JP5978886B2 - Blower - Google Patents

Description

  The present invention relates to a blower that achieves both noise reduction and blowing performance.

  Blowers are required to have blowing performance and low noise. Patent Document 1 is provided with a plurality of triangular protrusions (hereinafter referred to as serrations) protruding in the chord direction over the entire leading edge portion of the blade (blade), and reducing the rotational noise by the blower fan. What has been done is disclosed. The pressure surface and the suction surface of the blade of the blower are as shown in FIG. 1C, and the leading edge shape of the serration of the prior art of Patent Document 1 is formed so as to come out from the suction surface to the pressure surface. A plurality of triangular shapes (see FIGS. 2 and 5e of Patent Document 1) are formed. For this reason, although the low noise effect produced by serrations is great, no consideration has been given to both the fan performance and low noise, which is the original purpose of the fan, and the original air blowing performance obtained when there is no serration. May not be obtained.

JP 2000-087898 A

  In view of the above problems, the present invention realizes that the vertical vortex formed by serration of the leading edge of the blade is formed without waste, and realizes suppression of separation of suction air and reduction of turbulent noise by the leading edge of the blade, The present invention provides a blower that improves the blowing performance of the blower by making the air velocity distribution uniform.

In order to solve the above problems, the invention of claim 1 is directed to a drive motor (300), a hub (5) attached to the drive motor, and a plurality of blades (3) provided on the hub (5). ) Having a blower fan (1), the blade leading edge (6) of the blade (3) comprises a plurality of triangular protrusions along the blade leading edge (6) provided with a serration, smoothly continuous with the troughs (3-1) between the triangular protrusions, wing trailing edge (7) groove toward the direction (4) provided on the suction surface of the blade, the A curve formed in a cross section in the circumferential direction of the blade (3) is formed so as to protrude toward the suction surface side at the bottom of the groove (4) provided on the suction surface of the blade. It is a blower.

  In addition, the code | symbol attached | subjected above is an example which shows a corresponding relationship with the specific embodiment as described in embodiment mentioned later.

It is explanatory drawing for description of a general axial-flow fan. It is sectional drawing developed along the AA line of FIG. 1A. It is explanatory drawing explaining the positive pressure surface, negative pressure surface, etc. of the braid | blade of FIG. 1B. It is a front schematic diagram of a 1st embodiment of the present invention. It is an example of the simulation result which analyzed the structure of the flow around the leading edge serration in basic technology. It is explanatory drawing of the simulation result of FIG. FIG. 4 is a cross-sectional view of the blade of the simulation of FIG. 3. 1 is a perspective view of a first embodiment of the present invention. It is the perspective view and BB sectional drawing of 1st Embodiment of this invention. It is a CFD analysis result which compares the stagnation area | region in the serration valley part of this invention and basic technology. It is a graph which shows the frequency characteristic of this invention. It is a perspective view of one form. It is the perspective view and CC line sectional drawing of one form. It is the perspective view and DD line sectional drawing of 2nd Embodiment of this invention. It is the perspective view and EE sectional view taken on the line of the other form.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. About each embodiment, the same code | symbol is attached | subjected to the part of the same structure, and the description is abbreviate | omitted.
Referring to FIG. 2, the blower 10 is a blower in which the blower fan 1 is disposed in the shroud 200 and is rotationally driven by a drive motor (electric motor) 300. The blower 10 is fixed to the engine side of the automotive radiator by attachment portions 250 provided in the vicinity of the four corners of the shroud 200, and blows cooling air to the core portion of the radiator.

  The outer shape of the shroud 200 has a rectangular shape corresponding to the core portion of the radiator, and an annular shroud ring portion 210 containing the blower fan 1 is formed at the approximate center thereof. The shroud ring portion 210 is positioned on the radially outer side of the ring 2 of the blower fan 1. The case where there is no ring 2 of the ventilation fan 1 may be sufficient. The blower 10 and the blade 3 to be described later are not limited to automobile radiators, and may be applied to general industrial use. Although this embodiment demonstrates as an axial-flow fan, this invention is applicable also to a centrifugal blower, a mixed flow fan, etc.

  Between the shroud ring part 210 and the rectangular outer peripheral part of the shroud 200, an air guide part 220 that extends toward the windward side of the blower fan 1 is formed. A circular motor holding portion 230 is formed at the center of the shroud ring portion 210, and the motor holding portion 230 is radially extended radially outward by a plurality of motor stay portions 240 connected to the shroud ring portion 210. It is supported. The drive motor 300 is fixed to the motor holding unit 230, and the shaft of the drive motor 300 and the hub 5 (see FIG. 7) of the blower fan 1 are fixed. The blower 10 includes the blower fan 1, the drive motor 300, and the like. The hub 5 of the blower fan 1 has a cylindrical shape and is provided with a plurality of blades 3 radially. The chord, pressure surface, suction surface, angle of attack α, lift force and the like of the blade 3 are the same as general definitions as shown in FIGS.

  First, the effect of serration of basic technology is described. The simulation of FIG. 3 is the case of the blade cross section of FIG. 5 (the blade cross section of the present invention will be described later). FIG. 3 is a view of the blade leading edge as viewed from above. The arrow displayed in FIG. 3 is obtained by projecting the velocity vector of the flow around the serration (Tangential Velocity) onto a projection plane (S plane in FIG. 4) perpendicular to the YZ plane. It can be seen that a flow is generated from the valleys on both sides toward the upper surface of the mountain. In serration, at the beginning of the peak, a small engulfment occurs and grows into a larger engulfment as it goes to the valley. Then, it is considered that the downward flow is generated at the rear of the mountain, so that the separation that is particularly likely to occur on the suction surface having a large flow velocity is pressed downward to reduce the separation of the flow. As a result, it is possible to reduce the noise in the vicinity of the blade surface and reduce the pressure fluctuation on the blade surface, thereby producing an effect that leads to noise reduction.

(First embodiment)
In this embodiment, while utilizing the effect of serration of the basic technology described above, while further reducing the rotational noise by the blower fan, noise reduction is achieved without impairing the blower performance, which is the original purpose of the blower fan. And ensuring air blowing performance.
First, the operation principle of this embodiment will be briefly described with reference to FIGS. As a result of the research so far, when a triangle (serration) is installed at the blade leading edge portion as in the basic technology, as shown in the thickness t in FIG. It has been found that the stagnation region T occurs larger than the base thickness when no serration is installed. Therefore, in the present embodiment, a groove portion 4 is provided on the suction surface of the blade 3 so as to be smoothly continuous with the valley portion 3-1 and toward the blade trailing edge portion 7, as shown in the enlarged view of FIG. . The cross-sectional view taken along line B-B in FIG. 7 is formed as shown by a circle in the B-B cross-sectional view in FIG.

  The difference in action and effect at this time is shown by the CFD (Computational Fluid Dynamics) analysis of FIG. In the case of the basic technology, the suction surface side of the valley portion 3-1 is angular, whereas in this embodiment, the suction surface side of the valley portion 3-1 is upward as a result of the groove portion 4 being installed. It has a rounded shape (R shape, etc.). Although the shape of the groove part 4 may include various shapes, here, it is formed smoothly and continuously in three dimensions so as not to impair the streamlined shape of the blade. By installing the groove portion 4 having a smooth streamline shape, the flow that hits the serration valley portion 3-1 is made difficult to peel off. As shown in FIG. 8, it is clear that the stagnation region is reduced in the first embodiment of the present invention as compared to the stagnation region T in the case of the basic technology. In the stagnation region, there is no flow rate or a small flow rate, and the stagnation region is easily peeled off.

  Also in the present embodiment, as in the basic technology, a small entanglement occurs at the tip of the peak portion 3-2 of the serration and grows into a large entanglement as it goes to the valley portion 3-1. Then, a downward flow is generated behind the peak portion, so that the separation that is particularly likely to occur on the suction surface having a large flow velocity is pressed downward to reduce the separation of the flow. Thereby, it is possible to reduce the noise in the vicinity of the blade surface and suppress the pressure fluctuation on the blade surface, thereby producing an effect that leads to a reduction in noise.

  In addition, in the present embodiment, the wing cross-sectional shape of the valley portion 3-1 is streamlined as shown in the lower BB cross-sectional view of FIG. 7 as shown in the CFD analysis diagram of FIG. This leads to a lift-drag ratio (lift / efficiency) UP (drag reduction). Furthermore, since the blades can work more efficiently than the conventional and basic air blowing fans, the torque is low and the power used is small, so that further power saving can be obtained as an electric fan. . This embodiment reduces the drag at the valleys, reduces the air resistance of the blades and increases the lift / drag ratio without impairing the serration function (vertical vortex generation), and can work efficiently. It is.

  Furthermore, the frequency characteristic shown in FIG. 9 shows the noise reduction of this embodiment compared with the comparative technique which is the case of a blade without serration. As shown in the characteristics of FIG. 9, in this embodiment, the sound pressure level (SPL) is generally reduced. However, the reduction is particularly noticeable in a high frequency region of 2 k to 5 kHz, and turbulent noise is generated. It turns out that it has decreased.

  In 1st Embodiment of this invention, as shown in FIG. 6, although the embodiment at the time of directing the direction of a serration to the circumferential direction is shown, according to the flow of the airflow in the radial direction position of the ventilation fan 1 is shown. Thus, the pitch, height, or direction of the serration may be changed. The flow of airflow in the vicinity of the blade surface of the blower varies greatly depending on the part, and the air flow rate is higher toward the outer peripheral side with respect to the radial direction of the blower fan. It becomes a diagonal flow toward. Furthermore, a backflow that wraps from the pressure surface to the suction surface side also occurs at the blade tip.

  Changing the serration pitch, height, or direction according to the flow of these airflows at the radial position of the blower fan 1 is extremely important in reducing flow separation ( For example, the direction of serration is adjusted to the direction of backflow or diagonal flow at the location where backflow or mixed flow occurs). As a result, the basic effect of the original serration of the present embodiment can be further exhibited, and it is possible to reduce the disturbance near the blade surface and suppress the pressure fluctuation of the blade surface, thereby creating an effect that leads to low noise. Become.

  Regarding the triangular protrusions constituting the serration, here, the base of the triangular protrusion is called the pitch p of the serration (triangular protrusion), and the bisector of the apex angle θ of the triangular protrusion is expressed as serration. It is called the direction of (triangular protrusion), and the distance from the bisector of the apex angle to the base is called the height h of the serration (triangular protrusion). The size of the serration (triangular protrusion) means that either the pitch or height of the serration is large. The apex angle θ of the triangular protrusion is called the serration apex angle θ. Since the flow velocity increases toward the outer peripheral side with respect to the radial direction of the blower fan, the serration effect is further improved by increasing the serration pitch and height toward the outer peripheral side in the first embodiment. Although the present embodiment has been described in the case of a backward wing, it can also be applied to a forward wing. The same applies to other embodiments described later.

In this embodiment, the shape of the groove 4 is changed as shown in FIGS. 10 and 11, and the others are the same as those in the first embodiment. The shape of the groove portion 4 of this embodiment (the curved shape of the bottom portion of the groove portion 4) is smooth in the valley portion 3-1 so as to protrude toward the pressure surface side as seen in the CC cross-sectional view of FIG. Continuously, the blade is formed so as to be directed toward the blade trailing edge on the suction surface of the blade. This form also reduces the drag at the valleys without reducing the serration function (vertical vortex generation), reduces the air resistance of the wing, and increases the lift-drag ratio, so that it can work efficiently. is there. In the present embodiment, the shape of the groove portion 4 is made to flow in accordance with the angle of attack α, as compared with the first embodiment in which the shape of the groove portion 4 is convex toward the suction surface in the BB sectional view of FIG. Since peeling may be reduced, it is preferable to experimentally select a shape that is one form with the first embodiment. Of course, even if the bottom of the groove portion 4 is formed by a straight line having no unevenness in the BB cross-sectional view and the CC cross-sectional view, the effect is produced.

( Second Embodiment)
In the second embodiment, the cross-sectional shape of the groove 4 is changed as shown in the DD cross-sectional view of FIG. 12, and the rest is the same as that of the first embodiment. The bottom shape of the groove portion 4 on the suction surface of the second embodiment is the same as that of the first embodiment formed so as to be convex toward the suction surface side. On the positive pressure surface, a groove portion 4 ′ is provided in the same direction as the negative pressure surface toward the blade trailing edge. The groove 4 ′ provided on the pressure surface of the blade may be provided so as to be convex or concave on the pressure surface side. In this embodiment, the drag force at the valleys can be reduced on the suction surface and the pressure surface without impairing the serration function (longitudinal vortex generation), and the air resistance of the blade can be reduced to increase the lift-drag ratio. As in the second embodiment, the bottom shape of the groove portion 4 on the suction surface is formed to be convex toward the pressure surface side, and the groove portion that is convex or concave toward the pressure surface side on the pressure surface of the blade. 4 'may be provided.
In addition, as shown in FIG. 13, a groove portion 4 ′ smoothly extending continuously from the valley portion 3-1 toward the blade trailing edge portion may be provided only on the pressure surface of the blade. Even in this case, flow separation can be reduced according to the angle of attack α.

DESCRIPTION OF SYMBOLS 1 Blow fan 3 Blade 3-1 Valley part 3-2 Mountain part 4 Groove part 5 Hub 300 Drive motor

Claims (3)

A blower comprising a drive motor (300), a hub (5) attached to the drive motor, and a blower fan (1) having a plurality of blades (3) provided on the hub (5). ,
The blade leading edge (6) of the blade (3) is provided with serrations composed of a plurality of triangular protrusions along the blade leading edge (6), and a valley (3 -1) smoothly and continuously, a groove (4) directed toward the blade trailing edge (7) is provided on the suction surface of the blade,
A curve formed in a cross section in the circumferential direction of the blade (3) is formed so as to protrude toward the suction surface side at the bottom of the groove (4) provided on the suction surface of the blade. And blower. The groove portion (4 ') directed toward the blade trailing edge portion is also provided on the pressure surface of the blade smoothly following the valley portion (3-1) between the triangular protrusions. The blower according to 1 . The blower according to claim 1 or 2 , wherein a pitch (p), a height (h), or a direction of the serration is changed according to a flow of airflow at a radial position of the blower fan. .