WO2016158636A1

WO2016158636A1 - Fluid machine equipped with diffuser

Info

Publication number: WO2016158636A1
Application number: PCT/JP2016/059302
Authority: WO
Inventors: 夕美子関野; 啓悦渡邉; ファイドンクリスタコポロス; メーダッドザンゲネ
Original assignee: 株式会社荏原製作所
Priority date: 2015-03-30
Filing date: 2016-03-24
Publication date: 2016-10-06
Also published as: CN107949705B; EP3279479A1; EP3279479A4; JPWO2016158636A1; CN107949705A; US20180080471A1; JP6706248B2

Abstract

In order to provide each diffuser flow path in a fluid machine so as to achieve uniform flow downstream from a diffuser, this fluid machine has a diffuser for converting the kinetic energy of a fluid to pressure energy, the diffuser has first diffuser flow paths and second diffuser flow paths configured so as to enable a fluid to pass therethrough, and the first diffuser flow paths and the second diffuser flow paths have different shapes.

Description

Fluid machine with a diffuser

The present invention relates to a fluid machine including a diffuser.

For example, a diffuser pump that transports water is known as a fluid machine including a diffuser. In general, a diffuser pump can transfer water at high pressure by applying kinetic energy to water with a rotating impeller and converting it into pressure energy with a diffuser provided on the discharge side of the impeller.

As an example, a high-pressure multi-stage diffuser pump includes a plurality of impellers fixed to a rotating shaft. A diffuser is provided on the radially outer side of each stage of the impeller. The diffuser is formed with diffuser blades that define a plurality of diffuser flow paths configured to allow fluid discharged from the impeller to pass through. The fluid that has passed through the diffuser flow path is guided to the next stage impeller.

In the diffuser pump, the diffuser is designed to reduce the pressure loss of the fluid passing through the pump, make the flow uniform, and improve the pump efficiency. Conventionally, in order to improve the pump efficiency of the diffuser pump, various shapes of the diffuser channel have been studied (Patent Document 1). A diffuser pump generally includes a plurality of diffuser channels, but all conventional diffuser channels have the same shape.

JP 2013-209883 A

Conventionally, the diffuser flow paths are all designed to have the same shape. However, depending on the shape of the flow path downstream from the diffuser, the flow of fluid discharged from the diffuser may not always be uniform. If the flow of fluid discharged from the diffuser enters the next stage impeller without being properly rectified, the pump efficiency may decrease.

This disclosure is intended to provide each diffuser flow path to reduce pressure loss as a whole. Another object of the present disclosure is to provide each diffuser flow path for making the flow downstream of the diffuser uniform.

According to one aspect of the present disclosure, a fluid machine is provided, the fluid machine having a diffuser for converting the kinetic energy of the fluid into pressure energy. The diffuser has a first diffuser flow path and a second diffuser flow path configured to allow fluid to pass through, and the shapes of the first diffuser flow path and the second diffuser flow path are different.

According to an aspect of the present disclosure, in the fluid machine, each of the first diffuser channel and the second diffuser channel has an inlet of the diffuser channel, and at least one of the first diffuser channel and the second diffuser channel. In the section, the cross-sectional areas of the first diffuser flow path and the second diffuser flow path that are orthogonal to the flow path center at the same distance from the inlet of each diffuser flow path are different from each other.

According to an aspect of the present disclosure, in a fluid machine, the fluid machine includes a first impeller that rotationally drives and imparts kinetic energy to the fluid, and the first diffuser channel and the second diffuser channel Located downstream of the first impeller in the flow direction.

According to an aspect of the present disclosure, in the fluid machine, the first diffuser channel and the second diffuser channel each have an outlet of the diffuser channel, and the fluid machine includes the first diffuser channel and the second diffuser flow. For supplying a fluid to a first combined flow channel fluidly coupled to an outlet of each diffuser flow channel of the path, and a second impeller at the next stage located downstream of the first impeller in the fluid flow direction; A first return channel fluidly coupled to the first merge channel, and the first return channel extends in the direction of the rotation axis of the first impeller.

According to an aspect of the present disclosure, in the fluid machine, the second diffuser channel is located closer to the first return channel than the first diffuser channel, and the cross-sectional area of the second diffuser channel is the first It is larger than the cross-sectional area of the diffuser channel.

According to an aspect of the present disclosure, in the fluid machine, the first diffuser channel and the second diffuser channel have a cross-sectional area that increases from an inlet of each diffuser channel toward an outlet of the diffuser channel. The second diffuser flow path has a region in which the rate of increase in cross-sectional area is relatively large, a small region, and a large region in order from the diffuser flow channel inlet to the diffuser flow channel outlet.

According to one aspect of the present disclosure, in a fluid machine, the diffuser includes a third diffuser channel and a fourth diffuser channel configured to allow fluid to pass therethrough, and the third diffuser channel and the fourth diffuser channel. The channel is located downstream of the first impeller in the fluid flow direction, the third diffuser channel and the fourth diffuser channel each have an outlet of the diffuser channel, and the fluid machine includes the third diffuser channel A second merging channel fluidly coupled to the outlet of each diffuser channel of the fourth diffuser channel, and a second return fluidly coupled to the second merging channel for supplying fluid to the second impeller. And the second return channel extends in the direction of the drive shaft of the first impeller.

According to one aspect of the present disclosure, in the fluid machine, the third diffuser channel and the fourth diffuser channel have shapes that are rotationally symmetric with respect to the first diffuser channel and the second diffuser channel, respectively.

According to an aspect of the present disclosure, in the fluid machine, the third diffuser channel and the fourth diffuser channel have a cross-sectional area that increases from an inlet of each diffuser channel toward an outlet of the diffuser channel. The fourth diffuser flow path has a region in which the increase rate of the cross-sectional area is relatively large, a small region, and a large region in order from the inlet of the diffuser flow channel to the outlet of the diffuser flow channel.

It is sectional drawing which shows the whole multistage diffuser pump structure by one Embodiment. It is sectional drawing of the periphery of the impeller and diffuser blade | wing of a multistage diffuser pump by one Embodiment. FIG. 3 is a cross-sectional perspective view taken along the line AA and the rotation axis of FIG. FIG. 3 is a cross-sectional view taken along line AA in FIG. FIG. 6 is a plan view showing a diffuser flow path according to one embodiment. 6 is a graph showing the relative size of the cross-sectional area at each position of each diffuser channel, according to one embodiment. FIG. 6 is a cross-sectional perspective view of a diffuser channel, according to one embodiment. FIG. 8 is a view showing a cross-sectional shape at positions P01 to P06 of the diffuser flow path shown in FIG. It is a graph which shows the relative flow volume of the fluid in each diffuser flow path by one Embodiment and each diffuser flow path by a comparative example. It is a figure which shows the pressure loss of each diffuser flow path and merge flow path by one Embodiment, and each diffuser flow path and merge flow path of a comparative example. FIG. 6 is a diagram showing the flow velocity of fluid at cross-sectional positions P01 to P06 of a diffuser flow path 104-5 according to a comparative example. FIG. 6 is a diagram showing the flow velocity of the fluid at each of the cross-sectional positions P01 to P06 of the diffuser flow path 104-5 according to one embodiment.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the accompanying drawings, the same or similar components are denoted by the same reference numerals, and redundant description is omitted. Further, the features shown in each embodiment can be applied to other embodiments as long as they do not contradict each other.

FIG. 1 is a cross-sectional view illustrating an overall configuration of a multistage diffuser pump 1A according to an embodiment of the present disclosure. The multistage diffuser pump 1 </ b> A includes a rotating member 30 and a stationary member 40.

Rotating member 30 includes a rotating shaft 10 supported at both ends. First to seventh impellers I1 to I7 are attached to the impeller attachment portions 10a to 10g of the rotary shaft 10. The rotating member 30 is mounted so as to be rotatable within the stationary member 40.

The stationary member 40 has an outer trunk portion 25. The outer body portion 25 includes a cylindrical member 20 that includes a suction port Wi and a discharge port Wo. The outer body portion 25 includes a suction side plate 18 and a discharge side plate 22 that close both ends of the tubular member 20. The stationary member 40 further has an inner trunk portion 2A. Diffuser blades V1 to V7 that form pumps P1 to P7 of each stage together with the impellers I1 to I7 are formed in the inner trunk portion 2A.

The first pump P1 is in the low-pressure chamber R1 communicating with the water inlet Wi, and is composed of an impeller I1 and a diffuser blade V1. The second to seventh pumps P2 to P7 are composed of impellers I2 to I7 and diffuser blades V2 to V7. The seventh pump P7 communicates with the high-pressure chamber R2 that communicates with the discharge port Wo.

FIG. 2 is a cross-sectional view of the periphery of the impellers I1 and I2 and the diffuser blades V1 and V2 of the multistage diffuser pump according to the embodiment of the present disclosure. In the embodiment shown in FIG. 2, the impellers I <b> 1 and I <b> 2 fixed to the rotary shaft 10 include a plurality of impeller blades 50, a hub 52 in which the impeller blades 50 are arranged at equal intervals, and the impeller blades 50. A shroud 54 covering the front surface. A diffuser portion 100 is formed on the downstream side of the impellers I1 and I2, that is, on the radially outer side.

FIG. 3 is a cross-sectional perspective view taken along the line AA and the rotation axis of FIG. 4 is a cross-sectional view taken along line AA in FIG. 3 and 4, the impeller I and the rotating shaft 10 are omitted in order to clarify the illustration of the diffuser unit 100.

2 and 3, the diffuser unit 100 has a plurality of diffuser blades 102. A diffuser flow path 104 is defined by the wall surface 109 on the hub 52 side, the wall surface 110 on the shroud 54 side, and each diffuser blade 102. The hub 52 and the shroud 54 are a main plate and a side plate of the impeller 102, respectively. As will be described in detail later, each diffuser channel 104 is formed so that its cross-sectional area increases from the inlet 106 of the diffuser channel 104 toward the outlet 108 of the diffuser channel 104. Further, at least some of the diffuser channels 104 have different shapes. In FIG. 3, the arrow indicates the direction of fluid flow.

As shown in FIGS. 3 and 4, a merging channel 150 that is in fluid communication with the diffuser channel 104 is formed on the downstream side of the outlet 108 of the diffuser channel 104, that is, on the radially outer side. In the embodiment shown in FIG. 4, four diffuser channels 104 are in fluid communication with one merge channel 150, and two sets of four diffuser channels 104 and one merge channel 150 are formed. . In the illustrated embodiment, the merge channel 150 is in the same plane as the diffuser channel 104. In addition, the number of the diffuser flow path 104 and the merge flow path 150 is arbitrary. For example, in another embodiment, three diffuser channels may be in fluid communication with one merge channel, and three sets of them may be formed.

The fluid discharged by applying kinetic energy by the impeller I1 enters the diffuser flow path 104 and is converted into pressure energy. The fluid exiting from the outlet 108 of the diffuser channel 104 of each diffuser channel 104 enters a merging channel 150 formed downstream of the outlet 108 of the diffuser channel 104. In the diffuser pump according to the embodiment of the present disclosure, the plurality of diffuser flow paths 104 are shaped in consideration of the shape of the downstream merge flow path 150 so that the fluid discharged from the diffuser flow path 104 is not lost as much as possible. Designed.

In one embodiment, a return channel 200 that is in fluid communication with the merge channel 150 is formed downstream of the merge channel 150. In the illustrated embodiment, the return channel 200 extends in the direction of the rotating shaft 10 as a whole.

In one embodiment, a return channel 250 that is in fluid communication with the return channel 200 is formed downstream of the return channel 200. The return flow path 250 as a whole extends radially inward toward the rotary shaft 10. Downstream of the return flow path 250, the next stage impeller I2 is formed.

In the illustrated embodiment, the fluid exiting the impeller I1 passes through the diffuser flow path 104, and then is supplied to the next stage impeller I2 through the merging flow path 150, the return flow path 200, and the return flow path 250. Is done.

As described above, each diffuser channel 104 is formed so that its cross-sectional area increases from the inlet 106 of the diffuser channel 104 toward the outlet 108 of the diffuser channel 104. Further, at least some of the diffuser channels 104 have different shapes. Hereinafter, the shape of the diffuser flow path 104 in one embodiment will be described in detail.

FIG. 4 is a plan view showing the diffuser flow path 104 and the merge flow path 150 cut out along the line AA in FIG. In the illustrated embodiment, eight diffuser channels 104 are defined between the eight diffuser vanes 102. Diffuser flow paths 104-1, 104-8, 104-7, and 104-6 are in fluid communication with merge flow path 150-1. Diffuser flow paths 104-2, 104-3, 104-4, and 104-5 are in fluid communication with merge flow path 150-2. For convenience, the diffuser channels 104-1, 104-8, 104-7, and 104-6 are group 1 and the diffuser channels 104-2, 104-3, 104-4, and 104-5 are group 2. . The fluid that has passed through the diffuser channels 104 of the group 1 and group 2 is supplied to the impeller at the next stage through the merging channel 150, the return channel 200, and the return channel 250.

FIG. 5 is a plan view showing one of the diffuser channels 104 according to one embodiment. As shown in the figure, a curve connecting the centers of the circles inscribed in the two diffuser blades 102 is defined as the flow path center of the diffuser flow path 104. In addition, a cross section perpendicular to the center of the channel on the most upstream side (left side in FIG. 5) is defined as the inlet 106 of the diffuser channel 104. In addition, a cross section perpendicular to the center of the channel on the most downstream side (right side in FIG. 5) is defined as the outlet 108 of the diffuser channel 104.

In the embodiment shown in FIG. 5, the diffuser channel 104 has a channel cross-sectional area that increases from the inlet 106 of the diffuser channel 104 toward the outlet 108 of the diffuser channel 104. In one embodiment of the present disclosure, at least a part of the plurality of diffuser channels 104 in the same group is different in shape from the other diffuser channels 104 in the same group. More specifically, the degree of increase in the cross-sectional area of the diffuser flow path 104 is different. For example, the cross-sectional areas of the diffuser channels 104 orthogonal to the channel center at the same distance from the inlet 106 of each diffuser channel 104 are different.

In one embodiment, the diffuser flow path 104 located near the return flow path 200 that is in fluid communication with the merge flow path 150 can be configured such that the degree of increase in the cross-sectional area of the flow path increases. In the embodiment shown in FIGS. 3 and 4, the return flow path 200 is located near the diffuser flow paths 104-1 and 104-5. Therefore, the diffuser channels 104-1 and 104-5 close to the return channel 200 are more than the other diffuser channels 104-2, 104-3, 104-4, 104-6, 104-7, and 104-8. The degree of increase in the channel cross-sectional area is large.

FIG. 6 is a graph showing the relative sizes of the cross-sectional areas at the respective positions of the diffuser channels 104-1 to 104-8 according to one embodiment. The horizontal axis represents the positions P01 to P06 of the diffuser channel shown in FIG. The position P01 corresponds to the inlet 106 of the diffuser channel 104, and the position P06 corresponds to the outlet 108 of the diffuser channel 104. The vertical axis of the graph in FIG. 6 represents the relative flow path cross-sectional area when the cross-sectional area at the position P01 of one diffuser flow path 104 as a comparative example is 100.

In one embodiment, the cross-sectional area of the diffuser flow path 104 close to the return flow path 200 is a region where the increase rate of the cross-sectional area is relatively large from the inlet 106 of the diffuser flow path 104 to the outlet 108 of the diffuser flow path 104. , Small area, large area. For example, in the graph of FIG. 6, the increase rate of the cross-sectional area of the diffuser flow path 104-5 near the return flow path 200 is large from the position P01 to the position P02, and is increased from the position P02 to the position P03. It becomes relatively small, and the increase rate increases again from the position P03 to the position P04. With such a configuration, the mixing loss can be reduced when the fluid from the other diffuser flow path 104 is merged in the merge flow path 150.

In other embodiments, the Group 1 diffuser channels 104-1, 104-8, 104-7, 104-6 and the Group 2 diffuser channels 104-5, 104-4, 104-3, 104-2 are: The shapes may be rotationally symmetric.

7 and 8 are diagrams showing an example of a cross-sectional shape of the diffuser flow path 104 according to an embodiment. FIG. 7 is a cross-sectional perspective view of the diffuser flow path 104 and schematically shows a cross-sectional shape at positions P01 to P06. In FIG. 7, the front diffuser blade 102 is indicated by a broken line. FIG. 8 shows cross-sectional shapes at positions P01 to P06 shown in FIG. 7 and 8, the upper side is the wall surface 110 on the shroud 54 side, and the lower side is the wall surface 109 on the hub 52 side.

7 and 8, in one embodiment, the diffuser flow path 104 is provided with a convex portion in the direction of the rotating shaft 10 to change the size of the cross-sectional area. As shown in FIGS. 7 and 8, in one embodiment, the diffuser channel 104 is convex on the shroud side at positions P01 and P02, is convex on the hub side at position P03, and is shroud at positions P04 to P06. Convex on both the side and the hub side. The cross-sectional shape in each position of the diffuser flow path 104 is arbitrary, and can be made into a different shape in other embodiments. For example, as a non-limiting example, a convex shape is formed only on the wall surface 110 on the shroud side and a convex shape is formed only on the wall surface 109 on the hub side from the inlet 106 of the diffuser flow path 104 to the outlet 108 of the diffuser flow path 104. Thus, both the shroud-side wall surface 110 and the hub-side wall surface 109 can have any shape that is convex.

The graph shown in FIG. 9 shows the flow rate per unit time of each diffuser flow path in numerical fluid dynamics (in a pump including a diffuser flow path according to an embodiment of the present invention and a pump including a diffuser flow path according to a comparative example). The results obtained by flow analysis using CFD (Computational Fluids) are shown. In the graph of FIG. 9, the horizontal axis indicates the diffuser channels 104-1 to 104-8 shown in FIG. 4, and the vertical axis indicates the relative flow rate in each of the diffuser channels 104-1 to 104-8. Represents. When the relative flow rate is 1, it means that the fluid flows at the same flow rate in all the diffuser flow paths 104-1 to 104-8. In the comparative example, all the diffuser channels are the same as the cross section of the comparative example shown in FIG. 6, and the merging channel is the same as the example shown in FIG. 9. In the graph of FIG. 9, the cross sections of the diffuser channels 104-1 to 104-8 in the embodiment of the present invention are formed as shown in FIG.

As shown in the graph of FIG. 9, the diffuser channels 104-1 to 104-8 are changed by changing the cross-sectional shape for each of the diffuser channels 104-1 to 104-8 as in the embodiment of the present disclosure. The variation in the flow rate is small. That is, in the embodiment of the present disclosure, the mixing loss in the merging channel 150 downstream of the diffuser channel 104 is reduced as compared with the comparative example in which the shapes of the diffuser channels 104 are all the same.

FIG. 10 is a diagram illustrating a result of pressure loss in the diffuser flow path 104 and the merge flow path 150 according to the CFD simulation. In FIG. 10, the magnitude of the pressure loss is shown in gray scale, and the darker the black, the greater the pressure loss. As can be seen from FIG. 10, the pressure loss as a whole is smaller in the embodiment of the present disclosure than in the comparative example.

FIG. 11 is a diagram showing the flow velocity of the fluid at the respective cross-sectional positions P01 to P06 of the diffuser flow path 104-5 according to the comparative example. FIG. 12 is a diagram illustrating the flow velocity of the fluid at each of the cross-sectional positions P01 to P06 of the diffuser flow path 104-5 according to the embodiment of the present disclosure. In FIG. 11 and FIG. 12, the flow velocity at each of the cross-sectional positions P01 to P06 is indicated by an isovelocity line, indicating that the flow velocity is larger toward the center of the cross section. As can be seen from FIG. 11 and FIG. 12, in the embodiment of the present disclosure, the distortion of the uniform flow velocity line is smaller than that of the comparative example, and the flow velocity distribution has a clean curve. Therefore, in the embodiment of the present disclosure, the fluid flow through the diffuser flow path is uniform, and the rectifying effect is improved. According to the embodiment of the present disclosure, noise and vibration in the pump can be reduced by increasing the pressure loss and rectifying effect.

As described above, the embodiment of the present invention has been described, but the present invention is not limited to the above-described embodiment. The features of the above-described embodiments can be combined or exchanged as long as they do not contradict each other.

I1 to I7 ... impeller 100 ... diffuser section 104 ... diffuser flow path 106 ... diffuser flow path inlet 108 ... diffuser flow path outlet 150 ... confluence flow path 200 ... Return channel 250 ... Return channel

Claims

A fluid machine,
The fluid machine has a diffuser for converting fluid kinetic energy into pressure energy;
The diffuser has a first diffuser flow path and a second diffuser flow path configured to allow fluid to pass through,
A fluid machine in which shapes of the first diffuser flow path and the second diffuser flow path are different.
The fluid machine according to claim 1,
The first diffuser channel and the second diffuser channel each have an inlet of a diffuser channel;
The first diffuser channel and the second diffuser that are orthogonal to the channel center at a position where the distance from the inlet of each diffuser channel is equal in at least a part of the first diffuser channel and the second diffuser channel. Fluid machines with different cross-sectional areas of flow paths.
The fluid machine according to claim 1 or 2,
The fluid machine has a first impeller that rotationally drives to give kinetic energy to the fluid,
The fluid machine, wherein the first diffuser channel and the second diffuser channel are located downstream of the first impeller in a fluid flow direction.
The fluid machine according to claim 3,
The first diffuser flow path and the second diffuser flow path each have an outlet of a diffuser flow path,
The fluid machine includes: a first merging channel fluidly coupled to an outlet of each of the diffuser channels of the first diffuser channel and the second diffuser channel;
A first return channel fluidly coupled to the first merging channel for supplying fluid to a second impeller at the next stage located downstream of the first impeller in the fluid flow direction; A fluid machine, wherein the first return channel extends in a direction of a rotation axis of the first impeller.
The fluid machine according to claim 4,
The second diffuser channel is located closer to the first return channel than the first diffuser channel, and the cross-sectional area of the second diffuser channel is greater than the cross-sectional area of the first diffuser channel. Also big, fluid machinery.
The fluid machine according to claim 5,
The first diffuser flow path and the second diffuser flow path are configured such that a cross-sectional area increases from an inlet of each of the diffuser flow paths toward an outlet of the diffuser flow path,
The second diffuser flow path has a region in which an increase rate of a cross-sectional area is relatively large, a small area, and a large area in order from an inlet of the diffuser flow path to an outlet of the diffuser flow path.
The fluid machine according to any one of claims 4 to 6,
The diffuser has a third diffuser flow path and a fourth diffuser flow path configured to allow fluid to pass through, and the third diffuser flow path and the fourth diffuser flow path are the first diffuser in the fluid flow direction. Located downstream of one impeller,
The third diffuser channel and the fourth diffuser channel each have an outlet of the diffuser channel,
The fluid machine includes: a second merging channel fluidly coupled to an outlet of each of the diffuser channels of the third diffuser channel and the fourth diffuser channel;
A second return flow path fluidly coupled to the second merge flow path for supplying fluid to the second impeller, wherein the second return flow path is a drive shaft of the first impeller. A fluid machine extending in the direction of
The fluid machine according to claim 7,
The fluid machine, wherein the third diffuser channel and the fourth diffuser channel are rotationally symmetric with respect to the first diffuser channel and the second diffuser channel, respectively.
The fluid machine according to claim 7 or 8,
The third diffuser flow path and the fourth diffuser flow path are configured such that a cross-sectional area increases from an inlet of each of the diffuser flow paths toward an outlet of the diffuser flow path,
The fluid machine according to claim 4, wherein the fourth diffuser flow path has a relatively large area, a small area, and a large area of the cross-sectional area increase rate in order from the diffuser flow path inlet to the diffuser flow path outlet.