CN100465458C - Axial flow wind wheel - Google Patents

Abstract

An axial-flow wind rotor, including three blades arranged on the hub, the trailing edge area of the blades is recessed toward the air inlet direction of the leading edge of the blades, and the three blades are centered on the rotation center axis of the wind rotor with each other at 120°±15 The range of ° is equally spaced or unequally spaced; the outer diameter of the axial flow rotor is defined as D2, the diameter of the hub is defined as D1, and (D2-D1)/2 is set as the blade height Rm, and the starting point of the blade trailing edge depression The diameter of the circle where the position A is located is defined as D3, and there is (D3-D1)/2=(0.10-0.47)Rm. Because the blade trailing edge blade high middle and top area change the pressure distribution state of the blade earlier than the blade root area, so that the blade high-pressure airflow part flows to the blade low-pressure surface in advance, resulting in an increase in local pressure, which reduces the separation of the boundary layer as a whole. And make the boundary layer of the blade become turbulent before reaching the trailing edge of the blade, effectively reducing the eddy current noise and rotor wake, so it has lower noise and greater air volume.

Description

Axial flow wind wheel

technical field

The invention relates to an axial-flow wind wheel, in particular to a three-leaf axial-flow wind wheel suitable for an outdoor unit of an air conditioner.

Background technique

Axial flow fans are mostly used in outdoor units of air conditioners. In the previous axial flow fan, the rear edge in contact with the downstream side of the airflow (hereinafter, the rear edge of the blade in contact with the downstream side of the airflow is referred to as "blade trailing edge") protruded or flattened toward the downstream direction of the airflow outlet. Align to form 2 to 4 leaves.

In the conventional axial flow wind wheel with two blades, the single blade load is heavy, and each blade works under high load, the flow rate and static pressure are relatively low, the wind noise is high, and the motor is required to have a higher speed. The requirements for the strength and the load characteristics of the motor of the 2-blade axial flow wind wheel are relatively high. Because the air volume is sensitive to the change of load, the air volume of the conventional 2-blade axial-flow wind wheel is about 30% lower than that of the conventional 3-blade or 4-blade wind wheel, which is not conducive to quickly taking away the heat of the outdoor unit; if the ordinary 3-blade or 4-blade is used Although the axial flow fan can well solve the problem of insufficient flow rate and static pressure rise of the two-bladed axial flow wind wheel, the increase in the number of blades will lead to an increase in its own weight, an increase in the motor load, and the cost of the wind wheel will also increase. The increase in weight increases by more than 30% to 50%.

In addition, in a conventional axial-flow wind turbine, on two or more blades integrally formed around the hub (hub), the corner formed by the rear edge of the blade and the outer edge end of the blade forms a flat surface in the downstream direction of the airflow. No consideration is given to suppressing noise and improving flow by reducing boundary layer separation and reducing rotor wake, nor is it considered to reduce noise, nor is it considered by improving the blade trailing edge, blade middle and top regions. Treatments are performed to reduce rotor weight and motor load.

Contents of the invention

The purpose of the present invention is to provide an axial flow wind rotor that suppresses noise and increases flow rate by reducing boundary layer separation and rotor wake, reduces the rotational speed of the wind rotor and the weight of the wind rotor, reduces the cost of the wind rotor, and reduces the load of the motor at the same time. To overcome the deficiencies in the prior art.

An axial-flow wind rotor designed for this purpose includes three blades arranged on the hub. Its structural feature is that the trailing edge area of the blade is concave toward the air inlet direction of the leading edge of the blade, and the three blades are mutually aligned with the rotation center of the wind rotor. The axis is the center, and it is distributed at equal intervals or unequal intervals within the range of 120°±15°; the outer diameter of the axial flow rotor is defined as D2, the diameter of the hub is defined as D1, and (D2-D1)/2 is set as the blade Height Rm, the diameter of the circumference at the position A where the blade trailing edge depression begins is defined as D3, there is (D3-D1)/2=(0.10～0.47)Rm; the circumference diameter at the position B where the blade trailing edge depression ends is defined as D4, there is (D4-D1)/2=(0.8-1.0) Rm.

Therefore, the high center and top area of the blade trailing edge changes the pressure distribution state of the blade earlier than the blade root area, so that the high-pressure airflow part of the blade flows to the low-pressure surface of the blade in advance, resulting in an increase in local pressure and reducing the separation of the boundary layer as a whole , and make the blade boundary layer become turbulent before reaching the blade trailing edge, thereby effectively reducing vortex noise and rotor wake, so it has lower noise and greater air volume than conventional axial flow rotors.

In the above-mentioned axial flow wind rotor, the height of the rotor blade calculated from the lowest position of the trailing edge of the blade is defined as H2, and the maximum height of the concave part calculated from the lowest position of the trailing edge of the blade is defined as H1, and the value of H1/H2 is in In the range of 0.05 to 0.29.

In the above-mentioned axial flow rotor, the length of the blade chord line at the deepest position of the blade trailing edge depression is defined as L, the depth of the depression at this position along the chord length direction is δ, and the relationship between the depth of the depression δ and the length L of the blade chord line in this area The ratio ε (ε=δ/L) is in the range of 0.05 to 0.25.

The invention can effectively weaken the wake strength of the blade rotor and reduce the separation of the rotor boundary layer, thereby effectively reducing the noise of the wind wheel, reducing the weight of the wind wheel, reducing the manufacturing cost of the wind wheel, and reducing the load of the motor.

The three-blade axial-flow wind wheel of the present invention can not only solve the problem of increased motor load caused by the excessive weight of conventional 3-blade or 4-blade wind wheels, but also solve the blade load of conventional 2-blade axial-flow wind wheels The problem of reduced flow rate and insufficient static pressure rise caused by too large reduces the weight of the wind rotor, reduces the motor load and reduces the cost of the wind rotor by more than 25%. All advantages, with lower noise and motor load, and lower rotor weight and manufacturing cost of the rotor.

The present invention is especially suitable for outdoor units for air conditioners.

Description of drawings

Fig. 1 is a schematic diagram of the front view of an embodiment of the present invention.

Fig. 2 is a schematic perspective view of an embodiment of the present invention.

Fig. 3 is a schematic diagram of the diameter definition structure of the present invention.

Fig. 4 is a schematic diagram of the highly defined structure of the present invention.

Fig. 5 is a schematic diagram of the definition structure of the blade chord length and the concave length according to the present invention.

Fig. 6 is a graph showing the relationship between the distribution of the starting positions of the depressions and the magnitude of the noise.

Fig. 7 is a graph showing the rotor wake distribution of a conventional axial flow wind turbine.

Fig. 8 is a graph showing the rotor wake distribution of the present invention.

Fig. 9 is a graph showing the relationship between the maximum depth value of the trailing edge depression and the chord length of the blade at the position of the maximum depression depth, and the noise of the wind rotor and the load of the motor.

Fig. 10-Fig. 11 are schematic front view structural diagrams of two different specific embodiments of the present invention.

Fig. 12 is a schematic cross-sectional structural diagram of an embodiment of the present invention applicable to an air conditioner outdoor unit.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

In the figure, 1 is the axial flow rotor, 2 is the hub, 3 is the blade, 3a is the downstream side edge of the airflow, 3b is the concave part, D1 is the hub diameter, D2 is the outer diameter of the axial flow rotor, D3 is the blade The diameter of the circumference where the starting position A of the trailing edge depression is located, D4 is the circumference diameter of the position B where the blade trailing edge depression ends, Rm is the height of the blade, H1 is the maximum height of the depression part calculated from the lowest position C of the trailing edge of the blade 3, H2 is the height of the rotor blade calculated from the lowest position C of the trailing edge of the blade 3, δ is the depth of the depression, L is the length of the chord line of the blade, f is the point of the trailing edge of the blade top, k is the connecting line, 11 is the outdoor unit of the air conditioner, 12 is Shell, 13 is an outdoor heat exchanger, 14 is a compressor, 15 is a four-way valve, 16 is an electrical circuit, and 17 is an isolation plate.

Referring to Fig. 1-Fig. 2 and Fig. 10-Fig. 11, the three-blade axial flow wind wheel 1 includes the blade 3 arranged on the central hub 2, the three blades 3 have the same shape, and the trailing edge area of the blade 3 is forward to the blade 3 The air intake direction of the edge is concave, and the three blades 3 are centered on the central axis G of the wind rotor rotation, and are arranged at equal or unequal intervals along the circumference of the hub 2 within the range of 120°±15°. Formed on the downstream side edge portion 3a of the airflow is a concavity opposite to the airflow, and is approximately sickle-shaped, meniscus-shaped, circular-arc-shaped, V-shaped or zigzag-shaped rear edge recessed portion 3b.

Referring to Figure 3 and Figure 6, define the outer diameter of the axial flow rotor as D2, the hub diameter as D1, set (D2-D1)/2 as the blade height Rm, and the diameter of the circumference where the starting position A of the blade trailing edge depression is located Defined as D3, there is (D3-D1)/2=(0.10～0.47)Rm; the diameter of the circumference where the blade trailing edge depression ends at position B is defined as D4, and there is (D4-D1)/2=(0.8～1.0)Rm . The starting position A of the depression has a lower noise value starting from the blade height (0.10-0.47) Rm. When the starting position A of the depression is in the range of (0.10-0.47) Rm, the noise value is lower than 50.5 decibels. If the position is less than 0.10Rm or greater than 0.47Rm, the noise value is above 50.5 decibels, and the noise will not be sufficiently reduced.

Referring to Fig. 4, the height of the rotor blade calculated from the lowest position C of the trailing edge of the blade 3 is defined as H2, and the maximum height of the concave part calculated from the lowest position C of the trailing edge of the blade 3 is defined as H1, and the value of H1/H2 is in In the range of 0.05 to 0.29. Define the blade chord length where the deepest position e of the trailing edge depression of the blade 3 is located as L, see Figure 5, the depth of the depression at this position along the chord length direction is δ, the ratio of the depression depth δ to the blade chord length L in this area ε (ie ε=δ/L) is in the range of 0.05 to 0.25.

The blade chord length L at this time is the length in the circumferential direction of the blade 3 that intersects the circle when a circle is drawn within a range of a specified radius R from the center of rotation of the wind rotor. Since the blade is usually a curved shape, the blade chord The line length L is the length of the curve along the surface. If k is defined as the connection line between the starting position A of the depression and the point f of the blade tip and trailing edge, the depth of the depression δ at this time is the range of the specified radius R starting from the rotation center of the wind rotor. When a circle is drawn, the circle and the depression are the deepest The length in the circumferential direction formed by position e and line k.

Referring to Fig. 7-Fig. 8, Fig. 7 is the distribution curve of the rotor wake of the conventional three-blade axial flow wind wheel along the blade tip circumference, and Fig. 8 is the distribution curve of the rotor wake of the present invention along the blade tip circumference, and Cz represents the wind wheel rotation among the figure The axial speed of the rotor, Ut represents the peripheral speed of the outer circumference of the blade tip (Ut=πD2n/60), the axial speed Cz/Ut represents the dimensionless axial speed coefficient, and the change degree of the axial speed represents the strength of the rotor wake , the rotor axial speed of the present invention changes little (0.425-0.35)/0.425*100%=17%, while the axial speed change rate of the conventional axial flow wind wheel is (0.45-0.05)/0.45*100%=89% ; Therefore, the use of the axial flow wind wheel of the present invention can significantly weaken the rotor wake, thereby reducing noise and reducing motor load.

Referring to Figure 9, when the ratio ε(ε=δ/L) of the maximum depth δ of the depression at the trailing edge of the blade to the blade chord length L at the blade height where the maximum depth of the depression is located is within the range of 0.05 to 0.25, the wind rotor has a relatively high performance at the same time. Low noise and small motor load, the noise value at this time is less than 50.5 decibels, and the motor load is less than 52 watts, and when the ratio ε (ε=δ/L) is less than 0.05 or greater than 0.25, it cannot have both Lower noise and smaller motor load, neither noise nor motor load is effectively reduced.

Referring to Fig. 12, the air conditioner outdoor unit 11 houses an L-shaped outdoor heat exchanger 13 in the casing 12, the three-blade axial flow wind wheel 1 having the above-mentioned structural features, the compressor 14, the four-way valve 15 and the conversion The electrical circuit 16 of the device and the like, and the three-blade axial-flow wind wheel 1 and the compressor 14 are isolated with an isolation plate 17 . The three-blade axial-flow wind wheel 1 can effectively reduce the rotor wake and noise during actual operation, and also reduce the motor load and the weight of the wind wheel. The air-conditioning outdoor unit adopting the present invention can also have the characteristics of low motor load and high motor efficiency.

Claims (5)

1. An axial flow wind wheel, comprising three blades arranged on the hub, characterized in that the trailing edge region of the blade is sunken toward the air inlet direction of the leading edge of the blade, and the three blades are centered on the rotation central axis of the wind wheel, In the range of 120°±15°, they are equally spaced or unequally spaced; the outer diameter of the axial flow rotor is defined as D2, the diameter of the hub is defined as D1, and (D2-D1)/2 is set as the blade height Rm, and the blade The diameter of the circle at the position A where the trailing edge depression begins is defined as D3, and there is (D3-D1)/2=(0.10～0.47) Rm; the diameter of the circle where the blade trailing edge depression ends at position B is defined as D4, and there is (D4-D1 )/2=(0.8～1.0)Rm. 2. The axial flow wind rotor according to claim 1, characterized in that in the axial flow wind rotor, the height of the wind rotor blade calculated from the lowest position of the trailing edge of the blade is defined as H2, and the height calculated from the lowest position of the trailing edge of the blade is defined as H2. The maximum height of the concave part is defined as H1, and the value of H1/H2 is in the range of 0.05-0.29. 3. The axial-flow wind rotor according to claim 2, characterized in that in the axial-flow wind rotor, the length of the blade chord line at the deepest position of the blade trailing edge depression is defined as L, and the depth of the depression at this position is along the chord length direction is δ, and the ratio ε=δ/L of the depth of the depression to the chord length L of the blade in this region is in the range of 0.05-0.25. 4. The axial flow wind wheel according to claim 3, characterized in that the axial flow wind wheel is suitable for outdoor units for air conditioners. 5. The axial flow wind rotor according to claim 1, characterized in that the concave part of the blade is sickle-shaped, meniscus-shaped, arc-shaped, V-shaped or broken line-shaped.

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