can be equipped, at least partially, with a kind of intermediate membrane, so that a groove base exists approximately in the middle, on both sides. This also influences the flow conditions. It is also conceivable that the slots are closed on the suction or pressure side by the intermediate membrane, so that a groove base exists on the opposite side.

[0016] The slots can be identical in design. This applies to both the length and width of the slots. It is also conceivable to vary the length and width of the slots, again in accordance with the overall wing geometry.

[0017] Advantageously, the slot length is a multiple of the slot width. For example, the slot length can be 20 to 30 times the slot width.

[0018] The same applies to the webs between the slots, which are advantageously designed identically. The webs are preferably wider than the slots, thus providing the necessary stability to the leading edge. This is particularly true for the variant with slots open on the upstream side.

[0019] The wing can have different designs and shapes. In particular, the wing can be curved or twisted from the leading edge to the trailing edge. A wavy design is also possible.

[0020] With regard to reducing the radiated sound power, it is further advantageous if the wing is corrugated at the leading edge, i.e., at the airfoil, preferably in the area of ​​the slots. The wing can exhibit a sinusoidal oscillation in top and / or front view. This means that the wing can be curved or corrugated upwards and downwards and / or forwards. Regardless of this configuration, the slots are designed according to the invention.

[0021] An impeller according to the invention comprises at least two of the previously described wings. The wings can be an integral part of the impeller. In this case, the wings are molded on. It is also conceivable that the wings are fixedly or variably attached to a disc of the impeller.

[0022] Finally, a fan is claimed that is equipped with a corresponding impeller, which in turn comprises blades of the claimed type. This can be any fan whose blades have a leading edge or airflow edge, which may be slotted accordingly.

[0023] There are now various ways to advantageously elaborate and further develop the teaching of the present invention. For this purpose, reference should be made, on the one hand, to the claims subordinate to claim 1 and, on the other hand, to the following explanation of preferred embodiments of the invention with reference to the drawing. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawing, generally preferred embodiments and further developments of the teaching are also explained. The drawing shows Fig. 1 in a schematic view the impeller of an axial fan with five blades that have a slotted leading edge, Fig. 2 In schematic view, a further embodiment of an impeller according to the invention with five blades having a slotted front face, manufactured by complete die casting, Fig. 3 in a schematic front view the wheel made of Fig. 2 from the suction side, Fig. 4 in a schematic rear view the wheel made of Fig. 2 from the printed side, Fig. 5 in a schematic, enlarged view, a wing according to the invention with long, narrow and open slots, from the suction side, Fig. 6 in a schematic view, enlarged again, the slotted leading edge of the wing made of Fig. 5, from the suction side, Fig. 7 in a schematic view the wing Fig. 5, from the printed side, Fig. 8 in a schematic view the wing from the Fig. 5 to 7, from the leading edge, Fig. 9 in a schematic view another embodiment of a wing according to the invention, from the suction side, wherein the slots are shorter and wider and have a radius at the closed end, Fig. 10 in a schematic view the wing Fig. 9, from the printed side, Fig. 11 in a schematic view a further embodiment of a wing according to the invention, from the suction side, wherein the slots are longer and narrower and are equipped with an intermediate skin, Fig. 12 in a schematic view the wing Fig. 11 from the leading edge, Fig. 13 in a schematic view, enlarged, the wing from Fig. 11 from the leading edge, Fig. 14 in a schematic view a further embodiment of a wing according to the invention from the suction side, with closed leading edge or nose, Fig. 15 in a schematic view, enlarged, the wing from Fig. 14 in the area of ​​the closed front edge / nose, Fig. 16 in a schematic view the wing Fig. 14, from the printed side, Fig. 17 in a schematic view the wing as in Fig. 16, from the leading edge, Fig. 18 in a schematic view a further embodiment of a wing according to the invention with slanted slots from the suction side, Fig. 19 in an enlarged view the wing Fig. 18 from the suction side, Fig. 20 in a schematic view the wing from the Fig. 18 and Fig. 19 from the printed side, Fig. 21 in a schematic view the wing from the Fig. 18 to 20 from the leading edge, Fig. 22 in a schematic view a further embodiment of a wing according to the invention with a corrugated leading edge, from the suction side, Fig. 23 in a schematic view the wing Fig. 22 from the printed side, and Fig. 24 in a schematic view the wing from the Fig. 22 and Fig. 23 from the leading edge.

[0024] Fig. Figure 1 shows a schematic view of the impeller 1 of an axial fan with five blades 2 according to the invention.

[0025] The wings 2 are jagged at the trailing edge 3 and have so-called winglets 5 in the form of a chamfer at the wingtip 4.

[0026] At the leading edge 6 of the wing, a measure reducing the emitted sound power is implemented according to the invention, namely slots 7 are formed. The slots 7 are arranged parallel to each other and run essentially concentrically to the axis of rotation of the impeller 1.

[0027] The Fig. 2 and Fig. Figure 3 shows an impeller 1, manufactured using die casting. While Fig. 2. If the impeller 1 is shown in a view obliquely from the suction side, the impeller 1 is in Fig. 3 shown in a front view from the suction side.

[0028] Fig. Figure 4 shows the impeller 1 in a rear view as seen from the printing side.

[0029] The design of the leading edge of the wing 6 is clearly recognizable, namely the slots 7, which run approximately concentrically to the axis of rotation of the wheel 1.

[0030] Fig. Figure 5 shows the wing 2 according to the invention in an isolated, enlarged view, seen from the suction side.

[0031] The slots 7 are relatively narrow and long. The connecting webs 8 are noticeably wider than the slots 7. Furthermore, Fig. 5 recognize that the slots 7 are open from the leading edge 6 of the wing and have a radius 9 towards the closed end, which again implements a measure to reduce noise.

[0032] Fig. Figure 6 shows an enlarged view of the area of ​​the slots 7 and webs 8. I denotes the length of the slots, b1 the width of the slots 7, and b2 the width of the webs 8. A radius 9 is formed in the rear closed area of ​​the slots 7.

[0033] Fig. Figure 7 shows the wing 2 according to the invention as seen from the pressure side. The long, narrow slots 7 are clearly visible. The same applies to the webs 8 and the radius 9.

[0034] Fig. Figure 8 shows the wing 2 according to the invention as seen from the leading edge 6. It is clearly visible that the wing 2 is curved from the leading edge 6 to the trailing edge 3. The radius 9 is also visible.

[0035] The Fig. 9 and Fig. Figure 10 shows a further embodiment of a wing 2 according to the invention, wherein, compared to the previously discussed embodiment, shorter but wider slots 7 are formed. The radius 9 is also indicated here. The width of the webs 8 defines the distance between the slots 7.

[0036] Fig. 10 shows wing 2 from Fig. 9 from the printed side. Otherwise, the same explanations apply as for... Fig. 9.

[0037] The Fig. Figures 11 to 13 show a further embodiment of a wing 2 according to the invention, with long, narrow slots 7, an end radius 9 and an intermediate skin 10 extending over the entire slot 7.

[0038] Fig. Figure 12 shows the embodiment from Fig. Figure 11 shows a view from the leading edge of the wing (or airfoil) 6. It is also evident here that the wing 2 is curved from the leading edge 6 to the trailing edge 3.

[0039] Fig. Figure 13 shows the embodiment from Fig. Figure 12 shows an enlarged view. Here it can be seen that the intermediate skin 10 extends from the leading edge 6 to the closed end of the slots 7. The thickness of the intermediate skin 10 is denoted by d. This design ensures that the slots 7 function as a groove on both sides.

[0040] The Fig. Figures 14 to 17 show a further embodiment of a wing 2 according to the invention, namely with long, narrow slots 7 which are closed at the wing's leading edge 6. The closed design of the slots 7 forms a kind of wing leading edge 11. A radius 9 is formed at the inner end of each slot 7. The same applies to the end of the groove in the area of ​​the wing leading edge 11.

[0041] Fig. Figure 15 shows the slotted area of ​​wing 1. Fig. Figure 14 shows an enlarged view. The distance from the leading edge 6 to the slot 7 is denoted by 'a'. The essential features are the provision for the wing leading edge 11 in the area of ​​the wing leading edge 6 and the provision for the respective end radius 9 at the end of the groove, whereby the two radii may be of different shapes.

[0042] Fig. 16 shows wing 2 from the Fig. 14 and Fig. 15 as seen from the printed side.

[0043] Fig. Figure 17 shows the embodiment as seen from the leading edge 6, whereby this representation clearly conveys the curvature of the wing 2 from the leading edge 6 to the trailing edge 3.

[0044] The Fig. Figures 18 to 21 show a further embodiment of a wing according to the invention. This embodiment differs from the previously discussed embodiments in that the slots 7 and, correspondingly, the webs 8 are formed at an angle.

[0045] Fig. Figure 19 shows an enlarged view of the area of ​​the slots 7. α documents the angle of the slots 7, i.e., their inclination.

[0046] Fig. 20 shows wing 2 according to Fig. 18 from the printing side. The slots 7, the webs 8 and the radius 9 are clearly visible.

[0047] Fig. 21 shows the wing from the Fig. 18 to 20 seen from the wing leading edge 6 or the leading edge with a distinct bend from the wing leading edge 6 to the wing trailing edge 3.

[0048] The Fig. Figures 22 to 24 show a final embodiment of a wing 1 according to the invention, wherein long, narrow slots 7 and correspondingly shaped webs 8 are provided. In contrast to the previously discussed embodiments, the leading edge 6 of the wing is corrugated, namely such that the leading edge 6 of the wing has a sinusoidal shape in a top view and a linear or straight shape in a front view.

[0049] Fig. 23 shows the wing from Fig. 22 as seen from the printed side.

[0050] Fig. 24 shows the wing from the Fig. 22 and Fig.23, viewed from the leading edge 6 of the wing. This view shows the wave shape of the leading edge on the one hand and the bend of the wing 2 from the leading edge 6 to the trailing edge 3 on the other.

[0051] The exemplary embodiments discussed above demonstrate very specific measures at the wing leading edge 6 or at the airflow edge, namely the provision of slots 7, which can be of different dimensions and orientations. These measures result in an optimization with regard to the radiated sound power, namely a significant reduction in the radiated sound power.

[0052] Regarding further advantageous embodiments of the wings according to the invention, reference is made to the general part of the description and to the attached claims to avoid repetition.

[0053] Finally, it should be expressly pointed out that the exemplary embodiments of the wings according to the invention described above serve only to discuss the claimed teaching, but do not limit it to these exemplary embodiments. List of reference symbols 1 wheel 2 wings 3. Trailing edge of wing (trailing edge, trailing edge) 4 wingtip 5 Winglet 6 Wing leading edge (leading edge, airflow edge) 7 slots 8 Bridge 9 radius 10 Interdermis, intermediate layer 11 Wing nose b1 Width (of the slots) b2 Width (of the bridges) α Angle, inclination of the slots a distance from the front edge to the slot l Length of the slots d thickness of the intermembrane skin

Claims

[1] Blade (2) of an impeller (1) of a fan, wherein the blade (2) has an upstream leading edge (6) and a downstream trailing edge (3) and wherein the leading edge (6) is slotted at least over a region of a span, wherein the slots (7) are continuous, ie open, from a suction side to a pressure side. [2] Wing (2) according to claim 1, characterized by that the slots (7) are formed substantially over the entire free area of ​​the span. [3] Wing (2) according to claim 1 or 2, characterized by that the slots (7) run parallel to each other. [4] Wing (2) according to one of claims 1 to 3, characterized by that the slots (7) have a straight, curved, curved, twisted and / or oblique course. [5] Wing (2) according to one of claims 1 to 4, characterized by that the slots (7) are substantially concentric with the axis of rotation of the impeller (1). [6] Wing (2) according to one of claims 1 to 5, characterized by that the slots (7) are partially equipped with an intermediate skin (10). [7] Wing (2) according to one of claims 1 to 6, characterized by that the slots (7) on the front edge (6) are preferably completely closed. [8] Wing (2) according to claim 7, characterized by that the slots (7) in the closed front area of ​​the front edge (6) are equipped with an intermediate skin (10). [9] Wing (2) according to one of claims 1 to 8, characterized by that the slots (7) are identical. [10] Wing (2) according to one of claims 1 to 9, characterized by that a slot length corresponds to a multiple of a slot width, for example 20 to 30 times the slot width. [11] Wing (2) according to one of claims 1 to 10, characterized by that webs (8) between the slots (7) are identical. [12] Wing (2) according to claim 11, characterized by that the webs (8) are wider than the slots (7). [13] Wing (2) according to one of claims 1 to 12, characterized by that a slot end in the flow path towards the center of the wing from a wing underside to a wing upper side is provided with a radius (9). [14] Wing (2) according to one of claims 1 to 13, characterized by that the wing (2) is curved from the leading edge (6) to the trailing edge (3). [15] Wing (2) according to one of claims 1 to 14, characterized by that the wing (2) is corrugated at the leading edge (6), preferably in the region of the slots (7), namely with a sinusoidal oscillation in plan view and / or a sinusoidal oscillation in front view. [16] Impeller (1) for a fan, in particular for an axial fan, with at least two blades (2) according to one of claims 1 to 15. [17] Fan with an impeller (1) according to claim 16.

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