JPS5949438B2 - Impeller of linear radial type mixed flow blower - Google Patents

Description

[Detailed description of the invention] This invention is a linear radial type (so-called radial plate type)
This invention relates to a new impeller configuration for a mixed flow blower.

As shown in FIG. 1, the impeller of a normal linear radial centrifugal blower has an inlet edge 2 and an outlet edge 3 of the blade 1 parallel to the rotation axis 4, and the blade 1 is parallel to the rotation axis 4. When jumping from a parallel direction (direction of arrow P), as shown in Figure 2, in order to minimize the collision loss at the blade entrance, the blade 1 curves into an arc near the entrance edge 2, and then and extending radially in the radial direction towards the outlet edge 3.

However, although the blade 1 is curved in an arc shape near the inlet edge 2, there is no twist in the blade 1 in the direction of the rotation axis 4, and each plane a,, a perpendicular to the rotation axis 4. ,...an
It has a two-dimensional curved surface in which each cross section of the plane appears to overlap each other. Also, most of the cross section of the blade 1 is the inlet edge 2.
Most of the curved parts in the vicinity are circular arcs with a single radius or two circular arcs connected at most. Therefore, the production of the blades 1 in the impeller of a linear radial centrifugal blower is relatively simple. However, even with this type of blade 1, it is extremely difficult to manufacture one in which the radius of the arc gradually changes along the chord length (the length of the blade in the flow direction), which is close to the ideal from a hydrodynamic point of view. Therefore, although it is known that it is advantageous in terms of efficiency and noise, it has not yet been put into practical use. On the other hand, in the linear radial type mixed flow blower, as shown in FIG. 3, neither the inlet edge 12 nor the outlet edge 13 of the blade 11 is parallel to the rotation axis 14.

, and now, when gas flows in the gas passage between the main plate 16 and the side plate IT from the inlet edge 12 to the outlet edge 13, the gas flows in layers in the gas passage and in an infinite number of continuous flows. Assuming that the flow flows on a line, a plurality of representative streamlines among them are designated as representative streamlines 151, 152, . . . 15n, and these representative streamlines 15, 152, . . . 1
5n allows the gas passage to have multiple cross sections (in this example, n-
1 piece). In this way, the radius from the rotation axis 14 to the inlet edge 12 becomes γIO,
, riO2,..., γInn, and each radius from the axis 14 to the exit embroidery 3 is also γ. 011,
It changes gradually like γ0012, . . . , γ0ut0.

If these radii change, the rotational circumferential speed at the inlet and outlet points will change accordingly, so in order to reduce the collision loss at the inlet edge 12, the inlet angle β1 must be gradually changed along the inlet edge 13. Moreover, in order to align the boost head at the outlet edge 13, the outflow angle β2 must be varied gradually along the outlet edge. Here, even if the outflow angle β2 is set to a constant value without changing it, the booster head can be made uniform to some extent by appropriately selecting the ratio of the inner and outer diameters of the impeller (-γ0ut/γIn). Therefore, the outflow angle β
2 is often set to 900 (a constant value), which is advantageous in terms of strength. However, for the inflow angle β1, for the above-mentioned reasons, as shown in FIG.
, β11. Therefore, even if the outflow angle β2 is set to a constant value, the shape of the blade 11 becomes a plurality of twisted three-dimensional curved surfaces at least near the inflow point when viewed from the direction of the rotation axis 14. If the outflow angle β2 is also changed, a more complicated three-dimensional curved surface that is twisted from the inflow point to the outflow point will be obtained. In other words,
The impeller of the linear radial type mixed flow blower shown in Fig. 3 has a two-dimensional curved surface with a single circular arc or two circular arcs, which is the same as the blade 1 of the linear radial type centrifugal blower shown in Figs. 1 and 2. Feather 11
If only the representative streamlines 151, 152, ..., 15n are tilted and installed at an angle, the performance of the blower will deteriorate except for very small ones. It is extremely difficult to manufacture a blade 11 with a three-dimensional curved surface.

Originally, the impellers of this type of blower were not cast but mainly assembled from rolled steel plates, and they were produced in small quantities in a wide variety of sizes, including large ones with a diameter of 3 to 4 meters. Therefore, even if the blades of such an impeller have a quadratic curved surface, it is extremely difficult to produce a blower with a three-dimensional curved surface at a cost that is commensurate with commercial profitability.

This is because, contrary to the conventionally generally produced linear radial centrifugal blower having an impeller with two-dimensionally curved blades 1 as shown in Fig. 1, as shown in Figs. 3 and 4, Although linear radial type mixed flow fans that require blades 11 with three-dimensional curved surfaces are expected to have high performance intermediate between centrifugal fans and axial fans, This is one of the reasons why it has not been put into practical use yet.

Therefore, the purpose of the present invention is to utilize a part of a cylindrical surface, which is a two-dimensional curved surface, and a part of a two-dimensional plane as a blade.
A linear radial inclined type that has the same effect as a blade with a three-dimensional curved surface that is close to the hydrodynamic ideal, has excellent blower performance, and is easy to manufacture by eliminating the manufacturing difficulties described above. Our objective is to provide an impeller for a flow blower. In order to achieve the above object, the present invention makes one common cylindrical surface and one plane in contact with this cylindrical surface interpenetrate both conical surfaces constituted by the main plate and the side plate, so that the cylindrical surface The central axis of is in a twisted positional relationship that does not intersect with the rotation axis,
The inflow angle at the inlet point of the blade should gradually change along the inlet edge of the blade, the outflow angle at the outflow point of the blade should gradually change along the outlet edge of the blade, The inflow point and the outflow point are connected to curves located on the cylindrical surface or the plane, respectively, and a thin plate blade is formed by a part of the cylindrical surface and the plane.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Prior to describing embodiments of the invention, the basic principles of the invention will be described below with reference to the drawings.

As already partially explained in FIG.
A truncated conical main plate 16 concentric with the main plate 16 and a truncated conical main plate 16 concentrically arranged at a distance in the direction of the rotation axis 14 to form a diagonal gas passage between the main plate 16 and the main plate 16. side plate 17;
A large number of gas passages are arranged on a circumference concentric with the rotation axis 14 in this gas passage, and each of them is fixed at one side edge to the main plate 16 and the other side edge to the side plate 17 by welding or riveting, and , a blade 11 having a gas inlet edge 12 near the rotational axis 14 and a gas outlet edge 13 on the opposite side, so that gas flows continuously from the inlet edge 12 to the outlet edge 13 during operation.
It is composed of.

Representative streamlines 151, 152, . . . , 15n inside the impeller have half apex angles θ1, θ2, . Each conical surface is concentric with the rotation axis 14. The blades 11 move on each of these conical surfaces to the inflow points Ml, M2, . . .
, Mn and ends at the outflow point N,, N2, . . . Nn. FIG. 5 is a plan view of the conical surface formed by the representative streamline 151, which is one of the representative streamlines.
Only one cross section of 1 is drawn. The cross section of the blade 11 in FIG. 5 has a desired inflow angle β11 at the inflow point M1 and a desired outflow angle β21 (900 in this case) at the outflow point N1, and between them, an elliptical shape is formed near the inflow point M. Connected by a curve whose radius of curvature ρ gradually changes as if it were partially approximated,
Thereafter, it has a shape connected by straight lines extending radially in the radial direction.

The desired inflow angle β11 and radius of curvature ρ of this blade 11 are represented by representative streamlines 152, 153, . . . 15 in FIG. As shown in Fig. 4, β, 2, β, 3, etc.
, β1n, so the blade 11 is required to have a complex three-dimensional curved surface. FIG. 6 shows representative streamlines 151, 152, . . . , 15 shown in FIG. 3.

This is a mutual perspective view of each conical surface constituted by the newly assumed cylindrical surface 19 and the plane 20, and the conical surface constituted by the representative streamline 151 in FIG. 7A-C, the cylindrical surface 19 and the plane 20. The continuum diagram of is shown in projection. In FIG. 6, the cylindrical surface 19 of radius C is a distance U in the U-axis direction. ．． V-axis direction/distance V. , and is inclined by an angle K with respect to the central axis H of the conical surface 151. That is, the distance U from the central axis 0 of the cylindrical surface 19. Considering a plane that is far away and includes the center axis H (same as the rotational axis 14) (this plane also includes the axis at the same time), when viewed in a direction perpendicular to this plane, that is, in the U direction, the cylindrical surface 19 The central axis 0 is inclined by an angle K as shown in FIG. 7B. In other words, the central axis 0 of the cylindrical surface 19
is in a twisted positional relationship that does not intersect with the rotation axis H. The plane 20 is a plane including the V axis and the W axis, and this cylindrical surface 19 and the S of the V axis soil. They are in contact at the cylindrical line SlS2 passing through the point. Therefore, plane 20 is also a plane containing generatrix 22 of conical surface 1511. Here, U, V, and W have the vertex E of the conical surface 1511 as the origin, the W axis is parallel to the central axis 0 of the cylindrical surface 19, and the V axis is in the W axis direction (6th These are three-dimensional orthogonal coordinates taken so as to overlap M8l, which is the point of contact between the cylindrical surface 19 and the plane 20 on the curve 0 when viewed in the direction of the arrow Q in the figure.

From the way the W axis is taken, the inclination angle K of the cylindrical surface 19 is expressed by the angle formed by the W axis and the central axis H of the conical surface 1511. The conical surface 1511 is the same as the conical surface constituted by the representative streamline 151 in FIG.
The interpenetration line with the plane 20, that is, the line segment from M1 through M, l to N1 among the lines of contact, is shown by a thick line on the developed drawing of the conical surface 1511 in FIG. 7C, and this is This is equivalent to Figure 5. That is, one representative streamline 151 shown in FIG. 5 has a desired inflow angle β11 and an outflow angle β21 (900 in this case) on the conical surface 1511, and a radius ρ that gradually changes around the inflow point M1 during that time. The cross-sectional shapes of the blades 11, which are connected by gentle curves located on the cylindrical surface 19 (see FIG. 7) and then connected by straight lines extending radially in the radial direction, are shown in FIGS. 7A and B. The distance U shown in , vO, the inclination angle K1, and the radius C are obtained geometrically by the method described later. In addition,
Since the plane 20 includes the generatrix 22 of the conical surface 1511, the outflow angle β21 at the outflow point β21 is 902. Let us consider these relationships geometrically.

Now, in FIG. 7, a curve G is a part of the line of intersection between the conical surface 15,1 and the cylindrical surface 19, which is constituted by the representative streamline 151.
Consider an arbitrary point m on 1hi. Point m has coordinates (U,) on FIG. 7A, coordinates (V, w) on FIG. 7B, and coordinates (X, y) on FIG. 7C. here,
The coordinates (X, y) have the vertex E of the conical surface 1511 as the origin,
These are the coordinates of an X-Y coordinate system consisting of a Y-axis passing through the contact point M5l and the outflow point N1 and an X-axis perpendicular to the Y-axis. In this case, the following relationship exists.

x = f (θ1, U, γ) (1) y = f (θ1, U, γ) (2) u = f (UO, vO, K, θ1, C, γ) (3)
φ=f(θ,,U,γ) (4) Here, γ is the distance between the point m and the central axis H, as shown in FIG. 7B, and φ is the distance between the point m and the central axis H, as shown in FIG. 7C. This is the angle that the straight line connecting m and the origin E makes with the Y axis.

Furthermore, the relational expressions (1) to (4) based on the differential method are
), the radius ρ and angle (flow angle) β at point m in FIG. 7C can be obtained.

If the point m is on the inflow point M1, then β is the inflow angle β1
1, and the point m is the contact point M8 between the cylindrical surface 19 and the plane 20.
1, then β matches the flow angle β21 (90 in this case). Similarly, any point m is the representative streamline 15
1, the coordinate u expressed by equation (3) is u- regardless of the position of point m. 0
(3)′,
Equations (5) and (6) are each ρ-00 (infinity)
(5Yβ=β81=β21 (90 in this case) (6Y).

Whether the calculation is performed on the cylindrical surface 19 (on the curve Q1) or on the plane 20 (on the straight line M8lNl), the flow angle βS1 at the contact point M8l will be the same value (90 tangent in this case). , this is because the cylindrical surface 19 and the plane 20 are in contact at the cylindrical generatrix S1-S2, which includes the contact point M8l, and as a result, the intersecting line from the inflow point M1, passing through the contact point M8, and reaching the outflow point N1 is expressed in algebra as It becomes continuous.

Also, the radius of curvature ρ changes little by little as the point m moves from the inlet point M to the contact point M8l, so
The curve from the inflow point M1 to the contact point M8l is ideally smooth compared to the impeller of a conventional linear radial centrifugal blower in which a single or at most two radii are connected near the inflow point M1. .

As a result of the above, the representative streamline 15 shown in FIG. 3 is obtained as schematically shown in FIG. 6.

Hereinafter, each representative streamline 152, 153,
. . 150 are obtained as the intersecting lines with the cylindrical surface 19 and the plane 20. Figure 8A shows this state by the arrow Q in Figure 6.
This figure corresponds to FIG. 7A, and FIG. 8B corresponds to FIG. 7B.

Each of these mutual penetration lines corresponds to each conical surface 1521, 1531,...
, 15n1 can be easily calculated by performing the same calculation as that for the conical surface 1511. In other words, FIGS. 8A and B are in addition to the conical surface 1511 in FIG.
have a common axis H, and half apex angles θ2, θ3, ·
...θ.

Conical surfaces 1521, 1531, . . . , 15n1 are added. Such n conical surfaces 1511,1
521,..., 15n1 as the representative streamline 151,
152, 15n have the same arrangement as n conical surfaces, and the blade 11 in FIG. 3 is replaced by the cylindrical surface 1 with radius C in FIG.
9 and a part of the plane 20. Figure 6, Figure 8A
However, as is clear, if each phase penetration line on the n conical surfaces is viewed in the axial direction of the cylindrical surface 19 (in the direction of arrow Q in FIG. 6), each phase penetration line, that is, the blade 11, is a cylinder with radius C. As part of the two-dimensional curved surface composed of the surface 19 and the plane 20, there is no twist and the same cross-sectional shape appears to overlap.

If the conical surface 1511 is developed into a plane, as described above, Fig. 7C
However, the conical surfaces 1521, 1531, ... 1501
can be expanded in the same way, and the mutual line due to each expansion is
Although illustration is omitted in FIG. 8, as schematically shown in FIG. 6, starting from the inflow points M2, M3, . , . The spaces between the two are smoothly connected by a curve whose radius of curvature ρ changes little by little. Each interpenetrating line, that is, each representative streamline 152, 153, . . . , 15. The upper outflow angles β22, β23゜゜゜・β2n are the intersecting plane 2
Since 0 passes through the generatrix of each conical surface 1521, 1531, . . . , 15n1, it is 900 (a constant value). Of course, each intersecting line has contact points M82, m83, and the cylindrical surface 19 and the plane 20, respectively.
゜゜゜m8n is also continuous in algebra. As mentioned earlier in FIG. 3, the inflow angles β, 1, β12, ..., β, o differ slightly from each other for each representative streamline 15, 152, ..., 150. This is natural because the radial distance γIO of the inflow point is changing. As described above, each interpenetrating line, that is, each representative streamline 1
51,152,...,15. is calculated and determined, the curve Mr at the representative streamline 151;
The curve at 0. , for each remaining representative streamline.
―――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――――‖‖‖‖‖
Straight line M8lNl at 1, straight line M5 at representative streamline 15n.
NO, the straight line M8lm8 spans each remaining representative streamline. and a portion surrounded by curve q is cut out from plane 20. This cutting locus is the coordinate of m point in Fig. 7, that is, m (U, v,
w) Easier to know. On the other hand, the cutout locus when expanded on a plane is also 32+=Shizukugopo''Poten?
Cut out the part surrounded by and MlMn, and inflow point Ml
FM2Fl @ 2Mn to contact MSl) MS2yO Toki M8
.

You may bend the part that corresponds to radius C. In this case, radius C
Since the line of contact between the cylindrical surface 19 and the plane 20 is the generatrix S, -S2 of the cylindrical surface 19, it is easy to bend the steel plate by rolling, for example. As described above, from the cylindrical surface 19 and the plane 20, the blade 1 is
1, or by bending the previously cut steel plate to a radius C at the part near the inflow point and inserting it between the main plate 16 and the side plate 17 as shown in FIG. Even without using blades with three-dimensional curved surfaces, which are required for mixed flow blowers, it is possible to easily manufacture blades that have the same performance.

Actually, when designing the impeller of the linear radial type mixed flow blower according to the present invention, first, the representative streamline 15 shown in FIG.
Decide on 1 to 15n.

From this, the half apex angle θ1~θ of the conical surface. is decided. Since the inner and outer diameter ratio of the blade has a standard value determined depending on the air volume and wind pressure, the inflow angle β1 along the blade inlet edge 12 is determined from the rotation speed.
The distribution of is determined. The radial distance γ8 of the contact point M5 between the curved part and the straight part on the blade 11 has also been determined as a standard value based on experience. The distance U shown in FIGS. 6 and 7. ,v
Once the inclination angle K and the cylinder radius C are determined, O is uniquely determined from the radial distance γ81 (FIG. 7B) of the contact point M5. Therefore, the remaining variables are K and C, and by changing these two variables, K (5C) such that the inflow angle β1 at the entrance edge 12 becomes a predetermined value can be found.As described above, As design data, it is best to prepare data so that various dimensions can be found immediately when the inlet angle and inner/outer diameter ratio of the impeller are given.

For example, in the case of the inner/outer diameter ratio λ and the cone half-vertical angle θ, it is preferable to create a chart in which the cylinder radius C is used as a parameter, the horizontal axis is the inclination angle K, and the vertical axis is the inflow angle β1. In all of the basic principles explained above, the outflow angle β2 is set to a constant value of 90 by setting the plane 20 to be intersected so that the generatrix of the conical surface is included in the plane. In the embodiment of this invention, in order to change the performance of the blower by adjusting the pressure coefficient, β2 is
We will deal with the case of gradual change along the exit circle 13 of No. 1.

Even when the outflow angle β2 changes gradually in this way, various dimensions can be found by calculations similar to the basic principle described above.

For example, when attempting to gradually change the outflow angle β2 along the outlet edge 13 in order to make the boost head at the outlet edge 13 more uniform or to improve performance, the cylindrical surface 19 and the flat surface 20 The flow angle β5 at the contact point M8 may be set to an angle smaller (or larger) than 900. A continuation diagram corresponding to FIG. 7 in this case is shown in FIG. Here, the plane 20 is parallel to the W axis and at a point S on the V axis. It is set to intersect with the V-axis at a constant angle. Below, each conical surface 1511, 1521, ..., 150
1 and the cylindrical surface 19 and the plane 20 are obtained in the same way, the outflow angle β2 of the blade 11 becomes β2, , at each mutual penetration point.
β22, . (In this case, they are connected smoothly by a backward curved line). In theory, the blade 11 is also continuous in terms of algebra at the contact points M5l to M5O between the cylindrical surface 19 and the plane 20. FIG. 11 shows that a conical intermediate plate 21 is further inserted into the impeller of FIG.
and 112.

Depending on the circumstances, it is also possible to insert a plurality of intermediate plates to divide the blade 11 into more parts. This means that if there is only one cylindrical surface 19 and one flat surface 20 across all the representative streamlines 151 to 150 on the blade 11, the inflow angles β1 to β1 will be the same. This is because, if the necessary changes in the flow angles β21 to β2n cannot be satisfied, blades formed by interpenetration with a plurality of mutually different cylindrical surfaces and planes can be used. Still another reason is that the intermediate plate 21 is inserted to increase the strength of the impeller itself.
As mentioned above, this invention replaces the conventionally required three-dimensional curved surface in the impeller of a linear radial mixed flow blower.
By using a part of the cylindrical surface, which is a two-dimensional curved surface, and a part of the two-dimensional plane, it is possible to exhibit the same performance as an ideal three-dimensional curved blade.

In other words, the inlet and outlet angles of the blades gradually change depending on the position of each representative streamline in the gas passage in the impeller, and the curve near the inlet point also has a linear radial centrifugal shape. It is not an arc with a single radius or at most two arcs connected together as seen in blowers, but an arc with a radius of curvature along the chord length (the length of the blade in the flow direction), which is close to the hydrodynamic ideal. It has a shape that changes gradually. In this way, it was considered extremely difficult to manufacture because it required three-dimensionally curved blades, and for this reason, although it was expected to have a high performance intermediate between centrifugal fans and axial flow fans, it was not commercialized. According to the present invention, a linear radial type mixed flow blower can be manufactured at low cost and its industrial value can be increased.

[Brief explanation of drawings]

Figure 1 is a longitudinal sectional view of a part of the impeller of a linear radial type centrifugal blower, Figure 2 is a front view of Figure 1, and Figure 3 is a part of the impeller of a linear radial type mixed flow fan. 4 is a perspective view of the main part of FIG. 3, FIG. 5 is a plan development view of the conical surface 15, 1 formed by the representative streamline 151 of FIG. 3, and FIG. 6 is a plan view of the present invention. Figures 7A-C and 8A and B are projection views of Figure 6, and Figure 9 is a straight radial view based on the same basic principle. A partial perspective view showing an example of an impeller of a type mixed flow blower, FIGS. 10A-C are projection views corresponding to FIGS. 7A-C showing an embodiment of the present invention, and FIG. 11 shows an intermediate plate. It is a longitudinal cross-sectional view which shows a part of example of the impeller inserted. 11 (111, 112) ... feather, 12 ...
...Entrance edge, 13...Exit edge, 14I-1.
...rotation axis, 151, 152,..., 15.

Claims (1)

[Claims] 1. A truncated conical main plate concentric with the rotation axis, and a truncated conical side plate arranged concentrically at a distance in the direction of the rotation axis to form a diagonal gas passage with the main plate. , are disposed in the gas passage on a circumference concentric with the rotation axis, each having one side edge fixed to the main plate and the other side edge fixed to the side plate, and each of which is fixed to the rotation axis. It has a gas inlet edge near the center and a gas outlet edge on the opposite side, and is equipped with a vane through which gas flows continuously from the inlet edge to the outlet edge during operation, and on both conical surfaces constituted by the main plate and the side plate. On the other hand, one common cylindrical surface and one plane in contact with this cylindrical surface are made to intersect with each other, and the central axis of the cylindrical surface is in a twisted positional relationship that does not intersect with the rotational axis. The inflow angle at the inlet point of the vane should gradually change along the inlet edge of the vane, the outflow angle at the outflow point of the vane should gradually change along the outlet edge of the vane, and A linear radial type characterized in that these inflow points and outflow points are connected to match curves located on the cylindrical surface or the plane, respectively, and a thin plate blade is formed by a part of the cylindrical surface and the plane. Impeller of mixed flow blower.