A low noise propeller

Abstract

The invention belongs to the technical field of aircraft propeller design and relates to a low-noise propeller. The propeller parameters are as follows: the number of propeller blades is 3; the propeller diameter is 1770-1970 mm; each section of the blade adopts the airfoil ARA-D; when the relative radius is 0.3, the sweep is 53-59 mm, the chord length is 126-131 mm, and the twist angle is 17°-22°; when the relative radius is 0.6, the sweep is 43-48 mm, the chord length is 98-103 mm, and the twist angle is 1°-6°; when the relative radius is 0.8, the sweep is 33-39 mm, the chord length is 76-82 mm, and the twist angle is -5°-0°; when the relative radius is 0.95, the sweep is 21-26 mm, the chord length is 57-63 mm, and the twist angle is -9°-4°; the propeller meets the index requirement that the far-field noise is not greater than 66 dB under the conditions of a maximum flight speed of 50 m / s, a maximum flight altitude of 5000 m, and a cruising efficiency of 83%.

Description

Technical Field

[0001] The invention belongs to the technical field of aircraft propeller design and relates to a low-noise propeller. Background Art

[0002] Advanced aviation countries around the world have strict restrictions on the noise intensity of aircraft. For propeller aircraft, about 90% of the noise is generated by propellers. Propeller noise is one of the criteria for measuring the performance of propellers, and the main source of its noise is the sound of blade rotation. Propeller noise will have many adverse consequences, mainly in the following three aspects: First, during the flight of the propeller, the noise is transmitted to the interior of the cabin through the airflow, affecting the comfort and experience of the passengers in the cabin; second, the acoustic fatigue and structural vibration induced by propeller noise pose a great threat to flight safety; third, noise will affect the environment of the airport area. Therefore, under the premise that the aerodynamic performance of the propeller remains unchanged, reducing noise is crucial for both aircraft and propellers.

[0003] Among propeller aircraft with technical specifications of: maximum flight speed of 50m / s, maximum flight altitude of 5000m, and cruise efficiency of 83%, the minimum index of far-field noise in existing aircraft is 68dB, and the plane shape of its propeller blades can be seen. Figure 1 In order to further reduce far-field noise, the propeller blades need to be re-optimized and redesigned. Summary of the invention

[0004] The purpose of the present invention is to design a low-noise propeller to meet the conditions that the far-field noise is not greater than 66dB under the conditions of a maximum flight speed of 50m / s, a maximum flight altitude of 5000m and a cruising efficiency of 83%.

[0005] To solve this technical problem, the technical solution of the present invention is:

[0006] A low-noise propeller, the parameters of the low-noise propeller are as follows:

[0007] The number of propeller blades is 3; the propeller diameter is 1770-1970 mm; each section of the blade adopts the airfoil ARA-D; the chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions:

[0008] When the relative radius is 0.2, the sweep is 56-65 mm, the chord length is 135-140 mm, and the twist angle is 26°-31°;

[0009] When the relative radius is 0.25, the sweep is 55-62 mm, the chord length is 130-135 mm, and the twist angle is 22°-27°;

[0010] When the relative radius is 0.3, the sweep is 53-59 mm, the chord length is 126-131 mm, and the twist angle is 17°-22°;

[0011] When the relative radius is 0.45, the sweep is 48-53 mm, the chord length is 112-117 mm, and the twist angle is 8°-13°;

[0012] When the relative radius is 0.6, the sweep is 43-48 mm, the chord length is 98-103 mm, and the twist angle is 1°-6°;

[0013] When the relative radius is 0.7, the sweep is 39-44 mm, the chord length is 88-93 mm, and the twist angle is -3° to 3°;

[0014] When the relative radius is 0.8, the sweep is 33-39 mm, the chord length is 76-82 mm, and the twist angle is -5° to 0°;

[0015] When the relative radius is 0.9, the sweep is 26-32 mm, the chord length is 64-69 mm, and the twist angle is -8° to -3°;

[0016] When the relative radius is 0.95, the sweep is 21-26 mm, the chord length is 57-63 mm, and the twist angle is -9° to -4°;

[0017] When the relative radius is 0.975, the sweep is 18-23 mm, the chord length is 54-59 mm, and the twist angle is -10° to -5°;

[0018] The sweep is the distance from the axis to the leading edge.

[0019] Furthermore, the chord length, twist angle, and sweep value of each section under different relative radii satisfy the following conditions:

[0020] When the relative radius is 0.2, the sweep is 58-63 mm, the chord length is 136-139 mm, and the twist angle is 27°-30°;

[0021] When the relative radius is 0.3, the sweep is 54-58 mm, the chord length is 127-130 mm, and the twist angle is 18°-21°;

[0022] When the relative radius is 0.6, the sweep is 44-47 mm, the chord length is 99-102 mm, and the twist angle is 2°-5°;

[0023] When the relative radius is 0.7, the sweep is 40-43 mm, the chord length is 89-92 mm, and the twist angle is -2° to 2°;

[0024] When the relative radius is 0.8, the sweep is 34-38 mm, the chord length is 77-81 mm, and the twist angle is -4° to -1°;

[0025] When the relative radius is 0.9, the sweep is 27 to 31 mm, the chord length is 65 to 68 mm, and the twist angle is -7° to -4°.

[0026] Furthermore, the chord length, twist angle, and sweep value of each section under different relative radii satisfy the following conditions:

[0027] When the relative radius is 0.25, the sweep is 56-61 mm, the chord length is 131-134 mm, and the twist angle is 23°-26°;

[0028] When the relative radius is 0.45, the sweep is 49-52 mm, the chord length is 113-116 mm, and the twist angle is 9°-12°;

[0029] When the relative radius is 0.95, the sweep is 22-25 mm, the chord length is 58-62 mm, and the twist angle is -8° to -4°;

[0030] When the relative radius is 0.975, the sweep is 19 to 22 mm, the chord length is 55 to 58 mm, and the twist angle is -9° to -6°.

[0031] Furthermore, the chord length, twist angle, and sweep value of each section under different relative radii satisfy the following conditions:

[0032] When the relative radius is 0.2, the sweep is 59-62 mm, the chord length is 137-138 mm, and the twist angle is 28°-29°;

[0033] When the relative radius is 0.3, the sweep is 55-57 mm, the chord length is 128-129 mm, and the twist angle is 19°-20°;

[0034] When the relative radius is 0.6, the sweep is 45-46 mm, the chord length is 100-101 mm, and the twist angle is 3°-4°;

[0035] When the relative radius is 0.7, the sweep is 41-42 mm, the chord length is 90-91 mm, and the twist angle is -1° to 1°;

[0036] When the relative radius is 0.8, the sweep is 35-37 mm, the chord length is 78-80 mm, and the twist angle is -3° to -2°;

[0037] When the relative radius is 0.9, the sweep is 28 to 30 mm, the chord length is 66 to 67 mm, and the twist angle is -6° to -5°.

[0038] Furthermore, the chord length, twist angle, and sweep value of each section under different relative radii satisfy the following conditions:

[0039] When the relative radius is 0.25, the sweep is 58-60 mm, the chord length is 132-133 mm, and the twist angle is 24°-25°;

[0040] When the relative radius is 0.45, the sweep is 50-51 mm, the chord length is 114-115 mm, and the twist angle is 10°-11°;

[0041] When the relative radius is 0.95, the sweep is 23-24 mm, the chord length is 59-61 mm, and the twist angle is -7° to -6°;

[0042] When the relative radius is 0.975, the sweep is 20-21 mm, the chord length is 56-57 mm, and the twist angle is -8° to -7°.

[0043] Preferably, the chord length, twist angle, and sweep value of each section at different relative radii satisfy the following conditions:

[0044] When the relative radius is 0.2, the sweep is 61.77 mm, the chord length is 137.45 mm, and the twist angle is 28.95°;

[0045] When the relative radius is 0.3, the sweep is 56.36 mm, the chord length is 128.11 mm, and the twist angle is 19.96°;

[0046] When the relative radius is 0.6, the sweep is 45.70 mm, the chord length is 100.26 mm, and the twist angle is 3.29°;

[0047] When the relative radius is 0.8, the sweep is 36.12mm, the chord length is 78.99mm, and the twist angle is -2.72°.

[0048] When the relative radius is 0.25, the sweep is 58.84 mm, the chord length is 132.74 mm, and the twist angle is 24.19°;

[0049] When the relative radius is 0.45, the sweep is 50.65 mm, the chord length is 114.42 mm, and the twist angle is 10.02°;

[0050] When the relative radius is 0.7, the sweep is 41.63 mm, the chord length is 90.09 mm, and the twist angle is 0.00°;

[0051] When the relative radius is 0.9, the sweep is 28.44 mm, the chord length is 66.68 mm, and the twist angle is -5.23°.

[0052] When the relative radius is 0.95, the sweep is 23.56 mm, the chord length is 59.98 mm, and the twist angle is -6.52°;

[0053] When the relative radius is 0.975, the sweep is 20.83mm, the chord length is 56.49mm, and the twist angle is -7.19°.

[0054] The beneficial effect of the present invention is that the aerodynamic performance and noise level of the propeller are determined by the aerodynamic shape of the blade. To reduce the noise, the aerodynamic shape must be changed, and this change generally reduces the aerodynamic performance of the propeller. Therefore, it is difficult to reduce the noise of the propeller by 1 to 2 dB. The present invention reduces the noise by 2 dB, or 3%, while maintaining the aerodynamic performance of the propeller. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] In order to more clearly illustrate the technical solutions implemented in the present invention, the following is a brief explanation of the drawings required to be used in the examples of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0056] Figure 1 It is a schematic diagram of the plane shape of an existing propeller blade;

[0057] Figure 2 It is a schematic diagram of the plane shape of the propeller blade of the present invention. DETAILED DESCRIPTION

[0058] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. In each of the drawings and the following description, well-known structures and technologies are not shown to avoid unnecessary ambiguity of the present invention.

[0059] The number of propeller blades is 3; the propeller diameters are 1850mm, 1860mm, 1870mm, 1880mm, and 1890mm; each section of the blade adopts the airfoil ARA-D; after optimization, the following blade shapes are obtained:

[0060] The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions:

[0061] Table 1

[0062] Relative radius Sweep (distance from axis to leading edge) Chord Length Torsion Angle 0.2 61.77 137.45 28.95 0.25 58.84 132.74 24.19 0.3 56.36 128.11 19.96 0.45 50.65 114.42 10.02 0.6 45.70 100.26 3.29 0.7 41.63 90.09 0.00 0.8 36.12 78.99 -2.72 0.9 28.44 66.68 -5.23 0.95 23.56 59.98 -6.52 0.975 20.83 56.49 -7.19

[0063] Table 2

[0064]

[0065]

[0066] Table 3

[0067] Relative radius Sweep (distance from axis to leading edge) Chord Length Torsion Angle 0.2 62 138 29 0.25 59 133 25 0.3 57 129 20 0.45 51 115 11 0.6 46 101 4 0.7 42 91 1 0.8 37 79 -3 0.9 29 67 -6 0.95 24 60 -7 0.975 21 57 -8

[0068] Table 4

[0069] Relative radius Sweep (distance from axis to leading edge) Chord Length Torsion Angle 0.2 61.5 137.4 28.9 0.25 58.8 132.7 24.1 0.3 56.3 128.1 19.9 0.45 50.6 114.4 10.0 0.6 45.7 100.2 3.2 0.7 41.6 90.0 0.00 0.8 36.1 78.9 -2.7 0.9 28.4 66.6 -5.2 0.95 23.5 59.9 -6.5 0.975 20.8 56.4 -7.1

[0070] Table 5

[0071] Relative radius Sweep (distance from axis to leading edge) Chord Length Torsion Angle 0.2 61 138.4 28.1 0.25 59 133.7 24.2 0.3 56 129.1 18.9 0.45 51 115.4 11.0 0.6 45 101.2 4.2 0.7 42 91.0 1.00 0.8 36 79.9 -3.7 0.9 29 67.6 -6.2 0.95 24.5 60.9 -7.5 0.975 21.8 57.4 -8.1

[0072] Table 6

[0073] Relative radius Sweep (distance from axis to leading edge) Chord Length Torsion Angle 0.2 61.1 137.1 28.2 0.25 58.2 132.3 24.2 0.3 56.1 128.8 19.3 0.45 50.4 114.6 10.2 0.6 45.1 100.1 3.3 0.7 41.3 90.3 0.2 0.8 36.5 78.9 -2.3 0.9 28.7 66.1 -5.3 0.95 23.9 59.2 -6.4 0.975 20.1 56.1 -7.5

[0074] Table 7

[0075] Relative radius Sweep (distance from axis to leading edge) Chord Length Torsion Angle 0.2 61.9 138.1 27.2 0.25 58.7 133.3 25.1 0.3 55.7 129.2 18.8 0.45 48.6 115.4 11.1 0.6 43.7 101.1 2.1 0.7 43.6 91.1 0.2 0.8 37.1 79.2 -3.3 0.9 26.4 67.6 -4.9 0.95 25.5 58.2 -5.6 0.975 21.8 55.3 -6.8

[0076] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A low noise propeller, Features: The parameters of the low-noise propeller are as follows: The number of propeller blades is 3; the propeller diameter is 1770-1970 mm; each section of the blade adopts the airfoil ARA-D; the chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.2, the sweep is 56-65 mm, the chord length is 135-140 mm, and the twist angle is 26°-31°; When the relative radius is 0.25, the sweep is 55-62 mm, the chord length is 130-135 mm, and the twist angle is 22°-27°; When the relative radius is 0.3, the sweep is 53-59 mm, the chord length is 126-131 mm, and the twist angle is 17°-22°; When the relative radius is 0.45, the sweep is 48-53 mm, the chord length is 112-117 mm, and the twist angle is 8°-13°; When the relative radius is 0.6, the sweep is 43-48 mm, the chord length is 98-103 mm, and the twist angle is 1°-6°; When the relative radius is 0.7, the sweep is 39-44 mm, the chord length is 88-93 mm, and the twist angle is -3° to 3°; When the relative radius is 0.8, the sweep is 33-39 mm, the chord length is 76-82 mm, and the twist angle is -5° to 0°; When the relative radius is 0.9, the sweep is 26-32 mm, the chord length is 64-69 mm, and the twist angle is -8° to -3°; When the relative radius is 0.95, the sweep is 21-26 mm, the chord length is 57-63 mm, and the twist angle is -9° to -4°; When the relative radius is 0.975, the sweep is 18-23 mm, the chord length is 54-59 mm, and the twist angle is -10° to -5°; The sweep is the distance from the axis to the leading edge.

2. The low-noise propeller according to claim 1, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.2, the sweep is 58-63 mm, the chord length is 136-139 mm, and the twist angle is 27°-30°; When the relative radius is 0.3, the sweep is 54-58 mm, the chord length is 127-130 mm, and the twist angle is 18°-21°; When the relative radius is 0.6, the sweep is 44-47 mm, the chord length is 99-102 mm, and the twist angle is 2°-5°; When the relative radius is 0.7, the sweep is 40-43 mm, the chord length is 89-92 mm, and the twist angle is -2° to 2°; When the relative radius is 0.8, the sweep is 34-38 mm, the chord length is 77-81 mm, and the twist angle is -4° to -1°; When the relative radius is 0.9, the sweep is 27 to 31 mm, the chord length is 65 to 68 mm, and the twist angle is -7° to -4°.

3. The low noise propeller according to claim 1, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.25, the sweep is 56-61 mm, the chord length is 131-134 mm, and the twist angle is 23°-26°; When the relative radius is 0.45, the sweep is 49-52 mm, the chord length is 113-116 mm, and the twist angle is 9°-12°; When the relative radius is 0.95, the sweep is 22-25 mm, the chord length is 58-62 mm, and the twist angle is -8° to -4°; When the relative radius is 0.975, the sweep is 19 to 22 mm, the chord length is 55 to 58 mm, and the twist angle is -9° to -6°.

4. The low noise propeller according to claim 1, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.2, the sweep is 59-62 mm, the chord length is 137-138 mm, and the twist angle is 28°-29°; When the relative radius is 0.3, the sweep is 55-57 mm, the chord length is 128-129 mm, and the twist angle is 19°-20°; When the relative radius is 0.6, the sweep is 45-46 mm, the chord length is 100-101 mm, and the twist angle is 3°-4°; When the relative radius is 0.7, the sweep is 41-42 mm, the chord length is 90-91 mm, and the twist angle is -1° to 1°; When the relative radius is 0.8, the sweep is 35-37 mm, the chord length is 78-80 mm, and the twist angle is -3° to -2°; When the relative radius is 0.9, the sweep is 28 to 30 mm, the chord length is 66 to 67 mm, and the twist angle is -6° to -5°.

5. The low noise propeller according to claim 1, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.25, the sweep is 58-60 mm, the chord length is 132-133 mm, and the twist angle is 24°-25°; When the relative radius is 0.45, the sweep is 50-51 mm, the chord length is 114-115 mm, and the twist angle is 10°-11°; When the relative radius is 0.95, the sweep is 23-24 mm, the chord length is 59-61 mm, and the twist angle is -7° to -6°; When the relative radius is 0.975, the sweep is 20-21 mm, the chord length is 56-57 mm, and the twist angle is -8° to -7°.

6. The low noise propeller according to claim 1, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.2, the sweep is 61.77 mm, the chord length is 137.45 mm, and the twist angle is 28.95°; When the relative radius is 0.3, the sweep is 56.36 mm, the chord length is 128.11 mm, and the twist angle is 19.96°; When the relative radius is 0.6, the sweep is 45.70 mm, the chord length is 100.26 mm, and the twist angle is 3.29°; When the relative radius is 0.8, the sweep is 36.12mm, the chord length is 78.99mm, and the twist angle is -2.72°.

7. The low noise propeller according to claim 6, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.25, the sweep is 58.84 mm, the chord length is 132.74 mm, and the twist angle is 24.19°; When the relative radius is 0.45, the sweep is 50.65 mm, the chord length is 114.42 mm, and the twist angle is 10.02°; When the relative radius is 0.7, the sweep is 41.63 mm, the chord length is 90.09 mm, and the twist angle is 0.00°; When the relative radius is 0.9, the sweep is 28.44 mm, the chord length is 66.68 mm, and the twist angle is -5.23°.

8. The low noise propeller according to claim 7, Features: The chord length, twist angle, and sweep value of each section under different relative radii meet the following conditions: When the relative radius is 0.95, the sweep is 23.56 mm, the chord length is 59.98 mm, and the twist angle is -6.52°; When the relative radius is 0.975, the sweep is 20.83mm, the chord length is 56.49mm, and the twist angle is -7.19°.

Images