CN103438024A - Small-sized axial flow fan with blades distributed non-uniformly - Google Patents
Small-sized axial flow fan with blades distributed non-uniformly Download PDFInfo
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- CN103438024A CN103438024A CN2013102786828A CN201310278682A CN103438024A CN 103438024 A CN103438024 A CN 103438024A CN 2013102786828 A CN2013102786828 A CN 2013102786828A CN 201310278682 A CN201310278682 A CN 201310278682A CN 103438024 A CN103438024 A CN 103438024A
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Abstract
The invention discloses a kind of small axial flow fans of blade non-uniform Distribution. Though existing fan is relatively good, the noise problem of fan radiation must still be solved. The present invention includes casing, blade, wheel hub, motor, fixed frame, and fixed frame is fixed in casing, and wheel hub is connected to the motor by rotary shaft and is connect, and motor is fixed on fixed frame, and blade is circumferentially mounted on wheel hub to irregular pitch; The irregular pitch distribution of blade is modulated using sinusoidal frequency, and it is as follows that sinusoidal frequency modulates formula:
Wherein, Φ i indicates equal pitch fan i-th blade in the circumferential angle of impeller, and Φ ' i indicates irregular pitch fan i-th blade in the circumferential angle of wheel hub, and A is modulated amplitude, n is the cycle-index of modulation, and the circumferential angle change range of irregular pitch fan is -9.75 °~9.75 °. Economic, environmental protection of the invention and effective noise reduction.
Description
Technical field
The invention belongs to radiation fan noise reduction technology field, relate in particular to a kind of small axial flow fan of blade non-uniform Distribution.
Background technique
Small axial flow fan is easy to use, cost is low, is widely used in civilian and commercial heat dissipation ventilation.In recent years, due to the develop rapidly of computer industry and the raising of people's living standard, high-performance, low noise small axial flow fan become the first-selection of heat radiation, the noise of fan can be divided into discrete and broadband noise from the angle of noise frequency, and the control of noise is generally considered from three angles: the first is set about from the noise reduction sound source; It two is from the propagation of noise way, utilizes silencing apparatus or sound arrester noise reduction; It three is to set about from the noise recipient, and it is protected.The air power noise that fan blade produces is far longer than mechanical noise and the electromagnetic noise of blower fan, if can be by improving fan inlets and putlets of ventilation and blade structure, can reduce significantly the noise of fan radiation, and the noise reduction of trying every possible means from the blade aspect there are very large research and application prospect.So some methods that blade is processed occurred, common are: blade perforation reduce fan eddy current crack, adopt the sweepforward blade to reduce noise, the cutting of plate blade suction surface to reduce noise, adopt softly to go out limit and reduce small flow district noise etc., wherein, adopting not equidistant non-uniform Distribution blade is also a kind of noise reduction measure.What the blade of traditional small axial flow fan adopted is to be uniformly distributed, and the discrete noise peak value that such form fan produces is larger, by changing the distribution form of blade, adopts the irregular pitch non-uniform Distribution can effectively reduce the noise figure of fan.
Summary of the invention
The objective of the invention is for the deficiencies in the prior art, a kind of small axial flow fan of blade non-uniform Distribution is provided, by adopting the method for sinusoidal frequency modulation, the distribution form that changes blade is designed a kind of microminiature axial fan of irregular pitch non-uniform Distribution structure, reduces the noise at fan fundamental frequency and harmonic wave place.
The present invention includes casing, blade, wheel hub, motor, fixing frame, fixing frame is fixed in casing, and wheel hub is connected with motor by running shaft, and motor is fixed on fixing frame, and blade along circumferentially being arranged on wheel hub irregular pitch.
The irregular pitch of blade distributes and adopts the sinusoidal frequency modulation, and sinusoidal frequency modulation formula is as follows:
Wherein, Φ
imean the circumferential angle of i blade of equal pitch fan at impeller, Φ '
imean the circumferential angle of i blade of irregular pitch fan at wheel hub, A is modulated amplitude, and n is the cycle-index of modulation, and the circumferential angle of irregular pitch fan (being non-uniformity) excursion is-9.75 °～9.75 °.
The size of modulated amplitude A has determined the size that the circumferential angle of blade changes, it is the degree of blade uneven distribution, the A value conference reduce the acting ability of fan blade to gas, therefore need consider and guarantee under the influenced little prerequisite of small-sized fans aeroperformance institute this Sine Modulated mode of the employing blade that distributes.In the modulation system that the present invention adopts, research shows, some fans of 7 blades, work as A=5, and during n=1, the circumferential angle excursion of irregular pitch fan is-4.87 °～4.87 °, now the fundamental frequency place noise figure of the fan 1-2dB that descended; Work as A=10, during n=2, the circumferential angle excursion of irregular pitch fan is-9.75 °～9.75 ° now fundamental frequency place noise figure of the fan 1～3dB that descended.These two kinds of modulation systems, the static pressure of fan under design conditions rises all substantially constant.For this fan result of study demonstration of 7 blades, it is a scope preferably that circumferential angle changes-9.75 °～9.75 °, in this restriction range, can select the Leaf positional distribution mode an of the best by the different values of brew cycle frequency n.
The present invention for applicable object be small axial flow fan, adopt the Sine Modulated distribution mode to implement the uneven distribution of blade, the number of blade according to fan self, determine the circumferential angle excursion of each blade by modulated amplitude A, and by change modulates in proper order frequency n specifically be chosen in the circumferential angle of the best of the blade within excursion.
Beneficial effect of the present invention is as follows:
The present invention is mainly that the mounting type to blade changes, inhomogeneous a week of being distributed in wheel hub by fan blade, after blade irregular pitch non-uniform Distribution, distance between each blade does not wait, broken its periodic regularity, the equal pitch fan unicuspid peak value all occurs at fundamental frequency and harmonic wave place, and less peak value appears in the irregular pitch fan near fundamental frequency place and harmonic wave place and harmonic wave thereof, the irregular pitch fan scatters noise peak neighbouring in wider frequency band, thus the whole noise that has reduced fan.After deliberation, adopt the noise figure integral body of the fan of irregular pitch Leaf positional distribution to descend 1～3 decibel.Adopting irregular pitch blade non-uniform Distribution is a kind of effective small axial flow fan noise reduction measure.
The accompanying drawing explanation
Fig. 1 is fan scheme of installation of the present invention;
Fig. 2 is the noise pattern of prototype fan;
Fig. 3 is the noise pattern of fan of the present invention;
Fig. 4 is the circumferential angle figure of fan blade of the present invention at wheel hub.
In figure, casing 1, blade 2, wheel hub 3, motor 4, fixing frame 5.
Embodiment
Below in conjunction with accompanying drawing, the invention will be further described.
As shown in Figure 1, a kind of small axial flow fan of blade non-uniform Distribution, comprise casing 1, blade 2, wheel hub 3, motor 4, fixing frame 5, fixing frame 5 is fixed in casing 1, wheel hub 3 is connected with motor 4 by running shaft, motor 4 is fixed on fixing frame 5, and blade 2 along circumferentially being arranged on wheel hub 3 irregular pitch.
The irregular pitch of blade 2 distributes and adopts the sinusoidal frequency modulation, and sinusoidal frequency modulation formula is as follows:
Wherein, Φ
imean the circumferential angle of i blade of equal pitch fan impeller (being the general designation of blade and wheel hub), Φ '
imean the circumferential angle of i blade of irregular pitch fan at wheel hub 3, specifically can be with reference to Fig. 4, A is modulated amplitude, n is the cycle-index of modulation, and the circumferential angle of irregular pitch fan (being non-uniformity) excursion is-9.75 °～9.75 °.
When circumferentially angle changes in this scope, the fan that the aeroperformance of fan compares to the distribution of blade equal pitch changes little.When the blade equal pitch distributes, rotation blade periodically hits air particle, causes air circle pressure pulsation and produces the crest frequency noise of series of discrete; After blade adopts irregular pitch to distribute, the distance between each blade does not wait, and has broken its periodic regularity; As shown in Figure 2 and Figure 3, the equal pitch fan unicuspid peak value all occurs at fundamental frequency and harmonic wave place, and near the peak value that the irregular pitch fan occurs fundamental frequency place, harmonic wave place and harmonic wave thereof is less than the unicuspid peak value, and near the irregular pitch fan scatters noise peak in wider frequency band, on the whole by the reducing noise of fan 1-3dB.Specifically can be with reference to table 1.
The circumferential angle that table 1 is irregular pitch non-uniform Distribution fan and ricing scope
Process of the present invention is as follows:
Gas axially enters impeller from intake grill, because after fan blade of the present invention adopts irregular pitch to distribute, each blade is inconsistent along the circumferential angular distribution of circumference, the periodicity time lag of each blade cuts air-flow is also unequal, therefore the noise component and the frequency that produce are all incomplete same, therefore can avoid the noise stack of identical composition and frequency and the resonance peak that brings.Thereby reduced the blade frequencies noise.
Those skilled in the art it should be understood that can carry out various improvement and change to this invention in the situation that do not break away from summary of the invention.Therefore according to technical spirit of the present invention, simple modification made for the present invention and various similar changes and improvements, within all should belonging to the technology of the present invention scope.
Claims (2)
1. the small axial flow fan of a blade non-uniform Distribution, comprise casing, blade, wheel hub, motor, fixing frame, it is characterized in that:
Fixing frame is fixed in casing, and wheel hub is connected with motor by running shaft, and motor is fixed on fixing frame, and blade along circumferentially being arranged on wheel hub irregular pitch;
The irregular pitch of described blade distributes and adopts the sinusoidal frequency modulation, and sinusoidal frequency modulation formula is as follows:
Wherein, Φ
imean the circumferential angle of i blade of equal pitch fan at impeller, Φ '
imean the circumferential angle of i blade of irregular pitch fan at wheel hub, A is modulated amplitude, and n is the cycle-index of modulation.
2. the small axial flow fan of a kind of blade non-uniform Distribution as claimed in claim 1, it is characterized in that: by the different values of brew cycle frequency n, the circumferential angle of irregular pitch fan (being non-uniformity) excursion is-9.75 °～9.75 °.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2013102786828A CN103438024A (en) | 2013-07-03 | 2013-07-03 | Small-sized axial flow fan with blades distributed non-uniformly |
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| Application Number | Priority Date | Filing Date | Title |
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| CN2013102786828A CN103438024A (en) | 2013-07-03 | 2013-07-03 | Small-sized axial flow fan with blades distributed non-uniformly |
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| CN103438024A true CN103438024A (en) | 2013-12-11 |
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| CN2013102786828A Pending CN103438024A (en) | 2013-07-03 | 2013-07-03 | Small-sized axial flow fan with blades distributed non-uniformly |
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104832459A (en) * | 2014-02-10 | 2015-08-12 | 珠海格力电器股份有限公司 | Fan and air conditioner comprising fan |
| CN105782090A (en) * | 2016-04-26 | 2016-07-20 | 浙江理工大学 | Noise-lowering and vortex-reducing axial flow fan |
| CN115523186A (en) * | 2022-11-28 | 2022-12-27 | 佛山市南海九洲普惠风机有限公司 | Non-uniform distribution modulation method for blades, impeller and centrifugal fan |
| TWI825681B (en) * | 2022-04-19 | 2023-12-11 | 宏碁股份有限公司 | Centrifugal heat dissipation fan |
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| US5131604A (en) * | 1991-04-11 | 1992-07-21 | United Technologies Corporation | Helicopter antitorque device |
| US5306119A (en) * | 1992-03-24 | 1994-04-26 | Kawasaki Jukogyo Kabushiki Kaisha | Ducted tail rotor for rotor craft |
| CN1121020A (en) * | 1994-05-04 | 1996-04-24 | 法兰西欧洲科普特公司 | Counter-torque device with ducted rotor and phase modulation of the baldes, for helicopter |
| CN1126157A (en) * | 1994-05-04 | 1996-07-10 | 法兰西欧洲科普特公司 | Counter-torque device with rotor and flow-straight ening stator, both of which are ducted, and phase modulation of the blades of the rotor, for helicop |
| CN203384102U (en) * | 2013-07-03 | 2014-01-08 | 浙江理工大学 | Small axial flow fan with non-uniformly distributed blades |
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2013
- 2013-07-03 CN CN2013102786828A patent/CN103438024A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4585391A (en) * | 1982-10-06 | 1986-04-29 | Societe Nationale Industrielle Et Aerospatiale | Tail rotor arrangement with increased thrust for rotary wing aircraft and device for increasing the thrust of such an arrangement |
| US5131604A (en) * | 1991-04-11 | 1992-07-21 | United Technologies Corporation | Helicopter antitorque device |
| US5306119A (en) * | 1992-03-24 | 1994-04-26 | Kawasaki Jukogyo Kabushiki Kaisha | Ducted tail rotor for rotor craft |
| CN1121020A (en) * | 1994-05-04 | 1996-04-24 | 法兰西欧洲科普特公司 | Counter-torque device with ducted rotor and phase modulation of the baldes, for helicopter |
| CN1126157A (en) * | 1994-05-04 | 1996-07-10 | 法兰西欧洲科普特公司 | Counter-torque device with rotor and flow-straight ening stator, both of which are ducted, and phase modulation of the blades of the rotor, for helicop |
| CN203384102U (en) * | 2013-07-03 | 2014-01-08 | 浙江理工大学 | Small axial flow fan with non-uniformly distributed blades |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104832459A (en) * | 2014-02-10 | 2015-08-12 | 珠海格力电器股份有限公司 | Fan and air conditioner comprising fan |
| CN104832459B (en) * | 2014-02-10 | 2018-01-02 | 珠海格力电器股份有限公司 | A kind of fan and the air-conditioning including the fan |
| CN105782090A (en) * | 2016-04-26 | 2016-07-20 | 浙江理工大学 | Noise-lowering and vortex-reducing axial flow fan |
| TWI825681B (en) * | 2022-04-19 | 2023-12-11 | 宏碁股份有限公司 | Centrifugal heat dissipation fan |
| CN115523186A (en) * | 2022-11-28 | 2022-12-27 | 佛山市南海九洲普惠风机有限公司 | Non-uniform distribution modulation method for blades, impeller and centrifugal fan |
| CN115523186B (en) * | 2022-11-28 | 2023-01-31 | 佛山市南海九洲普惠风机有限公司 | Non-uniform distribution modulation method for blades, impeller and centrifugal fan |
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Application publication date: 20131211 |