CN105697394A - Micro-miniature efficient outlet flow field distortionless centrifugal fan - Google Patents

Abstract

The invention discloses a micro-miniature efficient outlet flow field distortionless centrifugal fan. The micro-miniature efficient outlet flow field distortionless centrifugal fan comprises blades (1), a wheel disc (2), a volute (3), a motor (4), a volute distortion calibration extension segment (5), a flowing mixing segment (6) and arc flow guide plates (7); the blades (1) are evenly fixed to the circumference of the wheel disc (2) and are driven by the motor (4) to rotate, and exterior air is sucked into an impeller; and gas flows in the volute (3) under the effect of centrifugal force, passes through the volute distortion calibration extension segment (5), is properly mixed in the flowing mixing segment (6) and is guided by the arc flow guide plates (7) to flow out of the fan. The micro-miniature efficient outlet flow field distortionless centrifugal fan has the beneficial effects that unevenness of the speed of an outlet of the micro-miniature centrifugal fan is removed, the more efficient environment is provided for radiator work, on the premise of ensuring the flow and efficiency, the thickness of the fan is reduced, and the application site of an attaching body or close body is facilitated.

Description

The efficient exit flow field of microminiature is undistorted centrifugal blower

Technical field

The present invention relates to ventilation, heat radiation and refrigerating field, in particular a kind of Miniature temperature controls ventilating system。

Background technology

Fig. 2 is conventional centrifugal blower fan sketch, and centrifugal blower is the principle being converted to potential energy according to kinetic energy, utilizes the impeller of high speed rotating to be accelerated by gas, and then slowing down to change flows to, and makes kinetic energy be converted to potential energy (pressure)。In one-stage centrifugal blower fan, gas is from axially into impeller, and gas is radially redirected when flowing through impeller, subsequently into diffuser。In diffuser, gas and changing flow direction causes deceleration, and this decelerating effect converts kinetic energy into pressure energy。Centrifugal fan device is applied to heat radiation refrigerating field a lot, and correlation technique and patent documentation show, distorts but without good solution for centrifugal blower output flow。

The shortcoming that existing centrifugal blower exists is as follows:

1. in blower fan there is distortion in air velocity in outlet；

2. three-dimensional blade profile is excessively simple, there are flow losses；

3. centrifugal blower is used in the electronic equipment of the narrow space such as server, air-conditioned seat, and the thickness of common centrifugal blower is relatively big, is taken up space more。

Therefore, prior art existing defects, it is necessary to improve。

Summary of the invention

The technical problem to be solved is to provide a kind of microminiature undistorted centrifugal blower of efficient exit flow field for the deficiencies in the prior art。

Technical scheme is as follows:

A kind of microminiature undistorted centrifugal blower of efficient exit flow field, including spiral case, is positioned at the motor at spiral case center, the wheel disc being arranged on motor output shaft, the blade that is uniformly distributed circumferentially on wheel disc；It is characterized in that:

Above-mentioned blade is blade of cutting sth. askew, described in blade of cutting sth. askew refer to that the leaf top leading edge of blade is chamfered, the 1/4～1 of leaf top excision vane overall length degree, the 1/8～1/2 of blade inlet edge excision blade total height；

Above-mentioned volute outlet connects spiral case distortion correction extension by the tangent mode that seamlessly transits；Spiral case distortion correction extension connects flowing blending section by the tangent mode that seamlessly transits, and spiral case distortion correction extension outlet is angled for 75-85 ° with volute outlet cross section institute, and flowing blends section and volute outlet cross section institute is angled for 100-110 °；

Above-mentioned flowing blends the outlet of section and has been evenly arranged 2-3 arc deflector；The radian of described arc deflector blends the outer side surface radian of section correspondence position and keeps consistent with described flowing；Definition arc deflector front end and rear end: defining according to air current flow direction, the end face that air-flow first passes through is front end, after through end face be rear end；After above-mentioned arc deflector is uniformly distributed along the outer side surface radian direction of correspondence position, the arc deflector being positioned at inner side keeps back-end location constant, and front end is deflection 10-14 ° to the inside again。

The operation logic of the efficient exit flow field of described microminiature is undistorted centrifugal blower is similar with common blower fan, under the drive of motor, wheel disc be distributed in blade thereon together high speed rotating, space in the middle part of blade with wheel disc is formed low pressure, air pressure outside centrifugal blower is higher, therefore air is pressed into the space in the middle part of wheel disc and is subject to the effect of centripetal force and rotates together with, and past the blades into spiral case, obtains the purpose that speed reaches to ventilate under the effect rotated。

Described blade of cutting sth. askew, in the spiral case that blade is not cut sth. askew, static pressure has large-area low-pressure area in the position that spiral case is connected with extension, there is mass air flow to walk around this panel region and flow to outlet, only minority of fluid flows through herein, make the uneven easy formation eddy current of barometric gradient of this panel region, reduce the static pressure of outlet。After blade is chamfered, owing to leaf road length shortens, friction loss suffered by air-flow declines, the higher static energy that air-flow obtains is made to maintain a segment distance at Ye Daozhong, the centrifugal blower high-pressure area installing blade of cutting sth. askew is bigger, therefore blade of cutting sth. askew improves the static pressure of centrifugal blower, improves the performance of centrifugal blower。

Described distortion correction extension and flowing blend section, although the distortion that main effect is the spiral case externally sidewind of only spiral case distortion correction extension improves serves certain effect, but for fluid inside, still much larger than outside, the interpolation of this section of spiral case inlet pressure, changes the direction of its outlet, and therefore fluid will carry out a degree of blending in this segment type line spiral case, reduce velocity gradient, reach the purpose of even speed size；Change fluid flow out the direction of centrifugal blower it addition, flowing blend section, it does not have the crowded phenomenon of flowing occurs, thus Way out choose the realization being conducive to streamline uniformity。Fluid is after entering in newly added molded line spiral case, mutually extrude between fluid and the fluid of close snail tongue side outside spiral case, originally the fluid inside that energy is higher transfers energy to the fluid that outside energy is relatively low, fluid inside speed reduces, lateral fluid speed rises, it is achieved that the uniformity of velocity magnitude。Meanwhile, streamline becomes linearly flowing from the turning flowing of the original port of export due to runner, and the impact by volute shape of flowing tends towards stability, so the phenomenon of extruding mutually also disappears between streamline, it is achieved that the uniformity in fluid velocity direction。

Described arc deflector, is arranged in flow field and has the function guiding fluid flowing。When fluid flows through deflector, the effect being subject to deflector shape forces flowing, deflector be arranged under the premise meeting flow field fluid flow inside rule, it is possible to strengthen internal flow stability, the stability of flowing can be broken when not meeting flow field internal flow rule, play the effect of flow-disturbing。With shell relatively, arc shape keeps consistent with the direction of streamline to the shape of outboard diversion plate camber line substantially, and flowing is not resulted in too much influence by therefore identical with shell maintenance yawing moment；The position of inner side deflector then needs to determine according to flow regime。Arc deflector front end speed increases, and rear end speed reduces, and makes the state parameter between each several part fluid more uniform。

Beneficial effects of the present invention:

1. devise novel volute of blower, and deflector is set in volute of blower, change the direction of flowing outlet and arrive the speed distortion that elimination fluid produces at fan outlet place, providing more efficient environment for radiator work；

2. blade has been carried out machining so that it is blade profile more meets the rule of fluid flowing in flow field, and compared to former blower fan, flow improves 2%, greatly reduces flow losses；

3. the molded line of pair blower fan and blade have carried out three dimensional design, under ensureing the premise of flow and efficiency, reduce the thickness of blower fan so that it is can use in more broadly field, be conducive to the application scenario of fit or near body。

Described blade and blade top leading edge is chamfered, and starts, downwardly toward blade inlet edge, to be switched to the 1/8 of blade inlet edge and this effect can be made to reach optimum from leaf top tail end。

Described spiral case distortion correction extension outlet and volute outlet cross section institute is angled is 80 °, and flowing blends that section is angled with volute outlet cross section institute to be 105 ° this effect can be made to reach optimum。

Accompanying drawing explanation

Fig. 1 is the undistorted centrifugal blower schematic diagram of the efficient exit flow field of microminiature of the present invention；

Fig. 2 is conventional centrifugal blower fan schematic diagram；

Fig. 3 cuts sth. askew form one blade schematic diagram；

Fig. 4 cuts sth. askew form two blade schematic diagram；

Fig. 5 cuts sth. askew form three blade schematic diagram；

The common centrifugal blower distribution of exit velocities figure of Fig. 6；

Centrifugal blower outlet VELOCITY DISTRIBUTION that the efficient exit flow field of Fig. 7 microminiature is undistorted；

Fig. 8 exit flow field the is undistorted centrifugal blower surface of revolution；

Fig. 9 deflector arranges the motion pattern during zero deflection of position；

Figure 10 deflector arranges motion pattern during location deflection 14 °；

Figure 11 tri-kinds cuts sth. askew blade main parameter calculation Comparative result figure；

Number in the figure title: 1. blade；2. wheel disc；3. spiral case；4. motor；5. spiral case distortion correction extension；6. flowing blends section；7 arc deflectors。

Detailed description of the invention

Embodiment 1

With reference to Fig. 1, the efficient exit flow field of microminiature is undistorted, and centrifugal blower includes blade 1, wheel disc 2, spiral case 3, motor 4, spiral case distortion correction extension 5, flowing blending section 6, arc deflector 7；Blade 1 is uniformly fixed in the circumference of wheel disc 2, rotates, be drawn in impeller by outside air under the drive of motor 4。Gas is flowed in spiral case 3 by centrifugal action, by spiral case distortion correction extension 5, blends in section 6 in flowing, and air carries out suitable blending, and even speed flow field, then at the dirty blowing machine of the guiding of arc deflector 7。

In centrifugal blower, entrance edge of blade is parallel with axle, but inlet air flow speed is uneven along leaf height direction, blade carries out suitable machining and can be effectively improved the impact on vane efficiency of this inhomogeneities。For centrifugal blower, owing to its main flow effect comes from the accumulation that inlet air flow produces, therefore cutting is concentrated mainly on blade inlet edge。For claim 1, being 90mm for external diameter, internal diameter is 70mm, aperture 40mm, width 20mm, the centrifugal blower of rotating speed 6000r/min, and when the amount of cutting sth. askew is identical, the checking having carried out three kinds of forms of cutting sth. askew calculates。Result of calculation shows, the 1/4～1 of vane overall length degree is excised on leaf top, in 1/8～1/2 scope of blade inlet edge excision blade total height, the flow of blade of cutting sth. askew all is higher than original unchamfered blade, form of wherein cutting sth. askew improves compressor flow for a pair good effect, meets the content described in claim 2。Blade is cut sth. askew and is decreased the deflection of inlet air flow, import impact loss is reduced, and thus reduction flow channels leading inlet place blocks along journey friction loss and Ye Dao import, import flow section overdraught velocity gradient is evenly distributed simultaneously, and air velocity adapts to the Rapid Variable Design from blade tip to bottom in turning process, and thus can reduce the separation losses that leaf road is bent to form, decrease impeller tip exit swirl and Secondary Flow to a certain extent。

The port of export of section is blended at runner, mutually extrude between fluid and the fluid of close snail tongue side outside spiral case, originally the fluid inside that energy is higher transfers energy to the fluid that outside energy is relatively low, fluid inside speed reduces, lateral fluid speed rises, fluid outside spiral case and the fluid velocity size near snail tongue side are all uniformly the velocity magnitude of middle main flow area, it is achieved that the uniformity of velocity magnitude。

When flowing blends section present position less than 100 °, the distortion of muzzle velocity blends section 6 with the flowing described in claim 1 and there is certain difference, in order to result that speed distortion correct is better described, define the concept of distortion variance (distortionvariance) herein, be used for weighing the degree of speed distortion:

$D=\frac{1}{n}\[{(V_1-\stackrel{\‾}{V})}^2+{(V_2-\stackrel{\‾}{V})}^2+\mathrm{...}+{(V_n-\stackrel{\‾}{V})}^2\]$

$\stackrel{\‾}{V}=\frac{1}{n}(V_1+V_2+\mathrm{...}+V_n)$

In formula: D_vRepresent distortion variance (DistortionVariance),

Represent the average speed that section is obtained according to each point,

V₁, V₂..., V_nThe speed at each point place that expression cross section place takes。

According to formula it can be seen that distortion variance shows that more greatly distortion is more strong, uniformity is more bad。Calculate flowing two kinds different respectively and blend the muzzle velocity distortion variance of fragment position, D₁Represent that the flowing at claim 1 defined blends section 6 scope, D₂Represent and do not blend section 6 scope in the flowing of claim 1 defined。

${\stackrel{\‾}{V}}_1=\frac{1}{35}(15.36+16.35+\mathrm{...}+16.62)=17.86m/s$

$D_1=\frac{1}{35}\[{(15.36-17.86)}^2+{(16.35-17.86)}^2+\mathrm{...}+{(16.62-17.86)}^2\]=1.142$

${\stackrel{\‾}{V}}_2=\frac{1}{35}(18.93+21.43+\mathrm{...}+18.49)=24.94m/s$

${\stackrel{\‾}{D}}_2=\frac{1}{35}\[{(18.93-24.94)}^2+{(21.43-24.94)}^2+\mathrm{...}+{(18.49-24.94)}^2\]=6.845$

Result of calculation indicates and obtains good rectification 100-110 ° of scope inner outlet speed distortion, and during less than this scope, the rectification effect of muzzle velocity distortion is not up to ideal state。

The setting of arc deflector 7 is to determine according to the situation of internal flow。The number of deflector is unsuitable too many, too much deflector can cause the runner between deflector excessively narrow and small, causing the unexpected of velocity gradient and barometric gradient, occur that vortex and backflow etc. are unfavorable for the situation of flowing, therefore the number of general arc deflector 7 is at about 2-3。For near the arc deflector 7 in outside, due to its camber line shape with shell relatively, arc shape keeps consistent substantially with the direction of streamline, and flowing is not resulted in too much influence by therefore identical with shell maintenance yawing moment。For the arc deflector 7 near inner side, because the outside away from shell, the flow trace of fluid is had some to change by the impact of self speed and lateral fluid, more stable flow field itself will be produced disturbance by the yawing moment keeping identical, produce unnecessary vortex and backflow, as shown in Figure 7。Therefore the track according to actual streamline, it is determined that the angle that inner side arc deflector 7 deflects to the inside is 10-14 °。

It should be appreciated that for those of ordinary skills, it is possible to improved according to the above description or converted。

Claims (3)

1. the undistorted centrifugal blower of the efficient exit flow field of microminiature, including spiral case (3), is positioned at the motor (4) at spiral case (3) center, the wheel disc (2) being arranged on motor (4) output shaft, the blade (1) that is uniformly distributed circumferentially on wheel disc (2)；It is characterized in that:

Above-mentioned blade (1) is blade of cutting sth. askew, described in blade of cutting sth. askew refer to that the leaf top leading edge of blade is chamfered, the 1/4～1 of leaf top excision vane overall length degree, the 1/8～1/2 of blade inlet edge excision blade total height；

Above-mentioned spiral case (3) outlet connects spiral case distortion correction extension (5) by the tangent mode that seamlessly transits；Spiral case distortion correction extension (5) connects flowing blending section (6) by the tangent mode that seamlessly transits, spiral case distortion correction extension (5) outlet is angled for 75-85 ° with spiral case (3) outlet institute, and it is angled for 100-110 ° with spiral case (3) outlet institute that flowing blends section (6)；

Above-mentioned flowing blends the outlet of section (6) and has been evenly arranged 2-3 arc deflector (7)；The radian of described arc deflector (7) blends the outer side surface radian of section (6) correspondence position and keeps consistent with described flowing；Definition arc deflector (7) front end and rear end: defining according to air current flow direction, the end face that air-flow first passes through is front end, after through end face be rear end；After above-mentioned arc deflector (7) is uniformly distributed along the outer side surface radian direction of correspondence position, the arc deflector being positioned at inner side keeps back-end location constant, and front end is deflection 10-14 ° to the inside again。

2. the undistorted centrifugal blower of the efficient exit flow field of microminiature according to claim 1, it is characterised in that: blade (1) leaf top leading edge is chamfered, and starts, downwardly toward blade inlet edge, to be switched to the 1/8 of blade inlet edge from leaf top tail end。

3. the undistorted centrifugal blower of the efficient exit flow field of microminiature according to claim 1, it is characterized in that: described spiral case distortion correction extension (5) outlet is angled with spiral case (3) outlet institute is 80 °, it is 105 ° that flowing blends section (6) angled with spiral case (3) outlet institute。