Embodiment
Following according to description of drawings one embodiment of the invention, use Fig. 2~Fig. 5 that the summary structure of the axial fan and the flow straightening grid of arranged in series is described.
Fig. 1 is the alternately summary pie graph of arranged in series of axial fan and flow straightening grid.
Fig. 2 is the side view of axial fan monomer.
Fig. 3 is the stereogram of axial fan monomer.
Fig. 4 is the side view of flow straightening grid monomer.
Fig. 5 is the stereogram of flow straightening grid monomer.
In Fig. 1, on the airflow direction shown in the arrow, first axial fan 1 and second flow straightening grid 2 that is in the downstream side of this first axial fan 1 are arranged from the upstream side arranged in series.Dispose second axial fan 3 in the downstream side of this first flow straightening grid 2, dispose second flow straightening grid 4 in the downstream side of this second axial fan 3.
In Fig. 2, Fig. 3, first axial fan 1 and second axial fan 3 have boss 101 in central authorities.Periphery at this boss 101 is equipped with multi-disc moving vane 102.On said boss 101, linking has motor 103, makes boss 101 rotations through this motor 103, thereby makes moving vane 102 rotations.Pillar 105 is used for said motor 103 is bearing in housing 104.
In Fig. 4, Fig. 5, first flow straightening grid 2 and second flow straightening grid 4 have inside casing 201 and housing 202.This inside casing 201 and housing 202 are through linking with the radial stator vane 203 that has stretched out multi-disc from inside casing 201.
In above-mentioned patent documentation 1, between first axial fan 1 and second axial fan 3, be gripped with flow straightening grid 2, there is not second flow straightening grid 4 in downstream side.Therefore, in patent documentation 1, through the effect of flow straightening grid 2, even can remove the rotation composition that the rotation composition of the air-flow that blows out from first axial fan 1 also can't be removed the air-flow that blows out from second axial fan 3.
Therefore, invention people of the present invention install second flow straightening grid 4 in the downstream side of second axial fan 3, and the shape of the stator vane of second flow straightening grid 4 has been carried out having obtained following each embodiment after the various researchs.
Embodiment 1
Fig. 6 is the barrel surface that the axial fan of the series connection use of embodiments of the invention 1 belongs to.
That is, Fig. 6 is that section with the stator vane 203 of section, first flow straightening grid 2 and second flow straightening grid 4 of the moving vane 102 of first axial fan 1 shown in Figure 1 and second axial fan 3 is as barrel surface and the figure that part is taken out.
In Fig. 6, on the airflow direction shown in the arrow, begin from upstream side, there is the moving vane 102a (below be called the first moving vane 102a) of first axial fan 1 of rotation to exist.In the downstream side of this moving vane 102a, there is the stator vane 203a (below be called the first stator vane 203a) of first flow straightening grid 2 to exist with state of rest.In the downstream side of this stator vane 203a, there is the moving vane 102b (below be called the second moving vane 102b) of second axial fan 3 to exist rotatably.Be provided with the stator vane 203b (below be called the second stator vane 203b) of second flow straightening grid 4 of state of rest in the downstream side of moving vane 102b of rotation.
The said first moving vane 102a and the second moving vane 102b rotate on same direction, and running shaft separately is present on the same straight line.In addition, the first stator vane 203a is the shape with respect to the sense of rotation U font warpage of moving vane 102a and moving vane 102b.The second stator vane 203b has the trailing edge shape towards the direction parallel with respect to airflow direction.
Through these flow straightening grids 2,4, air-flow in rotating field with relative velocity 302a, in static field, flow into moving vane 102a with absolute velocity 303a.In the rotating field of usually representing with three-dimensional cylindrical-coordinate system, relative velocity be as circular velocity and absolute velocity and and be presented.
The air-flow that has passed through said moving vane 102a in rotating field with relative velocity 302b, in static field, flow out with absolute velocity 303b.
Fig. 7 is the figure of relation of inflow velocity and the rate of outflow of the air-flow in the moving vane of the common axial fan of expression.
In Fig. 7, air-flow with respect to stator vane in rotating field with relative inflow velocity 302 (a) and relative fluid inlet angle 305 (a), in static field, flow into absolute inflow velocity 303 (a) and absolute fluid inlet angle 304 (a).Air-flow is through after the moving vane, in rotating field with the relative rate of outflow 302 (b) and relative current angle of departure 305 (b), in static field, flow out with the absolute rate of outflow 303 (b) and absolute efflux angle 304 (b).The variation of the speed of bearing because of the effect of stator vane about air-flow; In rotating field, being 306 (b) that differ from of the said relative inflow velocity 305 (a) and the said relative rate of outflow 305 (b), is 306 (a) that differ from of the said absolute rate of outflow 303 (b) and said absolute inflow velocity 303 (a) in static field.
Formula 1:
P
th=ρμ(v
θout-v
θin)=ρu(w
θin-w
θout)
Formula 1 expression is the resulting theoretical total head liter of air-flow owing to the effect of moving vane.Each symbol in the formula is P
ThRepresentation theory total head liter, ρ representes air density, u representes circular velocity, w
θ inThe rotation composition of representing relative inflow velocity, w
θ outThe rotation composition of representing the relative rate of outflow, v
θ inThe rotation composition of representing absolute inflow velocity, v
θ outThe rotation composition of representing the absolute rate of outflow.Formula 1 means that the resulting theoretical total head of air-flow rises and the ratio that is varied to of the speed that air-flow bore owing to the effect of moving vane.
In the said first moving vane 102a, only can obtain by formula 1 with inflow velocity and the corresponding theoretical total head liter of the rate of outflow with respect to the air-flow of the said first moving vane 102a among Fig. 6.
The air-flow that flows out from the said first moving vane 102a flows into the said first stator vane 230a with said absolute velocity 303b static field, slow down and flow out with absolute velocity 303c through the effect of the said first stator vane 203a.The said first stator vane 203a has with respect to the sense of rotation of the said second moving vane 102b shape with U font warpage; Consequently, said absolute velocity 303c have be called as oppositely prewhirl, with respect to the reverse rotation composition of the sense of rotation of the said second moving vane 102b.
Formula 2:
Formula 2 expressions are the resulting theoretical static pressure liter of air-flow owing to the effect of common stator vane.Each symbol in the formula is, Δ ps representation theory static pressure liter, and ρ representes air density, V
InRepresent absolute inflow velocity, V
OutRepresent the absolute rate of outflow.Can know that according to formula 2 absolute velocity of air-flow is slowed down owing to the effect of stator vane, the air-flow static pressure rises thus.
In the said first stator vane 203a, only can obtain by formula 2 with inflow velocity and the corresponding theoretical static pressure liter of the rate of outflow with respect to the air-flow of the said first stator vane 203a among Fig. 6.
The air-flow that flows out from the said first stator vane 203a rotating field with relative velocity 302c, in static field, flow into the said second moving vane 102b with absolute velocity 303c.The air-flow that has passed through the said second moving vane 102b in rotating field with relative velocity 302d, in static field, flow out with absolute velocity 303d.At this moment, in the theoretical total head of the air-flow shown in the formula 1 rises, because the symbol of the rotation composition of absolute inflow velocity is negative, so, be that positive situation is compared with this symbol, can increase theoretical total head liter.Because this effect, be the theoretical total head of the positive identical size of situation when rising air-flow being paid with the absolute symbol of the rotation composition of inflow velocity, can reduce circular velocity.
Formula 3:
Formula 3 expressions are based on the variation of the noise level of motor speed variation.Rotating speed before N in the formula representes to change, the rotating speed after N ' expression changes, L
ANoise before expression changes, L
A' noise after expression changes.
If the rotating speed of motor reduces through the circular velocity that reduces the said second moving vane 102b, then reduce suc as formula noise shown in 3.
The air-flow that flows out from the said second moving vane 102b flows into the said second stator vane 203b with said absolute velocity 303d static field, flow out by deceleration and with absolute velocity 303e through the effect of the said second stator vane 203b.At this moment, air-flow only obtains the theoretical static pressure liter shown in the formula 2.
Fig. 8 is the performance curve of expression axial fan and the plotted curve of resistance curve.
In Fig. 8, the air quantity of axial fan usually by operating point, be that the intersection point of the characteristic curve 402 of intrinsic air quantity of characteristic curve 401 and the axial fan of air quantity and the pressure loss in the Environmental Conditions of axial fan and pressure decides.Therefore, the effect through said second stator vane obtains the static pressure liter, representes that the characteristic curve of said air quantity and pressure is varied to the characteristic curve 403 of air quantity and pressure, and consequently, operating point is to big air quantity side shifting.That is, air quantity increases.
In the present embodiment, under the situation of said first axial fan, 1 fault shown in Figure 1, said first axial fan 1 becomes obstacle.At this moment, said second axial fan 2 turns round with maximum (top) speed.
As shown in Figure 6, through the effect of the said first stator vane 203a the said second moving vane 102b paid and oppositely to prewhirl, thus, in formula 1, can make to surpass the theoretical total head of not paying the air-flow when oppositely prewhirling and go up liter.In addition, through the effect of the said second stator vane 203b, in Fig. 1, can obtain to compare bigger air quantity with the situation that does not have said second flow straightening grid 4.That is the reduction of the air quantity in the time of, can be with said first axial fan, 1 fault suppresses forr a short time.
As stated, in the present embodiment, we can say, so can obtain that the noise of axial fan reduces and the mis-behave inhibitory action when air quantity increase and fault because the first stator vane 203a is different with the shape of the second stator vane 203b.
In addition, to describing through illustrated first axial fan 1 of Fig. 1 of embodiments of the invention 1 and the sense of rotation condition of different of second axial fan 2.
Usually, the fan that uses of two axial fan arranged in series that sense of rotation is different is called as the double-inversion fan.In this double-inversion fan, passed through with respect to airflow direction upstream side axial fan air-flow had is rotated into branch and for the fan in downstream side, becomes oppositely and prewhirl.Therefore, can expect all the time that the pressure that oppositely prewhirling shown in the embodiment 1 realized rises.
But; If since the variation of Environmental Conditions etc. and upstream the air inflow condition of the axial fan of side change, thereby excessive, then as shown in Figure 9 with respect to oppositely prewhirling of the axial fan in downstream side; The air-flow of vacuum side of blade can't tolerate big pressure rising and peel off, and produces loss.
Embodiment 2
Therefore, in embodiment 2, be provided with first moving vane 102a of rotation and the second moving vane 102c of rotation.In the sense of rotation of this second moving vane 102c not simultaneously; Towards oppositely, the second static stator vane 203b becomes the shape of trailing edge towards the direction parallel with respect to airflow direction to the first static stator vane 203a with respect to the sense of rotation of the said first moving vane 102a.
Below utilize Figure 10 that the effect of present embodiment is described.
Figure 10 is the barrel surface at the axial fan place of embodiments of the invention 2.
In Figure 10, the air-flow that has passed through the said first stator vane 203a has absolute velocity 303c in static field.Air-flow in rotating field with relative velocity 302d, in static field, flow into the said second moving vane 102c with absolute velocity 303d.At this moment; Effect through the said first stator vane 203a; Air-flow is oppositely prewhirled when flowing into the said second moving vane 102c can't be excessive, and the generation of the loss that therefore can suppress to cause because of peeling off of air-flow preferably can passing through type 1 obtains the theoretical total head liter of being expected.The air-flow that has passed through the said second moving vane 102c is shown in embodiment 1, through the effect acquisition static pressure liter of the second static stator vane 203b.
According to the above; Because in the present embodiment; The shape of the stator vane 203a that said first flow straightening grid 2 of Fig. 1 is had is different with the shape of the stator vane 203b that said second flow straightening grid 4 is had, so can obtain to suppress the effect of the loss occurrence in axial fan, particularly the double-inversion fan.
Embodiment 3
Utilize Figure 11 that embodiments of the invention 3 are described.
Figure 11 has the axial fan of embodiments of the invention 3 and the pie graph of flow straightening grid.
In Figure 11, structure is, begins to set gradually first axial fan 1, first flow straightening grid 2, the second flow straightening grid 2a, second axial fan 3 and the 3rd flow straightening grid 4 at the airflow direction shown in the arrow from upstream side.
Figure 12 is the barrel surface that the axial fan of the series connection use of embodiments of the invention 3 belongs to.
In Figure 12; Structure in the present embodiment is; The first static stator vane 203a has the shape with respect to the sense of rotation leading edge warpage of the first moving vane 102a of rotation; The second static stator vane 203b has the shape with respect to the sense of rotation trailing edge warpage of first moving vane, and the 3rd static stator vane 203 has the trailing edge shape towards the direction parallel with respect to airflow direction.
In other words, the first stator vane 203a and the second stator vane 203b form first illustrated among the embodiment 1 of Fig. 6 stator vane 203a with two blades.If will use the stator vane 203a of the die forming U font of one, then existing is the situation of shape that can't the demoulding, therefore forms stator vane with two blades in the present embodiment.Cut apart and easily to be shaped through such realization.
Below, utilize Figure 12 that the effect of present embodiment is described.
The air-flow that has passed through the said first stator vane 102a flows into the said first stator vane 203a with absolute velocity 301b in static field.The air-flow that in static field, has passed through the said first stator vane 203a has the absolute velocity 303c that the rotation composition has been relaxed, and flows into the said second stator vane 203b.The air-flow that has passed through the said second stator vane 203b has absolute velocity 303d, but it has oppositely prewhirling with respect to the second moving vane 102b that rotates.The air-flow that flows into the said second moving vane 102b is being paid when oppositely prewhirling; Because the rotation composition of the mitigation of the effect through said first stator vane 203a air-flow, thus the air-flow that may produce can obtain that air communication crossed the said second stator vane 203b time peel off the effect that suppresses.Consequently, the generation of the loss that can suppress to cause because of peeling off of air-flow, even can remove.
According to the above; Because in the present embodiment; The stator vane 203a that first flow straightening grid 2 among Figure 11 is had is different with the shape of the stator vane 203b that the second flow straightening grid 2a is had; So we can say, using the flow straightening grid desire that the air-flow that flows into said second axial fan 3 is paid when oppositely prewhirling, have the effect of the loss that inhibition causes because of peeling off of air-flow.
As another effect of present embodiment, can enumerate as stated and make the said first stator vane 203a through mold and the said second stator vane 203b time ratio is easier to make this point.
Embodiment 4
Utilize Figure 13 that embodiments of the invention 4 are described.
Figure 13 has the axial fan of embodiments of the invention 4 and the pie graph of flow straightening grid.
In Figure 13, on the airflow direction shown in the arrow, begin to have successively first flow straightening grid 2, first axial fan 1, second flow straightening grid 4, second axial fan 3 and the 3rd flow straightening grid 5 from upstream side.
The structure of present embodiment is; Shown in Figure 14 as as the barrel surface at Figure 13 place; The first static stator vane 203a has the shape of trailing edge warpage on the sense of rotation of the first moving vane 102a of rotation; The second static stator vane 203b has sense of rotation with respect to the second moving vane 102b of rotation with the shape of U font warpage, and the 3rd static moving vane 203c has the shape of trailing edge towards the direction parallel with respect to airflow direction.
Next, utilize Figure 14 that the effect of present embodiment is described.
Air-flow when flowing into the said first moving vane 102a, with the mode that has absolute velocity 303b in static field through the said first stator vane 203a.In axial fan, the Environmental Conditions of supposing owing to the design phase usually is different with actual Environmental Conditions, so because the loss that causes because of peeling off of air-flow can take place the inflow condition of the air that environment causes.The effect of the said first stator vane 203a is to suppress this loss, even can remove.
Based on the above; Because in the present embodiment; The shape of the stator vane 203c that stator vane 203b that the stator vane 203a that first flow straightening grid 2 shown in Figure 13 is had and second flow straightening grid 4 are had and the 3rd flow straightening grid 5 are had is different, changes the generation to the loss that variation brought of the inflow condition of said first axial fan 1 that is caused so can be inhibited because of Environmental Conditions.
Embodiment 5
Utilize Figure 15 that embodiments of the invention 5 are described.
Figure 15 is the summary pie graph of the blade server of embodiments of the invention 5.
In Figure 15, blade server 500 is made up of housing 501, the cooling fan assembly 503 that places the server blade 502 in the said housing and be used to cool off said server blade.
As said cooling fan assembly 503, in formation of the present invention, for example adopt embodiment 1, can obtain the blade server of big air quantity and low noise thus based on embodiment 1 effect.Even can realize the also good said cooling fan assembly of tediously long property when fault.
As the purposes of the cooling fan assembly in the present embodiment, not to only limit to blade server, cooling fan assembly can be an object with the Servers-all equipment class of rack server, PC server etc.
According to above the present invention, owing to can reduce the rotating speed of said second axial fan through the effect of first flow straightening grid, so can significantly reduce noise.In addition, owing under the effect of said first flow straightening grid and said second flow straightening grid, can obtain the static pressure liter, air quantity increases.
Moreover, owing to be provided with said second flow straightening grid, so even the first axial fan fault also can suppress the reduction of cooling performance.
On the other hand; Through peeling off of the air-flow that suppresses to produce at said second axial fan because of the effect of said first flow straightening grid; The generation that can suppress to lose moreover, can also suppress the loss that is produced because of the inflow condition to the air-flow of said first axial fan.
Have again because the axial fan of the big air quantity of low noise can be provided, so can realize fault the time tediously long property also well server use cooling fan assembly.