US20200240430A1 - Propeller fan and axial flow blower - Google Patents

Propeller fan and axial flow blower Download PDF

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Publication number
US20200240430A1
US20200240430A1 US16/643,647 US201716643647A US2020240430A1 US 20200240430 A1 US20200240430 A1 US 20200240430A1 US 201716643647 A US201716643647 A US 201716643647A US 2020240430 A1 US2020240430 A1 US 2020240430A1
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United States
Prior art keywords
rotor blade
region
distribution
angle
circumferential edge
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Abandoned
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US16/643,647
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English (en)
Inventor
Toshikatsu Arai
Hitoshi Kikuchi
Chikage Kadoi
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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Assigned to MITSUBISHI ELECTRIC CORPORATION reassignment MITSUBISHI ELECTRIC CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ARAI, TOSHIKATSU, KADOI, Chikage, KIKUCHI, HITOSHI
Publication of US20200240430A1 publication Critical patent/US20200240430A1/en
Abandoned legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/38—Blades
    • F04D29/384—Blades characterised by form
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D19/00—Axial-flow pumps
    • F04D19/002—Axial flow fans
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/26—Rotors specially for elastic fluids
    • F04D29/32—Rotors specially for elastic fluids for axial flow pumps
    • F04D29/325—Rotors specially for elastic fluids for axial flow pumps for axial flow fans
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
    • F04D29/661—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps
    • F04D29/667—Combating cavitation, whirls, noise, vibration or the like; Balancing especially adapted for elastic fluid pumps by influencing the flow pattern, e.g. suppression of turbulence
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/20—Rotors
    • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05D2240/303—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the leading edge of a rotor blade
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/20—Rotors
    • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05D2240/304—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the trailing edge of a rotor blade
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/20—Rotors
    • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
    • F05D2240/307—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the tip of a rotor blade

Definitions

  • the present invention relates to a propeller fan and to an axial flow blower for use in a ventilation fan, an air conditioner, and the like.
  • a rotor blade of a propeller fan of an axial flow blower has been improved to be swept forward in the rotation direction and to be inclined toward the upstream side of an airflow.
  • an outer circumferential part of a rotor blade be bent toward the upstream side of an airflow to reduce interference caused by blade tip vortex.
  • Patent Literature 1 describes that rotor blades are each inclined toward the upstream side at a certain first forward tilt angle in an inner circumferential portion of the rotor blade, while the rotor blades are each inclined toward the upstream side at a second forward tilt angle greater than the first forward tilt angle in an outer circumferential portion.
  • Patent Literature 2 describes that a stagger angle of the blade is linearly increased from the inner circumferential edge to the outer circumferential edge. Patent Literature 2 also describes that the stagger angle in an inner circumferential portion side has a distribution having a local minimum value, and the stagger angle in an outer circumferential portion side has a distribution having a local maximum value.
  • Patent Literature 3 describes that an angle of advance in an inner circumferential portion side of a rotor blade has a distribution of a quadratic function, while an angle of advance in an outer circumferential portion side thereof has a linear distribution.
  • Patent Literature 1 Japanese Patent No. 4680840
  • Patent Literature 2 Japanese Patent No. 6005256
  • Patent Literature 3 Re-publication of PCT International Publication No. WO 2015/125306 A1
  • the present invention has been made in view of the foregoing circumstances, and it is an object of the present invention to provide a propeller fan and an axial flow blower that can further reduce the noise level and further improve the fan efficiency.
  • the present invention provides a propeller fan including a boss portion that is driven rotationally, and more than one rotor blade radially attached to the boss portion to generate an airflow in a rotational axis direction, wherein a radial cross section of the rotor blade on an inner circumferential portion side of the rotor blade has a shape convex against a direction of the airflow, and a radial cross section of the rotor blade on an outer circumferential portion side of the rotor blade has a shape concave along the direction of the airflow, the radial cross section of the rotor blade is inclined toward an upstream side of the airflow in a leading edge side region with an inclination angle increasing toward a leading edge, and is inclined toward a downstream side of the airflow in a trailing edge side region with the inclination angle increasing toward a trailing edge, and a stagger angle of the rotor blade has a first stagger angle distribution having
  • the present invention enables a rotor blade to have a shape suitable for an airflow over a region from an inner circumferential edge to an outer circumferential edge, and can thus reduce noise possibly caused by a blade tip vortex and improve fan efficiency.
  • FIG. 1 is a perspective view illustrating an example of an axial flow blower.
  • FIG. 2 is a perspective view illustrating an example of a propeller fan.
  • FIG. 3 is a schematic view illustrating generation of a blade tip vortex.
  • FIG. 4 is a cross-sectional view of a rotor blade of the present embodiment, taken along a radial direction of the blade.
  • FIGS. 5A-5D are diagrams schematically illustrating a cross-sectional shape of a rotor blade of the present embodiment, a blade tip vortex, and a radial flow at a number of cross-sectional positions.
  • FIG. 6 is a diagram illustrating different cross-sectional positions.
  • FIG. 7 is a diagram illustrating a positional relationship between a rotor blade and a half bell mouth.
  • FIG. 8 is a diagram illustrating a positional relationship between a rotor blade and a full bell mouth.
  • FIG. 9 is a diagram illustrating a state of airflow to a rotor blade when a half bell mouth is used.
  • FIG. 10 is a diagram illustrating a state of airflow to a rotor blade when a full bell mouth is used.
  • FIG. 11 is a diagram for describing a definition of a stagger angle.
  • FIG. 12 is a diagram illustrating an example of a distribution of the stagger angle of a rotor blade of the present embodiment.
  • FIG. 13 is a diagram illustrating distributions of stagger angles of the rotor blades in Comparative Example 1 and Comparative Example 2.
  • FIG. 14 is a developed sectional view illustrating comparison between the stagger angle in Comparative Example 1 and the stagger angle in Comparative Example 2 in a first region.
  • FIG. 15 is a developed sectional view illustrating comparison between the stagger angle in Comparative Example 1 and the stagger angle in Comparative Example 2 in a second region.
  • FIG. 16 is a schematic view illustrating a rotor blade of Comparative Example 1.
  • FIG. 17 is a schematic view illustrating a rotor blade of Comparative Example 2.
  • FIG. 18 is a diagram for describing a definition of an angle of advance.
  • FIG. 19 is a graph illustrating an example of a distribution of an angle of advance of the rotor blade of the present embodiment.
  • FIG. 20 is a plan view illustrating a blade shape of Comparative Example 3 when an increase rate in the angle of advance is lower.
  • FIG. 21 is a plan view illustrating a blade shape of Comparative Example 3 when an increase rate in the angle of advance is higher.
  • FIG. 22 is a plan view illustrating a rotor blade of the present embodiment.
  • FIG. 23 is a diagram for describing a definition of a forward tilt angle.
  • FIG. 24 is a diagram illustrating a chord center line of a rotor blade of the present embodiment.
  • FIG. 25 is a graph illustrating an example of a distribution of a forward tilt angle of a rotor blade of the present embodiment.
  • FIGS. 26A-26C are diagrams illustrating a fan efficiency characteristic, a specific noise characteristic, and a static pressure characteristic of a rotor blade of Example 1, Example 2, and Comparative Example 5 in a case of use of a half bell mouth.
  • FIGS. 27A-27C are diagrams illustrating a fan efficiency characteristic, a specific noise characteristic, and a static pressure characteristic of a rotor blade of Example 1, Example 2, and Comparative Example 5 in a case of use of a full bell mouth.
  • FIGS. 28A-28C are diagrams illustrating a fan efficiency characteristic, a specific noise characteristic, and a static pressure characteristic of a rotor blade of Example 1, Example 3, and Comparative Example 5 in a case of use of a half bell mouth.
  • FIGS. 29A-29C are diagrams illustrating a fan efficiency characteristic, a specific noise characteristic, and a static pressure characteristic of a rotor blade of Example 1, Example 3, and Comparative Example 5 in a case of use of a full bell mouth.
  • FIG. 30 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the specific noise level in Example 1 and Comparative Example 5 in a case of use of a half bell mouth.
  • FIG. 31 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the fan efficiency in Example 1 and Comparative Example 5 in a case of use of a half bell mouth.
  • FIG. 32 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the minimum specific noise level in Example 1 and Comparative Example 5 in a case of use of a half bell mouth.
  • FIG. 33 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the maximum fan efficiency in Example 1 and Comparative Example 5 in a case of use of a half bell mouth.
  • FIG. 34 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the specific noise level in Example 1 and Comparative Example 5 in a case of use of a full bell mouth.
  • FIG. 35 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the fan efficiency in Example 1 and Comparative Example 5 in a case of use of a full bell mouth.
  • FIG. 36 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the minimum specific noise level in Example 1 and Comparative Example 5 in a case of use of a full bell mouth.
  • FIG. 37 is a graph illustrating relationships between the degree of the forward tilt angle distribution function and the maximum fan efficiency in Example 1 and Comparative Example 5 in a case of use of a full bell mouth.
  • FIG. 1 is a perspective view illustrating an example of an axial flow blower 100 according to an embodiment.
  • FIG. 2 is a perspective view illustrating an example of a propeller fan 10 according to the embodiment.
  • the axial flow blower 100 includes the propeller fan 10 , a body 20 , a bell mouth 30 , a motor (not illustrated), and a motor fixing member (not illustrated).
  • the propeller fan 10 and the motor are disposed inside the bell mouth 30 .
  • the propeller fan 10 includes a boss portion 2 having a cylindrical shape, and multiple rotor blades 1 having equal three-dimensional shapes.
  • the boss portion 2 is rotationally driven by the motor to rotate about a rotational axis O in a direction of an arrow W.
  • Each of the rotor blades 1 is radially attached to an outer periphery of the boss portion 2 .
  • the rotor blade 1 includes: a leading edge 1 a that is a front edge portion in the rotation direction W; a trailing edge 1 b that is a rear edge portion in the rotation direction W; an inner circumferential edge 1 c that is an edge portion on the inner circumferential side (nearer to the boss portion 2 ); and an outer circumferential edge 1 d that is an edge portion on the outer circumferential side.
  • FIG. 1 illustrates five of the rotor blades 1
  • FIG. 2 illustrates three of the rotor blades 1 .
  • any other number can also be adopted.
  • FIG. 3 illustrates one of the impeller blades 1 of the propeller fan 10 .
  • a pressure difference is caused between the blade pressure surface and the blade negative pressure surface of the rotor blade 1 .
  • this leads to a leakage vortex from the blade pressure surface subject to a higher pressure to the blade negative pressure surface subject to a lower pressure, in an outer circumferential portion of the rotor blade 1 .
  • This vortex is referred to as a blade tip vortex 5 .
  • FIG. 3 illustrates one of the impeller blades 1 of the propeller fan 10 .
  • the upstream blade surface is a negative pressure surface if subject to the lower pressure
  • the downstream surface is a pressure surface 1 g subject to a higher pressure with respect to the airflow direction A.
  • the rotational axis O is designated Z-axis
  • two axes perpendicular to the Z-axis are designated X-axis and Y-axis.
  • FIG. 4 is a cross-sectional view illustrating the shape, along the radial direction, of the rotor blade 1 according to the embodiment.
  • the rotor blade 1 has a radial cross section that is convex against the airflow direction A near the boss portion 2 , and is concave in the airflow direction A in an outer circumferential portion.
  • the rotor blade 1 has a vertex portion m 1 having a convex shape on an inner circumferential portion side, and a vertex portion m 2 having a concave shape on an outer circumferential portion side.
  • a cross section of the rotor blade 1 has an S-shape that is convex with respect to the airflow in an inner circumferential portion, and is concave with respect to the airflow in an outer circumferential portion.
  • the rotor blade 1 also has a radial cross-sectional shape changing over the region from the leading edge 1 a to the trailing edge 1 b. Specifically, in a leading edge region, the rotor blade 1 is inclined toward upstream of the airflow direction A so that an inclination angle ⁇ increases toward the leading edge 1 a. In a trailing edge region, the rotor blade 1 is inclined toward downstream of the airflow direction A so that the inclination angle ⁇ increases toward the trailing edge 1 b.
  • FIGS. 5A to 5D are diagrams schematically illustrating the blade shape, a blade tip vortex, and a radial flow in the radial cross section of the rotor blade 1 according to the embodiment. FIG.
  • FIG. 5A illustrates the cross-sectional shape taken along a line O-D 1 in FIG. 6 .
  • FIG. 5B illustrates the cross-sectional shape taken along a line O-D 2 in FIG. 6 .
  • FIG. 5C illustrates the cross-sectional shape taken along line O-D 3 in FIG. 6 .
  • FIG. 5D illustrates the cross-sectional shape taken along line O-D 4 in FIG. 6 . Note that, in FIG.
  • the line O-D 1 is a line resulting from extending a line connecting the rotational axis O and a rear end Fr of the leading edge 1 a to the outer circumferential edge 1 d; and the line O-D 4 is a line connecting the rotational axis O and a front end Rf of the trailing edge 1 b.
  • a leading edge region of the rotor blade 1 which is an area nearer to the leading edge 1 a than a blade center C, is inclined toward upstream of the airflow A, and the inclination angle ⁇ (O-D 1 ) in the O-D 1 cross section is greater than the inclination angle ⁇ (O-D 2 ) in the O-D 2 cross section.
  • the inclination angle ⁇ increases toward the leading edge 1 a.
  • the blade center C corresponds to a bisector of an angle formed between the lines O-D 1 and O-D 4 . Note that FIGS.
  • 5A-5D illustrate the inclination angle ⁇ as an angle formed between a line segment connecting the inner circumferential edge 1 c and the vertex portion m 2 on the outer circumferential side, and the XY-plane.
  • the leading edge region of the rotor blade 1 has a shape adaptable to the blade tip vortex 5 and to a lateral sink flow 9 toward the blade outer circumferential portion.
  • a trailing edge region of the rotor blade 1 which is a region nearer to the trailing edge 1 b than the blade center C, is inclined toward downstream of the airflow A, and the inclination angle ⁇ (O-D 4 ) in the O-D 4 cross section is greater than the inclination angle ⁇ (O-D 3 ) in the O-D 3 cross section.
  • the inclination angle ⁇ increases toward the trailing edge 1 b.
  • the trailing edge region of the rotor blade 1 has a shape such that the blade tip vortex 5 is controlled, and also a centrifugal component 14 of a flow on the inner circumferential portion side, which has been subject to a raised pressure, is prevented from leaking, thereby preventing reduction in efficiency.
  • a curvature radius value R 2 in an outer concave portion that is a region from the vertex portion m 2 in the outer circumferential portion to the outer circumferential edge 1 d has a distribution that gradually decreases from the leading edge 1 a toward the trailing edge 1 b.
  • a relationship of R 2 (O-D 1 )>R 2 (O-D 2 )>R 2 (O-D 3 )>R 2 (O-D 4 ) holds.
  • the curvature radius value R 2 gradually decreases at a rate that decreases toward the trailing edge 1 b.
  • the rotor blade 1 according to the embodiment illustrated in FIGS. 4 and 5 has a shape that allows the blade tip vortex 5 generated in an outer circumferential portion to smoothly leave from the blade surface, and allows the blade tip vortex 5 to be dispersed without concentration. In this way, the rotor blade 1 reduces turbulence caused by the blade tip vortex 5 , thereby making it possible to curb generation of noise.
  • FIG. 7 is a schematic cross-sectional view of an axial flow blower that uses the rotor blade 1 and a half bell mouth 30 a.
  • the half bell mouth 30 a surrounds the rotor blades 1 with allowing a region including the leading edge 1 a to be open.
  • FIG. 8 is a schematic cross-sectional view of an axial flow blower that uses the rotor blade 1 and a full bell mouth 30 b.
  • the full bell mouth 30 b surrounds the rotor blades 1 circumferentially to entirely cover a side face of the rotor blade 1 .
  • the half bell mouth 30 a and the full bell mouth 30 b both have an inlet curved surface Rin, a straight part ST having a cylindrical shape, and an outlet curved surface Rout.
  • FIG. 9 is a diagram illustrating a distribution of an airflow of the axial flow blower that uses the rotor blade 1 and the half bell mouth 30 a.
  • the axial flow blower including the half bell mouth 30 a is configured such that the region including the leading edge 1 a of the rotor blade 1 is widely open. This allows the lateral sink flow 9 and a passing-through-blade flow 11 directed from the leading edge 1 a toward the trailing edge 1 b to flow onto the rotor blade 1 . For this reason, the blade tip vortex 5 grows large from the leading edge 1 a side of the rotor blade 1 . In addition, a condition of the passing-through-blade flow 11 is changed from the leading edge 1 a to the trailing edge 1 b, so that the blade tip vortex 5 is subjected to significantly different conditions depending on the axial positions.
  • FIG. 10 is a diagram illustrating a distribution of an airflow of the axial flow blower that uses the rotor blade 1 and the full bell mouth 30 b.
  • the axial flow blower having the full bell mouth 30 b is configured such that the region including the leading edge 1 a is open to a very limited extent, thereby almost eliminating the lateral sink flow 9 .
  • almost only the passing-through-blade flow 11 flows toward the rotor blade 1 . Accordingly, the blade tip vortex 5 does not start to be generated from the leading edge 1 a, but starts to be generated from a point where the pressurization has been initiated to some extent.
  • the two types of bell mouths i.e., the half bell mouth 30 a and the full bell mouth 30 b may be used in one and the same product.
  • the cost for the rotor blades is doubled.
  • the same type of rotor blades are used even with different bell mouth types, and therefore, what is required is a rotor blade that can achieve a low noise level and high efficiency blowing even with different bell mouth types.
  • the present embodiment defines a stagger angle, an angle of advance, and a forward tilt angle among the geometry parameters for forming the rotor blade 1 for each of a first region that is an inner circumferential region and a second region that is an outer circumferential region, which are obtained by division of a region from the inner circumferential edge 1 c to the outer circumferential edge 1 d of the rotor blade 1 , to propose a shape of the first region and a shape of the second region that can achieve a reduced noise level and improvement in fan efficiency.
  • FIG. 11 is a developed sectional view of the rotor blade 1 taken along an arc 6 - 6 ′ having an arbitrary radius illustrated in FIG. 6 , in which the cylindrical surface along the arc 6 - 6 ′ is developed on a plane.
  • the stagger angle ⁇ is an angle formed between a chord line 41 and a line segment 42 .
  • the chord line 41 is a line connecting the leading edge 1 a on a cross-sectional surface 40 of the rotor blade 1 and the trailing edge 1 b on the said cross-sectional surface 40 .
  • the line segment 42 is a line that is parallel with the said rotational axis O and intersects the leading edge 1 a.
  • FIG. 12 is a diagram illustrating an example of a distribution of the stagger angle ⁇ of the present embodiment.
  • the horizontal axis corresponds to a radius R of the rotor blade 1
  • the vertical axis represents the stagger angle ⁇ .
  • the solid line Ls represents the distribution of the stagger angle ⁇ in the present embodiment
  • the broken line Lv 1 represents the distribution of the stagger angle ⁇ in Comparative Example 1.
  • the left end of the line segment Ls represents a stagger angle ⁇ c at a radial position Rc of the inner circumferential edge 1 c connected to the boss portion 2
  • the right end of the line segment Ls represents a stagger angle ⁇ d at a radial position Rd of the outer circumferential edge 1 d.
  • the stagger angle ⁇ of the present embodiment has a first stagger angle distribution Ls 1 in a first region AR 1 from the radial position Rc to a boundary position Re 1
  • the first stagger angle distribution Ls 1 has a local minimum value ⁇ min at a position Rmin near the boundary position Re 1 .
  • the position Rmin is between the midpoint of the first region AR 1 and the boundary position Re 1 .
  • the first stagger angle distribution Ls 1 has a distribution such that the stagger angle ⁇ gradually decreases from the radial position Rc toward the radial position Rmin and the stagger angle ⁇ gradually increases from the radial position Rmin toward the boundary position Re 1 .
  • the second stagger angle distribution Ls 2 has a distribution such that the stagger angle ⁇ gradually increases so that the distribution Ls 2 smoothly connects with the first stagger angle distribution Ls 1 .
  • the second stagger angle distribution Ls 2 has a distribution defined by a linear to quadratic function using the radius R as a parameter. Note that the second stagger angle distribution Ls 2 does not cover a linear function.
  • the second stagger angle distribution Ls 2 is defined as a function that is convex downward.
  • the second stagger angle distribution Ls 2 illustrated in FIG. 12 follows a 1.2-dimensional function. Setting is made such that the second stagger angle distribution Ls 2 has a higher absolute value of an increase rate than that of the decrease rate of the first stagger angle distribution Ls 1 .
  • FIG. 13 is a diagram illustrating the distribution Lv 1 of the stagger angle ⁇ in Comparative Example 1 and the distribution Lv 2 of the stagger angle ⁇ in Comparative Example 2.
  • Comparative Example 1 and Comparative Example 2 are described in Patent Literature 2.
  • the distribution Lv 1 is such that the stagger angle ⁇ increases linearly (in a manner of a linear function) at a constant increase rate.
  • the distribution Lv 2 has, similarly to the stagger angle ⁇ of the present embodiment, a distribution in a first region AR 1 ′ from the radial position Rc of the inner circumferential edge 1 c to a boundary position Re′, and a distribution in a second region AR 2 ′ from the boundary position Re′ to the radial position Rd of the outer circumferential edge 1 d.
  • the stagger angle ⁇ gradually decreases in the form of a curved line from the radial position Rc to the radial position Re′, and has a local minimum value at the radial position Re′.
  • the stagger angle ⁇ at the radial position Rc has the maximum value of the stagger angle ⁇ over the entire range of the rotor blade 1 .
  • the stagger angle ⁇ gradually increases from the boundary position Re′ and reaches a local maximum value, and gradually decreases from the radial position of the local maximum value toward the radial position Rd.
  • FIG. 14 is a developed sectional view illustrating comparison between the stagger angle in Comparative Example 1 and the stagger angle in Comparative Example 2 in the first region AR 1 ′.
  • FIG. 14 is a view of the rotor blades of Comparative Example 1 and Comparative Example 2 taken at the radius R 1 ′ illustrated in FIG. 13 , in which a cylindrical surface on the cross section is developed on a plane.
  • the broken line 43 corresponds to Comparative Example 1
  • the bold solid line 44 corresponds to Comparative Example 2.
  • the reference character ⁇ R11 represents the stagger angle at the radius R 1 ′ in Comparative Example 1
  • the reference character ⁇ R12 represents the stagger angle at the radius R 1 ′ in Comparative Example 2.
  • FIG. 14 shows that in the first region AR 1 ′, the blade is less inclined in Comparative Example 2 than in Comparative Example 1.
  • FIG. 15 is a developed sectional view illustrating comparison between the stagger angle in Comparative Example 1 and the stagger angle in Comparative Example 2 in the second region AR 2 ′.
  • FIG. 15 is a view of the rotor blades of Comparative Example 1 and Comparative Example 2 taken at the radius R 2 ′ illustrated in FIG. 13 , in which the cylindrical surface on the cross section is developed on a plane.
  • the broken line 45 corresponds to Comparative Example 1
  • the bold solid line 46 corresponds to Comparative Example 2.
  • the reference character ⁇ R21 represents the stagger angle at the radius R 2 ′ in Comparative Example 1
  • the reference character ⁇ R22 represents the stagger angle at the radius R 2 ′ in Comparative Example 2.
  • FIG. 15 shows that in the second region AR 2 ′, the blade is more inclined in Comparative Example 2 than in Comparative Example 1.
  • FIG. 16 is a schematic view illustrating the rotor blade of Comparative Example 1.
  • FIG. 17 is a schematic view illustrating the rotor blade of Comparative Example 2. As illustrated in FIGS. 16 and 17 , a blade height H 2 of Comparative Example 2 is greater than a blade height H 1 of Comparative Example 1 at the outer circumferential edge.
  • the blade angle is set to an appropriate value for a flow in each of a high flow rate region and a low flow rate region, thereby resulting in a reduced noise level and higher efficiency.
  • the blade height is larger in an outer circumferential portion. This will present no problem with a product having enough margin space in the height direction, but when a further reduced height is required, it will be difficult to use a stagger angle distribution as shown in Comparative Example 2.
  • the present embodiment uses the stagger angle distribution as illustrated in FIG. 12 to thereby make it possible to limit the height of the outer circumferential portion that can cause increase in height of a product and to also make the stagger angle distribution more appropriate.
  • the blade in the present embodiment has a shape that is similar to the shape in Comparative Example 1 on the outer circumferential portion side and similar to the shape in Comparative Example 2 on the inner circumferential portion side. Therefore, the present embodiment can limit the height of the outer circumferential portion, and match the angle of the blade with the angle of the flow. This can reduce leading edge separation and trailing vortex loss of the blade, and can thus achieve a reduced noise level and higher efficiency.
  • the use of a distribution having a local minimum value in the first region AR 1 where a flow rate is lower enables the stagger angle in the second region AR 2 to be adjusted, and also enables the first region AR 1 to smoothly connect with the second region AR 2 .
  • FIG. 18 is a plan view for describing the angle of advance ⁇ ⁇ .
  • the reference character g designates the chord center line.
  • the chord center line g is a line that connects the midpoints between the leading edge 1 a and the trailing edge 1 b at every radial position from the inner circumferential edge 1 c to the outer circumferential edge 1 d.
  • An angle formed between a straight line 51 connecting the rotational axis O and the said midpoint 52 on the inner circumferential edge 1 c, and a straight line 54 connecting an intersection point 53 between an arc on an arbitrary radius and the chord center line g and the rotational axis O is defined as an angle of advance ⁇ ⁇ .
  • FIG. 19 is a graph illustrating an example of a distribution of the angle of advance ⁇ ⁇ in the present embodiment, and a distribution of the angle of advance ⁇ ⁇ of Comparative Example 3.
  • the solid line corresponds to the present embodiment, and the broken line corresponds to Comparative Example 3.
  • the angle of advance ⁇ ⁇ linearly increases from the inner circumferential edge 1 c to the outer circumferential edge 1 d.
  • use of the distribution of Comparative Example 3 causes the outer circumferential portion to have a delta wing shape.
  • a delta wing shape causes a separation vortex to be generated from the delta wing portion, and the generated separation vortex can reduce or prevent generation of a leading edge separation vortex and a blade tip vortex, thereby making it possible to achieve a reduced noise level.
  • FIG. 20 is a diagram illustrating the blade shape in Comparative Example 3 when an increase rate of the angle of advance is low.
  • FIG. 21 is a diagram illustrating the blade shape in Comparative Example 3 when an increase rate of the angle of advance is greater than the increase rate of FIG. 20 .
  • the length of the inner circumferential edge 1 c in FIG. 20 is the same as the length of the inner circumferential edge 1 c in FIG. 21 .
  • the length of the outer circumferential edge 1 d in FIG. 20 is the same as the length of the outer circumferential edge 1 d in FIG. 21 .
  • the angle of advance ⁇ ⁇ 2 on the outer circumferential edge 1 d in FIG. 21 is greater than the angle of advance ⁇ ⁇ 1 on the outer circumferential edge 1 d in FIG. 20 .
  • the angle of advance of the rotor blade according to the present embodiment has different distributions in the first region AR 1 and in the second region AR 2 .
  • the first region AR 1 is an area from the radius Rc corresponding to the inner circumferential edge 1 c to a boundary position Re 2 .
  • the second region AR 2 is an area from the boundary position Re 2 to the outer circumferential edge 1 d.
  • the angle of advance ⁇ ⁇ has, in the first region AR 1 , a linear distribution that gradually increases from the radial position Rc toward the boundary position Re 2 .
  • the angle of advance ⁇ ⁇ has, in the second region AR 2 , a linear to quadratic function distribution that gradually increases from the boundary position Re 2 toward the radial position Rd.
  • the angle of advance ⁇ ⁇ in the second region AR 2 follows a linear to quadratic function using the radius R as a parameter.
  • the angle of advance ⁇ ⁇ in the second region AR 2 does not cover a linear function.
  • the angle of advance ⁇ ⁇ in the second region AR 2 is defined as a linear to quadratic function that is convex downward.
  • FIG. 19 shows a 1.2-dimensional function as a distribution function in the second region AR 2 .
  • the linear distribution in the first region AR 1 smoothly connects with a distribution of the 1.2-dimensional function in the second region AR 2 .
  • the distribution of the angle of advance ⁇ ⁇ in the second region AR 2 desirably has an increase rate higher than the increase rate of the distribution of the angle of advance ⁇ ⁇ in the first region AR 1 .
  • FIG. 22 illustrates an example of the shape of the rotor blade in the case of use of the angle-of-advance distribution according to the present embodiment illustrated in FIG. 19 .
  • Use of the angle-of-advance distribution according to the present embodiment enables a delta wing shape to be ensured for reducing the noise level in the blade outer circumferential portion, and an area of the blade to be increased in the blade inner circumferential portion thereby to increase the strength of the blade root portion.
  • FIG. 23 is a diagram for describing a definition of a forward tilt angle ⁇ z.
  • FIG. 23 is a revolved projection of a rotor blade having a constant forward tilt angle ⁇ z projected onto the plane including the rotational axis O and the X-axis.
  • the forward tilt angle ⁇ z is an angle formed between a chord center line g′ and a plane perpendicular to the rotational axis O of the rotor blade 1 .
  • a direction toward the upstream side of the flow is defined as positive for the angle ⁇ z.
  • FIG. 24 is a diagram illustrating the chord center line g of the rotor blade 1 according to the present embodiment in which the blade outer circumferential portion is bent toward the upstream direction side of the flow, and shows a revolved projection of the rotor blade projected onto the plane including the rotational axis O and the X-axis.
  • FIG. 25 is a graph illustrating an example of a distribution of the forward tilt angle ⁇ z of the present embodiment, and a distribution of the forward tilt angle ⁇ z of Comparative Example 4.
  • the solid line corresponds to the present embodiment, and the broken line corresponds to Comparative Example 4.
  • Comparative Example 4 is described in Patent Literature 1.
  • the forward tilt angle ⁇ z has a distribution in the first region AR 1 from the radial position Rc of the inner circumferential edge 1 c to a boundary position Re 3 , and a distribution in the second region AR 2 from the boundary position Re 3 to the radial position Rd of the outer circumferential edge 1 d.
  • the forward tilt angle ⁇ z has a constant value ⁇ z 1 in the first region AR 1
  • the forward tilt angle ⁇ z has a distribution with further inclination toward an upstream side of the flow in the second region AR 2 so as to follow an n-dimensional function (1 ⁇ n) using the radius R as a parameter.
  • the forward tilt angle ⁇ z has a constant value ⁇ z 1 in the first region AR 1 similarly to Comparative Example 4, while the forward tilt angle ⁇ z in the second region AR 2 follows a distribution based on a quadratic to quintic function using the radius R as a parameter, thereby achieving a further reduced noise level.
  • FIG. 25 in the second region AR 2 , of Comparative Example 4 is shown as following a quadratic function, and the present embodiment is shown as following a cubic function. Of quadratic to quintic functions, quadratic to cubic functions are particularly suitable.
  • FIGS. 26 to 37 illustrate evaluation results when rotor blades having a diameter of 260 (mm) are rotated at a constant rotational speed.
  • the specific noise level Kt with a total pressure as a reference, the specific noise level Ks with a static pressure as a reference, the fan efficiency Et with a total pressure as a reference, and the fan efficiency Es with a static pressure as a reference, which are used in FIGS. 26 to 37 are calculated values defined by the following expressions.
  • PS static pressure [Pa]
  • PS static pressure [Pa]
  • Correction A refers to correction to reduce the sound level at low frequencies to fit the characteristics of human auditory sense, and corresponds to, for example, correction based on Characteristic A determined in JIS C 1502-1990.
  • FIGS. 26A to 26C are diagrams illustrating different kinds of characteristics of the rotor blade of Comparative Example 5, the rotor blade of Example 1 in the embodiment, and the rotor blade of Example 2 in the embodiment in the case of use of the half bell mouth 30 a illustrated in FIG. 7 .
  • Comparative Example 5 is represented by the broken line.
  • the embodiment's Example 1 is represented by the solid line.
  • the embodiment's Example 2 is represented by the dashed-and-dotted line.
  • FIG. 26A illustrates relationships between the fan efficiency Es and the airflow rate.
  • FIG. 26B illustrates relationships between the specific noise level Kt and the airflow rate.
  • FIG. 26C illustrates relationships between the static pressure PS and the airflow rate.
  • the rotor blade of Comparative Example 5 has the rotor blade shape illustrated in FIGS. 4 and 5 , has the stagger angle distribution Lv 1 represented by the broken line in FIG. 12 , has the angle-of-advance distribution represented by the broken line in FIG. 19 , and has the forward tilt angle distribution represented by the broken line in FIG. 25 .
  • the rotor blade of the embodiment's Example 1 and the rotor blade of the embodiment's Example 2 each correspond to the rotor blade illustrated in FIGS. 4 and 5 , have the stagger angle distribution represented by the solid line in FIG. 12 , have the angle-of-advance distribution represented by the solid line in FIG. 19 , and have the forward tilt angle distribution represented by the solid line in FIG. 25 .
  • the rotor blade of Example 1 has, in the second region AR 2 , a stagger angle distribution that follows a 1.2-dimensional function being set, has, in the second region AR 2 , a angle-of-advance distribution that follows a 1.2-dimensional function being set, and has, in the second region AR 2 , a forward tilt angle distribution that follows a 3-dimensional function being set.
  • the rotor blade of Example 2 has, in the second region AR 2 , a stagger angle distribution that follows a 2-dimensional function being set, has, in the second region AR 2 , a angle-of-advance distribution that follows a 2-dimensional function being set, and has, in the second region AR 2 , a forward tilt angle distribution that follows a 3-dimensional function being set.
  • the fan efficiency Es can be improved by up to +3.5 points.
  • the specific noise level Kt can be improved by up to ⁇ 1 (dB).
  • FIGS. 27A to 27C are diagrams illustrating different kinds of characteristics of the rotor blade of Comparative Example 5 described above, the rotor blade of Example 1 in the embodiment described above, and the rotor blade of Example 2 in the embodiment described above in the case of use of the full bell mouth 30 b illustrated in FIG. 8 .
  • Comparative Example 5 is shown by the broken line.
  • the embodiment's Example 1 is shown by the solid line.
  • the embodiment's Example 2 is shown by the dashed-and-dotted line.
  • FIG. 27A illustrates relationships between the fan efficiency Es and the airflow rate.
  • FIG. 27B illustrates relationships between the specific noise level Kt and the airflow rate.
  • FIG. 27C illustrates relationships between the static pressure PS and the airflow rate.
  • the rotor blades of Examples 1 and 2 in the embodiment enable, as illustrated in FIG. 27C , an open airflow rate to be improved by +3.6(%) and a static pressure to be improved by up to +7.8(%) as compared to Comparative Example 5.
  • the fan efficiency Es can be improved by up to +7 points.
  • the specific noise level Kt can be improved by up to ⁇ 1.5 (dB).
  • FIGS. 26 and 27 indicate that the rotor blades of Examples 1 and 2 enable the blowing characteristic, the noise characteristic, and the fan efficiency characteristic to be improved irrespective of the form of a bell mouth used therein.
  • FIGS. 28A to 28C are diagrams illustrating different kinds of characteristics of the rotor blade of Comparative Example 5 described above, the rotor blade of Example 1 in the embodiment described above, and the rotor blade of Example 3 in the embodiment in the case of use of the half bell mouth 30 a illustrated in FIG. 7 .
  • Comparative Example 5 is shown by the broken line.
  • the embodiment's Example 1 is shown by the solid line.
  • the embodiment's Example 3 is represented by the dashed-and-dotted line.
  • FIG. 28A illustrates relationships between the fan efficiency Es and the airflow rate.
  • FIG. 28B illustrates relationships between the specific noise level Kt and the airflow rate.
  • FIG. 28C illustrates relationships between the static pressure PS and the airflow rate.
  • the rotor blade of Example 3 in the embodiment has a rotor blade shape illustrated in FIGS. 4 and 5 , has the stagger angle distribution represented by the solid line in FIG. 12 , has the angle-of-advance distribution represented by the solid line in FIG. 19 , and has the forward tilt angle distribution represented by the solid line in FIG. 25 .
  • the rotor blade of the embodiment's Example 3 has, in the second region AR 2 , a stagger angle distribution that follows a function to be set having a degree of 1.2, has, in the second region AR 2 , a angle-of-advance distribution that follows a function to be set having a degree of 1.2, and has, in the second region AR 2 , a forward tilt angle distribution that follows a function to be set having a degree of 4.
  • the rotor blade of Example 3 enables, as illustrated in FIG. 28C , the open airflow rate to be improved by +2.2(%) and the static pressure to be improved by up to +5.9(%) as compared to Comparative Example 5.
  • the fan efficiency Es can be improved by up to +4 points.
  • the specific noise level Kt can be improved by up to ⁇ 3 (dB).
  • FIGS. 29A to 29C are diagrams illustrating different kinds of characteristics of the rotor blade of Comparative Example 5 described above, the rotor blade of Example 1 in the embodiment described above, and the rotor blade of Example 3 in the embodiment described above in the case of use of the full bell mouth 30 b illustrated in FIG. 8 .
  • Comparative Example 5 is shown by the broken line.
  • the embodiment's Example 1 is shown by the solid line.
  • the embodiment's Example 3 is shown by the dashed-and-dotted line.
  • FIG. 29A illustrates relationships between the fan efficiency Es and the airflow rate.
  • FIG. 29B illustrates relationships between the specific noise level Kt and the airflow rate.
  • FIG. 29C illustrates relationships between the static pressure PS and the airflow rate.
  • the rotor blade of Example 3 in the embodiment enables, as illustrated in FIG. 29C , the open airflow rate to be improved by +3(%) and the static pressure to be improved by up to +6.9(%) as compared to Comparative Example 5.
  • the fan efficiency Es can be improved by up to +12 points.
  • the specific noise level Kt can be improved by up to ⁇ 2 (dB).
  • FIGS. 28 and 29 indicate that the rotor blade of Example 3 enables the blowing characteristic, the noise characteristic, and the fan efficiency characteristic to be improved irrespective of the form of a bell mouth used therefor.
  • FIG. 30 is a graph illustrating the specific noise characteristics at the open point of the rotor blade of Comparative Example 5 described above and the rotor blade of the embodiment's Example 1 described above in the case of use of the half bell mouth 30 a illustrated in FIG. 7 .
  • FIG. 30 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the specific noise level Kt at the open point. The degree has been changed from 1.2 to 5. Note that the forward tilt angle distribution in the second region AR 2 for the rotor blade of Comparative Example 5 follows a quadratic function as described above. As illustrated in FIG.
  • the rotor blade of the embodiment's Example 1 exhibits a specific noise level Kt higher than that of Comparative Example 5 when the degree is 1.2, but a specific noise level Kt improved as compared to Comparative Example 5 in the range of degree from 2 to 7.
  • FIG. 31 is a graph illustrating the fan efficiency characteristics at the open point of the rotor blade of Comparative Example 5 described above and the rotor blade of the embodiment's Example 1 described above in the case of use of the half bell mouth 30 a illustrated in FIG. 7 .
  • FIG. 31 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the fan efficiency Et at the open point. The degree has been changed from 1.2 to 5. As illustrated in FIG. 31 , the rotor blade of the embodiment's Example 1 exhibits a fan efficiency Et improved as compared to Comparative Example 5 in terms of all the degrees.
  • FIG. 32 is a graph illustrating the minimum specific noise characteristics at the time of application of static pressure of the rotor blade of Comparative Example 5 described above and the rotor blade of the embodiment Example 1 described above in the case of use of the half bell mouth 30 a illustrated in FIG. 7 .
  • FIG. 32 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the minimum specific noise level Ks at the time of application of static pressure. The degree has been changed from 1.2 to 5. As illustrated in FIG. 32 , the specific noise level Ks is higher than that of Comparative Example 5 when the degree is 1.2, but the specific noise level Ks is improved as compared to Comparative Example 5 in the range of degree from 2 to 5.
  • FIG. 33 is a graph illustrating the maximum fan efficiency characteristics of the rotor blade of Comparative Example 5 described above and the rotor blade of the embodiment's Example 1 described above in the case of use of the half bell mouth 30 a illustrated in FIG. 7 .
  • FIG. 33 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the maximum fan efficiency Esmax. The degree has been changed from 1.2 to 5. As illustrated in FIG. 33 , the maximum fan efficiency Esmax is improved as compared to Comparative Example 5 in terms of all the degrees.
  • FIG. 34 is a graph illustrating the specific noise characteristics at the open point of the rotor blade of Comparative Example 5 described above and the rotor blade of the embodiment's Example 1 described above in the case of use of the full bell mouth 30 b illustrated in FIG. 8 .
  • FIG. 34 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the specific noise level Kt at the open point. The degree has been changed from 1.2 to 5. As illustrated in FIG. 34 , the rotor blade of Example 1 in the embodiment exhibits a specific noise level Kt improved as compared to Comparative Example 5 in terms of all the degrees.
  • FIG. 35 is a graph illustrating the fan efficiency characteristics of the rotor blade of Comparative Example 5 described above and the rotor blade of the embodiment's Example 1 described above at the open point in the case of use of the full bell mouth 30 b illustrated in FIG. 8 .
  • FIG. 35 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the fan efficiency Et at the open point. The degree has been changed from 1.2 to 5.
  • the rotor blade of Example 1 in the embodiment exhibits a fan efficiency Et almost the same as that of Comparative Example 5 when the degree is 1.2.
  • the rotor blade of the embodiment's Example 1 exhibits a fan efficiency Et degraded with respect to that of Comparative Example 5 when the degree is 5, but a fan efficiency Et improved as compared to Comparative Example 5 over the range of degree from 2 to 4.
  • FIG. 36 is a graph illustrating the minimum specific noise characteristics at the time of application of static pressure of the rotor blade of Comparative Example 5 described above and the rotor blade of Example 1 in the embodiment described above in the case of use of the full bell mouth 30 b illustrated in FIG. 8 .
  • FIG. 36 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the minimum specific noise level Ks at the time of application of static pressure. The degree has been changed from 1.2 to 5. As illustrated in FIG. 36 , the rotor blade of the embodiment's Example 1 exhibits a specific noise level Ks improved as compared to Comparative Example 5 in terms of all the degrees.
  • FIG. 37 is a graph illustrating the maximum fan efficiency characteristics of the rotor blade of Comparative Example 5 described above and the rotor blade of Example 1 in the embodiment described above in the case of use of the full bell mouth 30 b illustrated in FIG. 8 .
  • FIG. 37 illustrates the relationships between the degree of the function used for the forward tilt angle distribution in the second region AR 2 and the maximum fan efficiency Esmax. The degree has been changed from 1.2 to 5. As illustrated in FIG. 37 , the maximum fan efficiency Esmax is improved as compared to Comparative Example 5 over the range of degree from 2 to 5.
  • the present embodiment enables the blowing characteristic, the noise characteristic, and the fan efficiency characteristic to be improved irrespective of the form of a used bell mouth as long as a distribution of the forward tilt angle ⁇ z in the second region follows a quadratic to quintic function.
  • the stagger angle ⁇ of the rotor blade has a first stagger angle distribution having a local minimum value in an area from the inner circumferential edge to the first boundary position Re 1 , and has a second stagger angle distribution that increases toward the said outer circumferential edge and follows an n-dimensional function using the radius of the said rotor blade as a parameter in an area from the first boundary position Rel to the outer circumferential edge.
  • n which is used in the n-dimensional, is a value ranging from 1 to 2, but exclusive of 1.
  • the angle of advance ⁇ ⁇ of the rotor blade has a first angle-of-advance distribution that linearly increases in an area from the inner circumferential edge to the second boundary position Re 2 , and has a second angle-of-advance distribution that increases toward the said outer circumferential edge and follows an m-dimensional function using the radius as a parameter in an area from the second boundary position Re 2 to the outer circumferential edge, where m is a value ranging from 1 to 2, but exclusive of 1. Therefore, the present embodiment enables a delta wing shape to be ensured for reducing the noise level in the blade outer circumferential portion, and at the same time, the strength at the blade root portion to be increased.
  • the forward tilt angle ⁇ z of the rotor blade has a first forward tilt angle distribution having a constant value in an area from the inner circumferential edge to the third boundary position Re 3 , and has a second forward tilt angle distribution that increases toward the outer circumferential edge and follows a p-dimensional function using the radius as a parameter in an area from the third boundary position Re 3 to the outer circumferential edge, where p is a value ranging from 2 to 5. Therefore, the present embodiment can achieve a further reduced noise level.
  • 1 rotor blade 1 a leading edge; 1 b trailing edge; 1 c inner circumferential edge; 1 d outer circumferential edge; 2 boss portion; 5 blade tip vortex; 10 propeller fan; 30 bell mouth; 30 a half bell mouth; 30 b full bell mouth; 100 axial flow blower; g chord center line; O rotational axis; W rotation direction; ⁇ stagger angle; ⁇ ⁇ angle of advance; ⁇ z forward tilt angle.

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11519422B2 (en) * 2018-05-09 2022-12-06 York Guangzhou Air Conditioning And Refrigeration Co., Ltd. Blade and axial flow impeller using same
USD1000667S1 (en) * 2023-03-01 2023-10-03 Dongliang Tang Fan light
US20240026898A1 (en) * 2022-07-25 2024-01-25 Sanyo Denki Co., Ltd. Axial fan

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4306808A1 (en) * 2021-03-12 2024-01-17 Daikin Industries, Ltd. Propeller fan and refrigeration device
KR102495315B1 (ko) * 2022-01-27 2023-02-06 김윤성 밸런싱홈에 의해 자기평형 기능을 갖는 축류 임펠러 및 이를 구비한 축류펌프
WO2023162377A1 (ja) * 2022-02-25 2023-08-31 パナソニックＩｐマネジメント株式会社 換気扇

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6065937A (en) * 1998-02-03 2000-05-23 Siemens Canada Limited High efficiency, axial flow fan for use in an automotive cooling system

Family Cites Families (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3234011A1 (de) * 1982-09-14 1984-03-15 Braun Ag, 6000 Frankfurt Axialluefter
JPS59173598A (ja) * 1983-03-23 1984-10-01 Nippon Denso Co Ltd 軸流フアン
JPS62282198A (ja) * 1986-05-30 1987-12-08 Mitsubishi Electric Corp 軸流フアン
JP3203994B2 (ja) * 1994-10-31 2001-09-04 三菱電機株式会社 軸流送風機
TW365354U (en) * 1996-11-14 1999-07-21 Yung-Ren Liou Improved fan blades
US6132171A (en) * 1997-06-10 2000-10-17 Matsushita Electric Industrial Co., Ltd. Blower and method for molding housing thereof
JPH11303794A (ja) * 1997-10-17 1999-11-02 Mitsubishi Electric Corp 軸流羽根車及び冷蔵庫
JP3483447B2 (ja) * 1998-01-08 2004-01-06 松下電器産業株式会社 送風装置
JP3960776B2 (ja) * 2001-11-09 2007-08-15 松下電器産業株式会社 空調用送風機羽根車
JP3629702B2 (ja) * 2001-12-21 2005-03-16 ダイキン工業株式会社 送風機
TWI288210B (en) * 2004-08-18 2007-10-11 Delta Electronics Inc Heat-dissipating fan and its housing
JP2007113474A (ja) * 2005-10-20 2007-05-10 Mitsubishi Electric Corp 送風機
JP4808482B2 (ja) * 2005-11-30 2011-11-02 山洋電気株式会社 軸流送風機
JP4752489B2 (ja) * 2005-12-20 2011-08-17 パナソニック株式会社 風向変更装置
CN100554702C (zh) * 2006-06-09 2009-10-28 日本电产株式会社 轴流风扇
WO2008141381A1 (en) * 2007-05-21 2008-11-27 Weir Minerals Australia Ltd Improvements in and relating to pumps
KR20090038649A (ko) * 2007-10-16 2009-04-21 현대중공업 주식회사 건설 중장비용 냉각 팬
JP4818310B2 (ja) * 2008-05-12 2011-11-16 三菱電機株式会社 軸流送風機
WO2012039092A1 (ja) * 2010-09-21 2012-03-29 三菱電機株式会社 軸流送風機
JP5653282B2 (ja) * 2011-04-20 2015-01-14 三菱電機株式会社 軸流ファン
JP5418538B2 (ja) * 2011-04-28 2014-02-19 三菱電機株式会社 送風機
WO2014024305A1 (ja) * 2012-08-10 2014-02-13 三菱電機株式会社 プロペラファン、並びに、それを備えた送風機、空気調和機及び給湯用室外機
JP5992778B2 (ja) * 2012-09-06 2016-09-14 山洋電気株式会社 軸流ファン
WO2014141417A1 (ja) * 2013-03-14 2014-09-18 三菱電機株式会社 羽根車及びこれを用いた軸流送風機
US10075031B2 (en) * 2013-03-26 2018-09-11 Mitsuba Corporation Electric motor
EP3085966B1 (en) * 2013-12-20 2020-05-20 Mitsubishi Electric Corporation Axial flow fan
WO2015125306A1 (ja) * 2014-02-24 2015-08-27 三菱電機株式会社 軸流送風機
JP5905985B1 (ja) * 2015-08-18 2016-04-20 山洋電気株式会社 軸流送風機及び直列型軸流送風機

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6065937A (en) * 1998-02-03 2000-05-23 Siemens Canada Limited High efficiency, axial flow fan for use in an automotive cooling system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11519422B2 (en) * 2018-05-09 2022-12-06 York Guangzhou Air Conditioning And Refrigeration Co., Ltd. Blade and axial flow impeller using same
US20240026898A1 (en) * 2022-07-25 2024-01-25 Sanyo Denki Co., Ltd. Axial fan
US11988225B2 (en) * 2022-07-25 2024-05-21 Sanyo Denki Co., Ltd. Axial fan
USD1000667S1 (en) * 2023-03-01 2023-10-03 Dongliang Tang Fan light

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CN111133201A (zh) 2020-05-08
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