CN116522485A - Noise reduction propeller and optimization method - Google Patents

Noise reduction propeller and optimization method Download PDF

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Publication number
CN116522485A
CN116522485A CN202310422200.5A CN202310422200A CN116522485A CN 116522485 A CN116522485 A CN 116522485A CN 202310422200 A CN202310422200 A CN 202310422200A CN 116522485 A CN116522485 A CN 116522485A
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CN
China
Prior art keywords
propeller
tip
optimization method
noise
rear edge
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Pending
Application number
CN202310422200.5A
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Chinese (zh)
Inventor
马祥森
王宣博
刘亚姣
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Aerospace Times Feihong Technology Co ltd
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Aerospace Times Feihong Technology Co ltd
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Priority to CN202310422200.5A priority Critical patent/CN116522485A/en
Publication of CN116522485A publication Critical patent/CN116522485A/en
Pending legal-status Critical Current

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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/15—Vehicle, aircraft or watercraft design
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/10—Noise analysis or noise optimisation
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F2119/00—Details relating to the type or aim of the analysis or the optimisation
    • G06F2119/14—Force analysis or force optimisation, e.g. static or dynamic forces
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation

Abstract

The invention relates to a noise reduction propeller and an optimization method, belongs to the technical field of aircraft propellers, and can solve the problem that the propeller can be efficiently used only in plain or plateau single environments, and simultaneously solve the problem of larger noise generated by rotation of the propeller; the optimization method optimizes the shapes of the blade tip and the rear edge of the propeller so as to improve the distribution of aerodynamic load along the spanwise direction, thereby improving the aerodynamic efficiency of the propeller and avoiding noise peak areas; simultaneously optimizing the diameter of the propeller so as to avoid the resonant frequency of the structure; the shape of the rear edge of the propeller is saw-tooth type or sine type; the propeller tip is an elliptic propeller tip with smooth transition; the propeller diameter was 17in.

Description

Noise reduction propeller and optimization method
Technical Field
The invention relates to the technical field of aircraft propellers, in particular to a noise reduction propeller and an optimization method.
Background
The middle-sized and small-sized fixed wing unmanned aerial vehicle and the rotary wing unmanned aerial vehicle mostly adopt a propeller as a part of a power device. The propeller means a device which rotates in the air or water by means of blades and converts the rotational power of an engine or a generator into driving force or propulsive force, and can be provided with two or more blades connected with a hub, and the backward surface of the blade is a spiral surface or a propulsive structure similar to the spiral surface. In general, unmanned aerial vehicle screw load noise is great because of the rapid speed of the oar tip and the air current separation of oar face.
In the area with higher altitude, the air is thinner, so that the pulling force provided by the propeller is smaller under the same rotating speed, and under the same structural condition, the larger the diameter of the propeller is, the larger the linear speed is, the larger the generated acting force is, and the larger the pulling force is. In general, few propellers with high efficiency in the full-height envelope range of 0-5000 m can be satisfied under the condition of maintaining the structure unchanged.
Accordingly, there is a need to develop a noise reduction propeller and optimization method suitable for use in both plateau and plateau environments to address the deficiencies of the prior art, to address or mitigate one or more of the problems described above.
Disclosure of Invention
In view of the above, the invention provides a noise reduction propeller suitable for a plateau and a plateau environment and an optimization method, which can solve the problem that the propeller can be efficiently used only in the plateau or the plateau single environment, and simultaneously solve the problem of larger noise generated by rotation of the propeller.
In one aspect, the invention provides an optimization method of a noise reduction propeller, wherein the optimization method optimizes the shapes of a propeller tip and a rear edge of the propeller so as to improve the distribution of aerodynamic loads along a spanwise direction, thereby improving the aerodynamic efficiency of the propeller and avoiding noise peak areas; while the diameter of the propeller is optimized to avoid the resonant frequency of the structure.
In aspects and any one of the possible implementations described above, there is further provided an implementation in which the optimizing method optimizes the shape of the trailing edge of the propeller to be a zigzag or sinusoidal shape.
In aspects and any one of the possible implementations described above, there is further provided an implementation in which the zigzag or sinusoidal arrangement is located from 1/2 radius of the propeller to the tip of the propeller.
In accordance with the above aspect and any one of the possible implementations, there is further provided an implementation in which the optimization method optimizes the tip of the propeller from a sharp tip to a smoothly transitioned elliptical tip.
In another aspect, the invention provides a noise reduction propeller, wherein the diameter of the propeller is 17in, the shape of the rear edge of the propeller is saw-tooth or sine, and the propeller tip is an elliptic tip with smooth transition.
Aspects and any one of the possible implementations as described above, further provide an implementation, where the zigzag type is specifically: a plurality of inward depressions are arranged on a smooth boundary line of the rear edge of the propeller;
the number of the depressions is 8-13, and the depth of the depressions is not more than 10% of the cross-section chord length of the position.
Aspects and any one of the possible implementations as described above, further provide an implementation, where the sine type is specifically: setting the smooth boundary line of the rear edge of the propeller to be sine curve;
the period of the sinusoidal curve is 8-13, and the amplitude is not more than 10% of the section chord length of the position.
In aspects and any one of the possible implementations described above, there is further provided an implementation in which the zigzag or sinusoidal arrangement is located from 1/2 radius of the propeller to the tip of the propeller.
The aspects and any possible implementation as described above further provide an implementation in which the arc of the elliptical tip is 115-123 degrees.
In aspects and any one of the possible implementations described above, there is further provided an implementation in which the optimization method optimizes the propeller diameter to 17in.
The aspects and any possible implementation as described above further provide an implementation in which different sinusoids on the same propeller have the same or different periods and amplitudes.
The aspects and any possible implementation as described above further provide an implementation in which different recesses on the same propeller have the same or different depths.
Compared with the prior art, one of the technical schemes has the following advantages or beneficial effects: the invention optimizes the blade tip and the rear edge of the propeller at a typical rotating speed, can efficiently work within a full-height envelope of 0-5000 m, effectively reduces the sound pressure intensity, greatly reduces the noise and vibration of the whole machine, and increases the indexes such as the navigation time, the thrust-weight ratio, the maximum speed and the like of the system.
Of course, it is not necessary for any of the products embodying the invention to achieve all of the technical effects described above at the same time.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic view of a propeller assembly provided in one embodiment of the present invention;
FIG. 2 is a schematic view of an overall zigzag trailing edge propeller according to an embodiment of the present invention;
FIG. 3 is a schematic view of a zigzag trailing edge of a propeller provided in accordance with one embodiment of the present invention;
FIG. 4 is a schematic illustration of the sinusoidal trailing edge of a propeller provided by an embodiment of the present invention;
FIG. 5 is a graph showing the noise contrast before and after the trailing edge and tip optimization of a propeller provided by an embodiment of the present invention.
Detailed Description
For a better understanding of the technical solution of the present invention, the following detailed description of the embodiments of the present invention refers to the accompanying drawings.
It should be understood that the described embodiments are merely some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The invention designs an energy optimization method of an unmanned aerial vehicle power device based on tasks and environments for simultaneously adapting to plain and plateau environments, and continuously optimizes and iterates the energy of the power device according to control effects and environmental factors, so that the energy conversion efficiency of a motor and a propeller is obviously improved, and the system can reach an optimal working point on both plain and plateau.
On the premise of meeting the requirements of the external dimension constraint and aerodynamic characteristics of the unmanned aerial vehicle, the novel blade airfoil profile of the full-height envelope is designed, the blade tip and the rear edge part of the propeller are optimized, so that the distribution of aerodynamic load along the span-wise direction is improved, the small blade cuts the air sound, the aerodynamic efficiency of the propeller is improved, the noise peak area is avoided, and the optimal matching of the motor and the propeller in the full-height envelope range of 0-5000 m is realized; the diameter of the propeller can also be optimized so that it avoids the resonant frequency of the structure. The optimized propeller shape is shown in fig. 1 and 2.
Blade parameters are calculated based on momentum phyllin theory and propeller diameter is optimized. According to momentum theory, the speed increase at the paddle wheel is half the slip speed increase. The incoming speed of the propeller relative to the air flow through the propeller disk is greater than the speed V of the aircraft 0 . Let the slip speed increment be aV 0 The inflow velocity increment is xi aV 0 Then, the momentum theory is adopted to obtain:
dT＝2πρV 0 2 a(1+ξa)rdr
the axial velocity of the phyllanthin relative to the air flow is:
V＝V 0 +ξaV 0
the geometric synthesis speed of phyllin is as follows:
the included angle between the geometric synthesis speed and the rotation plane is as follows:
the angle of attack of the airflow relative to the phyllanthin is:
α＝θ-φ 0
phi is replaced by phi 0 V is used to replace V 0 From this, it is possible to:
T c '＝Kcos(φ+γ)
Q′ c ＝Krsin(φ+γ)
let the total number of blades of the propeller be N B The radius of the paddle hub is r 0 The integral along the spanwise direction is available:
the circumferential force of the propeller is:
the torque of the propeller is:
the propeller absorbs power as follows:
P w ＝2πn s M
the effective power of the propeller is as follows:
P e ＝TV 0
the propeller efficiency is:
the planar shape of the propeller is optimally modified, mainly for the tip and trailing edge portions of the propeller. Starting at the 1/2 radius of the propeller, and optimizing the trailing edge of the propeller to be saw-tooth or sine-shaped from the tip of the propeller.
As shown in fig. 3, the zigzag trailing edge means that the zigzag trailing edge is recessed inwards at a plurality of positions on the smooth boundary line of the propeller, the number of the concave points is selected by the combination of the diameter of the propeller and the chord length of the section, generally 8-13 concave points (preferably 10 concave points) are formed, and the depth of the concave points is not more than 10% of the chord length of the section (the chord length of the section means the width of the propeller where the concave points are formed); the concave shape may be triangular or rectangular with rounded corners, or any other smoothly transitioned shape. The depth of the different recesses on the same propeller may be different.
As shown in FIG. 4, the sine-shaped trailing edge is formed by modifying the smooth boundary line of the trailing edge of the propeller into a sine curve, wherein the cycle period of the curve is selected by the combination of the diameter of the propeller and the chord length of the section, and is generally 8-13 cycles (preferably 10 cycles), and the amplitude of the sine curve is not more than 10% of the chord length of the section. The sinusoids of the same propeller may be of different periods, different magnitudes.
In the above-described zigzag and sinusoidal trailing edge propellers, the tip is optimized from the originally sharper tip to an elliptical tip of about 120 (115-123) degrees of smooth transition.
Example 1: this embodiment is mainly directed to optimizing propeller diameter
Limited by the aircraft platform structure, the maximum selectable size of the propeller is 18in, the diameter of the propeller is optimized, and 15×5.1 (in), 16×5.4 (in), 17×5.8 (in) and 18×6.1 (in) propellers are designed and selected as analysis and comparison objects; in is inches.
The rotational speed, torque and power demand of the different diameter propellers at an altitude of 4500m were calculated and the results are shown in table 1:
table 1 results of propeller calculations
The comparison of the calculation results shows that: as the rotational speed of the propeller is lower with a larger diameter, less power is required, and at the same time, the torque is also larger, and the structural weight is also heavier.
The lower the rotational speed of the propeller, the lower the tip speed of the propeller, which is beneficial for reducing the flight noise of the platform, but the lower rotational speed will have an adverse effect on the flight control of the platform.
The torque of the propeller influences the matching design of the propeller and the motor, and the larger the torque is, the smaller the KV value of the motor is, the larger the internal resistance of the motor is, and the lower the efficiency is. Therefore, the torque of the propeller should not be too large, otherwise the design difficulty of matching the propeller with the motor is increased.
The smaller the required power of the propeller is, the higher the efficiency value of the propeller is under the condition of certain required pulling force.
In combination with the above, the aircraft platform chooses to use 17 x 5.8 (in) propellers, 17in being the optimal propeller diameter.
Example 2:
as shown in fig. 1, a propeller 1 is fixed to a motor 2 by a propeller blade and a screw 3. When a common propeller is used for flight test, the unmanned aerial vehicle respectively carries out 8m high hovering and 36km/h horizontal forward flying, the sound pressure measuring instrument is vertically arranged on the ground, the measuring port is opposite to the unmanned aerial vehicle, the maximum noise values in the two states are respectively measured, and the maximum noise values are converted into the noise values at the position of 1m according to an empirical formula, wherein the noise values are 83dB and 85dB respectively. When the optimized propeller with the zigzag trailing edge structure shown in the figure 3 is adopted, the noise value of the propeller is obviously reduced by 75dB compared with that of the original propeller, and the noise is obviously reduced. The common propeller is difficult to work efficiently in two environments under the same structure and pneumatic layout due to different air densities of a plateau and a plain, and the diameter and the wing profile of the propeller are optimized, so that the full-height applicability can be achieved, the torque and the power can be output efficiently under the drive of a motor, and the propeller can work efficiently on the plateau and the plain.
Example 3:
when a common propeller is in flight test, the unmanned aerial vehicle respectively carries out 8m high hovering and 36km/h horizontal forward flying, the sound pressure measuring instrument is vertically arranged on the ground, the measuring port is opposite to the unmanned aerial vehicle, the maximum noise values in two states are respectively measured, and the noise values at the position of 1m are respectively 83dB and 85dB according to the conversion of an empirical formula. The invention has the advantages that the noise value of the propeller at the rear edge of the sine structure shown in fig. 4 is about 74.5dB when the propeller has the same rotating speed of 3000RPM, and the noise is smaller than that of the original propeller at the rotating speed of 3000RPM, so that the system can reach the optimal working point on plain and plateau. Noise (sound level pressure) of different airfoil propellers at different rotating speeds is shown in fig. 5, noise of the optimized sawtooth type and sine type propellers is greatly lower than that of the original airfoil type, and therefore the noise of the optimized sawtooth type and sine type propellers can be obviously reduced by optimizing the rear edge and the tip of the propeller.
The noise reduction propeller and the optimization method suitable for the plateau and the plateau environment provided by the embodiment of the application are described in detail. The above description of embodiments is only for aiding in understanding the method of the present application and its core ideas; meanwhile, as those skilled in the art will have modifications in the specific embodiments and application scope in accordance with the ideas of the present application, the present description should not be construed as limiting the present application in view of the above.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or system that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or system. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or system comprising such elements. By "substantially" is meant that within an acceptable error range, a person skilled in the art is able to solve the technical problem within a certain error range, substantially achieving the technical effect.
The terminology used in the embodiments of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used in this application and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. In the present application, the terms "upper", "lower", "left", "right", "inner", "outer", "middle", and the like indicate an azimuth or a positional relationship based on the azimuth or the positional relationship shown in the drawings. In addition to the above terms may be used to denote orientation or positional relationships, other meanings may be used, such as the term "upper" may also be used in some cases to denote some sort of attachment or connection. The specific meaning of these terms in this application will be understood by those of ordinary skill in the art as appropriate. The term "and/or" as used herein is merely one association relationship describing the associated object, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.

Claims (10)

1. The optimization method is characterized by optimizing the shapes of the tip and the rear edge of the propeller so as to improve the distribution of aerodynamic loads along the spanwise direction, thereby improving the aerodynamic efficiency of the propeller and avoiding noise peak areas; while the diameter of the propeller is optimized to avoid the resonant frequency of the structure.
2. The optimization method of a noise reducing propeller according to claim 1, wherein the optimization method optimizes the shape of the trailing edge of the propeller to be a zigzag type or a sinusoidal type.
3. The optimization method of a noise reduction propeller according to claim 2, wherein the zigzag or sinusoidal arrangement position is from 1/2 radius of the propeller to the propeller tip.
4. The optimization method of a noise reduction propeller according to claim 1, wherein the optimization method optimizes the tip of the propeller from a sharp tip to a smoothly transitioned elliptical tip.
5. The noise reduction propeller is characterized in that the shape of the rear edge of the propeller is saw-tooth or sine, and the propeller tip is an elliptic propeller tip with smooth transition.
6. The noise reducing propeller of claim 5, wherein the zigzag pattern is specifically: a plurality of inward depressions are arranged on a smooth boundary line of the rear edge of the propeller;
the number of the depressions is 8-13, and the depth of the depressions is not more than 10% of the cross-section chord length of the position.
7. The noise reducing propeller of claim 5, wherein the sinusoidal shape is specifically: setting the smooth boundary line of the rear edge of the propeller to be sine curve;
the period of the sinusoidal curve is 8-13, and the amplitude is not more than 10% of the section chord length of the position.
8. The noise reducing propeller of claim 5, wherein the zigzag or sinusoidal arrangement is from 1/2 radius to tip of the propeller.
9. The noise reducing propeller of claim 5, wherein the arc of the elliptical tip is 115-123 °.
10. The method of optimizing a noise reducing propeller of claim 5, wherein the diameter of the propeller is 17in.
CN202310422200.5A 2023-04-19 2023-04-19 Noise reduction propeller and optimization method Pending CN116522485A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310422200.5A CN116522485A (en) 2023-04-19 2023-04-19 Noise reduction propeller and optimization method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310422200.5A CN116522485A (en) 2023-04-19 2023-04-19 Noise reduction propeller and optimization method

Publications (1)

Publication Number Publication Date
CN116522485A true CN116522485A (en) 2023-08-01

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ID=87393398

Family Applications (1)

Application Number Title Priority Date Filing Date
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Country Status (1)

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