CN117108555A

CN117108555A - Flow guiding device and fan with same

Info

Publication number: CN117108555A
Application number: CN202310589742.1A
Authority: CN
Inventors: O·哈弗; T·皮萨尔奇克; D·格伯特; P·海内克
Original assignee: Ebm Papst Mulfingen GmbH and Co KG
Current assignee: Ebm Papst Mulfingen GmbH and Co KG
Priority date: 2022-05-24
Filing date: 2023-05-24
Publication date: 2023-11-24
Also published as: DE102022113142A1

Abstract

The invention relates to a fan and a flow guiding device (1) for a fan, wherein the flow guiding device (1) has a plurality of flow guiding blades (L) arranged in a star shape in a central position (P), each flow guiding blade (L) having a leading edge (2, 4) and a trailing edge (3), wherein the flow guiding blade (L) has a leading edge (4) which is zigzag or wave-shaped at least in a partial region, which has a periodically repeated wave shape.

Description

Flow guiding device and fan with same

Technical Field

The present invention relates to a flow guiding device and a fan with the same, in particular to a radial fan, an axial fan or an oblique fan with the same.

Background

Fans are used in many fields. In many applications, the airflow is highly turbulent. Turbulent flow out of the fan results in a significant increase in acoustic radiation, which means that annoying noise is generated. With current fans or impellers, a fan blade that is advantageous in terms of flow mechanics enables high performance, in particular in terms of achieving flow or pressure build-up. Basically, a low noise fan with good aerodynamic properties is needed at the same time, despite the turbulence. However, a problem is often that during operation of the fan, intense noise is generated, particularly noise caused by rotor-stator interactions.

In the prior art, there are a number of structural measures to reduce these problems. Many solutions relate to the blade shape of the fan blade. In order to reduce the operating noise, DE 19948075A uses an axial fan with blades having double sickle-shaped leading blade edges with protruding outer corners. US 3416725A shows a blade shape with a double sickle-shaped leading edge and a slightly single sickle-shaped trailing edge.

DE 10326637 B3 describes another solution, namely a blower with S-shaped sickle-shaped blades of alternating rotational direction, in which the leading edge is sharply retracted in the outward direction. The trailing edge of the zigzag or wave shape is used to reduce trailing edge noise (e.g. GB 2497739 or EP 1801422 A2). DE 102009044824 A1 uses apertures in the form of perforations in the region of the trailing edge in order to reduce noise generated at the trailing edge. The leading edge of the wave or saw shape is also considered a way to reduce turbulent noise.

However, these solutions relate to the blade shape of the fan blade. However, alternatives having the technical effect of conventional fans (radial fans, axial fans or diagonal fans) in terms of smooth running and noise generation are also desired.

Disclosure of Invention

Against this background, the problem addressed by the present invention is to provide a fan that is particularly noise-free during operation.

The present invention solves this problem by a fan according to the independent claim. The dependent claims contain advantageous further developments.

The invention relates to a solution consisting of an axial fan, an oblique fan or a radial fan and a deflector device improved according to the invention.

Before describing the present invention in more detail, specific terms and terms used will be explained for better understanding of the present invention.

The flow guiding device within the scope of the invention is a vane-type guide grate, which is arranged on the outflow side after the fan for guiding the air.

Also contemplated are typical axial or diagonal fans having a plurality of fan blades arranged in a star configuration, typically on a central hub, for drawing and/or pressurizing flow-wise aspects of air surrounding the fan or gas being carried by the fan. The fan blades may be interconnected by a circumferential ring (centrifugal ring) on the radially outermost contoured surface.

In addition, each fan blade has a leading front edge that leads when running in a particular direction of rotation and a trailing edge that lags behind in a particular direction of rotation when the fan is running. Furthermore, depending on the direction of rotation and the fan blade profile, there is a suction side, which is typically on the convex side of the fan blade, and a pressure side, which is typically on the concave side of the fan blade. Typically, the leading and trailing edges are typically optimally shaped for only one direction of rotation. In this respect, the fan blade has a suction side, which sucks in the inflow air during operation, and a pressure side opposite the suction side, at which a pressure for the discharge air is built up. The side then has a flow guide.

Thus, the leading edge of each wind guiding blade of the deflector faces the fan, while the trailing edge of the wind guiding blade of the deflector faces away from the fan.

The basic idea of the invention is that the front edge of the wind-guiding blade of the wind-guiding device has at least partially a special three-dimensional (or two-dimensional) wave shape or is designed as a corresponding three-dimensional or two-dimensional wave shape.

For this purpose, according to the invention, a deflector for a fan is provided, wherein the deflector has a plurality of air guiding blades arranged (preferably in a central position, for example in a star shape around a central axis) each having a leading edge and a trailing edge, the blade profile of which is designed to be curved and/or twisted, wherein each of the air guiding blades has a leading edge which is zigzag or wave-shaped at least in a partial region, which has a preferably periodically repeated wave shape. Alternatively, a non-periodic wave shape may be selected.

In a particularly advantageous embodiment, it is provided that the wave curve of the crests and troughs formed by the wave shape extends substantially or completely in the plane formed by the respective wind-guiding blade in the region of the leading edge and/or that the crests extend substantially along a tangent to the surface of the wind-guiding blade in the region of the respective crests. In other words, this means that the corresponding wave crest extends from the blade edge along the extension of the blade profile, instead of from the surface of the profile of the wind guiding blade, so that the leading edge itself is designed as a wave form. In this respect, the surface curve of the blade profile is not modified at the leading edge by the wave shape according to the invention, but the leading edge itself is modified.

In a preferred exemplary embodiment of the invention, the wave-shaped leading edge of the wind guiding blade has a plurality or a large number of periodically repeating wave portions or wave shapes.

In a particularly advantageous embodiment, the wave shape of the leading edge of the wind guiding blade may be described or approximated according to one of the following mathematical functions:

a. according to a sinusoidal or near-sinusoidal wave shape, or

According to a power function of order n, in particular of the form

f(x)＝a·x ⁿ

Wherein a=f (r)

Where a is a function describing the relationship of tip extension to radius r, and where n is preferably in the range between-5 and 5.

In the case of wave or wave shapes that can be approximated by a power function or an alternative polynomial function, the troughs are advantageously rounded or have rounded corners.

Furthermore, it is advantageous if the leading edge of the wind-guiding blade has a wavy or zigzag edge shape substantially in the entire curve, but, viewed in the radial direction, is at least over 20%, preferably over 50% of the length of the wind-guiding blade in the region of the continuous portion.

Another variant is that the leading edge of the wind guiding vane region has a non-undulating edge curve between or near the undulating curves, but has the above-described curves at least over successive partial regions.

The combination of a plurality of geometric design elements according to the invention is particularly advantageous, wherein the wave shape is defined by at least one of the following structural measures:

i) The angle of attack curve has two or more inflection points on the radius;

ii) a superimposed variation of periodic or non-periodic waves with respect to a continuous (i.e. wave-free) leading edge curve only;

iii) The chord length of the wind guide blade is changed;

iv) the cross-sectional area becomes longer in the direction of the leading edge, in particular continuously;

v) the curvature of the wind-guiding blade changes in the region of the leading edge.

In a further preferred embodiment of the invention, the profile of the wind guiding blade has, at least as seen in a cross-sectional plane of the peak area, a protrusion protruding from the upper surface and a recess protruding into the lower surface, or vice versa.

The invention relates in particular to an axial or diagonal fan and a radial fan, each having a flow guiding device as described above or one or more wind guiding blades downstream of the fan in the flow direction.

The present invention has the following advantages and features. The special design of the leading edge with the modification is basically directed to a different sound generation mechanism than the modification of the trailing edge or the air outlet edge. An advantage of the present invention compared to trailing edge modification is that it clearly reduces noise generated by the interaction of the impeller and the stator.

The leading edge modification is also designed for axial or diagonal fans with a centrifugal ring. The leading edge modification is also designed for radial or diagonal fans with cover plates. The invention can also be used to reduce noise in typical flow conditions (no head gap vortex, increased tangential component due to closed loops, back flow in the outer region and wake effects of gap flow) and to minimize noise by reducing the interaction mechanisms resulting therefrom, except for the points mentioned below.

In particular, the modification of the flow guiding device according to the invention has the following advantages over the solutions known from the prior art:

leading to a reduction of the sound power level and a reduction of the tonal components in the sound radiation. The latter, in addition to reducing the class a of noise, also helps to improve psychoacoustic perception.

The usual design of the deflector with a severe crescent shape used to achieve the acoustic target value can be replaced by a design with a reduced crescent shape and a modified leading edge according to the invention.

The crescent shape which can be weakened results in an increase in the strength of the gas outlet guide with a load-bearing function. The increased strength allows for reduced material usage.

The reduced crescent shape also means that even in the case of non-load-bearing guides, the material requirement is reduced due to the reduced blade length.

At the same noise level, the distance to the upstream impeller can be reduced by the described modification. This results in a more compact fan unit and/or an increased blade area of the deflector, thereby improving efficiency.

Drawings

Other advantageous further developments of the invention are characterized in the dependent claims or are presented in more detail below with the description of preferred embodiments of the invention with reference to the accompanying drawings.

The drawings show:

FIG. 1 is a first exemplary embodiment of a deflector;

FIG. 2 is an alternative second exemplary embodiment of a deflector;

FIG. 3 is a third exemplary embodiment of a deflector;

FIG. 4 is a fourth exemplary embodiment of a deflector;

FIG. 5 shows a wind guiding blade with a wave-shaped front edge, and

FIG. 6 is a portion of a wind-guiding vane having a partially undulating leading edge.

Detailed Description

The present invention is explained in more detail below using exemplary embodiments with reference to fig. 1 to 6, in which like reference numerals denote like structural and/or functional features.

Fig. 1 to 4 show an alternative exemplary embodiment of a deflector 1 with wind guiding blades L, each having a wave-shaped leading edge 2, 4.

The flow guiding device 1 shown is designed for a fan, wherein each flow guiding device 1 has a plurality of flow guiding blades L arranged in a star-like manner in a central position P, each flow guiding blade L having an inlet edge 2,4 (leading edge) and an outlet edge 3 (trailing edge), wherein the flow guiding blades L have a zigzag or wave-shaped leading edge 4 in at least part of the area.

The wind guide vanes L are attached inside the center ring 10 (or the mounting body 10 shown in the drawings) and extend radially outwardly to the circumferential ring 11. As shown, a mounting flange 12 may also be provided on the circumferential ring 11. The wave-shaped leading edge 4 of the wind guiding blade L has a plurality or a large number of periodically repeated wave shapes, which can be clearly seen in the detailed view of fig. 5, and in this exemplary embodiment extends L along the entire length of the wind guiding blade.

Fig. 6 shows a part of an alternative wind guiding blade L, wherein the leading edges 2,4 have a wave-shaped curve only in a partial region with reference number 4 (and thus locally).

The practice of the invention is not limited to the preferred exemplary embodiments specified above. Rather, a number of variants using the illustrated solution are conceivable, even in the case of radically different designs.

Claims

1. A deflector (1) for a fan, wherein the deflector (1) has a plurality of wind guiding blades (L), each wind guiding blade (L) having a leading edge (2, 4) and a trailing edge (3), the blade profile of the wind guiding blade being designed to be curved and/or twisted, wherein each wind guiding blade (L) has a leading edge (4) which is zigzag or wave-shaped at least in a partial region, which has a periodically or aperiodically repeated wave shape.

2. A deflector according to claim 1, characterized in that the wave curves of the crests and troughs formed by the wave shape extend substantially or entirely in the plane formed by the wind guiding vanes (L) in the region of the leading edge and/or the crests extend substantially along the tangent of the surface of the wind guiding vanes (L) in the region of the respective crests.

3. A deflector according to claim 1 or 2, characterized in that the wave-shaped leading edge (4) of the wind guiding blade (L) has a plurality of identical or different wave shapes, each periodically repeated.

4. A deflector according to claim 1, 2 or 3, characterized in that the wave shape along the leading edge (2, 4) is described according to one of the following mathematical functions:

a. sinusoidal or nearly sinusoidal waveforms;

b.n or an nth power function, wherein n is greater than or equal to-5 and less than or equal to 5.

5. A deflector according to any of the preceding claims, characterized in that the leading edge (4) of the wind guiding blade (L) has a wave-or zigzag-shaped edge shape substantially in the whole curve, but is, seen in radial direction, at least over a continuous part-area, greater than 20%, preferably greater than 50% of the length (L) of the wind guiding blade.

6. A deflector according to claim 4 or 5, characterized in that the leading edge (4) of the wind guiding blade (L) has a non-undulating edge curve between or near undulating contours, but a curve according to claim 3 at least over a continuous part-area.

7. A deflector according to any of the preceding claims, characterized in that the wave shape is characterized by at least one of the following structural measures:

a) The angle of attack curve has two or more inflection points on a radius;

b) A superimposed variation of periodic or non-periodic waves with respect to a continuous leading-edge curve without waveform only;

c) The chord length of the wind guide blade is changed;

d) The cross-section becomes longer in the direction of the leading edge, preferably continuously;

e) The curvature of the wind-guiding blades changes in the region of the leading edge.

8. A deflector according to any of the preceding claims, characterized in that the wave shape is designed with a peak at the leading edge (4) at the respective inner or outer leading edge end.

9. A deflector according to any of the preceding claims, wherein the plurality of deflector blades (L) are arranged in a star-like configuration in a central position (P).

10. Wind guiding blade (L) designed for a wind guiding device (1) of a fan, wherein the wind guiding blades (L) are each provided with a leading edge (2, 4) and a trailing edge (3), wherein the wind guiding blades (L) are formed with a leading edge (4) that is zigzag or wave-shaped at least in partial areas, the leading edge having a periodically repeated wave shape, as defined in claims 1 to 8.

11. An axial fan or diagonal fan with a centrifugal ring, further having a flow guiding device (1) according to any one of claims 1 to 9 or one or more air guiding blades (L) according to claim 10 downstream of the fan in the flow direction.

12. Diagonal or radial fan with a cover plate, further having a flow guiding device (1) according to any one of claims 1 to 9 or one or more wind guiding blades (L) according to claim 10 downstream of the fan in the flow direction.

13. An axial fan or diagonal fan or radial fan having a flow guiding device (1) according to any one of claims 1 to 9.