CN109373399B - Broadband noise reduction method for range hood with noise interference device - Google Patents
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24C—DOMESTIC STOVES OR RANGES ; DETAILS OF DOMESTIC STOVES OR RANGES, OF GENERAL APPLICATION
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- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/161—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general in systems with fluid flow
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- G—PHYSICS
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- G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
- G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
- G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
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Abstract
A broadband noise reduction method for a range hood with a noise interference device is provided with a range hood main body and the noise interference device, wherein the noise interference device is assembled on the range hood main body. The noise interference device can be designed according to the frequency generated by the fan blade of the range hood to obtain the first main frequency f of the resonance frequency0,1A second main frequency f0,2First noise reduction subharmonic frequency fS1And a second noise-reduced subharmonic frequency fS2The noise interference device of (2), therefore, the noise interference device can cancel the noise having the same resonance frequency as the above-mentioned resonance frequency. Meanwhile, as the noise waves enter the noise interference device, interference waves with phase differences with the noise waves of the main air duct are formed after the noise waves leave the noise interference device, and the interference waves weaken or reduce the amplitude of the rest noise waves. Therefore, the noise interference device can reduce wide-frequency noise waves generated by the range hood and achieve the maximum broadband noise reduction effect.
Description
Technical Field
The invention relates to the field of range hoods, in particular to a broadband noise reduction method for a range hood with a noise interference device.
Background
The hearing of people is often damaged when the users are in a high-noise environment for a long time, and the emotional problems of the users are caused when the users are in the noise environment for a long time. Along with the improvement of the life quality of people, the tolerance of people to noise is lower and lower. Therefore, the noise reduction of the range hood is more and more emphasized.
Noise reduction of a range hood in the prior art is realized mostly by an active noise reduction mode and a passive noise reduction mode. The active noise reduction mode only can act on the noise with the frequency within 1000Hz, and the noise more than 1000Hz can be processed only by a passive noise reduction technology. Passive noise reduction, however, is primarily achieved by wrapping the noise source or duct with sound absorbing cotton. But has several disadvantages as follows: firstly, the air pressure loss is too large, noise and fluid need to penetrate through the sound absorption cotton, sound energy is lost by friction, the noise reduction effect is achieved, and meanwhile, the air performance is reduced. Secondly, it is difficult to select proper sound-absorbing cotton, and few supply factories can provide data of sound absorption rate of sound-absorbing cotton under different frequencies, so manufacturers of range hoods can only find out proper type or thickness of sound-absorbing cotton in continuous trial and error. Thirdly, the noise reduction frequency of the sound absorption cotton is uncontrollable, the common sound absorption cotton cannot achieve the maximum noise reduction effect under the specified narrow frequency, and different strategies cannot be mutually matched in design to effectively reduce noise.
Therefore, aiming at the defects of the prior art, it is necessary to provide a broadband noise reduction method for a range hood with a noise interference device to solve the defects of the prior art.
Disclosure of Invention
The invention aims to provide a broadband noise reduction method of a range hood with a noise interference device to avoid the defects of the prior art. The broadband noise reduction method of the range hood with the noise interference device can reduce specific multi-frequency noise to achieve broadband noise reduction.
The above object of the present invention is achieved by the following technical measures:
the range hood is provided with a range hood main body and a noise interference device, and the noise interference device is assembled on the range hood main body.
The resonance frequency of the noise interference device is overlapped with wide-frequency noise waves generated during the operation of the range hood.
Preferably, the noise interference device is provided with two openings which are respectively communicated with the main air duct of the cigarette machine main body and have different horizontal positions.
The wide-frequency noise waves are transmitted in the main air duct, and when encountering a noise interference device, the wide-frequency noise waves are divided into a first wide-frequency noise wave and a second wide-frequency noise wave, and the first wide-frequency noise wave is continuously transmitted in the main air duct; and the second path of wide-frequency noise wave enters the noise interference device, resonates with the noise interference device, and exits from one opening of the noise interference device and is converged into the main air duct.
After being converged into the main air duct, a first path of wide-frequency noise wave transmitted from the noise interference device has a phase difference with a second path of wide-frequency noise wave transmitted from the main air duct, the first path of wide-frequency noise wave and the second path of wide-frequency noise wave are interfered to form interference wide-frequency noise waves, and the amplitude of the interference wide-frequency noise waves relative to the wide-frequency noise waves is weakened and the noise is reduced.
Preferably, the resonance frequency is a first main frequency f0,1A second main frequency f0,2First noise reduction subharmonic frequency fS1And a second noise-reduced subharmonic frequency fS2。
A resonance frequency obtaining step of the noise interference device:
step one, obtaining the fan blade generation frequency f of the range hoodF；
Step two, generating frequency f according to the fan blade obtained in the step oneFDetermining a first main frequency f of a target noise reduction frequency of a noise interference device0,1；
Step three, according to the first main frequency f obtained in the step two0,1And then, according to the actual requirement, firstly setting the length L of a specific noise interference deviceaOr the shortest distance Δ L of two openings, and then determining the corresponding Δ L or LaAs a result, L needs to be satisfieda＞ΔL；
Step four, obtaining L according to the step threeaAnd Δ L, determining the noise interference device diameter C;
step five, according to L of step threeaAnd the value of delta L, and calculating to obtain a second main frequency f of the target noise reduction frequency of the noise interference device0,2；
Step six, according to the first main frequency f obtained in the step two0,1And the second main frequency f obtained in the fifth step0,2Calculating to obtain the first noise reduction subharmonic frequency f of the target noise reduction frequency of the noise interference deviceS1And a second noise-reduced subharmonic frequency fS2。
Preferably, the first step is specifically that the frequency f generated by the fan blade of the range hoodFObtained by the method of the formula (I),
fFβ Ψ ω formula (i),
where β is 1/60, Ψ is the number of blades of the fan blade, and ω is the rotational speed of the main blade.
Preferably, the second step is to generate the frequency f according to the fan blade obtained in the first stepFObtaining a first main frequency f of a target noise reduction frequency of the noise interference device by a formula (II)0,1，
f0,1＝d fFThe compound of the formula (II),
where d is a noise reduction weight factor and d is a positive number.
Preferably, in the third step, L is determined by formula (III)aAnd the value of al is calculated,
wherein t is the sound velocity, N is the subharmonic frequency multiple, and N is obtained by the formula (IV),
n ═ 2p +1)/2 formula (iv),
wherein p is a multiple weighting factor and p is 0 or any positive integer.
Preferably, the fourth step is specifically the L obtained according to the third stepaAnd Δ L, C is obtained by the formula (V),
preferably, the fifth step is specifically L according to the third stepaAnd the value of the sum delta L is obtained through the formula (VI), and the second main frequency f of the target noise reduction frequency of the noise interference device is obtained0，2，
Where k is the ratio of the multiples of the sub-harmonic frequency, and k is 2/3.
Preferably, in the sixth step, specifically,
step 6.1, obtaining the first main frequency f according to the step two0,1Obtaining target noise reduction frequency of noise interference device by formula (VII)First noise reduction subharmonic frequency fs1，
fs1＝[3f0,1,5f0,1,...........,xf0,1]The compound of the formula (VII),
wherein x is more than or equal to 2m +1, m is 1, 2, 3. -, ∞,
step 6.2, obtaining the second main frequency f according to the step five0,2Obtaining a second noise reduction subharmonic frequency f of the target noise reduction frequency of the noise interference device by the formula (VIII)s2，
fs2＝[2f0,2,3f0,2,...........,yf0,2]In the formula (VIII),
wherein y is more than or equal to 2.
Preferably, the noise interference device is provided in plurality.
Preferably, C is a single value or a plurality of values.
Preferably, L is as defined aboveaEither a single value or multiple values.
Preferably, Δ L is a single value or a plurality of values.
Preferably, the phase difference is 150 ° to 180 °.
The invention relates to a broadband noise reduction method of a range hood with a noise interference device. The resonance frequency of the noise interference device is overlapped with wide-frequency noise waves generated when the range hood runs. The noise interference device is provided with two openings which are respectively communicated with a main air duct of the cigarette machine main body, and the horizontal positions of the two openings are different. The noise interference device can be designed according to the frequency generated by the fan blade of the range hood to obtain the first main frequency f of the resonance frequency0,1A second main frequency f0,2First noise reduction subharmonic frequency fS1And a second noise-reduced subharmonic frequency fS2The noise interference device of (2), therefore, the noise interference device can cancel the noise having the same resonance frequency as the above-mentioned resonance frequency. Meanwhile, as the noise waves enter the noise interference device, interference waves with phase difference with the noise waves of the main air duct are formed after the noise waves leave the noise interference device, and the interference waves enable the noise waves to remainThe amplitude of the lower noise wave is reduced or decreased. Therefore, the noise interference device can reduce wide-frequency noise waves generated by the range hood and achieve the maximum broadband noise reduction effect.
Drawings
The invention is further illustrated by means of the attached drawings, the content of which is not in any way limiting.
Fig. 1 is a flow chart of a broadband noise reduction method of a range hood with a noise interference device according to the present invention.
Fig. 2 is a schematic structural view of the noise interference device and the main duct according to embodiment 1.
Fig. 3 is a schematic cross-sectional view of fig. 2.
FIG. 4 shows the length L of the noise interference deviceaSchematic representation of (a).
Fig. 5 is a schematic diagram of the shortest distance Δ L of two openings.
FIG. 6 is a schematic structural diagram of a noise interference device and a main air duct in embodiment 2.
In fig. 1 to 6, the following components are included:
noise interferes with the device 1 and the main duct 2.
Detailed Description
The technical solution of the present invention is further illustrated by the following examples.
Example 1.
A broadband noise reduction method for a range hood with a noise interference device comprises the range hood body and the noise interference device 1, wherein the noise interference device 1 is assembled on the range hood body.
The resonance frequency of the noise interference device 1 overlaps with wide frequency noise waves generated when the range hood is operated.
As shown in FIGS. 2 to 5, the noise interference device 1 is provided with two openings which are respectively communicated with the main duct 2 of the cigarette maker main body and have different horizontal positions as shown by K in FIG. 31K of2As shown.
The wide-frequency noise waves are transmitted in the main air duct, and when encountering the noise interference device 1, the wide-frequency noise waves are divided into a first wide-frequency noise wave and a second wide-frequency noise wave, and the first wide-frequency noise wave is continuously transmitted in the main air duct 2; the second path of wide-frequency noise wave enters the noise interference device 1, resonates with the noise interference device 1, and exits from one of the openings of the noise interference device and enters the main air duct 2.
After being converged into the main air duct, a first path of wide-frequency noise wave transmitted from the noise interference device 1 has a phase difference with a second path of wide-frequency noise wave transmitted from the main air duct 2, the first path of wide-frequency noise wave and the second path of wide-frequency noise wave interfere to form an interference wide-frequency noise wave, and the amplitude of the interference wide-frequency noise wave relative to the wide-frequency noise wave is weakened and the noise is reduced.
The resonance frequency being a first main frequency f0,1A second main frequency f0,2First noise reduction subharmonic frequency fS1And a second noise-reduced subharmonic frequency fS2。
A resonance frequency obtaining step of the noise interference device 1, as shown in fig. 1:
step one, acquiring the generation frequency f of a fan blade of a range hoodF；
Step two, generating frequency f according to the fan blade obtained in the step oneFObtaining a first main frequency f of a target noise reduction frequency of the noise interference device 10,1；
Step three, according to the first main frequency f obtained in the step two0,1And then, according to the actual requirement, firstly setting the length L of a specific noise interference deviceaOr the shortest distance Δ L of two openings, and then determining the corresponding Δ L or LaAs a result, L needs to be satisfieda＞ΔL；
Step four, obtaining L according to the step threeaAnd Δ L, determining the diameter C of the noise interference device 1;
step five, according to L of step threeaAnd the value of Delta L, calculating to obtain a second main frequency f of the target noise reduction frequency of the noise interference device 10,2；
Step six, according to the first main frequency f obtained in the step two0,1And the second main frequency f obtained in the fifth step0,2Calculating the first noise reduction subharmonic frequency f of the target noise reduction frequency of the noise interference device 1S1And a firstSecond noise reduction subharmonic frequency fS2。
Wherein the first step is specifically that the frequency f generated by the fan blade of the range hoodFObtained by the method of the formula (I),
fFβ Ψ ω formula (i),
where β is 1/60, Ψ is the number of blades of the fan blade, and ω is the rotational speed of the main blade.
Wherein the second step is specifically that the fan blade generation frequency f obtained according to the first stepFObtaining a first main frequency f of a target noise reduction frequency of the noise interference device 1 by formula (II)0,1，
f0,1＝d fFThe compound of the formula (II),
where d is a noise reduction weighting factor, and d is a positive number, d can be any positive number such as 0.1, 5, 10, 21, 10000, etc.
Wherein the third step is to determine L by the formula (III)aAnd the value of al is calculated,
wherein t is the sound velocity, N is the subharmonic frequency multiple, and N is obtained by the formula (IV),
n ═ 2p +1)/2 formula (iv),
wherein p is a multiple weighting factor, p is 0 or any positive integer, and p can be 0, 1, 2, …, 10000, ….
Wherein L isa＞ΔL。
It should be noted that, the present invention can set a specific L according to the actual requirementaOr Δ L, and then another value range can be obtained as long as L is satisfiedaMore than Delta L.
Wherein the fourth step is specifically that L obtained according to the third stepaAnd Δ L, C is obtained by the formula (V),
wherein the fifth step is specifically according to the stepL of IIIaAnd the value of Δ L is given by the formula (VI) to obtain the second main frequency f of the target noise reduction frequency of the noise interference device 10，2，
Where k is the ratio of the multiples of the sub-harmonic frequency, and k is 2/3.
Wherein the sixth step is specifically that,
step 6.1, obtaining the first main frequency f according to the step two0,1Obtaining a first noise-reduction subharmonic frequency f of a target noise-reduction frequency of the noise interference device 1 by the formula (VII)s1，
fs1＝[3f0,1,5f0,1,...........,xf0,1]The compound of the formula (VII),
wherein x is more than or equal to 2m +1, m is 1, 2, 3. -, ∞;
step 6.2, obtaining the second main frequency f according to the step five0,2The second noise-reduction subharmonic frequency f of the target noise-reduction frequency of the noise interference device 1 is obtained by the formula (VIII)s2，
fs2＝[2f0,2,3f0,2,...........,yf0,2]In the formula (VIII),
wherein y is more than or equal to 2.
It should be noted that the resonance frequency of the same noise interference device 1 is the first main frequency f0,1A second main frequency f0,2First noise reduction subharmonic frequency fs1And a second noise-reduced subharmonic frequency fs2. The noise interference device 1 of the invention therefore only needs to be based on the frequency f generated by the fan bladesFThe first main frequency f of the noise interference device 1 is obtained by calculation0,1Thereby obtaining L of the noise interference device 1aΔ L and C. When L isaΔ L and C, a second main frequency f of the noise interference device 1 is obtained0,2First noise reduction subharmonic frequency fs1And a second noise-reduced subharmonic frequency fs2The noise interference device can cancel the noise having the same resonance frequency as the above. At the same time becauseThe noise wave enters the noise interference device, and after the noise wave leaves the noise interference device, an interference wave with a phase difference with the noise wave of the main air duct is formed, and the amplitude of the rest noise wave is weakened or reduced by the interference wave. Therefore, the noise interference device can reduce wide-frequency noise waves generated by the range hood and achieve the maximum broadband noise reduction effect.
The noise wave of the range hood is mainly based on the frequency f generated by the fan bladeFThe frequency f is generated when the fan blade is operatedFThe inside of the range hood can generate resonance to form wide-frequency noise waves.
The noise reduction principle of the noise interference device 1 of the present invention is as follows: the noise interference device 1(Herschel-Quincke tube) achieves a sound reduction effect based on resonance and interference between sound waves. Because the noise interference device 1 has a plurality of resonance frequencies: first main frequency f0,1A second main frequency f0,2First noise reduction subharmonic frequency fs1And a second noise-reduced subharmonic frequency fs2. The wide-frequency noise waves generated by the range hood are transmitted in the main air duct 2, when encountering a noise interference device, the wide-frequency noise waves are divided into a first wide-frequency noise wave and a second wide-frequency noise wave, the first wide-frequency noise wave and the second wide-frequency noise wave are transmitted in the main air duct 2, and when encountering the noise interference device 1, the first wide-frequency noise wave is continuously transmitted in the main air duct 2. When the second channel width frequency noise wave has the first main frequency f0,1A second main frequency f0,2First noise reduction subharmonic frequency fs1And a second noise-reduced subharmonic frequency fs2And at the same or similar frequency, the second path of wide-frequency noise wave enters the noise interference device 1 and resonates with the noise interference device 1, and exits from one of the openings of the noise interference device 1 and enters the main air duct. After being converged into the main air duct 2, a first path of wide-frequency noise wave transmitted from the noise interference device 1 has a phase difference with a second path of wide-frequency noise wave transmitted by the main air duct 2, the first path of wide-frequency noise wave and the second path of wide-frequency noise wave interfere to form an interference wide-frequency noise wave, and the amplitude of the interference wide-frequency noise wave relative to the wide-frequency noise wave is weakened and the noise is reduced.
The invention carries out actual measurement of noise spectrum on the range hood with the noise interference device 1 obtained after calculation, for example, a noise collector is used for carrying out noise signal acquisition around the range hood, and the acquired real-time signal (time domain) is converted from the time domain to the frequency domain after fast Fourier conversion. A signal of the frequency spectrum is obtained in the frequency domain in order to decide whether the noise interference device 1 is to denoise all or a particular noise frequency. If the decibel value of a single frequency or a plurality of frequencies in the frequency spectrum is higher than 40dB, it indicates that the noise frequency is not eliminated or the elimination effect is not good, so that it is possible to increase a plurality of noise interference devices 1 or adjust L of the noise interference devices 1aAl and C are above the 40dB specific noise frequency for these decibel values.
The broadband noise reduction method of the range hood with the noise interference device comprises the range hood body and the noise interference device, wherein the noise interference device is assembled on the range hood body. The resonance frequency of the noise interference device is overlapped with wide-frequency noise waves generated when the range hood runs. The noise interference device is provided with two openings which are respectively communicated with a main air duct of the cigarette machine main body, and the horizontal positions of the two openings are different. The noise interference device can be designed according to the frequency generated by the fan blade of the range hood to obtain the first main frequency f of the resonance frequency0,1A second main frequency f0,2First noise reduction subharmonic frequency fS1And a second noise-reduced subharmonic frequency fS2The noise interference device of (2), therefore, the noise interference device can cancel the noise having the same resonance frequency as the above-mentioned resonance frequency. Meanwhile, as the noise waves enter the noise interference device, interference waves with phase differences with the noise waves of the main air duct are formed after the noise waves leave the noise interference device, and the interference waves weaken or reduce the amplitude of the rest noise waves. Therefore, the noise interference device can reduce wide-frequency noise waves generated by the range hood and achieve the maximum broadband noise reduction effect.
Example 2.
A broadband noise reduction method of a range hood with a noise interference device is shown in figure 6, and other characteristics are the same as those of embodiment 1, except that: the noise interference device 1 of the range hood of the present invention can also be provided in a plurality of numbers, such as 2, 4, 10, 500 or 10000, etc., and the specific noise interference device 1 is determined according to the actual situation. The embodiment is specifically 4.
The range hood of the present invention may have a single value or a plurality of values for C of the plurality of noise interference devices 1. L isaMay be a single value or may be a plurality of values. Δ L may be a single value or a plurality of values, specifically LaThe number of the sum Δ L values depends on the actual situation. L of the present embodimentaAnd Δ L have a plurality of different values, respectively.
In addition, the compound is represented by the formula (III)
It can be seen that for the same f0,1，LaAnd the values of al are not exclusive. That is to say for signals having the same first main frequency f0,1May also be different as long as L isaAnd Δ L satisfies the formula (III).
When L isaAnd Δ L having a plurality of different values, a first main frequency f of the plurality of noise interference devices 10,1Possibly different, when the first main frequency f0,1At different times, the second main frequency f0,2First noise reduction subharmonic frequency fs1And a second noise-reduced subharmonic frequency fs2And also different. The frequency range of the plurality of noise interference devices 1 is wider than that of embodiment 1, thereby achieving better broadband noise reduction.
Example 3.
A broadband noise reduction method of a range hood with a noise interference device is the same as that of embodiment 1 in other characteristics, and is different in that: l of the present embodimentaSpecifically 10cm,. DELTA.L specifically 3cm, and C0.18 cm.
The phase difference of the invention can be 150-180 degrees. The interference effect is best when the phase difference is 180 °.
Compared with embodiment 1, L of the noise interference device 1 of the present embodimentaDelta L, C, and a range hood equipped with the noise interference device 1 having excellent noise reduction performanceAnd (4) point.
Finally, it should be noted that the above embodiments are only used for illustrating the technical solutions of the present invention and not for limiting the protection scope of the present invention, and although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that modifications or equivalent substitutions can be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.
Claims (9)
1. A broadband noise reduction method of a range hood with a noise interference device is characterized in that: the range hood is provided with a range hood main body and a noise interference device, and the noise interference device is assembled on the range hood main body;
the resonance frequency of the noise interference device is overlapped with wide-frequency noise waves generated when the range hood operates;
the noise interference device is provided with two openings which are respectively communicated with a main air duct of the cigarette machine main body and have different horizontal positions;
the wide-frequency noise waves are transmitted in the main air duct, and when encountering a noise interference device, the wide-frequency noise waves are divided into a first wide-frequency noise wave and a second wide-frequency noise wave, and the first wide-frequency noise wave is continuously transmitted in the main air duct; the second path of wide-frequency noise wave enters the noise interference device, resonates with the noise interference device, and is discharged from one opening of the noise interference device and converged into the main air duct;
after being converged into the main air duct, a first path of wide-frequency noise wave transmitted from the noise interference device has a phase difference with a second path of wide-frequency noise wave transmitted from the main air duct, the first path of wide-frequency noise wave and the second path of wide-frequency noise wave are interfered to form interference wide-frequency noise waves, and the amplitude of the interference wide-frequency noise waves relative to the wide-frequency noise waves is weakened and the noise is reduced;
the resonance frequency is a first main frequency f0,1A second main frequency f0,2First noise reduction subharmonic frequency fS1And a second noise-reduced subharmonic frequency fS2；
The resonance frequency of the noise interference device is obtained by the following steps:
step one, obtaining the fan blade generation frequency f of the range hoodF；
Step two, generating frequency f according to the fan blade obtained in the step oneFDetermining a first main frequency f of a target noise reduction frequency of a noise interference device0,1；
Step three, according to the first main frequency f obtained in the step two0,1And then, according to the actual requirement, firstly setting the length L of a specific noise interference deviceaOr the shortest distance Δ L of two openings, and then determining the corresponding Δ L or LaAs a result, L needs to be satisfieda＞ΔL；
Step four, obtaining L according to the step threeaAnd Δ L, determining the noise interference device diameter C;
step five, according to L of step threeaAnd the value of delta L, and calculating to obtain a second main frequency f of the target noise reduction frequency of the noise interference device0,2；
Step six, according to the first main frequency f obtained in the step two0,1And the second main frequency f obtained in the fifth step0,2Calculating to obtain the first noise reduction subharmonic frequency f of the target noise reduction frequency of the noise interference deviceS1And a second noise-reduced subharmonic frequency fS2。
2. The broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the first step is specifically that the frequency f generated by the fan blade of the range hoodFObtained by the method of the formula (I),
fFβ Ψ ω formula (i),
where β is 1/60, Ψ is the number of blades of the fan blade, and ω is the rotational speed of the main blade.
3. The broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the second step is specifically that the fan blade generation frequency f obtained according to the first stepFObtaining a first main frequency f of a target noise reduction frequency of the noise interference device by a formula (II)0,1，
f0,1＝dfFThe compound of the formula (II),
where d is a noise reduction weight factor and d is a positive number.
4. The broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the third step is specifically that the first step is,
determination of L by the formula (III)aAnd the value of al is calculated,
wherein t is the sound velocity, N is the subharmonic frequency multiple, and N is obtained by the formula (IV),
n ═ 2p +1)/2 formula (iv),
wherein p is a multiple weighting factor and p is 0 or any positive integer.
5. The broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the fourth step is specifically to obtain L according to the third stepaAnd Δ L, C is obtained by the formula (V),
6. the broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the fifth step is specifically according to L of the third stepaAnd the value of the sum delta L is obtained through the formula (VI), and the second main frequency f of the target noise reduction frequency of the noise interference device is obtained0，2，
Where k is the ratio of the multiples of the sub-harmonic frequency, and k is 2/3.
7. The broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the sixth step is specifically that,
step 6.1, obtaining the first main frequency f according to the step two0,1Obtaining a first noise reduction subharmonic frequency f of a target noise reduction frequency of the noise interference device through a formula (VII)s1，
fs1＝[3f0,1,5f0,1,...........,xf0,1]The compound of the formula (VII),
wherein x is more than or equal to 2m +1, m is 1, 2, 3. -, ∞;
step 6.2, obtaining the second main frequency f according to the step five0,2Obtaining a second noise reduction subharmonic frequency f of the target noise reduction frequency of the noise interference device by the formula (VIII)s2，
fs2＝[2f0,2,3f0,2,...........,yf0,2]In the formula (VIII),
wherein y is more than or equal to 2.
8. The broadband noise reduction method of a range hood with a noise interference device according to claim 5, wherein: the noise interference device is provided with a plurality of noise interference devices;
c is a single value or a plurality of values;
said LaA single value or multiple values;
the Δ L is a single value or a plurality of values.
9. The broadband noise reduction method of a range hood with a noise interference device according to claim 1, wherein: the phase difference is 150-180 degrees.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201811420947.2A CN109373399B (en) | 2018-11-27 | 2018-11-27 | Broadband noise reduction method for range hood with noise interference device |
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