DE102017103933A1 - Flow-optimized fan housing - Google Patents

Abstract

Housing (1) for a radial fan wherein the housing (1) has a fan space, which is enclosed by a spiral fan chamber wall (8) and which is designed to receive a radial fan (2), and wherein the fan chamber in each case with an axial inflow channel (4 ) and a tangential outflow channel (5) is connected, wherein at the transition between the fan space and the outflow channel (5) opposite to the flow direction in the outflow channel (5) protruding extension (6) is formed.

Description

The invention relates to a housing for a radial fan wherein the housing has a fan space which is enclosed by a spiral fan chamber wall and which is designed to receive a radial fan, and wherein the fan chamber is connected in each case with an axial inflow channel and a tangential outflow channel.

Background of the invention

Radial fans are used e.g. used in the automotive sector. They are used, for example, for ventilating / cooling LED headlamps or electronic components. The radial fans are exposed to increasing demands on their performance and the noise. In most cases, a certain working air pressure to be supplied by the radial fan is required. Against this background, the goal of any design is to create radial fans that can provide the required working pressure with as little loss and noise as possible. To improve the efficiency of radial fans, various approaches are known from the prior art.

Out DE 102 11 548 A1 a housing for a radial fan is known, which has a deviating from the spiral shape free space narrowing between a housing inner wall and a radial fan to reduce noise.

Out DE 10 2009 033 773 A1 For example, there is known a radial fan housing having an adjustable tongue device in an exhaust region disposed between a helical housing inner wall and a radial fan.

The approaches of the prior art have the disadvantage that at high speeds and pressures caused by turbulence in the region of the effluent recirculation of air through the inflow channel is not prevented or even new turbulence generated by inappropriate formation of Verstellzungen.

The invention therefore has for its object to provide a housing for radial fans, which at least mitigates these disadvantages.

Brief description of the invention

This object is achieved by the invention specified in the independent claims. Advantageous developments can be found in the dependent claims.

According to the invention a housing of the type defined above is formed at the transition between the fan chamber and the downstream channel projecting into the downstream channel projection. The extension is formed for example in the form of a nose. In this case, the extension is formed on one side of the downflow channel, which connects to the fan room wall at the beginning of the spiral. The extension widens in its course along a direction which is parallel to the axis of rotation of the radial fan and points in the direction of the upper side of the housing.

The extension forms a barrier and prevents the recirculation of blown air. Since the extension is located in the region of the largest pressure jump, it helps to reduce the pressure loss due to recirculation. At the same speed then a higher pressure ratio is reached, or is a predetermined pressure ratio with less speed achievable. A radial fan operated at reduced speed works more energy efficient and has a longer service life. Occurring turbulence can be perceived as noise and therefore undesirable. According to a further advantage, the extension contributes to reducing the formation of noise.

In one embodiment of the invention, the extension connects tangentially to the spiral fan chamber wall. The spiral fan wall and the extension form a smooth transition. As a result, the air can flow undisturbed and laminar on the wall and the extension. A laminar flow reduces noise.

In one embodiment of the invention, the extension forms an extension of the spiral fan chamber wall or has a constant distance to the inflow axis. If the extension forms an extension of the spiral fan chamber wall, the distance of the extension narrows to a radial fan wheel the further the extension projects into the exhaust air flow. This has proven to be particularly favorable for reducing turbulence in the transition region between the housing and the outflow channel. If the extension has a constant distance to the inflow axis, this has proven to be a particularly favorable form of design for preventing recirculation.

In one embodiment of the invention, the extension (along the inflow axis) in the inflow direction on a freeform or curved shape or is straight. The extension can be adapted to the specific flow conditions along the axis and not only inhibits the recirculation.

In one embodiment of the invention, the extension tapers in the inflow direction and can, for example, circular-segment-shaped or parabolic be educated. The recirculation is inhibited in the housing in close proximity to the inflow channel, in the range of the highest speeds and the largest pressure differences. The extension achieves the greatest positive effect at this point.

In one embodiment of the invention, the extension is formed only in the direction of the inflow opening, in particular, the apex line of the extension widens in the inflow direction continuously, for example, quarter-circle. In the lower part of the housing in the inflow direction, the extension is not formed, therefore, the air can flow freely there. There is no harmful resistance produced by the extension at this point. This further reduces the noise.

In one embodiment of the invention, the extension is arranged at the inner end of the spiral fan chamber wall. This is the area of the largest pressure jump and thus the area where most of the recirculation occurs. The extension achieves its greatest positive effect here.

In one embodiment of the invention, a maximum circumferential extent of the extension in the outflow channel is equal to or smaller than an imaginary line parallel to the walls of the downflow channel and tangent to an outer envelope of a radial fan. The extension extends only so far in the downstream channel, that an "effective width of the Abstromkanals" is not affected. The extension "separates" only that part of the exhaust air stream, which has a velocity component in the direction of an inner wall of the Abstromkanals and in the region of the transition between the spiral wall of the housing and the inner wall of the Abstromkanals vortex and therefore forms harmful resistance.

The size of the extension should be chosen so that an efficient suppression of the return flow is achieved, without representing a bottleneck for the air to be bled. The air flow in the downstream channel is strongest on the side of the channel which is formed as a continuation of the spiral fan space wall. Therefore, the extension is formed on the opposite side of the downflow channel, where it connects to the beginning of the spiral.

In a projection of the extension on a plane perpendicular to the direction of the course of the Abstromkanals cutting plane of the Abstromkanals, it may therefore be advantageous if the maximum horizontal extent x of the extension in this regard between 1/5 and 4/5 the width B of the downstream channel, in particular between 1/4 and 2/3 of the width B of the outflow channel corresponds. Along the direction perpendicular thereto, parallel to the axis of rotation, it is advantageous if the vertical extension Z of the extension extends at least over 1/3 of the height H of the outflow channel. However, the extension can also increase continuously over the full height of the outflow channel.

In one embodiment of the invention, the extension has a first flank lying in the outflow channel, in the direction of the outflow, and a second flank, wherein the first flank has a continuously running curvature and the second flank is nestled against a wall of the outflow channel. The curvature of the first flank can be constant over its course, for example. The osculation of the second flank against the wall of the outflow channel avoids dead water behind the extension, reduces harmful resistance and thus reduces the formation of noise.

In one embodiment of the invention, the extension is rounded at a transition between the first flank and the second flank along its apex line. The rounding allows the low-resistance flow around the extension. Further swirls and noises are avoided.

A backflow of air in the direction of the inlet opening can be minimized by means of the extension particularly efficient when the air only has to overcome a small distance from the outflow channel to the inlet opening. This is the case, in particular, for small radial fans, which for example have an inlet opening with a diameter smaller than 10 cm. Likewise, the effect of the extension is particularly large if the air would have to overcome only a relatively small distance in the radial direction in the absence of extension. This is the case, for example, if the distance of the fan chamber wall to the inlet opening in the region of the outflow channel is less than 2 cm. For example, a fan according to the invention may have an inlet opening with a diameter of about 3.5 cm and a minimum distance between the inlet opening and the fan chamber wall of about 3 mm.

According to a further aspect of the invention, a radial fan is provided with a housing of the above type.

list of figures

• Die 1 eine beispielhafte Ausführung des erfindungsgemäßen Gehäuses und eines darin anordenbaren beispielhaften Radiallüfterrads in Explosionsdarstellung;
• die 2 eine Schnittdarstellung in Draufsicht auf ein beispielhaftes Gehäuse mit einem Radiallüfterrad;
• die 3 eine Seitenansicht der in 2 gezeigten Anordnung;
• die 4 eine Draufsicht zur Darstellung eines Schnittes eines beispielhaften erfindungsgemäßen Gehäuses;
• die 5 eine Ansicht des Gehäuses gemäß 4 entlang des Schnittes B-B.

Hereinafter, exemplary embodiments of the invention are described in more detail with reference to the accompanying drawings. Show it:

• The 1 an exemplary embodiment of the housing according to the invention and an exemplary radial fan wheel can be arranged therein in an exploded view;
• the 2 a sectional view in plan view of an exemplary housing with a radial fan;
• the 3 a side view of in 2 shown arrangement;
• the 4 a plan view showing a section of an exemplary housing according to the invention;
• the 5 a view of the housing according to 4 along the section BB.

figure description

The 1 shows an exploded view of the housing according to the invention 1 and a radial fan wheel arranged therein 2 , The radial fan 2 is along a radial fan wheel axis 3 in the case 1 insertable and fixable in this. The housing 1 has an upper surface coaxial with the radial fan axis 3 arranged, circular opening, which has an inflow channel 4 forms. Tangential to an envelope of the radial fan 3 , or perpendicular to the radial fan wheel axle 3 shows the case 1 a drainage channel 5 on. An extension 6 in the form of a nose is in the area of a wall 7 arranged the discharge channel.

The 2 shows the case 1 with inserted radial fan 2 in plan view. The housing 1 points with respect to the radial fan wheel axis 3 a partially spiraling fan room wall 8th on. That means the radius of the fan room wall 8th starting at a transition 10 between the walls of the outlet channel 7 and the fan room wall 8th in the direction of rotation 9 of the radial fan 2 continuously increases.

The extension 6 is at the transition 10 between the walls of the outlet channel 7 and the fan room wall 8th arranged. The extension 6 is wedge-shaped and protrudes with a point 11 contrary to the direction of rotation 9 of the radial fan 2 in the downstream channel 5 and thus into an exhaust air stream. The extension 6 narrows the outflow channel 5 and forms a barrier to the exhaust air flow. The extension 6 has a first edge 12 and a second flank 13 on. The first flank 12 forms a continuation of the fan room wall 8th contrary to the direction of rotation 9 of the radial fan 2 , The first flank 12 forms with the wall 8th a uniform, uninterrupted surface. The first flank 12 of the extension 6 has a constant curvature. The radius of curvature of the first flank 12 of the extension 6 is equal to the smallest radius of the spiral fan room wall 8th at the transition 10 between the walls of the outlet channel 7 and the fan room wall 8th ,

The extension 6 is thus of the radial fan 2 evenly spaced. The second flank 13 is in the downstream direction of the air to the wall 7 the downstream channel nestled. The summit 11 of the extension is rounded, ie it has an outer contour in the form of a radius.

The extension is at the transition between the downstream channel and at a beginning AS of the spiral of the fan chamber wall 8th educated. The distance of the fan room wall 8th to the axis of rotation 3 of the radial fan 2 is the lowest at the beginning AS of the spiral. In addition, the divergence of the exhaust air flow is smallest in this area. Both circumstances favor in a conventional radial fan backflow of air back to the inflow channel 4 , The return flow is efficiently prevented or at least minimized by the extension according to the invention. Of course, the housing according to the invention for radial fans for different flow media can be used. Instead of air, other gases or gas mixtures can be transported.

The 3 shows a side view of in 2 shown arrangement. The summit 11 of the extension 6 has an axial extent and forms in the direction of the radial fan axis 3 a crest line 14 , The crest line 14 is curved. The crest line 14 extends with respect to an inflow direction along the radial fan axis 3 decreasing. In other words, the extension tapers 6 along the inflow direction. Its largest extension has it on the side of the case 1 on which the inflow channel 4 lies. In the side view of 3 the width B and the height H of the outflow channel are illustrated. The contour of the extension begins in the vertical direction at about 1/3 of the height H and ends at the top of the downstream channel. In the horizontal direction, the extension widens continuously over its vertical course, having a maximum extent x at the top of the downstream channel. In the example, the maximum horizontal extent x is approximately equal to x = 2/5 B. It is advantageous if the extension tangentially conforms to the side surface and top of the downflow channel, so that a transition is realized without edges, whereby the noise is kept small.

The 4 shows a plan view of the housing 1 , The contours of an envelope of the radial fan 2 are indicated as solid double circles. The extension 6 does not protrude beyond its maximum circumferential extent to an imaginary line tangent to the envelope of the radial fan 3 and parallel to one of the walls 7 the discharge channel 5 runs.

The 5 shows a representation of the housing 1 along the in 4 displayed section BB. The extension 6 is only on the side of housing 1 on which the inflow channel 4 is trained. The extension 6 thus forms a barrier only in this area. The crest line 14 of the extension 6 runs in the axial direction along a circular arc.

LIST OF REFERENCE NUMBERS

1

casing

2

radial fan

3

Radiallüfterradachse

4

influx channel

5

outflow channel

6

extension

7

Wall (of the discharge channel)

8th

spiral fan room wall

9

Direction of rotation of the radial fan

10

crossing

11

Tip of the appendage

12

first flank of the extension

13

second flank of the extension

14

crest line

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 10211548 A1 [0003]
• DE 102009033773 A1 [0004]

Claims (12)

Housing (1) for a radial fan wherein the housing (1) has a fan space, which is surrounded by a spiral fan chamber wall (8) and which is adapted to receive a radial fan (2), and wherein the fan chamber each with a, on a housing top formed, axial inflow channel (4) and a tangential discharge channel (5) is connected, characterized in that at the transition between the fan chamber and the outflow channel (5) in the outflow channel (5) protruding extension (6) is formed, wherein the extension is formed on one side of the outflow channel (5), which connects at the beginning of the spiral (AS) to the fan chamber wall (8) and wherein the extension in its course along a direction parallel to the axis of rotation (3) of the radial fan (2) is and points in the direction of the housing top, further into the outflow channel (5) protrudes. Housing (1) to Claim 1 , wherein the extension (6) connects tangentially to the spiral-shaped fan space wall (8). Housing (1) according to one of Claims 1 or 2 wherein the extension (6) forms a continuation of the spiral-shaped fan chamber wall (8) or has a constant spacing relative to the axis of rotation (3) of the radial fan wheel (2). Housing (1) according to one of the preceding claims, wherein the extension (6) along a direction parallel to the axis of rotation (3), a free-form or curved shape or is straight. Housing (1) according to one of the preceding claims, wherein the cross section of the extension (6) in a plane perpendicular to the axis of rotation (3), starting from the beginning at the beginning (AS) of the spiral, tapering in the direction of the outflow channel. Housing (1) to Claim 5 , wherein the extension (6) is formed only in the direction of the inflow opening, in particular wherein the cross section of the extension (6) in a plane perpendicular to the axis of rotation (3) increases continuously in the inflow direction. Housing (1) according to one of the preceding claims, wherein the extension at the inner end (10) of the spiral-shaped fan chamber wall (8) is arranged. Housing (1) according to one of the preceding claims, wherein in a projection of the extension (6) perpendicular to the direction of the course of the Abstromkanals (5) sectional plane of the Abstromkanals (5), the maximum horizontal extent (x) of the extension in the downstream channel (5) in between 1/5 and 4/5 of the width (B) of the outflow channel (5). Housing (1) according to one of the preceding claims, wherein the vertical extension (Z) of the extension (6) along at least parallel to the axis of rotation (3) extending direction at least over 1/3 of the height (H) of the Abstromkanals (5). Housing (1) according to one of the preceding claims, wherein the extension has a downstream in the outflow channel (5), in the direction of the outflow first edge (12), and a second edge (13), wherein the first edge (12) is a constant Has curvature and the second edge (13) is nestled against a wall of the Abstromkanals (7). Housing (1) according to one of the preceding claims, wherein the extension (6) is rounded at a transition between the first flank (12) and the second flank (13) along its apex line (14). A radial fan with a radial fan driven by an electric motor (2), comprising a housing (1) according to one of Claims 1 to 11 ,

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