JP2008223760A - Impeller for blower - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an impeller for a blower capable of more effectively inhibiting the separation of an airflow by modifying conventional impellers which do not always show effective separation inhibition effects even if a projection is formed on a blade surface when a shape of the projection is regular such as a shape of a fixed height, a fixed width and a fixed length. <P>SOLUTION: In the impeller for the blower provided with a plurality of blades and a rotary support means rotatably supporting the blades, many projections or grooves having irregular shapes extending in a cord length direction are formed on the surface of the blade. By such a structure, many irregular projections or grooves form tumble having high boundary layer breakage effects and effectively inhibit the development of a boundary layer, and more effectively reduce the separation of an airflow as compared to regular projections or grooves. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a configuration of an impeller of a blower that prevents separation of a flow around a blade.

  In an impeller of a blower, when separation occurs in the flow around the blade, a vortex is generated on the downstream side. The vortex becomes a sound source and raises the blowing sound of an air conditioner or the like. Therefore, suppressing such separation is an important issue to be addressed, leading to lower noise in air conditioners and the like.

  From this point of view, various countermeasures have been taken.

  For example, in an axial blower such as a propeller fan, when the propeller fan rotates, the air pressure on the low pressure side surface of each blade during the rotation is high on the front side of the blade and low on the rear side, which is downstream of the blade itself. It becomes more prominent according to the inclination to the side. As a result, separation of the air flow occurs on the downstream low pressure surface side of the blade, and pressure fluctuation occurs in the separation portion, generating noise.

  Therefore, as a countermeasure against this problem, there is one in which a plurality of circular dimples are formed on the low pressure surface side of the blade, and the amount of noise generated is reduced by the effect of reducing the separation of the dimples (see Patent Document 1). .

  When a plurality of dimples are provided on the low pressure surface side of the blade in this way, a flow is generated in the dimples, whereby the flow velocity at the wall surface is locally recovered, and the development of the boundary layer can be suppressed. It is considered that the pressure fluctuation at the section is also reduced, which can contribute to noise reduction.

  However, in the case of this prior art, the relationship between the size and rotational speed of the impeller and the dimple and hole diameter has not been clearly elucidated. And even when the size of the dimples is different, it is not clear how much dimples are arranged at which position on the wing surface, and it can be said that a good effect is not necessarily obtained. On the contrary, according to the experimental results conducted by the inventors of the present application, it was confirmed that the noise sometimes increased.

  Similarly, in an axial fan such as a propeller fan, for example, short fin-like protrusions are distributed over the entire blade surface of each blade, and the flow is disturbed by the fin-like protrusions to promote turbulent transition. In some cases, a turbulent boundary layer on the blade surface is more actively formed by the mixing action of turbulent flow to prevent separation (see Patent Document 2).

Japanese Patent Laid-Open No. 3-294699 (page 1-2 of the specification, FIGS. 1 and 3) Japanese Unexamined Patent Publication No. 2003-278696 (page 2 of the specification, FIG. 3)

  However, as a result of the experiment, even when a fin-like short protrusion is provided on the surface of the blade as in the latter prior art, the protrusion has a constant height, a constant width, and a constant length. In the case of a regular shape such as a fixed position, an effective peeling suppressing effect is not always exhibited.

  The present invention has been made based on such circumstances, and more effectively by providing a plurality of irregularly shaped ridges or ridges extending in the chord length direction on the blade surface of the blade. An object of the present invention is to provide an impeller for a blower that can suppress peeling.

  The present invention has been made for the purpose of solving the above-described problems, and comprises the following effective problem solving means.

(1) First problem solving means The first problem solving means of the present invention is an impeller of a blower comprising a plurality of blades and a rotation support means for rotatably supporting the blades, wherein the blades A large number of irregularly-shaped ridges extending in the chord length direction are juxtaposed on the wing surface.

  According to such a configuration, a large number of irregularly-shaped ridges extending side by side in the chord length direction are more effective in crushing the boundary layer than the regular-shaped ridges. By forming a high vertical vortex, the development of the boundary layer whose thickness increases more effectively from the front edge side to the rear edge side is suppressed, and the peeling is more effectively reduced.

  In addition, the vertical vortex attracts the downstream airflow toward the blade suction surface side, so that the separation can be more effectively reduced.

  As a result, the blowing noise can be more effectively reduced and the blowing efficiency can be further improved.

(2) Second Problem Solving Means The second problem solving means of the present invention is that, in the configuration of the first problem solving means, the heights of the protruding portions are different from each other in the juxtaposition direction. It is characterized by becoming.

  According to such a configuration, the plurality of irregularly-shaped ridges more effectively suppress the development of the boundary layer, and more effectively reduce peeling.

(3) Third problem solving means The third problem solving means of the present invention is that, in the configuration of the first or second problem solving means, the widths of the ridges are different from each other adjacent to each other. It is characterized by having become.

  According to such a configuration, the plurality of irregularly-shaped ridges more effectively suppress the development of the boundary layer, and more effectively reduce peeling.

(4) Fourth Problem Solving Means According to a fourth problem solving means of the present invention, in the configuration of the first, second, or third problem solving means, the width of each protrusion is in the chord length direction. It is characterized by changes.

  According to such a configuration, the plurality of irregularly-shaped ridges more effectively suppress the development of the boundary layer, and more effectively reduce peeling.

(5) Fifth Problem Solving Means The fifth problem solving means of the present invention is the configuration of the first, second, third or fourth problem solving means, wherein the height of each ridge portion is a wing. It is characterized by changes in the chord length direction.

  According to such a configuration, the plurality of irregularly-shaped ridges more effectively suppress the development of the boundary layer, and more effectively reduce peeling.

(6) Sixth problem-solving means The sixth problem-solving means of the present invention is the height of each protrusion in the configuration of the first, second, third, fourth, or fifth problem-solving means. Is characterized in that it changes within a range of 0.6 to 1.8 times the thickness of the boundary layer generated on the blade surface.

  According to such a configuration, the plurality of irregularly-shaped ridges more effectively suppress the development of the boundary layer and reduce peeling as effectively as possible.

(7) Seventh Problem Solving Means Seventh problem solving means of the present invention is an impeller of a blower comprising a plurality of blades and rotation support means for rotatably supporting the blades, wherein the blades A number of irregularly shaped ridges extending in the chord length direction are juxtaposed on the wing surface.

  According to such a configuration, a large number of irregularly-shaped concave ridges extending side by side in the chord length direction are more effective in crushing the boundary layer than the regular-shaped concave ridges. By forming a high vertical vortex, the development of the boundary layer whose thickness increases more effectively from the front edge side to the rear edge side is suppressed, and the peeling is more effectively reduced.

  In addition, the vertical vortex attracts the downstream airflow toward the blade suction surface side, so that the separation can be more effectively reduced.

  As a result, the blowing noise can be more effectively reduced and the blowing efficiency can be further improved.

(8) Eighth problem-solving means The eighth problem-solving means of the present invention is that, in the configuration of the seventh problem-solving means, the depths of the concave portions are different from each other in the juxtaposition direction. It is characterized by becoming.

  According to such a configuration, the plurality of irregularly-shaped concave ridge portions more effectively suppress the development of the boundary layer, and more effectively reduce the peeling.

(9) Ninth problem-solving means The ninth problem-solving means of the present invention is the configuration of the seventh or eighth problem-solving means, wherein the widths of the concave portions are different from each other between adjacent ones. It is characterized by having become.

  According to such a configuration, the plurality of irregularly-shaped concave ridge portions more effectively suppress the development of the boundary layer, and more effectively reduce the peeling.

(10) Tenth Problem Solving Means The tenth problem solving means of the present invention is the configuration of the seventh, eighth, or ninth problem solving means, wherein the width of each recess is in the chord length direction. It is characterized by changes.

  According to such a configuration, the plurality of irregularly-shaped concave ridge portions more effectively suppress the development of the boundary layer, and more effectively reduce the peeling.

(11) Eleventh problem-solving means The eleventh problem-solving means of the present invention is the configuration of the seventh, eighth, ninth, or tenth problem-solving means, wherein the depth of each concave stripe portion is a wing It is characterized by changes in the chord length direction.

  According to such a configuration, the plurality of irregularly-shaped concave ridge portions more effectively suppress the development of the boundary layer, and more effectively reduce the peeling.

(12) Twelfth Problem Solving Means The twelfth problem solving means of the present invention is the depth of each concave strip in the seventh, eighth, ninth, tenth or eleventh problem solving means. Is characterized in that it changes within a depth range of 0.6 to 1.8 times the thickness of the boundary layer generated on the blade surface.

  According to such a configuration, the plurality of irregularly-shaped concave ridge portions further effectively suppress the development of the boundary layer and reduce the separation as effectively as possible.

  As a result, according to the present invention, it is possible to more effectively suppress the development of the boundary layer and more effectively reduce the peeling as compared with the case of the conventional regular-shaped protrusion.

  Therefore, it is possible to realize an air conditioner with high blowing performance and as low noise as possible.

<First Embodiment>
Hereinafter, the configuration of the best embodiment 1 for carrying out the present invention will be described with reference to the accompanying drawings.

  First, FIG. 1 to FIG. 6 show the configuration of a blower impeller according to the first preferred embodiment of the present invention and a ceiling-embedded indoor unit for an air conditioner constructed using the blower impeller. Yes.

  1 to 4, reference numeral 2 is a cassette-type main body casing of the ceiling-embedded air conditioner 1. The main body casing 2 is embedded in the ceiling 3 such that its intake / blowout panel (lower surface panel portion) 4 continues in substantially the same plane as the ceiling 3.

  The intake / blowout panel 4 of the main body casing 2 is provided with a square air suction port 5 at the center, and further, a bell mouth 6 for a turbofan 11 which is an example of a centrifugal fan as a blower. Are connected.

  Further, air blowout ports 9, 9... Having a predetermined width are provided on the outer peripheral portion 4 side of the air suction port 5 of the intake / blowout panel 4 of the main body casing 2.

  In the main casing 2, a ventilation passage 10 is formed in the circumferential direction from the air suction port 5 through the bell mouth 6 to the air outlets 9, 9. The turbo fan 11 is located in the center of the road 10 behind the bell mouth 6 (upper part in the drawing) and the air suction side (side plate 15 side described later) corresponds to the bell mouth 6 is connected to the fan motor 13 and the fan motor 13. The main body casing 2 is suspended from the top plate 2a via a rotary drive shaft 13a.

  An air heat exchanger 12 is provided in the ventilation path 10 so as to surround the turbo fan 11.

  On the other hand, the turbo fan 11 has a circular main plate 14 fixed to the rotational drive shaft 13a of the fan motor 13 via a boss portion 14a and the other end forming an air suction port in the centrifugal direction in the turbo fan impeller. A large number of blades (moving blade blades) 16, 16... Are arranged in parallel in the circumferential direction with a predetermined blade angle and a predetermined blade interval between the side cylindrical side plate 15. On the other hand, on the inner side of the shallow cylindrical air suction side end of the side plate 15, the downstream cylindrical air outlet side end of the bell mouth 6 is loosely fitted with a predetermined dimension so as to be relatively rotatable with a predetermined gap. Has been.

  The bell mouth 6 smoothes the air from the air suction port 5 on the main body casing 2 side in the centrifugal direction in the impeller with respect to the air suction side end of the side plate 15 forming the air suction port of the turbofan impeller. As shown in the figure, the air inlet having a predetermined curvature radius that extends inwardly from the mounting edge to the intake / blowout panel 4 and gradually decreases in opening diameter from the air flow upstream side to the air flow downstream side. And an air flow guide surface composed of an air outlet portion.

  And the aerodynamic noise generated at the time of blowing by smoothly guiding the air on the suction side of the turbo fan impeller in the blow-off side centrifugal direction on the suction side corresponding to the side plate 15 of the turbo fan impeller by its shape Is trying to reduce.

  By the way, as already described, in the impeller of the turbofan 11 which is an example of the blower as described above, for example, as shown in FIG. 7, the front edge 16 a to the rear edge 16 b side of the blades 16, 16. As the thickness of the boundary layer gradually increases, separation of the flow around the blade tends to occur. When such peeling occurs, a vortex is generated on the downstream side. The vortex becomes a sound source and raises the blowing sound of an air conditioner or the like. Therefore, suppressing such separation leads to a reduction in noise of the air conditioner 1 and is an important issue to be tackled.

  From this point of view, various countermeasures have been taken.

  For example, in an axial blower such as a propeller fan, when the propeller fan rotates, the air pressure on the low pressure side surface of each blade during the rotation is high on the front side of the blade and low on the rear side, which is It becomes more prominent according to the degree of inclination toward the downstream side. As a result, separation of the air flow occurs on the downstream low pressure surface side of the blade, and pressure fluctuation occurs in the separation portion, generating noise.

  Therefore, as a countermeasure against this problem, there is one in which a plurality of circular dimples are formed on the low pressure surface side of the blade, and the amount of generated noise is reduced by the action of reducing the separation of the dimples.

  When a plurality of dimples are provided on the low pressure surface side of the blade in this way, a flow is generated in the dimples, whereby the flow velocity at the wall surface is locally recovered, and the development of the boundary layer can be suppressed. It is considered that the pressure fluctuation at the section is also reduced, which can contribute to noise reduction.

  However, in the case of this prior art, the relationship between the size and rotational speed of the impeller and the dimple and hole diameter has not been clearly elucidated. In addition, regarding the size of the dimples, it has not been clarified as to how much dimples are arranged at which position on the blade surface, and it cannot be said that a good effect is necessarily obtained. According to the results of experiments conducted by the inventors of the present application, it has been confirmed that noise may increase.

  Similarly, in an axial fan such as a propeller fan, for example, short fin-like protrusions (or grooves) are distributed over the entire blade surface of each blade, and the turbulent flow is disturbed by the fin-like protrusions. Some have promoted the transition and more actively formed a turbulent boundary layer on the blade surface by the mixing action of the turbulent flow to prevent separation.

  However, as a result of the experiment, even when the protrusions are provided on the surface of the blade as described above, if the protrusions are short and regularly distributed in a fixed fin shape, they are not necessarily provided. Effective peeling suppression effect is not exhibited.

  Therefore, in this embodiment, for example, as shown in FIGS. 5 and 6, blades on the suction surface side and the pressure surface side (or at least the blade surface on the suction surface side) of the blades 16, 16,. It is characterized in that peeling can be effectively suppressed by providing a plurality of irregularly-shaped convex strips 160a to 160i... Extending in the chord length direction.

  That is, in the case of the present embodiment, each blade surface on the suction surface side and the pressure surface side of the impeller blades 16, 16... Of the turbo fan 11 has a chord length direction (thickness of the boundary layer). Is provided with a group of ridges 160 formed of a number of irregular ridges 160a to 160i... Extending in the direction from the front edge 16a to the rear edge 16b.

  And each protruding item | line part 160a-160i ... of this protruding item | line group 160 makes a mutually different length in the juxtaposed direction (width direction of the blade | wing 16), for example, and has become different height, The width | variety of each protruding item | line part 160a-160i ... becomes a thing of a mutually different dimension between adjacent things. The pitch Pa is also random.

  Further, the height and width of each of the ridges 160a to 160i... Change in the chord length direction.

  And now, for example, if the height of the ridges 160a to 160i... To be changed in the chord length direction as described above is H, the height H is, for example, on the blade surface shown in FIG. In this case, the distance L from the leading edge 16a to the trailing edge increases, and the boundary layer thickness that increases toward the downstream side is assumed to be BL, and is in the range of 0.6 to 1.8 times the thickness BL. It is formed to change with height.

  Now, the blowing sound of the blades 16, 16... Of the configuration shown in FIGS. 5 and 6 provided with the ridge group 160 configured of such irregularly shaped ridges 160 a to 160 i. Although the ridge group 160 which consists of many ridge parts 160a-160i ... extended in a chord length direction on the wing surface is formed, each ridge part 160a-160i ... of the same ridge group 160 is formed. The length, height, and width of each of the blades are substantially constant, and have a regular shape that does not change at all, for example, compared with the blowing sound of the blades 16 ', 16',. For example, as shown in the graph of FIG.

  In the case of the blade 16 ′ of FIG. 8 provided with regular ridges, the blowing noise can be reduced as compared with the blade 16 ′ having no ridges at all. 5 and 6 of the present embodiment in which the length, height, and width of the blade are irregularly changed in the chord length direction, the blade 16 'of the regular ridge portion having the configuration shown in FIG. 8 is used. It can also be seen that the blowing sound is greatly reduced over a wide air volume range from the small air volume region to the large air volume region.

  This is because a large number of irregularly-shaped ridges 160a to 160i... Form a vertical vortex having a higher boundary layer crushing effect than the regular-shaped ridges, thereby effectively boundarying. This is thought to be due to the suppression of layer development and a sufficient reduction in the amount of peeling.

  In this case, each of the irregularly-shaped convex strips 160a to 160i... Has a height H (see FIG. 6) that changes in the chord length direction, and is a boundary generated on the blade surface of the blade. The case where the thickness changed within the range of 0.6 to 1.8 times the layer thickness BL (see FIG. 7) (H / BL was 0.6 to 1.8) was most effective.

  Therefore, according to the thickness BL (1 to 2 mm at the maximum) of the boundary layer that grows from the front edge side to the rear edge side, the height of the ridges 160a to 160i is appropriately set within the above range. Thus, the plurality of irregularly-shaped ridges 160a to 160i... More effectively suppress the development of the boundary layer and reduce peeling as effectively as possible.

  In the formation of the irregularly shaped protrusions 160a to 160i..., The protrusions 160a to 160i... Are formed on the basis of a regular one such as the pattern of FIG. A design method is used in which the formation pattern is changed with the predetermined irregularity as described above in accordance with the blade surface position in the chord length direction.

<Best Embodiment 2>
Next, FIG. 10 and FIG. 11 show a configuration of a blower impeller according to the second preferred embodiment of the present invention.

  In the first embodiment described above, for example, as shown in FIGS. 5 and 6, the blades 16, 16... Have blades on the suction surface side and pressure surface side blade surfaces (or at least the suction surface side blade surfaces). By providing a large number of irregularly-shaped ridges 160a to 160i... Extending in the chord length direction, peeling can be effectively suppressed.

  That is, in the case of the configuration of the first embodiment, the blade surface on the suction surface side and the pressure surface side of the impeller blades 16, 16,... A ridge group 160 including a plurality of irregularly-shaped ridges 160a to 160i... Extending in the direction from the front edge 16a to the rear edge 16b (in which the layer thickness increases) is provided.

  And each ridge part 160a-160i ... of this ridge group 160 makes length mutually different, for example in the juxtaposition direction (width direction), and also becomes different height, and each ridge. The widths Wa of the portions 160a to 160i... Have dimensions different from each other between adjacent ones.

  Further, the height H and width Wa of each of the ridges 160a to 160i... Change in the chord length direction (from the leading edge 16a to the trailing edge 16b).

  The height H of each of the ridges 160a to 160i... Changing in the chord length direction is, for example, the distance L from the leading edge 16a to the trailing edge 16b on the blade surface shown in FIG. The boundary layer thickness BL was increased and increased in the range of 0.6 to 1.8 times the boundary layer thickness BL.

  On the other hand, in the second embodiment, for example, as shown in FIG. 10, the blade surfaces on the suction surface side and the pressure surface side of the blades 16, 16,... (Or at least the blade surfaces on the suction surface side). ) Is provided with a number of irregularly shaped recesses 160a ′ to 160i ′... That extend in the chord length direction, so that peeling can be effectively suppressed. .

  That is, in the case of the second embodiment, each blade surface on the suction surface side and the pressure surface side of the impeller blades 16, 16,... A groove group 160 ′ is provided which includes a plurality of irregularly shaped groove portions 160a ′ to 160i ′... Extending in the direction from the front edge 16a to the rear edge 16b (in which the thickness BL increases).

  And each groove part 160a'-160i '... of this groove group 160' makes length mutually different, for example in the juxtaposition direction (width direction of the blade | wing 16), and different depth D and each. In addition, the width Wb of each of the concave portions 160a ′ to 160i ′... Has a size different from that of adjacent ones. The pitch Pb is also random.

  Further, the depth D and the width Wb of each of the concave portions 160a ′ to 160i ′... Are the same as the convex portions 160a to 160i. As well as the chord length direction (from the leading edge 16a to the trailing edge 16b).

  The depth D is, for example, 0.6-1... Of the boundary layer thickness BL that increases as the distance L from the leading edge 16a to the trailing edge 16b increases on the blade surface shown in FIG. It is formed to change within a range of 8 times (D / BL is 0.6 to 1.8).

  Now, the blowing sound of the blades 16, 16... Having the configuration of FIG. 10 provided with the groove group 160 'having the configuration of the irregularly shaped recess portions 160a' to 160i '. Although a groove group 160 'composed of a plurality of groove sections 160a' to 160i '... extending in the chord length direction is formed on the blade surface, each groove section 160a' of the groove group 160 'is formed. ... 160i ′... Regular wings 16 ′, 16 ′... (Protrusions of the blades 16 ′ in FIG. 8). When compared with the blowing sound of the parts 160a to 160i (similar to those focusing on the concave portion between the portions 160a to 160i), it was possible to obtain the blowing sound reduction effect as shown in the graph of FIG. .

  In the case of the blade 16 'provided with the regular concave portions 160a' to 160i ', the blowing sound can be reduced as compared with the blade 16' provided with no concave portions at all. In the blade 16 of FIG. 10 according to the second embodiment in which the length, depth, and width of the groove portion are irregularly changed in the chord length direction, the air volume range is smaller than that of the regular groove portion blade 16 ′. It can be seen that the blowing sound is further greatly reduced over a wide air flow range from the high air flow range to the large air flow range.

  This is because a large number of irregularly shaped concave strips 160a ′ to 160i ′... Form a vertical vortex having a higher boundary layer crushing effect than the regular shaped concave strips. It is thought that this is because the development of the boundary layer is suppressed and the amount of peeling is sufficiently reduced.

  In this case, each of the irregularly shaped concave strips 160a ′ to 160i ′,... Has a groove depth D of the concave strips 160a ′ to 160i ′. According to the simulation result (measurement of blowing sound under the same air volume) obtained by making the dimensionless in FIG. 11, for example, as shown in FIG. 11, the groove depth D (FIG. 11) changes in the chord length direction. 10) changes within a range of 0.6 to 1.8 times the boundary layer thickness BL (see FIG. 7) generated on the blade surface of the blade 16 (D / BL is 0.6 to 1.). 8) was the most effective.

  Therefore, according to the thickness BL of the boundary layer that grows from the front edge 16a side to the rear edge 16b side, the groove depth D of the groove portions 160a ′ to 160i ′. By appropriately setting within the double range, the above-mentioned irregularly shaped concave strips 160a ′ to 160i ′... Further effectively suppress the development of the boundary layer and peel as effectively as possible. It turns out that it comes to reduce.

  The same can be said for the concave portions formed between the convex portions 160a to 160i... Of the best embodiment 1 described above, and the convex portions 160a to 160i. The height H and the depth of the concave portion formed between them correspond to each other, and act by the substantially same mechanism with respect to the above-described action of reducing the blowing sound.

  Therefore, also in the case of the above-mentioned Embodiment 1, if the height H of each convex-line part 160a-160i ... is similarly set in the range of 0.6-1.8 times the thickness BL of a boundary layer. It is clear that the same blowing noise reduction effect as in the case of FIG. 11 can be obtained.

  In the formation of the irregularly shaped concave ridges 160a ′ to 160i ′..., For example, as in the case of the above-described convex ridges 160a to 160i. A design method is used in which the formation pattern of each of the concave portions 160a ′ to 160i ′... Is changed with the predetermined irregularity as described above according to the blade surface position in the chord length direction. It is done.

(Other embodiments)
In the above description, the turbo fan 11 has been described as an example of the blower. However, the present invention can be applied to other axial fans such as a centrifugal fan and a propeller fan in a similar manner.

It is sectional drawing which shows the structure of the air conditioner comprised using the impeller of the air blower (turbofan) which concerns on this Embodiment 1 applied to the ceiling embedded type air conditioner, and the impeller. . It is a perspective view of the impeller of the blower (in this case, the up-and-down relationship is shown opposite to that in FIG. 1, and this point is the same in the case of FIGS. 3 and 4 below). It is a side view of the impeller of the blower. It is a partially expanded plan view which shows the attachment state between the main board and side board of the blade | wing of the impeller of the air blower. It is a top view which shows the structure of the blade | wing surface of the impeller of the blower. It is an expanded sectional view (AA line sectional view of Drawing 5) showing the detailed composition of the blade surface of the impeller of the blower. It is a graph which shows the relationship between the change (increase amount) of the thickness of the boundary layer of the blade | wing blade of the impeller of the blower, and the distance from the blade leading edge. It is a top view which shows the structure at the time of making the protruding strip part of the surface of the blade | wing of the impeller of the air blower into a regular structure. It is the graph which contrasted the difference of the generation amount of the ventilation sound of the convex strip part shape of the blade | wing of FIG. 5 and FIG. 6 and the convex strip part shape of the blade | wing of FIG. 8 on the basis of the case where there is no convex strip part. It is a partially expanded sectional view which shows the structure of the principal part of the impeller blade | wing of the air blower (turbo fan) which concerns on this Embodiment 2 applied to the ceiling embedded type air conditioner. It is a graph which shows the relationship between the effective depth of the groove | channel of a groove part with respect to the thickness of the boundary layer of the impeller of the impeller of the air blower, and ventilation sound.

Explanation of symbols

  6 is a bell mouth, 10 air passages, 11 is a turbo fan, 14 is a main plate, 14a is a hub, 15 is a side plate, 16 is a blade, 160 is a ridge group, and 160a to 160i are ridges forming the ridge group 160. , 160 'is a groove group, and 160a' to 160i 'are groove portions forming the groove group 160'.

Claims (12)

  An impeller of a blower provided with a plurality of blades and rotation support means for rotatably supporting the blades, and a plurality of irregularly shaped blades extending in the chord length direction on the blade surface of the blades An impeller of a blower characterized in that ridges are arranged side by side.   The impeller of the blower according to claim 1, wherein the height of each protrusion is different from each other in the juxtaposed direction.   The impeller of the blower according to claim 1 or 2, wherein the widths of the protruding portions are different from each other between adjacent ones.   The impeller of a blower according to claim 1, 2 or 3, wherein the width of each ridge varies in the chord length direction.   The impeller of the blower according to claim 1, 2, 3, or 4, wherein the height of each ridge varies in the chord length direction.   The height of each ridge portion changes within a range of 0.6 to 1.8 times the thickness of the boundary layer generated on the blade suction surface. 4, 4 or 5 blower impeller.   An impeller of a blower provided with a plurality of blades and rotation support means for rotatably supporting the blades, and a plurality of irregularly shaped blades extending in the chord length direction on the blade surface of the blades An impeller for a blower characterized in that concave ridges are arranged side by side.   The impeller of the blower according to claim 7, wherein the depths of the concave portions are different from each other in the juxtaposed direction.   The impeller of a blower according to claim 7 or 8, wherein the width of each concave line portion is different between adjacent ones.   The impeller of the blower according to claim 7, 8 or 9, wherein the width of each concave strip portion changes in the chord length direction.   The impeller of a blower according to claim 7, 8, 9 or 10, wherein the depth of each concave line portion changes in the chord length direction.   The depth of each concave stripe part changes in the range of 0.6-1.8 times the thickness of the boundary layer which arises in a blade suction surface, The 7, 7, 9 characterized by the above-mentioned. , 10 or 11, the impeller of the blower.

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