JPH07310642A - Hydraulic machinery and manufacture thereof - Google Patents

Abstract

PURPOSE:To uniformize velocity of flow flowing in the annular flow passage of an annular body and to reduce incurring of a collision loss and a hydraulic loss at the inlet of an annular flow passage by a method wherein a plurality of rib-form protrusions or grooves are formed in the specified spot of the inner surface of a spiral case. CONSTITUTION:In the section of the inlet part of a spiral case 2, a portion extending to an outer periphery spaced away from the rotary shaft 7 of an impeller 6 is partitioned into n+1 virtual part cases by (n) virtual curved surfaces. Rib-form protrusions 8 or grooves 9 are formed along an intersection line between a given virtual curved surface and the inner surface of the helical case 2 so that an i-th virtual curved surface extends to an annular flow passage in a position thetaSAi in a peripheral direction from the inlet part of the helical case 2 and an i+1-th virtual curved surface extends to the inlet of the annular flow passage in a position thetaSAi +1. However, Ai+1 represents the casing sectional area of an i+ 1-th virtual part case and SAi represents a total of the sectional areas of first -i-th virtual part case. When SAO is the total sectional area of the inlet part, a formula of thetaSAi=SAi+SA0X 360 is established.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic machine such as a hydraulic turbine or a pump hydraulic turbine having a projection or a groove on the inner surface of a spiral casing, and a method for manufacturing the hydraulic machine.

[0002]

2. Description of the Related Art FIG. 11 is a sectional view showing an example of a water turbine having a conventional spiral casing, FIG. 12 is a view showing a flow state in the water turbine of FIG. 11, and FIG. 13 is a conventional spiral casing. It is a schematic diagram of the flow of.

The main components of a water turbine are a spiral casing 2 connected to a penstock 1, two opposing annular plates 3, a stay vane 4 sandwiched between the annular plates 3, a movable guide vane 5 for adjusting the flow rate, and a high speed. It is composed of an impeller 6 that rotates in the direction of and a rotating shaft 7 that is an axis of the impeller 6.

The stay vanes 4 and the guide vanes 5 are
A plurality of blades are arranged on the outer circumference of the impeller 6. Then, the water flow from the water pressure pipe 1 passes through the fixed vane 4 and the movable guide vane 5 that are fixed from the spiral casing 2, and then flows out through the impeller 6. In general, since the water flow from the penstock 1 is bent in the circumferential direction by the spiral casing 2, the flow speed distribution in the spiral casing 2 is high on the inner peripheral side and conversely on the outer peripheral side as shown in FIG. It has a slow distribution.

On the other hand, on the other hand, the pressure distribution is low on the inner peripheral side and high on the outer peripheral side. Usually a spiral casing 2
In the vicinity of the center of the height of the stay vane 4 inside, this pressure gradient is almost balanced with the centrifugal force due to the water flow being bent in the circumferential direction, and a balanced flow state is achieved.

[0006]

However, in the vicinity of the upper and lower inner wall surfaces of the spiral casing 2, since the flow velocity is reduced due to the influence of the viscosity of the fluid, the above-mentioned balance between the pressure gradient and the centrifugal force cannot be maintained. As shown in FIG. 13, an excessive inward flow 11 larger than the inward flow in the central portion is generated near the wall surface of the spiral casing 2. As a result, a vortex as shown in the figure is generated in the cross section of the spiral casing 2, or the meridional flow rate of the flow flowing into the stay vane 4 becomes uneven as shown in FIG. Since the inflow angle differs in the meridional plane direction, the collision loss at the inlet of the stay vane 4 increases, and the loss of the water turbine significantly increases.

The excessive inward flow 11 as described above is
It is generally called a secondary flow because it flows in a plane orthogonal to the direction of the main flow, but as a method of reducing the flow loss due to this secondary flow, it has been conventional to bind it with fins of the secondary flow. This method has been generally used, and it is described in Opportunity Engineering Handbook A4 Fluid Engineering Japan Opportunity Society. Specifically, for example, as shown in FIG. 15, in a bent pipe such as an elbow, the water flow guide plate 14 dividing the flow passage can reduce the loss due to the secondary flow.

Further, in Japanese Utility Model Laid-Open No. 59-172228, a water flow guide plate that divides the cross section of the spiral casing into two parts is disclosed.
A method has been proposed in which a secondary flow, that is, an excessive flow is suppressed from being provided in the spiral casing flow passage.

However, unlike the curved pipe such as the elbow, the flow field of the spiral casing always has a flow flowing into the stay vane 4, so that the flow field of the water flow guide plate 14 as shown in FIG. If it is oriented in the tangential direction of the curve, even natural inward runout toward the inlet of the stay vane is suppressed, so that the flow path as a whole may not be able to reduce the flow loss.

As described above, in order to achieve the efficiency improvement in the conventional hydraulic machine, an excessive inward flow in the spiral casing is suppressed, and there is no vortex and a uniform flow velocity distribution is achieved at the inlet of the stay vane. Development of hydraulic machinery is desired.

Therefore, according to the present invention, it is possible to prevent an excessive inward flow in the spiral casing, increase the collision loss at the stay vane inlet, and reduce the hydraulic loss that has been conventionally caused by the inward flow. An object of the present invention is to provide a highly efficient hydraulic machine and a manufacturing method thereof.

[0012]

In order to achieve the above object, the invention corresponding to claim 1 is provided with an impeller rotating shaft, an impeller, a spiral casing, and an annular body, and the spiral is provided on the outer periphery of the impeller. In a hydraulic machine in which the center of the casing coincides with the impeller rotating shaft and is arranged on the outer periphery of the annular flow path of the annular body, in the cross section of the inlet portion of the spiral casing, the casing is separated from the impeller rotating shaft. When the outer peripheral side is partitioned into n + 1 virtual partial casings by n virtual curved surfaces, the total cross-sectional area of the inlet is SA
0, the i + 1-th virtual partial casing cross-sectional area formed by the i-th virtual curved surface on the inner peripheral side and the i + 1-th virtual curved surface (the outermost casing inner wall surface when i = n) is A
i + 1, where the sum of the first to i-th virtual partial casing cross-sectional areas is SAi, the i-th virtual curved surface is at the position θSAi (degrees) in the circumferential direction from the inlet of the spiral casing. Reaches the entrance, and the i + 1th virtual curved surface is θS
A protrusion or groove was formed on the inner surface of the spiral casing along the intersection of the virtual curved surface defined by the following equation and the inner surface of the spiral casing so as to reach the inlet of the annular flow path at the position of Ai + 1 (degrees). It is a hydraulic machine.

ΘSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, 1 ≦ i ≦ n.

In order to achieve the above-mentioned object, the invention according to claim 2 is such that n rib-shaped protrusions at a distance h from the inner wall surface of the spiral casing are provided on the inner surface of the spiral casing, and n + 1 spiral casings are provided. N to divide into partial caseins
The hydraulic machine according to claim 1, wherein the hydraulic machine is provided along a virtual curved surface and the distance h is defined by the following equation.

0.0005 × Ds ≦ height h ≦ 0.025 × Ds where Ds is the inner diameter of the winding start cross section of the spiral casing. In order to achieve the above-mentioned object, the invention according to claim 3 provides the inner surface of the spiral casing with n rib-shaped projections at a distance h from the inner wall surface of the spiral casing, and with the spiral casing having n + 1 partial casings. It is provided along n virtual curved surfaces that are divided into two parts, and the installation range of the tips of the rib-like projections in the cross section of the inlet of the spiral casing has a width Db between the outermost periphery of the cross section of the spiral casing and the inlet of the annular flow path.
3. When, the center position of the cross section of the spiral casing or, when the cross section of the spiral casing can be approximated by a circle, is within the range defined by ± 0.25 × Db from the center position. It is a hydraulic machine.

In order to achieve the above object, the invention according to claim 4 is such that a virtual curved surface that divides the spiral casing into partial casings at an interval b on the inner surface of the spiral casing, and a virtual inner wall surface of the spiral casing. Along the line of intersection,
The hydraulic machine according to claim 1, wherein a groove having a width b and a depth h is provided.

In order to achieve the above object, the invention according to claim 5 is provided with an impeller rotating shaft, an impeller, a spiral casing, and an annular body, and the center of the spiral casing is on the outer periphery of the impeller. It is arranged on the outer circumference of an annular flow path that is coincident with the wheel rotation axis and has in the annular body, and in the cross section of the inlet portion of the spiral casing, extends from the impeller rotation axis to the outer circumference side. , When partitioning into n + 1 virtual partial casings by n virtual curved surfaces,
The total cross-sectional area of the inlet portion is SA0, and the i + 1th virtual partial casing section formed by the i-th virtual curved surface on the inner peripheral side and the i + 1th virtual curved surface (the outermost casing inner wall surface when i = n) When the area is Ai + 1 and the total of the first to i-th virtual partial casing cross-sectional areas is SAi, the i-th virtual curved surface is at the position θSAi (degrees) in the circumferential direction from the inlet of the spiral casing. Reaching the inlet of the flow path, i
The + 1st virtual curved surface is formed on the inner surface of the spiral casing along the line of intersection between the virtual curved surface and the inner surface of the spiral casing defined by the following equation so as to reach the inlet of the annular flow path at the position of θSAi + 1 (degree). When manufacturing a hydraulic machine having protrusions or grooves, when the spiral casing is composed of a plurality of flat plates, each flat plate is bent so as to match a predetermined shape of the spiral casing, and then each of the bent Be sure to form a projection or groove on each flat plate so that it matches the projection or groove finally formed on the inside of the flat plate, and after assembling each flat plate by welding etc. after forming this projection or groove It is a method of manufacturing a hydraulic machine characterized by the above.

ΘSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, 1 ≦ i ≦ n.

In order to achieve the above object, the invention according to claim 6 is characterized in that, when the spiral casing is composed of a plurality of flat plates, before bending each flat plate to fit a predetermined shape of the spiral casing. In, the groove is formed in advance on one side of each flat plate so as to match the groove finally formed on the inside of each flat plate before bending,
The hydraulic machine according to claim 5, wherein after the grooves are formed, the flat plates are bent so as to fit the predetermined shape of the spiral casing, and then the bent flat plates are assembled by welding or the like. Is the manufacturing method.

In order to achieve the above object, the invention according to claim 7 is provided with an impeller rotating shaft, an impeller, a spiral casing, and an annular body, and the center of the spiral casing is on the outer periphery of the impeller. It is arranged on the outer circumference of an annular flow path that is coincident with the wheel rotation axis and has in the annular body, and in the cross section of the inlet portion of the spiral casing, extends from the impeller rotation axis to the outer circumference side. , When partitioning into n + 1 virtual partial casings by n virtual curved surfaces,
The total cross-sectional area of the inlet portion is SA0, and the i + 1th virtual partial casing section formed by the i-th virtual curved surface on the inner peripheral side and the i + 1th virtual curved surface (the outermost casing inner wall surface when i = n) When the area is Ai + 1 and the total of the first to i-th virtual partial casing cross-sectional areas is SAi, the i-th virtual curved surface is at the position θSAi (degrees) in the circumferential direction from the inlet of the spiral casing. Reaching the inlet of the flow path, i
The + 1st virtual curved surface is formed on the inner surface of the spiral casing along the line of intersection between the virtual curved surface and the inner surface of the spiral casing defined by the following equation so as to reach the inlet of the annular flow path at the position of θSAi + 1 (degree). When manufacturing a hydraulic machine having protrusions or grooves, when the spiral casing is composed of a plurality of flat plates, this flat plate is bent before it is bent to fit the predetermined shape of the spiral casing. The projections or grooves are formed on one side of each flat plate so as to match the projections or grooves that are finally formed on the inside of each previous flat plate, and then each flat plate is formed after the projections or grooves are formed. Is bent so as to fit the predetermined shape of the spiral casing, and then the bent flat plates are assembled by welding or the like.

ΘSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, 1 ≦ i ≦ n. Is.

[0022]

According to the inventions corresponding to claims 1 to 4,
Since a plurality of rib-shaped projections or grooves are formed on the inner surface of the spiral casing, in the flow flowing into the spiral casing, an excessive inward flow across the projections or grooves is blocked by the projections or grooves. Or, it flows along an imaginary curved surface composed of groove protrusions, and a predetermined winding angle θ
At the position of SAi or θSAi + 1, it smoothly flows into the inlet of the annular flow path. As a result, the flow velocity flowing into the annular flow passage of the annular body is made uniform, so that the vortex generated in the conventional example does not occur and the collision loss at the inlet of the annular flow passage does not increase. The hydraulic loss generated by the excessive inward flow is reduced. According to the inventions corresponding to claims 5 to 7, workability is facilitated and manufacturing cost is reduced.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. First, the principle configuration of a hydraulic machine according to the present invention will be described with reference to FIGS. 1 and 2. As shown in FIG. 1A, a rib-shaped projection 8 is formed on the inner surface of the spiral casing 2 from the casing inlet.

As shown in FIG. 1B, a groove 9 is formed on the inner surface of the spiral casing 2 from the casing inlet. In this case, the direction in which the rib-shaped projection 8 or the groove 9 extends is not the tangential direction of the spiral casing 2 but extends as shown in FIG. That is, on the outer periphery of the impeller 6, the annular plate 3 whose center coincides with the impeller rotating shaft 7 and faces
In a hydraulic machine having an annular flow passage formed by, and a casing 2 formed in a spiral shape on the outer periphery of the annular flow passage, in a cross section of an inlet portion of the casing 2 connected to the hydraulic pipe 1, an impeller rotating shaft is provided. From the inner peripheral side near 7 to the outer peripheral side away from the impeller rotating shaft 7, by n virtual curved surfaces,
When partitioning into n + 1 virtual partial casings, the total cross-sectional area of the inlet of the casing 2 is SA0, the i-th virtual curved surface from the inner peripheral side and the i + 1-th virtual curved surface (when i = n, the outermost casing inner wall surface). ), The cross-sectional area of the i + 1-th virtual partial casing is Ai + 1, and the total cross-sectional area from the first to the first virtual partial casing is SAi. At the position of θSAi (degrees) in the circumferential direction, it reaches the inlet of the annular flow path, i
The + 1st virtual curved surface reaches the inlet of the annular flow path at the position of θSAi + 1 (degrees).

That is, θSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, the rib-shaped projection 8 or the groove 9 is formed along the virtual intersection line between the virtual curved surface defined by the relationship of 1 ≦ i ≦ n and the inner surface of the casing.

As described above, since a plurality of rib-shaped projections 8 or grooves 9 (hereinafter referred to as projections 8 and 9) are formed on the inner surface of the spiral casing, the flow flowing from the hydraulic pipe 1 into the spiral casing 2 is described. , The excessive inward flow across the projections 8 and 9 is blocked by the projections 8 and 9, and flows along the virtual curved surface formed by the projections 8 and 9, and the predetermined winding angle θSAi or θSAi + 1 At the position, it smoothly flows into the inlet of the annular channel. As a result, the flow velocity flowing into the stay vanes 4 sandwiched between the two opposed annular plates 3 is made uniform, so that the vortex shown in FIG. 13 does not occur,
Since the collision loss at the inlet of the stay vane 4 does not increase, the hydraulic loss that has been conventionally caused by an excessive inward flow is reduced.

In order to exert such an effect, the height h of the rib-shaped projections 8 from the inner wall surface of the casing must be about the thickness of the deceleration area because the inward flow occurs in the deceleration area near the wall surface. I have to.

Generally, the flow velocity distribution in the conduit is u / Uo = (y / R) ^{1 / n} . Where u: flow velocity, Uo: maximum flow velocity in cross section,
It is represented by y: distance from the wall surface, R: radius of the pipeline.

The index n value changes depending on the number of Reynolds in the pipeline, but in the case of a hydraulic machine, it is in the range of 10 ⁵ to 10 ⁷ , so it can be considered that n = 10. In this case u / U
u / Uo is the deceleration region near the wall surface where o is 0.75 or less.
= 0.5 to 0.75, the height h of the rib-shaped projection 8 is 0.00 with respect to the inner diameter D (= 2 * R) of the conduit.
The range is from 05 to 0.025. That is, 0.000
There is no effect of the rib-shaped projection 8 having a height h of 5XD or less, and it is not necessary to set the height h of the rib-shaped projection 8 to 0.025XD or more.

On the other hand, the groove 9 corresponds to the case where the number n of virtual curved surfaces is increased, and the height h may be lower than that of the rib-shaped projection 8, but the interval is narrower than that of the rib-shaped projection 8. , There must be a large number. The height of the groove 9 is 1 to 2 of the pipe inner diameter.
% Is suitable and by doing so reduces the flow loss in the line.

Next, embodiments of the present invention will be described with reference to the drawings. 3 is a sectional view showing a first embodiment of a hydraulic machine according to the present invention, and FIG. 4 is a horizontal sectional view of a water turbine for explaining the operation of FIG. This embodiment is an example in which two sets of rib-shaped projections 8 are provided on the inner surface of the spiral casing 2. That is, when the cross section of the inlet portion of the casing 2 connected to the penstock 1 is divided into four virtual partial casings by the three virtual curved surfaces, the total sectional area of the inlet portion of the casing 2 is SA0, i = 1 to 3 4 divided into virtual curved surfaces
The cross-sectional area of each virtual casing is A1, A2,
A3 and A4, the first virtual curved surface reaches the inlet of the annular flow path 3 at the position θSA1 in the circumferential direction from the casing inlet, and the second virtual curved surface makes the annular flow at the position θSA2 in the circumferential direction from the casing inlet. If it reaches the inlet of the passage 3, and the third virtual curved surface reaches the inlet of the annular flow passage 3 at the position of θSA3 in the circumferential direction from the casing inlet, θSA1 (degree) = SA1 ÷ SA0 × 360 (degree) θSA2 ( Degree) = (A1 + A2) ÷ SA0 × 360 (degree) θSA3 (degree) = (A1 + A2 + A3) ÷ SA0 × 360 (degree) The fourth virtual curved surface corresponds to the outer peripheral wall of the casing, and when substituted into the above equation, θSA4 becomes 360 degrees, that is, the inlet of the spiral casing.

Since the thickness of the deceleration region generated along the inner wall of the casing is determined by the inlet diameter Ds at the start of winding of the spiral casing, the height h of the rib-like projection 8 from the inner wall of the casing is determined by the following equation. To be

0.0005XDs ≤ height h ≤ 0.025XDs Further, in the middle of the casing, the tangential direction of the casing wall surface and the direction of the pressure gradient (= the direction orthogonal to the impeller rotation axis) match, so the inward flow However, since the casing wall surface inclines from the horizontal on the inner and outer peripheries of the casing, the direction of the pressure gradient (= direction orthogonal to the impeller rotation axis) does not match the direction of the wall surface. Inward flow is less likely to occur than in the middle of the casing. Therefore, the tip position of the rib-like projection 8 at the casing inlet is defined as the center position of the cross section of the spiral casing (with a circular cross section when the outermost position of the inlet cross section of the spiral casing and the width to the inlet of the annular flow path are Db). If it can be approximated, its center) ±
It may be installed in the range of 0.25 × Db.

Here, a method of manufacturing the spiral casing 2 described above will be described with reference to FIG. First,
After bending a plurality of flat plates in accordance with a predetermined shape of the spiral casing 2, they are integrally assembled by welding or the like. At that time, the rib-shaped projections 8 may be attached to the inner surface of the casing by welding or the like after the integrated assembly is completed.
As for workability, it is easier to weld the rib-like projections 8 when the casing is divided into spiral small parts before being assembled together. Therefore, after the rib-shaped projection 8 is bent, it is attached to the spiral small portion 12 in the state shown in FIG. 7 before being integrally assembled and then integrally assembled by welding.

FIG. 5 shows a cross-sectional flow state of the spiral casing 2 according to the first embodiment described above. According to this figure, the conventional excessive inward flow is blocked by the rib-shaped projections 8, so that the fluid smoothly flows into the stay vanes 4. That is, as shown in FIG. 6, a uniform flow velocity distribution is formed in the height direction at the inlet of the stay vane 4, so that the efficiency of the hydraulic machine is improved.

Further, as defined above, the rib-shaped projection 8
Since it is formed in the spiral casing, a great effect can be obtained in a high specific velocity hydraulic machine or a large hydraulic machine in which an inward flow is remarkable.

Next, the second embodiment of the present invention will be described with reference to FIG.
And it demonstrates with reference to FIG. FIG. 8 is a cross-sectional view of the water turbine, which is an example in which the groove 9 is formed on the inner surface of the spiral casing 2. They are arranged in two directions (non-parallel to the tube axis direction of the spiral casing 2) intersecting with each other. The formation range of the groove 9 is the same as that of the first embodiment described above, but the method of forming the groove 9 is as follows. That is, as shown in FIG. 9A, after providing parallel grooves 9 on one surface of the flat plate 13 in advance, bending is performed according to the shape of the spiral casing 2, and after this bending, welding or the like is performed. assemble. Figure 9 (b)
The width b and the depth h of the pipe should be 1 to 2% of the inner diameter of the pipe.
It is similar to the embodiment.

In the second embodiment described above, since the groove 9 is machined in the flat plate 13 before bending the spiral casing into a predetermined shape, the manufacturing time is shorter than that of the first embodiment, and the cost is reduced. Can be cheaper.

FIG. 10 is a view for explaining the third embodiment of the present invention, in which the groove 9 formed in the spiral casing is not parallel to the axial direction of the spiral casing 2 in the second embodiment. It is an example manufactured as follows. That is, it is arranged so as to be parallel to the direction orthogonal to the cross section of the spiral casing 2, and in this case also, the same effect as that of the above-described embodiment can be obtained. In particular, in a low specific speed hydraulic machine, the spiral casing 2 is smaller than that of a high specific speed,
Since the inward flow direction is also close to the circumferential direction, only the processing is performed so that the direction of the groove 9 becomes a direction orthogonal to the cross section of the spiral casing 2 after bending, and the same effect as the above-described embodiment is obtained. Is obtained, which is particularly effective for low specific speed hydraulic machines.

[0040]

According to the present invention described above, it is possible to prevent an excessive inward flow in the spiral casing, increase the collision loss at the stay vane inlet does not occur, and the conventional inward flow causes. It is possible to provide a highly efficient hydraulic machine and a manufacturing method thereof, which can reduce the hydraulic power loss.

[Brief description of drawings]

FIG. 1 is a sectional view for explaining the principle configuration of a hydraulic machine according to the present invention.

FIG. 2 is a horizontal sectional view of the water turbine for explaining the operation of FIG.

FIG. 3 is a sectional view showing a first embodiment of the hydraulic machine according to the present invention.

FIG. 4 is a horizontal sectional view of the water turbine for explaining the operation of FIG.

FIG. 5 is a schematic diagram of water flow in the spiral casing of FIG.

6 is a schematic diagram of the water flow at the inlet of the stay vane of FIG. 1. FIG.

FIG. 7 is a diagram for explaining a method of manufacturing a spiral casing in the first embodiment of the hydraulic machine according to the present invention.

FIG. 8 is a sectional view of a hydraulic machine according to a second embodiment of the present invention.

FIG. 9 is a diagram for explaining a method of manufacturing a spiral casing in the second embodiment of the hydraulic machine according to the present invention.

FIG. 10 is a diagram for explaining a method of manufacturing a spiral casing in the third embodiment of the hydraulic machine according to the present invention.

FIG. 11 is a sectional view showing an example of a water turbine having a conventional spiral casing.

FIG. 12 is a diagram showing a flow state in the water turbine of FIG. 11.

FIG. 13 is a schematic diagram of a flow in a conventional spiral casing.

FIG. 14 is a state diagram of a conventional flow of a stay vane inlet.

FIG. 15 is a horizontal cross-sectional view of a bent pipe to which a water flow guide plate is attached.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Water pressure pipe, 2 ... Spiral casing, 3 ... Annular plate, 4 ... Stay vane, 5 ... Guide vane, 6 ... Impeller, 7 ... Rotating shaft, 8 ... Rib-shaped projection, 9 ... Groove, 10a ... I-th virtual Curved surface, 10b ... i + 1th virtual curve, 12 ... small portion casing after bending, 13 ... flat plate.

Claims (7)

[Claims] 1. An annular ring provided with an impeller rotating shaft, an impeller, a spiral casing, and an annular body, wherein the center of the spiral casing coincides with the impeller rotating shaft on the outer periphery of the impeller and has the annular body. In the hydraulic machine arranged on the outer periphery of the flow path, in the cross section of the inlet portion of the spiral casing, up to the outer peripheral side away from the impeller rotation axis, by n virtual curved surfaces, into n + 1 virtual partial casings. At the time of partitioning, the total cross-sectional area of the inlet portion is SA0, the i + 1th virtual surface formed by the i-th virtual curved surface on the inner peripheral side and the i + 1th virtual curved surface (the outermost casing inner wall surface when i = n) When the partial casing cross-sectional area is Ai + 1 and the total of the first to i-th virtual partial casing cross-sectional areas is SAi, the i-th virtual curved surface is θ in the circumferential direction from the inlet of the spiral casing.
At the position of SAi (degrees), the inlet of the annular flow path is reached, and i + 1
The virtual curved surface is projected at the inner surface of the spiral casing along a line of intersection between the virtual curved surface defined by the following equation and the inner surface of the spiral casing so as to reach the inlet of the annular flow path at a position of θSAi + 1 (degrees). Or a hydromachine with a groove. θSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, 1 ≦ i ≦ n. 2. The n-shaped rib-shaped projections at a distance h from the inner wall surface of the spiral casing are formed on the inner surface of the spiral casing along n virtual curved surfaces dividing the spiral casing into n + 1 partial casings. The hydraulic machine according to claim 1, wherein the distance h is defined by the following equation while being provided. 0.0005 × Ds ≦ height h ≦ 0.025 × Ds where Ds is the inner diameter of the winding start cross section of the spiral casing. 3. The inner surface of the spiral casing is provided with n rib-shaped projections at a distance h from the inner wall surface of the spiral casing, along n virtual curved surfaces dividing the spiral casing into n + 1 partial casings. In addition, the installation range of the tip of the rib-like projection in the cross section of the inlet of the spiral casing is such that when the width between the outermost periphery of the cross section of the spiral casing and the inlet of the annular flow path is Db, the center position of the cross section of the spiral casing. 3. The hydraulic machine according to claim 2, wherein when the cross section of the spiral casing can be approximated to be circular, the range is set to ± 0.25 × Db from the center position. 4. An imaginary curved surface dividing the vortex casing into partial casings at an interval b on the inner surface of the vortex casing, and an imaginary line of intersection with the inner wall surface of the vortex casing,
The hydraulic machine according to claim 1, wherein a groove having a width b and a depth h is provided. 5. An annular ring having an impeller rotating shaft, an impeller, a spiral casing, and an annular body, wherein the center of the spiral casing coincides with the impeller rotating shaft on the outer periphery of the impeller, and the annular body has the annular body. N + 1 virtual partial casings, which are arranged on the outer periphery of the flow path and have n virtual curved surfaces up to the outer peripheral side away from the impeller rotating shaft in the cross section of the inlet portion of the spiral casing. , The total cross-sectional area of the inlet portion is SA0, and the i + 1th virtual curved surface on the inner peripheral side and the i + 1th virtual curved surface (the outermost casing inner wall surface when i = n) are formed When the virtual partial casing cross-sectional area is Ai + 1 and the total of the first to i-th virtual partial casing cross-sectional areas is SAi,
The i-th virtual curved surface reaches the inlet of the annular flow path at a position of θSAi (degrees) in the circumferential direction from the inlet portion of the spiral casing, and the i + 1th virtual curved surface at the θSAi + 1 (degrees) of the annular flow path. In the case of manufacturing a hydraulic machine in which a protrusion or a groove is formed on the inner surface of the spiral casing along the intersection of the virtual curved surface defined by the following equation and the inner surface of the spiral casing so as to reach the inlet of When each flat plate is bent so as to match the predetermined shape of the spiral casing, the projection or groove finally formed on the inside of each bent flat plate. A method for manufacturing a hydraulic machine, characterized in that a protrusion or a groove is formed on each flat plate so as to coincide with the above, and each flat plate is assembled by welding or the like after forming the protrusion or the groove. θSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, 1 ≦ i ≦ n. 6. When the spiral casing is composed of a plurality of flat plates, before the flat plates are bent so as to conform to a predetermined shape of the spiral casing, the flat casing is preformed with respect to the inner side of the flat plates before the bending process. Then, a groove is previously formed on one side of each flat plate so as to coincide with the groove to be finally formed, and after this groove is formed, each flat plate is bent so as to match the predetermined shape of the spiral casing. The method for manufacturing a hydraulic machine according to claim 5, wherein each of the bent flat plates is then assembled by welding or the like. 7. An annular ring provided with an impeller rotating shaft, an impeller, a spiral casing, and an annular body, wherein the center of the spiral casing coincides with the impeller rotating shaft on the outer periphery of the impeller and has the annular body. N + 1 virtual partial casings, which are arranged on the outer periphery of the flow path and have n virtual curved surfaces up to the outer peripheral side away from the impeller rotating shaft in the cross section of the inlet portion of the spiral casing. , The total cross-sectional area of the inlet portion is SA0, and the i + 1th virtual curved surface on the inner peripheral side and the i + 1th virtual curved surface (the outermost casing inner wall surface when i = n) are formed When the virtual partial casing cross-sectional area is Ai + 1 and the total of the first to i-th virtual partial casing cross-sectional areas is SAi,
The i-th virtual curved surface reaches the inlet of the annular flow path at a position of θSAi (degrees) in the circumferential direction from the inlet portion of the spiral casing, and the i + 1th virtual curved surface at the θSAi + 1 (degrees) of the annular flow path. In the case of manufacturing a hydraulic machine in which a protrusion or a groove is formed on the inner surface of the spiral casing along the intersection of the virtual curved surface defined by the following equation and the inner surface of the spiral casing so as to reach the inlet of In the case where the flat plate is made of a flat plate, the flat plate is finally formed on the inner side of the flat plate before bending the flat plate so as to match the predetermined shape of the spiral casing. A protrusion or groove is formed in advance on one side of each flat plate so as to coincide with the protrusion or groove, and after this protrusion or groove is formed, each flat plate is bent to match the predetermined shape of the spiral casing, Hydraulic machine fabrication method, characterized in that each flat plate was processed and to assemble by welding or the like. θSAi (degrees) = SAi ÷ SA0 × 360 (degrees) θSAi + 1 (degrees) = [(SAi + Ai + 1) ÷ SA0] × 360
(Degree) However, 1 ≦ i ≦ n.