JPH04321794A - Flow generator - Google Patents

Abstract

PURPOSE:To improve the performance of a flow generator to the utmost limits and reduce noise. CONSTITUTION:Many flow generating plates P, P1, P1a, P1b, P2, and P3 arranged in parallel with each other are rotated around an axis O-O to generate the movement of fluid such as air. In order to most efficiently move fluid by only sticking of the fluid to flow generating plates, the clearance between flow generating plates is set as follows. That is, the aforementioned clearance is set so as to be twice the middle value (c) of the distance between the flow generating plate surface which contacts with a part (a) of the nearest fluid boundary layer which moves almost together with a flow generating plate and a part of a fluid boundary layer which is hardly affected by the centrifugal force caused by the rotation of the flow generating plates. In the case of air fluid, the clearance is about 0.5mm. In order to improve the efficiency of flow generation, the surface of the flow generating plates is made in the shape of wave 10. In addition, a part of the wave shaped surface is provided with straightening parts 13 each consisting of a ring-like flat plate, and a straightening auxiliary plate 14 is provided between the straightening 13 when required.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blower, a pump, or the like for supplying fluid.

0002

[Prior Art] A plurality of annular current plates are arranged in a direction perpendicular to the axis of rotation, and these plates are rotated around the axis of rotation, so that the surface of the current plate and the fluid (air)
The disc-type current generator that sends fluid by friction with the
This method is known from Japanese Patent No. 8-17359 and the like.

0003

[Problem to be solved by the invention] This type of drafter is
It has the advantage of being inexpensive due to its simple structure, but
There is a problem in that sufficient performance cannot be obtained in terms of flow rate, etc. On the other hand, an induction motor is often used to drive the current generator, but since the maximum rotation speed of the induction motor is determined by the power supply frequency, the upper limit of the rotation speed of the current generator is determined. This limitation also occurs due to the durability of bearings, etc. When the maximum rotational speed is thus limited, if a larger flow rate is required, it is necessary to improve the space efficiency of the drafter (increase the flow rate with the same dimensions) instead of increasing the rotational speed.

[0004] Although this type of current generator generates lower noise than conventional current generators, it still has a protrusion for promoting current flow on the current flow plate in order to increase the current flow force of the current flow generator. If installed, wind noise is likely to occur. An object of the present invention is to maximize the performance of this type of draft generator and to reduce noise caused by wind blowing and the like to the utmost.

[0005]

[Means for Solving the Problems] The current generating system of the present invention includes a plurality of current generating plates arranged at intervals in a direction substantially perpendicular to the rotational axis, and these current generating plates are driven to rotate around the rotational axis. and a means for displacing the fluid solely by the phenomenon of adhesion with the fluid in contact therewith, the surface having a surface along which the fluid moved by the phenomenon of adhesion finally leaves the current plate. It is formed in the radial direction up to the outer edge of the separating plate, and the surface of the plate is provided with a protrusion for promoting drafting, and the gap between adjacent drafting plates has a strong adhesion to the drafting plate, so that the drafting plate is formed in a radial direction. Distance between the surface of the current plate that is in contact with the closest fluid boundary layer that rotates almost together with the plate and the fluid boundary layer that has weak adhesion to the current plate and is hardly affected by centrifugal force due to the rotation of the current plate. is set to twice the intermediate value of
The gap is considered to be the gap in which centrifugal force is most likely to act on the fluid most effectively, and a rectifying section made of an annular flat plate is provided in a part of the flow-starting plate in the radial direction, excluding the flow-stimulating protrusion. ing.

[0006]

[Function] In the current generator of the present invention, when the current generation plate is rotationally driven, the nearby fluid boundary layer portion that is in contact with the surface of the current generation plate causes the current generation to flow due to the adhesion force to the current generation plate. It rotates together with the plate, and is sent radially outward by the resultant force of centrifugal force and adhesive force generated accordingly. Further, the fluid adjacent to the closest layer portion is also dragged by the movement of the closest fluid boundary layer portion due to shear stress, and is sent radially outward with a little delay. As the distance from the nearest fluid boundary layer section increases, the fluid flow lags behind the nearest fluid boundary layer section. By determining the gap between the draft plates so that there is no fluid layer portion where such a delay becomes large, the performance of the draft generator, such as the flow rate, is improved to the utmost. In the fluid boundary layer, where the adhesion force of the drafting plate to the fluid affects the fluid, due to the phenomenon of adhesion to the drafting plate,
Centrifugal force acts as the current plate rotates. The larger the distance from the surface of the current plate, the smaller this centrifugal force becomes.
It is maximum near the surface of the current plate. The current action is caused by the resultant force of centrifugal force and adhesion force. Near the surface of the current plate, the centrifugal force is large, but the adhesion force is also large.

[0007] The adhesion force can be considered to be infinite at the point in contact with the current plate. Therefore, the centrifugal force on the surface of the current plate and in the vicinity thereof is reduced by the adhesive force. The fluid actually remains attached on the surface of the current plate. On the other hand, when moving away from the current plate surface, the centrifugal force becomes weak due to weak adhesion, making it difficult to generate current. Therefore, in the middle part,
There must be a location where the adhesion force is moderate and the centrifugal force acts, and where this centrifugal force overcomes the adhesion force and generates current most efficiently. The present invention utilizes this location to improve the performance of the flow generator, such as the flow rate.

[0008]Furthermore, the annular flat plate rectifier provided on the current flow plate rectifies the flow of fluid disturbed by the flow promotion protrusion, leading to the generation of noise.

[0009]

[Embodiments] Prior to describing embodiments of the present invention, the basic principle of the present invention will be explained. In FIGS. 1 and 2, O-O is the rotation axis of the current generator, and a plurality of annular plate-shaped current generation plates P are integrally arranged perpendicular to this rotation axis. . The current plates P are arranged parallel to each other with a gap CL between them, and have a circular opening 2 in the center. A spacer 3 is provided on the current plate P to maintain a gap CL, and in order to make the current plate P rotatable, a rotating shaft 4 is provided on the current current plate P at both ends as shown in FIG.
a and 4b are fixed, and a motor M is connected to one rotation 4b. The rotating shafts 4a and 4b are supported by bearings (not shown). As shown in FIG. 3, the current plate P can be housed in a casing 5 having a discharge port 6. Note that one rotating shaft 4a and its bearing may be omitted.

Now, when these current generation plates P are rotated together around the rotational axis OO, assuming that the surface 7 (FIG. 2) of the current generation plates is in contact with a fluid such as air, The fluid in the gap CL is sent with a component directed outward in the radial direction of the current plate as shown by the arrow, and as a result, the fluid is sucked through the opening 2 in the direction of the rotational axis OO. An example of a draft generator operating on this principle is described in Japanese Patent Publication No. 17359/1983.

The reason why the air is dragged and sent to the surface 7 of the current plate P in this way is that the fluid in contact with the solid surface is attached to the solid, and this occurs due to the rotation of the solid based on the adhesion. This is because fluid movement occurs due to the resultant force of the centrifugal force and the adhesive force. The adhesion phenomenon will be explained with reference to FIG. In the figure, it is assumed that the fluid adjacent to the surface of the solid P' is flowing to the left in the figure. In this case, the closer the fluid molecules are to the surface of the solid P', the more they are influenced by the adhesive force of the solid, and the flow rate becomes slower. This phenomenon is explained by shear stress. The length of the arrow indicates the flow velocity. Fluid molecules that are in direct contact with a solid adhere to the solid and do not move, and in the extremely thin boundary layer part A in the area close to the solid, the fluid is greatly influenced by the solid due to the action of the above-mentioned shear stress due to the viscosity of the fluid. receive. Although some shear stress is continuously acting in the region B outside the boundary layer portion A, the fluid is hardly affected by the solid P'. This phenomenon occurs regardless of the material of the solid surface. The above relative velocity relationship means that when the fluid stops,
It also exists when solids move. In the case of a flat disk rotating in air, the thickness of the boundary layer portion, which is largely affected by the centrifugal force generated by rotation, is considerably smaller than 1 mm, as described below.

Now, if the current plate P is rotated in the direction of arrow D as shown in FIG. 5, the airflow generated only on one surface of the current plate P will be caused by It is discharged tangentially to the outer peripheral edge of the plate P, and its flow rate Q is expressed as Q=k・R・N. Here, R is the radius of the outer periphery of the current plate, N is the number of rotations, and k is a constant. That is, the flow rate is determined in proportion to the radius and the rotational speed (ie, the circumferential speed of the flow-starting plate).

[0013] Thus, considering only one surface of the current plate, if the radius and rotational speed are determined as the factors that determine the flow rate, the flow rate can only be increased by increasing the constant k. Now, the increase in the constant k will be described later, but the specified radius and specified length (axial direction) of the draft generator
The only way to improve the performance of a draft generator within this range is to improve space efficiency within the specified length. The main purpose of the present invention is to improve this space efficiency.

[0014] The thinner the thickness of the current plate is within a certain axial length range, the better. This is because only the surface of the current plate is involved in the feeding of fluid, and the thickness of the plate does not contribute to the current flow. Therefore, the current plate only needs to withstand the required mechanical strength requirements. In this case, the mechanical strength of this type of draft generator is mainly limited to the plane tension and centrifugal force of the plate generated around the in-plane fixed part of the draft plate, and other forces such as twisting, bending, etc. There is no effect. Therefore, even if the current plate is made of plastic such as polyethylene terephthalate (PET), it is sufficiently durable.

[0015] In this way, if the current plate can be made as thin as possible, the space efficiency with respect to the flow rate in the rotational axis direction, that is, in the thickness direction of the current plate, will be determined only by the gap size between the current plate. .

[0016] Therefore, in order to determine the optimum gap size, the following experiment was conducted. 2 as shown in Figures 6 and 7.
A flat hollow annular plate P" is fixed to a rotating shaft 9 so that the gap CL between the two can be adjusted, a small hole 8 is formed near the circumferential edge, and the annular plate is
The annular plate was rotated in air around an axis passing through its center while releasing a corrosive gas toward P'' as shown by the arrow.The corrosive gas was subjected to the centrifugal force exerted by the annular plate P''. As it flowed with the air currents, we observed its corrosion trajectory. Note that the gas was sent to the hole 8 via the rotating shaft 9 as shown in FIG.

According to the observation results of this trajectory, the annular plate
The larger the gap P'' is, the more gas flows around the annular plate P'' in the circumferential direction opposite to the rotational direction E, as shown by the arrow f. The degree of this "wrapping" can be expressed by the angle θ in FIG. The trajectory of the gas appears in shading as shown in Figure 8,
The darker parts of the locus have a higher flow rate, and the thinner parts have a lower flow rate. The fact that there are many flows with a large wraparound angle θ means that there are many areas where the influence of the adhesive force of the annular plate P'' is small, and the rolling energy of the annular plate P'' is not fully utilized. become. on the other hand,
The fact that there are many flows with a small wraparound angle θ indicates that the annular plate
This means that the adhesive force of P'' is strong, and the generated centrifugal force is attenuated by the adhesive force, resulting in less flow.

The following analytical results were obtained from the observation of such "wrapping". Gap between annular plates 0.13~0.
An air layer between 25 mm, that is, an air layer with a thickness of 0.13/2 to 0.25/2 mm from the surface of each annular plate, which is considered to be mostly attached to the surface of the annular plate, This air layer is the layer indicated by a in FIG. 4.

[0019] Furthermore, the air in the portion where the gap exceeds 1.0 mm, that is, the air that is separated from the surface of each annular plate by a distance exceeding 1.0/2 mm, is affected by the adhesive force and centrifugal force of the annular plates. This air is outside the area indicated by c in FIG. 4. Further, in the gap corresponding to the thickness of the air layer in the above part a, the adhesion force is so strong that even centrifugal force makes it difficult to flow. This air layer, ie, the closest fluid boundary layer portion a, is extremely thin as described above, so its thickness can be almost ignored. Also, since the air in the area beyond c is less susceptible to the action of the annular plate, there must be an area b (Figure 4) between a and c above where it is easily affected by centrifugal force and has maximum space efficiency. It is. The area would be around 0.38/2 to 0.5/2 mm.

On the other hand, when the flow rate and static pressure of a blower constructed by superimposing flow plates with an inner diameter of 50 mm and an outer diameter of 74 mm and an axial length of 21 mm were measured while changing the gap between them, the results shown in FIG. 9 were obtained. Obtained. This result and the analysis result described above generally agree. Therefore, when the fluid is air, the gap between the draft plates of the draft generator is approximately 0.5
It has been found that maximum space efficiency is obtained if the distance from the surfaces of the opposing flow plates to their midpoint is approximately 0.5/2 mm.

It is clear from the foregoing that in the case of other fluids, there are respective optimum flow plate gaps, and the optimum gaps can be determined by the same procedure as described above. Therefore, the final space efficiency of the drafter is
It is determined by the number of surfaces that can have the maximum space efficiency per surface of the current plate within a predetermined axial length.

As already mentioned, the flow rate Q generated by the current plate is expressed as Q=k·R·N (R is the outer diameter of the current plate and N is the rotational speed). Therefore, in order to increase Q, it is a good idea to increase the constant k. The following constant k
An example of increasing the amount of

One of the factors included in the constant k is the surface area of the current plate. It is considered that by increasing this surface area, the constant k can be increased and the flow rate Q can be increased. If the inner and outer radii of the flow-starting plate are regulated, the surface area can be increased by forming unevenness. Increasing the surface area of the current plate does not mean simply increasing the surface area. As already mentioned, the fluid (
In the case of air), it is most likely to move due to the influence of the current plate, so the distance from the surface of the current plate to about 0.5
The increase in surface area at the /2 mm position is considered to be the most efficient.

[0024] In order to realize this, it is considered that it is best to form a waveform on the surface of the current plate with the wave crest facing approximately in the radial direction. An example is shown in FIG. The annular flow generating plate P1 shown in the figure has a waveform 10 that is inclined with respect to the radial line in a direction opposite to the rotational direction indicated by the arrow. The cross section of this waveform is, for example, a triangular cross section with an apex angle of 60°. When a waveform having an equilateral triangular cross section with an apex angle of 60° is formed in this way, the surface area of the current plate becomes twice that of a flat current plate. However, as shown in Figure 11, if the equilateral triangular waveform is small, 0.5/2 from the surface of the waveform
The locus 11 of a point located at a distance of mm (0.25 mm) becomes an extremely low arcuate waveform as shown in the same figure, and the distance is 0.25 mm.
The shape of the closest boundary layer portion, which is most affected by the current plate up to the position, is not much different from the case of a flat current plate, and the effect of increasing the constant k is small.

On the other hand, when the equilateral triangular waveform is large as shown in FIG. 12, the shape of the closest boundary layer part that is most affected by the current plate up to a position 0.25 mm from the surface of the waveform is as shown in the figure. As shown by 12, it changes considerably and exhibits a large wavy shape compared to 0.25 mm. It has been concluded that this promotes the formation of a turbulent boundary layer, which will be described later, and thereby increases the thickness of the fluid layer affected by the draft plate, making it possible to increase the flow rate. Note that if the unevenness is considerably smaller than 0.25 mm, for example, a fine satin surface or a felt surface will not be useful for increasing the surface area of the drafting plate.

Although it is possible to increase the flow rate by forming a considerably large corrugated surface in this way, this is only for one surface of a single current plate.

[0027] By the way, theoretical calculations show that the slopes of a current plate with a triangular waveform surface with an apex angle of 60° have a distance of 0.5 m in the direction perpendicular to the slopes.
If they are arranged to face each other with a gap of m, the two current plates will face each other with an interval of 0.5 mm/sin 30°, that is, 1 mm, in the direction of the rotational axis, and the axial distance between the current plates will be This is twice 0.5 mm, and the number of flow plates that can be installed within a certain axial dimension is half that of a flat flow plate. Therefore, theoretically,
Even if the area of each surface of the current plate is doubled and the flow rate is increased, this increase will be canceled out by the reduction in the number of plates by half. This fact holds true even when the apex angle of the triangular waveform is other than 60°.

However, the results of this theoretical calculation do not match the experimental results. According to experimental results, a large waveform has the effect of increasing the flow rate. The experimental results are shown in Table 1 below.

[0029]

[Table 1]

The results in Table 1 are different from the results of theoretical calculations. In particular, the current plate gap (value measured in the direction perpendicular to the slope of the waveform) was considerably different from the optimum value of 0.5 mm in Experiments III and IV (medium wave), and was 1.2 mm for each.
3mm and 1.0mm. In the case of III, the top of the waveform is rounded, so even if the previous theoretical value is considered irrelevant, the top of the waveform forms the vertex of an equilateral triangle.
In the case of V, the spacer thickness, which should be theoretically mm, was experimentally 2.0 mm.

The reason for this can be considered to be the turbulent boundary layer. When fluid is flowing along the surface of a plate, if the roughness of height h is uniformly distributed on the plate surface, and the length of the plate in the flow direction is d, then the value of h/d is It is known from fluid mechanics that when the value exceeds a certain value, the laminar boundary layer changes to a turbulent boundary layer. The thickness of the turbulent boundary layer increases rapidly in a region where the flow velocity exceeds a certain value. Under the experimental conditions shown in Table 1, the fluid flowing on the surface of the drafting plate satisfies the above conditions due to the formation of a waveform, and the turbulent flow boundary has a moderate adhesion force to the surface of the drafting plate and is subjected to an effective centrifugal force. It is believed that a layer is formed whose thickness exceeds the thickness of the laminar boundary layer that occurs in the case of a flat draft plate.

In any case, it is recognized that the formation of the waveform increases the flow rate of the fluid flowing between the flow-starting plates. It was also observed that the flow rate increased more with medium waves than with small waves, and furthermore, with medium waves having a triangular top, the flow rate and static pressure increased more than with small waves with a rounded and incomplete top. Is recognized. The state of increased flow rate is also shown in FIG. In this way, by forming the waveform on the current plate, the total flow rate etc. increases and the optimum gap also increases, so the number of required current plates becomes smaller, and their assembly becomes easier. The drafter can now be lightweight.

When waveforms are formed on the current plate P1 in a direction having a radial component as described above, each waveform 10 has a radial direction as shown in FIG. The chevron at the inner peripheral edge is smaller than the chevron at the outer peripheral edge. Therefore, the gap between the two adjacent flow plates P1 in the rotational axis direction becomes larger on the inner circumferential edge side than on the outer circumferential edge side, and the fluid suction port becomes larger accordingly. This means that there are fewer restrictions on the amount of possible currents.

Note that in the example of FIG. 10, the waveform wraps around in the opposite direction to the rotation direction, and in the example of FIG. 14, the waveform is oriented in the radial direction, but the waveform is curved in the rotation direction Sometimes. In either case, when the current plate rotates, the fluid that flows from the inner circumferential edge toward the outer circumferential edge does not all flow along the corrugated grooves, but some fluid flows beyond the corrugated grooves.

The most contributing factor to the current flow is the current flow plate P.
It is near the outer periphery of. This is because the peripheral speed is highest at the outer periphery. As described above, it is desirable to design the current flow plate assembly so that the optimum effective gap is formed near the outer periphery that contributes most to the current flow.

As described above, it is highly desirable to form a waveform with a radial component in the flow plate to increase the flow rate. Although we have mainly mentioned increasing the flow rate above, this current plate type current generator is originally a high rotation, high static pressure type, so it is more important to take measures to increase the flow rate. It is.

On the other hand, considering that the current generator is often driven by an induction motor, it is most desirable for this type of current generator to be able to produce a large flow rate at as low a rotation as possible.

Although the draft generator described above generates lower noise than conventional draft generators, it still produces wind noise due to the corrugated portion on the outer periphery of the draft plate cutting the discharged fluid (air). Occur. The present invention provides a draft generator having means for suppressing the generation of wind noise, examples of which are shown in FIGS. 15 to 18.

In the embodiment of the present invention shown in FIGS. 15 and 16, each current plate P1a is integrally provided with a flat annular flat rectifier 13 along the outer periphery of the current current plate 1 shown in FIG. ing. The rectifying plate 13 protrudes outward in the radial direction, and the turbulent flow of fluid generated in the radially inner corrugated portion 10 is rectified while flowing along the flat rectifying portion 13 . The thus rectified fluid stream is discharged to the outside without significantly disturbing the stationary fluid outside the current plate. The width of the rectifier 13 is determined to be a width necessary to attenuate fluctuations in the pressure of the turbulent flow, etc., depending on the viscosity of the fluid, the state of the corrugated portion of the current plate, the gap between the current plates, and the like.

A flow straightening section similar to the annular plate-shaped flow straightening section 13 may be formed on the inner peripheral edge of the current flow plate if necessary. In the embodiment shown in FIG. 17, the current plate P1b has an annular flat rectifying section 13a in the radial middle part of the corrugated section, and also has a rectifying section similar to the rectifying section shown in FIG. 16 on the outer peripheral edge. A rectifying section 13 is provided. The intermediate rectifier 13a rectifies the fluid flowing along the corrugated portion in the middle. An annular rectifying auxiliary plate 14 may be provided between the intermediate rectifying portions 13a to further improve the rectifying state. In addition, as shown in FIG.
may be provided. A rectifying auxiliary plate may also be provided between the rectifying portions on the inner peripheral edge.

[0041] In the embodiments described above, the current generator was a normal centrifugal type, but the principle of the current generator according to the present invention can also be used in a cross-flow fan.

[0042]

Effects of the Invention According to the present invention, the gap between the drafting plates is determined so that the drafting plate acts most effectively on the fluid to create a flow, and the drafting plate has a protrusion for promoting drafting. By providing the section to make it easier to generate a current, the fluid flow can be generated most efficiently, and the annular flat plate rectifying section can regulate the flow and prevent the generation of noise.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing the basic configuration of a current generator of the present invention.

FIG. 2 is a sectional view in the direction of the rotation axis.

FIG. 3 is a cross-sectional view taken in a direction perpendicular to the axis of rotation.

FIG. 4 is an explanatory diagram of a boundary layer.

FIG. 5 is an explanatory diagram of a phenomenon during rotation of a current plate.

FIG. 6 is a plan view of a current plate used in the experiment that formed the basis of the present invention.

FIG. 7 is a cross-sectional view of FIG. 6.

FIG. 8 is a perspective view showing experimental results.

FIG. 9 is a diagram showing experimental results.

FIG. 10 is a plan view of an example of a corrugated current plate.

FIG. 11 is a diagram illustrating a comparison of the increase in surface area of the wave-formed current plate.

FIG. 12 is another comparative explanatory diagram of the increase in surface area of the corrugated current plate.

FIG. 13 is a graph showing experimental results regarding flow rate.

FIG. 14 is an explanatory diagram of the waveform of the current plate.

FIG. 15 is a plan view showing an example of a current plate used in the present invention.

FIG. 16 is a side view of the drafting plate of FIG. 15.

FIG. 17 is a side view showing another embodiment of the current flow plate and a flow rectification auxiliary plate used in the present invention.

FIG. 18 is a side view showing still another embodiment of the current flow plate used in the present invention and rectification assistance.

[Explanation of symbols]

P Current plate P1 Flow plate P1a Flow plate P1b Current plate CL Gap M Motor 4a Rotation axis 4b Rotation axis 0 Rotation axis 10 Waveform (protrusion for promoting flow) 13 Annular flat plate rectifier 13a Annular flat plate rectifier 14 Annular rectifying auxiliary plate

Claims (2)

[Claims] 1. The current generating plate comprises a plurality of current generating plates arranged at intervals in a direction substantially perpendicular to the rotational axis, and means for rotationally driving these current generating plates around the rotational axis, the current generating plate comprising: It has a surface along which the fluid is moved only by adhesion with the fluid in contact with it, and this surface is formed radially up to the outer edge of the buff plate along which the fluid to be moved by the adhesion phenomenon finally leaves the buff plate. , a protrusion for promoting flow generation is provided on the surface of the flow generation plate, and the gap between adjacent flow generation plates is a close fluid boundary that has a strong adhesion force to the flow generation plate and rotates almost together with the flow generation plate. It is set to twice the intermediate value of the distance between the surface of the drafting plate in contact with the layer portion and the fluid boundary layer portion where the adhesion force to the drafting plate is weak and there is almost no influence of centrifugal force due to the rotation of the drafting plate, The gap is considered to be the gap in which centrifugal force is most likely to act on the fluid most effectively, and a rectifying section made of an annular flat plate is provided in a part of the flow-starting plate in the radial direction, excluding the flow-stimulating protrusion. The current flow machine. 2. The current generator according to claim 1, wherein a rectifying auxiliary plate is provided between the rectifying portions of adjacent current generating plates in parallel to the rectifying portions.