Propeller fan and refrigeration device

Abstract

A propeller fan (10) includes a blade (14) rotating around a prescribed rotation axis (A), and a ring (16) connected to a blade end (20) of the blade (14). A curved portion (32) is provided on the blade end (20) side of the blade (14), and a cross-sectional shape in a rotation radius direction of the blade (14) is convex toward a pressure surface side. When an axial height (H) of a position of a blade root (18) on an arc (36) in a distance along the rotation axis (A) is set, and a position where the axial height (H) becomes largest in the rotation radius direction is set as a maximum warping position (X2), the axial height (H) at the maximum warping position (X2) is largest on a trailing edge (24) side of the blade (14).

Description

Technical Field

[0001] This disclosure relates to a propeller fan and a refrigeration device. Background Technology

[0002] To date, propeller fans have been used in refrigeration devices and the like to generate airflow. Among propeller fans, ring-type propeller fans are known, which include a ring arranged to surround multiple blades (see, for example, Patent Document 1). In ring-type propeller fans, the ring is connected to the blade ends of each blade, and each blade and the ring rotate together.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Publication No. 2021-4608 Summary of the Invention

[0006] -The technical problem the invention aims to solve-

[0007] In a propeller fan with an annulus, a stagnant zone of airflow becomes significant at the corner of the negative pressure side where the blade connects to the annulus, due to the influence of the boundary layer. In this propeller fan, air flowing along the positive pressure side of the blade forms a flow that is drawn into the negative pressure side as it reaches the rear end of the blade and leaves the positive pressure side, creating a vortex known as a wake vortex. The larger the stagnant zone formed on the negative pressure side of the blade, the more extensive and energetic the wake vortex becomes. When this wake vortex collides with the leading edge of the blade, it generates pressure loss, thus reducing the propeller fan's airflow performance.

[0008] The purpose of this disclosure is to improve the air delivery performance of a ring-type propeller fan.

[0009] - Technical solutions used to solve technical problems -

[0010] The first aspect of this disclosure pertains to a propeller fan 10. The propeller fan 10 of the first aspect includes blades 14 that rotate about a predetermined axis of rotation A and a ring 16 connected to the blade tip 20 of the blades 14. A bend 32 is provided on the blade tip 20 side of the blades 14, the bend 32 having a convex profile in the direction of the rotation radius of the blades 14 protruding towards the positive pressure surface 26. At the bend 32, the height at the position of the blade root 18 on the mid-arc line 36 along the direction of the rotation axis A is defined as the axial height H. When the position where this axial height H is maximum in the direction of the rotation radius is defined as the maximum warpage position X2, the axial height H at the maximum warpage position X2 is maximum on the trailing edge 24 side of the blades 14.

[0011] In this first aspect, in the curved portion 32, which is a convex section protruding towards the positive pressure surface 26 in the rotational radius direction and located on the blade tip 20 side of the blade 14, the axial height H at the maximum warping position X2 is greatest on the trailing edge 24 side of the blade 14. Therefore, the dead water region DA generated at the corner WC on the negative pressure surface 28 side of the portion where the blade 14 connects to the ring 16 is smaller. The smaller the dead water region DA, the more difficult it is for the wake vortex to expand, and the lower the energy. As a result, energy loss caused by the collision of the wake vortex with the leading edge 22 of the blade 14 can be suppressed, thereby improving the air delivery performance of the propeller fan 10.

[0012] The second aspect of this disclosure, based on the propeller fan 10 of the first aspect, involves setting the distance from the blade root 18 to the blade tip 20 of the blade 14 to R in the blade cross-section through the rotation axis A, and setting the distance from the blade root 18 of the blade 14 to any position to r, such that the maximum warpage position X2 is within the range of 0.6 ≤ r / R ≤ 0.8.

[0013] In this second aspect, since the maximum warping position X2 in the curved portion 32 of the blade 14 is within the range of 0.6 ≤ r / R ≤ 0.8, the dead water region DA generated at the corner WC on the negative pressure surface 28 side of the part where the blade 14 and the ring 16 connect can be appropriately reduced. This is advantageous for suppressing the generation of wake vortices.

[0014] The third aspect of this disclosure, based on the propeller fan 10 of the first or second aspect, is that the axial height H at the maximum warpage position X2 increases from the leading edge 22 of the blade 14 toward the trailing edge 24.

[0015] In this third aspect, the axial height H at the maximum warping position X2 in the curved portion 32 of the blade 14 increases from the leading edge 22 toward the trailing edge 24 of the blade 14. Therefore, the dead water region DA generated at the corner WC on the negative pressure surface 28 side of the portion where the blade 14 connects to the ring 16 can be reduced from the leading edge 22 toward the trailing edge 24. This is advantageous for suppressing the generation of wake vortices.

[0016] The fourth aspect of this disclosure pertains to a propeller fan 10. The propeller fan 10 of the fourth aspect includes blades 14 that rotate about a predetermined axis of rotation A and a ring 16 connected to the blade tip 20 of the blades 14. In the propeller fan 10 of the fourth aspect, the angle formed by the blades 14 and the ring 16 on the side of the negative pressure surface 28 of the blades 14 is [missing information]. It is largest on the trailing edge 24 side of the blade 14.

[0017] In this fourth aspect, the angle formed by the blade 14 and the ring 16 on the negative pressure surface 28 side of the blade 14 in the direction of the rotation radius of the blade 14. The dead water region DA generated at the corner WC of the negative pressure surface 28 at the junction of blade 14 and ring 16 is smaller because the dead water region DA is the largest on the trailing edge 24 side of blade 14. The smaller the dead water region DA, the more difficult it is for the wake vortex to expand, and the lower the energy. As a result, energy loss caused by the collision between the wake vortex and the leading edge 22 of blade 14 can be suppressed, thereby improving the air delivery performance of propeller fan 10.

[0018] The fifth aspect of this disclosure is based on the propeller fan 10 of the fourth aspect, wherein the angle It increases in size from the leading edge 22 toward the trailing edge 24 of the blade 14.

[0019] In this fifth aspect, the angle formed by the blade 14 and the ring 16 on the negative pressure surface 28 side of the blade 14 in the direction of the rotation radius of the blade 14. The dead water region DA at the corner WC on the negative pressure surface 28 side of the section where the blade 14 connects to the ring 16 increases from the leading edge 22 toward the trailing edge 24, thus making the dead water region DA decrease from the leading edge 22 toward the trailing edge 24. This is advantageous for suppressing the generation of wake vortices.

[0020] The sixth aspect of this disclosure, based on the propeller fan 10 of the fourth or fifth aspect, includes the angle on the trailing edge 24 side of the blade 14. The portion above 130°.

[0021] In this sixth aspect, the angle formed by the blade 14 and the ring 16 on the negative pressure surface 28 side of the blade 14 in the direction of the rotation radius of the blade 14. The portion exceeding 130° is contained on the trailing edge 24 side of the blade 14, thus appropriately reducing the dead water region DA generated at the corner WC on the negative pressure surface 28 side of the section where the blade 14 and ring 16 connect. This is advantageous for suppressing the generation of wake vortices.

[0022] The seventh aspect of this disclosure is based on the propeller fan 10 of any one of the first to sixth aspects, wherein serrations 40 are provided on the trailing edge 24 of the blades 14.

[0023] In this seventh aspect, since serrations 40 are provided on the trailing edge 24 of the blade 14, the wind noise of the blade 14 generated by the rotation of the propeller fan 10 can be reduced.

[0024] The eighth aspect of this disclosure pertains to a refrigeration device 1. The refrigeration device 1 of the eighth aspect includes a propeller fan 10 as described in any one of the first to seventh aspects.

[0025] In this eighth aspect, since the propeller fan 10 includes any of the first to seventh aspects, energy saving can be achieved in the cooling device 1 while ensuring the air volume delivered by the propeller fan 10. Attached Figure Description

[0026] Figure 1 This is a perspective view illustrating a simplified structure of the cooling device according to an example embodiment;

[0027] Figure 2 This is an example showing along Figure 1 A cross-sectional view of the main part of the cooling device, cut along line II-II;

[0028] Figure 3 This is a perspective view illustrating an embodiment of a propeller fan;

[0029] Figure 4 This is a rear view of a propeller fan illustrating an embodiment;

[0030] Figure 5 This is an example showing along Figure 4 A cross-sectional view of the blades of a propeller fan cut along the V-V line.

[0031] Figure 6 This is an example showing along Figure 4 A cross-sectional view of the blades of a propeller fan cut along line VI-VI.

[0032] Figure 7 This is an example showing along Figure 4 A cross-sectional view of the blades of a propeller fan cut along line VII-VII.

[0033] Figure 8 This is a cross-sectional view of the circumferential blades of a propeller fan, illustrating an embodiment.

[0034] Figure 9 This is a graph illustrating the relationship between the radius ratio and axial height of a propeller fan according to an example embodiment;

[0035] Figure 10 This is a graph illustrating the relationship between the angle from the leading edge of the blade and the axial height at the second maximum warping position of a propeller fan according to an example embodiment.

[0036] Figure 11 This is a graph illustrating the relationship between the angle from the leading edge centered on the blade's rotation axis and the angle formed by the blade and the ring at the blade tip corner in a propeller fan embodiment.

[0037] Figure 12This is a graph showing the fluid simulation results on the negative pressure side of the blades of the propeller fan according to the embodiment;

[0038] Figure 13 This is a graph showing the fluid simulation results on the positive pressure side of the blades of the propeller fan according to the embodiment;

[0039] Figure 14 This is a graph illustrating the relationship between airflow and static pressure in a propeller fan, as exemplified by an embodiment.

[0040] Figure 15 This is a graph illustrating the relationship between airflow and static pressure efficiency in a propeller fan according to an example embodiment.

[0041] Figure 16 This is a perspective view showing a propeller fan of the first modified example;

[0042] Figure 17 This is a perspective view showing a propeller fan of the second modified example;

[0043] Figure 18 The cooling device of the third variation is equivalent to Figure 2 A sectional view of the part;

[0044] Figure 19 This is a graph showing the fluid simulation results on the negative pressure side of the blades of a comparative propeller fan;

[0045] Figure 20 This is a graph showing the fluid simulation results on the positive pressure side of the blades of a comparative propeller fan. Detailed Implementation

[0046] Exemplary embodiments will now be described with reference to the accompanying drawings.

[0047] (Implementation Method)

[0048] In this embodiment, the propeller fan 10 is used in the air supply device 5. The air supply device 5 is installed as follows: Figure 1 The cooling device 1 shown is an example of a refrigeration device. The cooling device 1 includes four pairs of heat exchangers 3a and 3b. These four pairs of heat exchangers 3a and 3b are arranged in a horizontal row. Each pair of heat exchangers 3a and 3b is separated from each other facing upwards, forming a V-shape when viewed from the side.

[0049] The air supply device 5 is arranged above each pair of heat exchangers 3a and 3b. The air supply device 5 includes a top panel 6, a propeller fan 10, a fan motor (not shown), and an air supply grille 11.

[0050] The upper panel 6 covers four pairs of heat exchangers 3a and 3b from above. Multiple heat exchangers are formed on the upper panel 6. Figure 2 The air outlets 7 are shown. Multiple air outlets 7 are arranged in four rows along the arrangement direction of the heat exchangers 3a and 3b, and in two columns perpendicular to the arrangement direction of the heat exchangers 3a and 3b. The two air outlets 7 arranged perpendicular to the arrangement direction of the heat exchangers 3a and 3b are located above a shared pair of heat exchangers 3a and 3b. Each air outlet 7 is composed of a circular cylindrical flared opening 8 integrally formed with the upper panel 6.

[0051] The flare 8 extends downward from the periphery of the air outlet 7 opening on the upper panel 6. A propeller fan 10 is positioned inside the flare 8 with its rotation axis A pointing vertically. The propeller fan 10 rotates under the drive of a fan motor, directing air upward. In this example of the propeller fan 10, the lower side is the upstream side, and the upper side is the downstream side. An air outlet grille 11 is located on the upper panel 6 and downstream of the propeller fan 10.

[0052] - Structure of a propeller fan -

[0053] The propeller fan 10 is an axial fan made of synthetic resin. The propeller fan 10 is a propeller fan 10 with a ring 16. For example... Figure 3 and Figure 4 As shown, the propeller fan 10 includes a hub 12, four blades 14, and a ring 16. The hub 12, four blades 14, and ring 16 are integrally formed. The propeller fan 10 is formed, for example, by injection molding. It should be noted that the propeller fan 10 can also be made of metal.

[0054] The hub 12 is cylindrical. This hub 12 serves as the rotating shaft of the propeller fan 10 and is located at the center of the propeller fan 10. A shaft hole 13 is formed in the center of the hub 12. The drive shaft of a fan motor (not shown) is mounted on the hub 12 through the shaft hole 13. When the fan motor is driven, the hub 12 rotates around the rotation axis A. The central axis of the hub 12 coincides with the rotation axis A of the propeller fan 10.

[0055] Four blades 14 are spaced apart from each other at a certain angle in the circumferential direction of the hub 12. Each blade 14 extends outward from the outer periphery of the hub 12 in the direction of the rotation radius. The four blades 14 are radially distributed from the hub 12 towards the outer side of the propeller fan 10 in the direction of the rotation radius. When viewed from the front or the back, adjacent blades 14 do not overlap. Each blade 14 is formed as a plate that is smoothly curved along the direction of rotation radius and the direction of rotation D.

[0056] Each blade 14 has the same shape. In each blade 14, the inner end of the propeller fan 10 on the radially central side, that is, the end perpendicular to the rotation axis A (rotation radius direction), is the blade root 18. In each blade 14, the outer end of the propeller fan 10 on the radially peripheral side, that is, the outer end perpendicular to the rotation axis A (rotation radius direction), is the blade tip 20. The blade root 18 and blade tip 20 of each blade 14 extend along the rotation direction D of the propeller fan 10.

[0057] The blade root 18 of each blade 14 is connected to the hub 12. In each blade 14, the distance Ri from the rotation axis A of the propeller fan 10 to the blade root 18 is substantially constant along the entire length of the blade root 18. The blade tip 20 of each blade 14 is connected to the ring 16. In each blade 14, the distance Ro from the rotation axis A of the propeller fan 10 to the blade tip 20 is substantially constant along the entire length of the blade tip 20.

[0058] In each blade 14, the length of the blade tip 20 is greater than the length of the blade root 18. In the rotation direction D of the propeller fan 10, the leading edge of the blade tip 20 is located further forward than the leading edge of the blade root 18. In the rotation direction D of the propeller fan 10, the trailing edge of the blade tip 20 is located further rearward than the trailing edge of the blade root 18. In each blade 14, the leading edge in the rotation direction D is the leading edge 22. In each blade 14, the trailing edge in the rotation direction D is the trailing edge 24.

[0059] The leading edge 22 and trailing edge 24 of each blade 14 extend from the hub 12 side toward the ring 16 side. The leading edge 22 of each blade 14 is curved in a manner that is concave towards the rearward side in the rotation direction D of the blade 14. The trailing edge 22 of each blade 14 is curved in a manner that is concave towards the frontward side in the rotation direction D of the blade 14. The two portions of the leading edge 22 and trailing edge 24 of each blade 14 on the side near the blade root 18 extend substantially parallel to each other. The two portions of the leading edge 22 and trailing edge 24 of each blade 14 on the side near the blade tip 20 extend separately toward the blade tip 20.

[0060] Each blade 14 is inclined relative to a plane orthogonal to the rotation axis A of the propeller fan 10. The leading edge 22 of each blade 14 is located at one end of the hub 12 (in Figure 3 Near the upper end of the wheel hub 12. The trailing edge 24 of each blade 14 is located at the other end of the hub 12. Figure 3 Near the downward-facing end). In each blade 14, the surface facing the front side in the rotation direction D (in... Figure 3 The face facing downwards is the positive pressure surface 26, and the face facing the rear side of the rotation direction D (in...) Figure 3 The surface facing upwards (28) is the negative pressure surface.

[0061] The ring 16 is arranged to surround the plurality of blades 14. The ring 16 is formed in a circular shape. The outer peripheral surface of the ring 16 is opposite to the inner peripheral surface of the bell mouth 8 (see reference). Figure 2 The inner circumferential surface of ring 16 is connected to the blade tips 20 of the four blades 14. That is, the blade tips 20 of the four blades 14 are connected by ring 16. Viewed from the side of propeller fan 10, ring 16 covers the entire edge from the leading edge 22 to the trailing edge 24 of each blade 14. The two ends of ring 16 are curved toward the outer periphery of propeller fan 10.

[0062] In the propeller fan 10, as the four blades 14 rotate, air flows from the intake side (lower side) at the back to the exhaust side (upper side) at the front. The rotation of the propeller fan 10 causes the air supply device 5 to deliver air. When the propeller fan 10 rotates around the rotation axis A, air is pushed out by the positive pressure surface 26. At this time, the following state occurs: on the positive pressure surface 26 side of the blades 14, the pressure increases to expel air; on the other hand, on the negative pressure surface 28 side of the blades 14, the pressure decreases.

[0063] When the propeller fan 10 rotates, the air flowing along the positive pressure surface 26 of the blade 14 reaches the trailing edge 24 or blade tip 20 of the blade 14 and leaves the positive pressure surface 26, forming an airflow that is drawn in from the positive pressure surface 26 to the negative pressure surface 28, thus creating a vortex. The vortex generated on the blade tip 20 side of the blade 14 is called the blade tip vortex. The vortex generated on the trailing edge 24 side of the blade 14 is called the wake vortex. Both the blade tip vortex and the wake vortex cause energy loss, thus becoming the main reason for the reduction in air supply performance.

[0064] In the propeller fan 10, due to the presence of the ring 16, the air propelled by the propeller fan 10 is less likely to flow from the positive pressure surface 26 side of the blade 14 around the blade tip 20 to the negative pressure surface 28 side. This suppresses the generation of blade tip vortices. However, in this propeller fan 10 with the ring 16, a stagnant water region DA is generated at the corner (hereinafter referred to as the blade tip corner) WC formed on the negative pressure surface 28 side of the portion where the blade 14 connects to the ring 16, due to the influence of the boundary layer. In the propeller fan 10 of this example, the shape of each blade 14 was studied to suppress the generation of this stagnant water region DA.

[0065] - The shape of the leaves -

[0066] like Figures 5-7As shown, each blade 14 has a first curved portion 30 and a second curved portion 32. The first curved portion 30 is located on the blade root 18 side of the blade 14, i.e., on the inner side in the direction of rotation radius. The cross-sectional shape of the first curved portion 30 in the direction of rotation radius of the blade 14 protrudes convexly towards the negative pressure surface 28. The second curved portion 32 is located on the blade tip 20 side of the blade 14, i.e., on the outer side in the direction of rotation radius. The cross-sectional shape of the second curved portion 32 in the direction of rotation radius of the blade 14 protrudes convexly towards the positive pressure surface 26.

[0067] The first bend 30 constitutes more than 70% of the portion of the blade 14 located further inward than the center position in the direction of rotation radius, preferably more than 80%. The second bend 32 constitutes more than 70% of the portion of the blade 14 located further outward than the center position in the direction of rotation radius, preferably more than 80%. In this example, the inner half of each blade 14 in the direction of rotation radius is constituted by the first bend 30. The outer half of each blade 14 in the direction of rotation radius is constituted by the second bend 32.

[0068] Figure 8 The blade cross-section shown is obtained by unfolding a cross-section of a blade 14 located at a distance Rn from the rotation axis A of the propeller fan 10, i.e., an arc-shaped cross-section centered on the rotation axis A, into a plane. For example... Figure 8 As shown, each blade 14 is warped in a manner that bulges towards the negative pressure surface 28. Figure 8 In the blade cross-section shown, the line segment connecting the leading edge 22 and the trailing edge 24 of the blade 14 is the blade chord 34.

[0069] The angle between the blade chord 34 and the plane perpendicular to the rotation axis A of the propeller fan 10 is the mounting angle α. The mounting angle α of each blade 14 varies according to the radius ratio r / R. The radius ratio r / R is the ratio of the distance from the blade root 18 to the blade tip 20 of the blade 14 to R (Ro-Ri) in the blade cross-section through the rotation axis A (in the direction of the rotation radius of the blade 10), and the distance from the blade root 18 of the blade 14 to any position to r (Rn-Ri). The radius ratio (r / R) indicates the position of the blade 14 from the blade root 18 in the direction of the rotation radius.

[0070] The length of the blade chord 34 is called the blade chord length c. The blade chord length c is the value obtained by dividing the length Rnθ of the arc with radius Rn and central angle θ by the cosine of the installation angle α, cosα (c = Rnθ / cosα). It should be noted that θ is the central angle of the blade 14 at a distance Rn from the rotation axis A of the propeller fan 10 (refer to...). Figure 4 ), and its unit is radian.

[0071] <Leaf String Length>

[0072] like Figure 8 As shown, the chord length c of each blade 14 varies according to the radius ratio r / R. The chord length c is approximately constant at the first bend 30. Here, "approximately constant" means that the variation range of the chord length c is within ±10% of the chord length c at the blade root 18. The variation range of the chord length c at the first bend 30 is preferably within ±5% of the chord length c at the blade root 18. The chord length c gradually increases towards the blade tip 20 at the second bend 32. The variation range of the chord length c per unit length in the direction of rotation radius in the second bend 32 increases towards the blade tip 20. The chord length c of each blade 14 does not reach a maximum value in the middle of the second bend 32, but reaches a maximum value at the blade tip 20.

[0073] <Maximum warp position height, axial height>

[0074] exist Figures 5-7 In the blade cross-section shown, the line connecting the midpoints of the positive pressure surface 26 and the negative pressure surface 28 is the mid-arc line 36. On each blade 14, the height from the blade root 18 on the mid-arc line 36 in the direction extending along the rotation axis A is the axial height H. The axial height H at the first bend 30 of each blade 14 is the height towards the positive pressure surface 26. The axial height H at the second bend 32 of each blade 14 is the height towards the negative pressure surface 28.

[0075] exist Figure 9 The curves shown are represented by dashed lines. Figure 5 The variation of axial height H in the blade profile is represented by a dashed line. Figure 6 The variation of axial height H in the blade profile is represented by a solid line. Figure 7 The variation of axial height H in the blade profile. For example... Figures 5-8 As shown, the axial height H of each blade 14 varies smoothly along its entire length in the direction of rotation radius in any cross-sectional shape from the blade root 18 to the blade tip 20.

[0076] In the first bend 30, the position where the axial height H is greatest in the direction of rotation radius is the first maximum warp position X1. In the propeller fan 10 of this example, the first maximum warp position X1 is closer to the blade root 18 side as it moves from the leading edge 22 of the blade 14 toward the trailing edge 24. Furthermore, the axial height H at the first maximum warp position X1 is greatest on the leading edge 22 side of the blade 14. Specifically, the axial height H at the first maximum warp position X1 decreases from the leading edge 22 of the blade 14 toward the trailing edge 24, reaching its minimum at the trailing edge 24 of the blade 14. The axial height H at the first maximum warp position X1 can also be approximately constant over the entire width along the direction of the blade chord 34 of the first bend 30.

[0077] In the second bend 32, the position where the axial height H is greatest in the direction of rotation radius is the second maximum warp position X2. In the propeller fan 10 of this example, if the position of the second maximum warp position X2 is expressed in terms of the radius ratio (r / R), then the second maximum warp position X2 lies in the range of 0.6 ≤ r / R ≤ 0.8. The second maximum warp position X2 is approximately constant over the entire width along the direction of the blade chord 34 of the second bend 32. The axial height H at the second maximum warp position X2 is greatest on the trailing edge 24 side of the blade 14. Figure 10 As shown, specifically, the axial height H at the second maximum warping position X2 increases from the leading edge 22 of the blade 14 toward the trailing edge 24, and is the maximum at the trailing edge 24 of the blade 14.

[0078] In the direction of the rotation radius of blade 14, blade 14 and ring 16 form a blade tip corner WC on the negative pressure surface 28 side of blade 14. The angle formed by blade 14 and ring 16 at this blade tip corner WC (hereinafter referred to as the angle of blade tip corner WC) The angle of the blade tip corner WC varies depending on the axial height H of the blade 14 at the second maximum warping position X2. That is, for each blade 14, the greater the axial height H at the second maximum warping position X1, the greater the angle of the blade tip corner WC. The larger the angle of the leaf tip corner (WC). It is largest on the trailing edge 24 side of blade 14. Specifically, as... Figure 11 As shown, the angle of WC at the blade tip corner. The blade 14 widens from its leading edge 22 toward its trailing edge 24, reaching its maximum at the trailing edge 24. The angle WC at the leaf tip corner is also present on the trailing edge 24 side of the blade 14. The portion above 130°.

[0079] -Performance of propeller fans-

[0080] exist Figure 19 and Figure 20 In the simulation, the isosurface of turbulent kinetic energy (wind speed) is colored using grayscale to represent the fluid simulation results of the comparative example propeller fan 100. In this fluid simulation, the airflow is 280 m³ / s on the high-volume side. 3 / min. The comparative example propeller fan 100 is a fan in which the cross-sectional shape of each blade 14 in the direction of rotation radius does not produce bending. For example... Figure 19As shown, in the comparative example propeller fan 100, a dead water region DA (the area enclosed by double-dotted lines) is generated at the blade tip corner WC on the negative pressure surface 28 side of the blade 14. This dead water region DA extends over a large area from the leading edge 22 of the blade 14 towards the trailing edge 24, and the wind speed at the blade tip corner WC is low over a wide range from the leading edge 22 to the trailing edge 24. Figure 20 As shown, in the comparative example propeller fan 100, the high turbulent kinetic energy region TA (the region enclosed by the double-dotted line) is larger on the side of the positive pressure surface 26 of the blade 14, starting from the leading edge 22 of the blade 14, and the energy loss caused by the wake vortex is greater.

[0081] exist Figure 12 and Figure 13 In this example, the isosurface of turbulent kinetic energy (wind speed) is colored using grayscale to represent the fluid simulation results of the propeller fan 10. In this fluid simulation, the airflow is 280 m³ / s on the high-volume side. 3 / min. For example Figure 12 As shown, in the propeller fan 10 of this example, although a dead water region DA (the area surrounded by double-dotted lines) is generated on the leading edge 22 side of the blade tip corner WC on the negative pressure surface 28 side of the blade 14, the range of this dead water region DA is relatively narrow, and the wind speed at the blade tip corner WC increases. Figure 13 As shown, in the propeller fan 10 of this example, the high turbulent kinetic energy region TA (the region enclosed by the double-dotted line) starting from the leading edge 22 of the blade 14 on the side of the positive pressure surface 26 of the blade 14 is small, and the energy loss caused by the wake vortex is small.

[0082] exist Figure 14 In the diagram, solid lines represent the airflow-static pressure characteristic (P-Q curve) of the air supply device using the propeller fan 10 of this example, while dashed lines represent the airflow-static pressure characteristic (P-Q curve) of the air supply device using the propeller fan 100 of the comparative example. Similar to the above, the propeller fan 100 of the comparative example is a fan whose cross-sectional shape in the direction of the rotation radius of each blade 14 does not exhibit bending. Figure 14 As shown, compared with the air supply device using the propeller fan 100 of the comparative example, the air supply device 5 using the propeller fan 10 of this example has a larger static pressure and a larger air volume at the same air volume throughout the entire region of the graph.

[0083] exist Figure 15In the diagram, solid lines represent the relationship between airflow and static pressure efficiency of the air supply device using the propeller fan 10 of this example, while dashed lines represent the relationship between airflow and static pressure efficiency of the air supply device using the propeller fan 100 of the comparative example. Similar to the above, the propeller fan 100 of the comparative example is a fan whose cross-sectional shape in the direction of the rotation radius of each blade 14 does not exhibit bending. Figure 15 As shown, compared with the air supply device using the propeller fan 100 of the comparative example, the air supply device using the propeller fan 10 of this example has improved static pressure efficiency relative to the same air volume over the entire area of ​​the graph, especially on the side with a large air volume.

[0084] -Features of the implementation method-

[0085] According to this embodiment of the propeller fan 10, in the second curved portion 32, which is convex in the cross-sectional shape protruding towards the positive pressure surface 26 in the direction of rotational radius, located on the blade tip 20 side of the blade 14, the axial height H at the second maximum warping position X2 is the largest on the trailing edge 24 side of the blade 14. Therefore, the dead water region DA generated at the blade tip corner WC is smaller. The smaller the dead water region DA, the more difficult it is for the wake vortex to expand, and the lower the energy. As a result, energy loss caused by the collision of the wake vortex with the leading edge 22 of the blade 14 can be suppressed, thereby improving the air delivery performance of the propeller fan 10.

[0086] According to this embodiment of the propeller fan 10, since the second maximum warping position X2 of the second curved portion 32 of the blade 14 is within the range of 0.6 ≤ r / R ≤ 0.8, the dead water region DA generated at the blade tip corner WC can be appropriately reduced. This is advantageous for suppressing the generation of wake vortices.

[0087] According to this embodiment of the propeller fan 10, the axial height H at the second maximum warping position X2 in the second curved portion 32 of the blade 14 increases from the leading edge 22 towards the trailing edge 24 of the blade 14, thus making the dead water region DA generated at the blade tip corner WC smaller from the leading edge 22 towards the trailing edge 24 of the blade 14. This is advantageous for suppressing the generation of wake vortices.

[0088] According to this embodiment of the propeller fan 10, in the direction of the rotation radius of the blade 14, the angle formed by the blade 14 and the ring 16 at the blade tip corner WC is... The dead water region DA generated at the blade tip corner WC is smaller because the dead water region DA is the largest on the trailing edge 24 side of the blade 14. The smaller the dead water region DA, the more difficult it is for the wake vortex to expand, and the lower the energy. As a result, energy loss caused by the collision between the wake vortex and the leading edge 22 of the blade 14 can be suppressed, thereby improving the air delivery performance of the propeller fan 10.

[0089] According to this embodiment of the propeller fan 10, in the direction of the rotation radius of the blade 14, the angle formed by the blade 14 and the ring 16 at the blade tip corner WC is... The diameter of the dead water zone DA generated at the blade tip corner WC decreases from the leading edge 22 towards the trailing edge 24, thus reducing the size of the dead water zone DA generated at the leading edge 22 towards the trailing edge 24. This is advantageous for suppressing the generation of wake vortices.

[0090] According to this embodiment of the propeller fan 10, in the direction of the rotation radius of the blade 14, the angle formed by the blade 14 and the ring 16 at the blade tip corner WC is... The portion exceeding 130° is contained on the trailing edge 24 side of the blade 14, thus appropriately reducing the dead water zone DA generated at the blade tip corner WC. This is advantageous for suppressing the generation of wake vortices.

[0091] The cooling device 1 according to this embodiment includes a propeller fan 10 with improved air delivery performance, thus achieving energy saving while ensuring the air delivery volume of the propeller fan 10.

[0092] (Other implementation methods)

[0093] The above implementation method can also adopt the following structure.

[0094] -First variation-

[0095] like Figure 16 As shown, the propeller fan 10 may also include five blades 14. The number of blades 14 included in the propeller fan 10 may be three or less, or more than six. In the propeller fan 10, adjacent blades 14 may partially overlap each other when viewed from the front or the back.

[0096] - Second variation -

[0097] like Figure 17 As shown, in the propeller fan 10, serrations 40 may also be provided on the trailing edge 24 of each blade 14. The serrations 40 are formed in a serrated shape, for example. The serrations 40 are provided on the generally entire trailing edge 24 of each blade 14. The serrations 40 may also be provided only on a part of the trailing edge 24 of each blade 14, such as the blade tip 20 side.

[0098] According to this second variation of the propeller fan 10, since serrations 40 are provided on the trailing edge 24 of each blade 14, air turbulence flowing on the negative pressure surface 28 side of the blade 14 can be suppressed by the serrations 40. As a result, the wind noise generated by the blades as the propeller fan 10 rotates can be reduced. Moreover, it is expected that the air delivery efficiency of the propeller fan 10 can be improved.

[0099] -Third variation-

[0100] like Figure 18 As shown, in the cooling device 1, the flare 8 may also be located only on the downstream side (upper side in this example) of the airflow direction of the propeller fan 10. That is, the flare 8 may not extend to the outer periphery of the propeller fan 10 (strictly speaking, the outer side of the ring 16). In this example, the flare 8 is located near the downstream end of the ring 16. The flare 8 in this example is formed as a cone extending from the upstream side to the downstream side of the airflow direction of the propeller fan 10.

[0101] - Other variations -

[0102] In the propeller fan 10, the inner portion of each blade 14 in the direction of rotation radius (corresponding to the portion of the first curved portion 30) can also be formed into a shape other than a plate with a generally flat cross-sectional shape in the direction of rotation radius and a convex shape protruding towards the positive pressure surface 26. The propeller fan 10 can be used not only in the cooling device 1, but also in various devices that require air supply, such as air conditioning devices or ventilation devices.

[0103] The above describes the embodiments and modifications, but it is understood that various changes can be made to the scheme and specific circumstances without departing from the spirit and scope of the claims. As long as the function of the object of this disclosure is not affected, the above embodiments and modifications can be appropriately combined and substituted.

[0104] -Industry Applicability-

[0105] In summary, this disclosure is useful for propeller fans and refrigeration devices.

[0106] - Symbol Explanation -

[0107] A rotating axis

[0108] c Leaf chord length

[0109] D Rotation direction

[0110] H-axis height

[0111] WC leaf tip corner

[0112] X1 First Maximum Warpage Position

[0113] X2 Second Maximum Warpage Location (Maximum Warpage Location)

[0114] 1. Cooling device (refrigeration device)

[0115] 3a Heat exchanger

[0116] 3b Heat Exchanger

[0117] 5. Air supply device

[0118] 6. Top panel

[0119] 7 air outlets

[0120] 8-mouth

[0121] 10 Propeller Fans

[0122] 11. Air supply grille

[0123] 12-inch wheels

[0124] 13 Shaft Holes

[0125] 14 blades

[0126] 16 rings

[0127] 18 Leaf roots

[0128] 20 Leaf tips

[0129] 22. Prelude

[0130] 24. Trailing edge

[0131] 26 Positive pressure surface

[0132] 28 Negative pressure surface

[0133] 30 First Bend

[0134] 32 Second bend

[0135] 34 Leaf String

[0136] 36. Mid-arc line

[0137] 40 serrations

Claims

1. A propeller-type fan, characterized in that: The propeller fan is a propeller fan (10) including blades (14) and rings (16). The blade (14) rotates about a predetermined axis of rotation (A). The ring (16) is connected to the blade tip (20) of the blade (14). A curved portion (32) is provided on the blade tip (20) side of the blade (14). The curved portion (32) protrudes into a convex shape in the cross-sectional shape of the blade (14) in the direction of the rotation radius towards the positive pressure surface (26). At the bend (32), the axial height (H) is defined as the height from the blade root (18) on the central arc (36) in the direction of the rotation radius of the blade (14) towards the positive pressure surface (26) in the direction along the rotation axis (A). When the position where this axial height (H) is the largest in the direction of the rotation radius is defined as the maximum warping position (X2), the axial height (H) at the maximum warping position (X2) is the largest on the trailing edge (24) side of the blade (14). In the blade profile through the rotation axis (A), the distance from the blade root (18) to the blade tip (20) of the blade (14) is set as R, and the distance from the blade root (18) to any position of the blade (14) is set as r, the maximum warping position (X2) is in the range of 0.6≤r / R≤0.

8.

2. The propeller fan according to claim 1, characterized in that: The axial height (H) at the maximum warping position (X2) increases from the leading edge (22) of the blade (14) toward the trailing edge (24).

3. The propeller fan according to claim 1, characterized in that: The trailing edge (24) of the blade (14) is provided with serrations (40).

4. A propeller-type fan, characterized in that: The propeller fan includes blades (14) and rings (16). The blade (14) rotates about a predetermined axis of rotation (A). The ring (16) is connected to the blade tip (20) of the blade (14). A curved portion (32) is provided on the blade tip (20) side of the blade (14). The curved portion (32) protrudes into a convex shape in the cross-sectional shape of the blade (14) in the direction of the rotation radius towards the positive pressure surface (26). In the direction of the rotation radius of the blade (14), the angle formed by the blade (14) and the ring (16) on the negative pressure surface (28) side of the blade (14) is ( The maximum value is on the trailing edge (24) side of the blade (14). At the bend (32), the height from the position of the blade root (18) on the middle arc (36) in the direction of the rotation radius of the blade (14) to the side of the positive pressure surface (26) in the direction along the rotation axis (A) is set as the axial height (H), and the position where the axial height (H) is the largest in the direction of the rotation radius is set as the maximum warping position (X2). In the blade profile through the rotation axis (A), the distance from the blade root (18) to the blade tip (20) of the blade (14) is set as R, and the distance from the blade root (18) to any position of the blade (14) is set as r, the maximum warping position (X2) is in the range of 0.6≤r / R≤0.

8.

5. The propeller fan according to claim 4, characterized in that: The angle ( The blade (14) increases in size from the leading edge (22) toward the trailing edge (24).

6. The propeller fan according to claim 4, characterized in that: The angle is included on the trailing edge (24) side of the blade (14). () refers to the portion above 130°.

7. The propeller fan according to claim 4, characterized in that: The trailing edge (24) of the blade (14) is provided with serrations (40).

8. A refrigeration device, characterized in that: The refrigeration device includes a propeller fan (10) as described in any one of claims 1 to 7.

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