JP2013053524A - Multi-pressure centrifugal turbo machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a multi-pressure centrifugal turbo machine which can supply a plurality of pressure levels by means of one centrifugal turbo machine.SOLUTION: One centrifugal impeller 15 which rotates within a casing 11 includes: one fluid inlet 21 which axially introduces a fluid; and a high-pressure outlet fluid path 23H and a low-pressure outlet fluid path 23L which discharge the fluid having an increased pressure in the radially outward direction by means of different pressures. The fluid having a pressure which has been increased by the centrifugal impeller 15 is discharged in the radially outward direction by means of two different pressures.

Description

  The present invention relates to a multi-pressure centrifugal turbomachine such as a centrifugal pump, a blower and a compressor which can provide two pressure levels by one unit.

Conventional centrifugal turbomachines usually have one inlet and one outlet and supply one pressure and flow rate with one device. In addition, as a centrifugal turbomachine, a centrifugal pump, a centrifugal blower, a centrifugal compressor, and the like are known, and basically have the same configuration.
The centrifugal pump has an impeller configured such that the impeller outlet radius of the pump is larger than the impeller inlet shroud radius of the pump, and the flow of the impeller outlet flows radially outward in the meridian plane. This is a device for boosting.

A centrifugal blower has a form similar to that of a centrifugal pump, and is a device that boosts the pressure of a compressible fluid. Centrifugal blower, generally when boosting is sucked from the atmospheric pressure refers to a device in the numerical range of pressure increase approximately 1000kg / m ² ~10000kg / m ² by boosting.
The centrifugal compressor is a device that boosts the compressive fluid to a higher pressure than the centrifugal blower described above.

In the following description, the above-described centrifugal turbomachine impeller forms are collectively referred to as “centrifugal impellers”. In addition, the form in which the flow at the outlet of the impeller flows at a certain angle from the radial direction is generally referred to as “diagonal flow impeller”, but this mixed flow impeller is also included in the “centrifugal impeller” in the following description. To do.
A centrifugal turbomachine equipped with such a centrifugal impeller sucks a fluid flow in the axial direction from the inlet, and since the flow path of the centrifugal impeller is bent radially from the axial direction, the flow is radially outward at the outlet. To leak. In the case of a centrifugal pump, generally, the blade leading edge of the impeller inlet has a meridian surface shape that inclines toward the suction side on the casing side with respect to the rotation shaft, but the basic structure allows suction in the axial direction and outflow in the radial direction. Is common to centrifugal blowers and centrifugal compressors.

The centrifugal turbomachine equipped with the centrifugal impeller described above has a mechanism for increasing the pressure by giving rotational energy to the flow of the sucked fluid by being driven to rotate around the rotation axis. The mechanism is the same in a centrifugal pump, a centrifugal blower, and a centrifugal compressor.
Further, a diffuser comprising a circular blade row is provided downstream of the outlet of the centrifugal impeller, and a diffuser having blades is called a vane diffuser, and a diffuser without blades is called a vaneless diffuser. The presence or absence of such blades is usually determined according to the required performance of the centrifugal turbomachine. A scroll that collects the flow and discharges it to the downstream pipe is provided downstream of the diffuser. However, in the case of a centrifugal pump, there are many structures in which the above-described diffuser itself is not installed, and therefore the outlet of the centrifugal impeller In many cases, a scroll is installed directly downstream.

On the other hand, various plants may require a plurality of pressures in the same working fluid. In such a plant, for example, a configuration in which different pumps are installed and used for each plant is generally used, and pumps having different pressure and flow rate settings are prepared for each plant.
Further, in a radial turbine in which a swirling fluid that flows into a turbine wheel using a flow velocity component in the radial direction as a main component is used, and a flow that discharges energy by converting swirling energy of the flow into rotational power is discharged in the axial direction, The flow rate of the fluid is divided into a plurality of flow paths inside the turbine, and a turbine blade inlet is formed for each flow path, and the inlet radius of the turbine blade is different. (See Patent Documents 1 to 3)

JP 63-302134 A Special table 2008-503585 Japanese Utility Model Publication No. 61-202601

As described above, in various conventional plants that require a plurality of pressure levels in the same working fluid, different centrifugal pumps such as centrifugal pumps are installed for each required pressure level. For this reason, a drive source such as an electric motor is required for each centrifugal turbomachine, and as a result, a problem has been pointed out that a large number of devices are required for the configuration of the plant, which makes it complicated.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a multi-pressure centrifugal turbomachine capable of supplying a plurality of pressure levels with a single centrifugal turbomachine.

In order to solve the above problems, the present invention employs the following means.
In the double pressure centrifugal turbomachine of the present invention, a single centrifugal impeller that rotates in a casing includes a single fluid inlet that introduces fluid in the axial direction, and a plurality of fluids that discharge the pressurized fluid radially outward at different pressures. A fluid outlet, and the fluid pressurized by the centrifugal impeller is discharged radially outward at a plurality of different pressures.

According to such a multi-pressure centrifugal turbomachine of the present invention, the centrifugal impeller has one fluid inlet for introducing the fluid in the axial direction, and a plurality of fluid outlets for discharging the pressurized fluid radially outward at different pressures. The fluid pressurized by the centrifugal impeller is discharged radially outward at a plurality of different pressures, so that the fluid pressurized to a plurality of pressure levels by a single centrifugal turbomachine can be supplied.
The multi-pressure centrifugal turbomachine of the present invention can be applied to a centrifugal compressor, a centrifugal blower, a centrifugal pump, and the like.

In the above-described multi-pressure centrifugal turbomachine, the fluid outlet is arranged such that the discharge pressure is sequentially reduced from the fluid inlet toward the downstream side in the axial direction, and the centrifugal impeller is a high pressure adjacent to the low pressure side impeller. It is preferably arranged so as to penetrate the back plate of the side impeller.
Alternatively, in the above-described multi-pressure centrifugal turbomachine, it is preferable that the fluid outlet has a low-pressure side having a low discharge pressure disposed in the middle of the shroud surface of the centrifugal impeller.

  In the above-described double pressure centrifugal turbomachine, the centrifugal impeller preferably includes shrouds provided on at least a part of the inlet side and the outlet side of the blade length. It is possible to reduce the thrust force that must be borne by the thrust bearing that is generated by the centrifugal impeller and borne by the thrust impeller.

In the above multi-pressure centrifugal turbomachine, the centrifugal impeller includes a high-pressure impeller that discharges a pressurized fluid radially outward from the fluid outlet at a high pressure, and a pressurized fluid radially outward from the fluid outlet at a low pressure. A low-pressure impeller for discharging is preferably provided.
That is, a centrifugal impeller of a multi-pressure centrifugal turbomachine has one fluid inlet for introducing fluid in an axial direction, and two fluid outlets for discharging pressurized fluid radially outward at two different pressures of high pressure and low pressure. The high-pressure impeller of the centrifugal impeller constitutes a high-pressure fluid outlet, and the low-pressure impeller constitutes a low-pressure fluid outlet, so that the fluid pressurized to two high and low pressure levels is supplied by one centrifugal turbomachine. It becomes possible.

  In the double pressure centrifugal turbomachine in which the low pressure side having a low discharge pressure is arranged in the middle of the shroud surface of the centrifugal impeller, the centrifugal impeller forms a back plate of the low pressure impeller, and the upstream end of the high pressure impeller is connected to the upstream end of the high pressure impeller. What protruded inside the exit radius of the low-pressure impeller is preferable.

  In the above-described double pressure centrifugal turbomachine, the centrifugal impeller may have a split / separate structure in which a high pressure impeller portion and a low pressure impeller portion separable from the vicinity of the back plate surface of the high pressure impeller portion are combined and integrated. .

  In the double pressure centrifugal turbomachine in which the low pressure side having a low discharge pressure is arranged in the middle of the shroud surface of the centrifugal impeller, the back plate surface of the low pressure impeller has a low pressure so that the shroud upstream end of the high pressure impeller protrudes toward the flow path. It is desirable to have a structure of dividing and assembling on the impeller back plate surface.

  According to the above-described present invention, a single-pressure centrifugal turbomachine can provide a multiple pressure centrifugal turbomachine capable of supplying a plurality of pressure levels. Therefore, when applied to various plants that require a plurality of pressure levels in the same working fluid, The remarkable effect that the equipment required for the configuration of the plant can be reduced and the device configuration can be simplified can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment about the multi-pressure type centrifugal turbomachine which concerns on this invention, (a) is sectional drawing which shows the principal part (meridian shape) at the time of applying to a centrifugal compressor, (b) is a low-pressure impeller. It is a schematic perspective view which shows the structural example at the time of dividing | segmenting a part from a high voltage | pressure impeller. It is the front view which looked at the principal part cross section of the centrifugal compressor shown to Fig.1 (a) and (b) from the axial direction. It is the front view which looked at the principal part cross section which shows the modification at the time of installing a splitter blade | wing in the centrifugal compressor of FIG. 2 from the axial direction. It is sectional drawing which shows the principal part (meridian surface shape) at the time of replacing with the centrifugal compressor shown in FIG. 1, and applying to a centrifugal pump. It is the front view which looked at the principal part cross section of the centrifugal pump shown in FIG. 3 from the axial direction. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows the structural example which applied the multi-pressure type centrifugal turbomachine which concerns on this invention to a plant, (a) is an application example which pressurizes the fluid introduce | transduced from air | atmosphere or a plenum to different pressures, ) Is an application example in which the fluid is circulated by increasing the pressure to different pressures between the two plants, and (c) is an application example in which the fluid is circulated by increasing the pressure to different pressures between different systems in one plant. It is. It is sectional drawing which shows the principal part (meridian shape) at the time of applying to a centrifugal compressor as 2nd Embodiment about the double pressure type centrifugal turbomachine which concerns on this invention. It is sectional drawing of the meridional shape which shows a modification about 2nd Embodiment shown in FIG. It is a figure which shows the static pressure distribution of a shroud surface from a backplate back surface and a centrifugal impeller inlet_port | entrance part about the centrifugal compressor of embodiment shown in FIG. It is a figure which shows the static pressure distribution of a shroud surface from the backplate back surface and the centrifugal impeller inlet_port | entrance about the centrifugal compressor of this embodiment shown in FIG.7 and FIG.8. It is sectional drawing which shows the principal part (meridian shape) at the time of applying to a centrifugal compressor as 3rd Embodiment about the double pressure type centrifugal turbomachine which concerns on this invention. It is the front view which looked at the principal part cross section of the centrifugal compressor shown in FIG. 11 from the axial direction. It is sectional drawing of meridional surface shape which shows the 1st modification which provided the shroud in the centrifugal compressor shown in FIG. It is sectional drawing of the meridional surface shape which shows the 2nd modification which provided the shroud in the centrifugal compressor shown in FIG. It is the figure which showed the static pressure distribution of a shroud surface from a backplate back surface and a centrifugal impeller entrance part about the centrifugal compressor shown in FIG. It is the figure which showed the static pressure distribution of the shroud surface from the back board back surface of the impeller with a shroud, and the centrifugal impeller inlet part about the centrifugal compressor shown in FIG. It is a figure which shows the problem regarding the leakage flow from a blade tip about the centrifugal compressor shown in FIG. It is sectional drawing of meridian-surface shape which shows the shroud installation example of the 3rd modification which solves the problem of the leakage flow from the blade tip demonstrated in FIG. It is a figure which shows the problem of the area | region which flows around a low pressure outlet flow path about the centrifugal compressor shown in FIG. FIG. 20 is a meridional cross-sectional view showing a shroud installation example of a fourth modification that solves the problem of a region that flows around the low-pressure outlet flow path described in FIG. 19. FIG. 18 is a meridional cross-sectional view showing a shroud installation example of a fifth modification that solves the problem of the region that flows around the low-pressure outlet flow path described in FIG. 17.

Hereinafter, an embodiment of a multi-pressure centrifugal turbomachine according to the present invention will be described with reference to the drawings.
<First Embodiment>
The multi-pressure centrifugal turbomachine of the embodiment shown in FIG. 1 and FIG. 2 is a booster capable of boosting to a plurality of (two or more) pressure levels and supplying it by a single unit. Specifically, an incompressible fluid is supplied. There are a centrifugal pump for boosting pressure, a centrifugal blower for boosting a compressive fluid, a centrifugal compressor, and the like. In the following description, a centrifugal compressor capable of supplying two pressure levels of high pressure and low pressure as a single unit will be described as an example of a double pressure centrifugal turbomachine.

1A is a cross-sectional view showing a meridional shape of a main part of a multi-pressure centrifugal compressor (multi-pressure centrifugal turbomachine) according to the present embodiment, and FIG. 2 is shown in FIG. It is the front view which looked at the principal part cross section of the centrifugal compressor from the axial direction.
The illustrated centrifugal compressor C includes a casing 11, a rotating shaft 13 that is rotatably supported by the casing 11, and a centrifugal impeller 15 that is attached to the outer periphery of the rotating shaft 13 and rotates within the casing 11. . A driving source (not shown) such as an electric motor that rotates the centrifugal impeller 15 is connected to one end of the rotating shaft 13.

The centrifugal impeller 15 includes a hub 17 attached to the outer periphery of the rotating shaft 13 and a plurality of centrifugal impeller blades (hereinafter referred to as “wings”) 19 provided on the outer peripheral surface of the hub 17 at radially spaced intervals. Composed. The blades 19 are provided so as to protrude outward from the outer peripheral surface of the hub 17.
The casing 11 and the centrifugal impeller 15 of the centrifugal compressor C are introduced by a blade 19 that introduces fluid in an axial direction from a flow path inlet 21 provided on the left side of the paper in FIG. 1A and rotates integrally with the centrifugal impeller 15. The pressurized fluid is allowed to flow radially outward.

  The centrifugal impeller 15 that rotates in the casing 11 includes a high-pressure impeller 19H whose outlet radius on the casing 11 side is R1, and a low-pressure impeller 19L whose outlet radius on the casing 11 side is R2. In the configuration example shown in FIG. 1A, the high-pressure impeller 19H and the low-pressure impeller 19L are integrally configured. In this case, the centrifugal impeller 15 has an outlet radius R1 of the high-pressure impeller 19H with respect to the impeller inlet radius Ri. Is set large (R1> Ri), and in the axial direction of the rotary shaft 13, a high pressure impeller 19H is disposed on the upstream side near the flow path inlet 21, and the low pressure impeller 19L is disposed on the back plate 31H of the high pressure impeller 19H. It is disposed on the opposite side of the flow path inlet 21 through the opened through flow path 33. In FIG. 1A, the alternate long and short dash line Pi in the drawing is an isobaric line.

The fluid pressurized by the high-pressure impeller 19H flows outward in the radial direction through the high-pressure outlet channel 23H that opens to the outer peripheral tip side of the high-pressure impeller 19H. A high-pressure side diffuser 25H is provided downstream of the high-pressure outlet channel 23H, and a scroll 27H is further provided downstream thereof. The high-pressure outlet channel 23H, the diffuser 25H, and the scroll 27H configured as described above serve as a high-pressure side compressor outlet 29H that supplies a fluid at a high pressure P1.
The casing 11 in which the high-pressure impeller 19H rotates includes a partition wall 37 that faces the back plate 31H of the high-pressure impeller 19H provided on the downstream side and that forms a low-pressure side wall surface.

Similarly to the high pressure impeller 19H, the low pressure impeller 19L protrudes outward from the outer peripheral surface of the hub 17, and is provided so as to penetrate the lower part of the back plate 31H of the high pressure impeller 19H toward the downstream side in the axial direction. . On the back side of the back plate 31H, the low pressure impeller 19L having an exit radius of R2 rotates integrally with the coaxial high pressure impeller 19H.
The outlet radius R2 of the low pressure impeller 19L is smaller than the outlet radius R1 of the high pressure impeller 19H (R2 <R1).

  The fluid pressurized by the low pressure impeller 19L flows outward in the radial direction through the low pressure outlet channel 23L that opens to the outer peripheral tip side of the low pressure impeller 19L. A low pressure side diffuser 25L is provided downstream of the low pressure outlet channel 23L, and a scroll 27L is further provided downstream thereof. The low-pressure outlet flow path 23L, the diffuser 25L, and the scroll 27L configured as described above serve as a low-pressure side compressor outlet 29L that supplies fluid at a low pressure P2 (P1> P2).

The outlet radius R2 of the low pressure impeller 19L is set to a value (R2> Rps) larger than the upper wall surface radius Rps of the through passage 33 indicated by hatching in the drawing (R2> Rps), and the low pressure outlet passage 23L of the low pressure side compressor outlet 29L is A radially outward impeller outlet is provided. The through flow path 33 is a flow path for guiding the fluid branched from the high pressure impeller 19H side to the low pressure impeller 19L side.
In addition, the casing 11 in which the low pressure impeller 19L rotates forms a low pressure side wall surface 39 facing the back plate 31L of the low pressure impeller 19L provided on the downstream side.

In the front view in the axial direction shown in FIG. 2, the centrifugal impeller 15 that compresses the gas rotates at a high peripheral speed that is several times higher than a centrifugal pump that compresses the liquid, which will be described later. The 19H and low-pressure impeller 19L is constituted by a blade whose impeller blade has a substantially radial element at the blade leading edge.
Further, in the case of the centrifugal compressor C, at the high pressure impeller outlet 23H and the low pressure impeller outlet 23L, the backward angle β1 at which the blades of the high pressure impeller 19H are attached to the back plate 31H, and the blades of the low pressure impeller 19L are those of the low pressure impeller 19L. The backward angle β2 of the angle attached to the back plate 31L is set to a range of about 10 degrees to 45 degrees, for example.

The centrifugal impeller 15 of the centrifugal compressor C described above includes a high-pressure splitter blade 35H and a low-pressure splitter, respectively, between the blades of the high-pressure impeller 19H and the low-pressure impeller 19L, as in the centrifugal impeller 15 'of the modification shown in FIG. It is good also as a structure in which the wing | blade 35L was installed.
3 is substantially the same as the centrifugal impeller 15 shown in FIG. 2 except for the splitter blades 35H and 35L.

Next, the centrifugal pump impeller 55 of the centrifugal pump CP shown in FIGS. 4 and 5 is an application of the configuration of the centrifugal impeller 15 described above.
The centrifugal pump CP includes a casing 51, a rotating shaft 53 that is rotatably supported by the casing 51, and a centrifugal pump impeller 55 that is attached to the outer periphery of the rotating shaft 53 and rotates within the casing 51. A driving source (not shown) such as an electric motor that rotates the centrifugal pump impeller 55 is connected to one end of the rotating shaft 53.

The centrifugal pump impeller 55 includes a hub 57 attached to the outer periphery of the rotating shaft 53, and a plurality of centrifugal impeller blades (hereinafter referred to as “wings”) 59 provided radially spaced on the outer peripheral surface of the hub 57. Consists of. The blades 59 are provided so as to protrude outward from the outer peripheral surface of the hub 57.
The casing 51 and the centrifugal pump impeller 55 of the centrifugal pump CP introduce the fluid in the axial direction from the flow path inlet 61 and discharge the fluid pressurized by the blade 59 rotating integrally with the centrifugal pump impeller 55 outward in the radial direction.

  The centrifugal pump impeller 55 that rotates in the casing 51 includes a high-pressure impeller 59H whose outlet radius on the casing 51 side is R1, and a low-pressure impeller 59L whose outlet radius on the casing 51 side is R2. In this case, the centrifugal pump impeller 55 is set such that the outlet radius R1 of the high-pressure impeller 59H is larger than the impeller inlet radius Ri (R1> Ri), and is close to the flow path inlet 61 in the axial direction of the rotary shaft 53. A high pressure impeller 59H is disposed on the upstream side, and the low pressure impeller 59L is disposed on the opposite side of the flow path inlet 61 through a through flow path 73 opened in the back plate 71H of the high pressure impeller 59H.

The fluid pressurized by the high pressure impeller 59H flows outward in the radial direction through the high pressure outlet channel 63H that opens to the outer peripheral tip side of the high pressure impeller 59H. A scroll 67H is provided downstream of the high-pressure outlet channel 63H. The high-pressure outlet channel 63H and the scroll 67H configured as described above serve as a high-pressure side pump outlet 69H that supplies a fluid at a high pressure P1.
The casing 11 in which the high-pressure impeller 59H rotates includes a partition wall 77 that faces the back plate 71H of the high-pressure impeller 59H provided on the downstream side and that forms a low-pressure side wall surface.

Similarly to the high pressure impeller 59H, the low pressure impeller 59L protrudes outward from the outer peripheral surface of the hub 57, and is provided so as to penetrate the lower part of the back plate 71H of the high pressure impeller 59H toward the downstream side in the axial direction. . On the back side of the back plate 71H, the low pressure impeller 59L having an exit radius R2 rotates integrally with the coaxial high pressure impeller 59H.
The outlet radius R2 of the low pressure impeller 59L is smaller than the outlet radius R1 of the high pressure impeller 59H (R2 <R1).

  The fluid pressurized by the low pressure impeller 59L flows outward in the radial direction through the low pressure outlet channel 63L that opens to the outer peripheral tip side of the low pressure impeller 59L. A scroll 67L is provided downstream of the low pressure outlet channel 63L. The low pressure outlet channel 63L and the scroll 67L configured as described above serve as a low pressure side pump outlet 69L that supplies a fluid at a low pressure P2 (P1> P2).

The outlet radius R2 of the low pressure impeller 59L is set to a value (R2> Rps) larger than the upper wall surface radius Rps of the through passage 73 shown by hatching in the drawing, and the low pressure outlet passage 63L of the low pressure side pump outlet 69L has a radius. It has an outward impeller exit. The through flow path 73 is a flow path for guiding the fluid branched from the high pressure impeller 59H side to the low pressure impeller 59L side.
The casing 51 in which the low-pressure impeller 59L rotates forms a low-pressure side wall 79 facing the back plate 71L of the low-pressure impeller 59L provided on the downstream side.

In the case of the centrifugal pump CP, the impeller blade leading edge of the blade 59 has a shape that is inclined from the radial direction on the meridian surface, and often has a shape constituted by a convex curve upstream. Further, the backward angles β1 and β2 are both set in a range of about 45 degrees to 70 degrees.
Further, in the centrifugal pump CP, since the backward angle of the blades 59 is large, as a result, the distance between the adjacent blades becomes small and the length of the blades becomes long. Is roughly halved and is rarely provided with a splitter.

As described above, in the centrifugal pump CP, the high-pressure side pump outlet 69H and the low-pressure side pump outlet 69L are generally configured without a diffuser. However, like the centrifugal compressor C, a configuration including a diffuser may be used.
For a centrifugal blower (not shown), the impeller shape or the like is similar to the middle or one of the centrifugal compressor C and the centrifugal pump CP described above.
In any of the centrifugal compressor C, the centrifugal blower, and the centrifugal pump CP, the fluid outlet of the casing may be an annular passage formed on the outer peripheral side of the rotating shaft.

Thus, in the present embodiment, the characteristic common features of centrifugal turbomachines such as the centrifugal compressor C, the centrifugal blower, and the centrifugal pump CP are on the back plates 31H and 71H side of the high-pressure impellers 19H and 59H, and The hubs 13 and 57 are provided with through-flow passages 33 and 73 for diverting and guiding a part of the fluid to be pressurized, and have blades of low-pressure impellers 19L and 59L branched from the hubs 13 and 57 side. That is.
The fluid guided to the high pressure impellers 19H and 59H without flowing to the through flow paths 33 and 73 is boosted to high pressure P1 by the blades of the high pressure impellers 19H and 59H, and the low pressure impeller from the through flow paths 33 and 73. The fluid guided to the 19L and 59L sides is pressurized to low pressure P2 by the blades of the low pressure impellers 19L and 59L.

  That is, the centrifugal turbomachine of the embodiment described above includes one inlet for the fluid to be pressurized, and the centrifugal impeller and the centrifugal pump impeller that rotate in the casing are provided with one fluid inlet and two fluid outlets, and Since there are two outlets for the pressurized fluid, a double-pressure centrifugal turbomachine having a 1-impeller 2-pressure configuration is obtained. That is, the above-described multi-pressure centrifugal turbomachine can pressurize the fluid with one impeller installed on the same power shaft and supply the fluid with two different pressures and flow rates.

Such a multi-pressure centrifugal turbomachine can provide two pressure levels and flow rates without using a plurality of centrifugal pumps CP, centrifugal blowers, and centrifugal compressors C. For example, as shown in FIG. The system configuration can be simplified in various plants and facilities, and a high-performance plant can be provided at low cost.
In FIG. 6A, reference numeral 1 in the drawing denotes a double-pressure centrifugal turbomachine described in the present embodiment, and 3 denotes an electric motor (drive source) that drives the double-pressure centrifugal turbomachine. In this case, the same fluid introduced from the fluid supply source 5 of the atmosphere or the plenum is pressurized by the multi-pressure centrifugal turbomachine 1 and the fluid whose pressure is increased to the high pressure P1 is supplied to the plant 7A, and the fluid whose pressure is increased to the low pressure P2 This is an example of a plant configuration that supplies the power to the plant 7B. That is, one multi-pressure centrifugal turbomachine 1 can boost the same fluid to different pressure levels P1 and P2 and supply them to the plants 7A and 7B.

In the plant configuration example shown in FIG. 6 (b), the same fluid introduced from the plants 7A and 7B is boosted by the multi-pressure centrifugal turbomachine 1, and the fluid pressurized to the high pressure P1 is supplied to the plant 7A. The fluid whose pressure has been increased to P2 is supplied to the plant 7B.
In the example of the plant configuration shown in FIG. 6C, the same fluid introduced from different systems in the plant 7C is boosted by the multi-pressure centrifugal turbomachine 1 and boosted to the high pressure P1 and the low pressure P2. Supply to different systems of the plant 7C.

  By the way, in the above description, the centrifugal impeller blade 19 in which the high-pressure impeller 19H and the low-pressure impeller 19L are integrally formed is used. However, for example, as shown in FIG. Further, the configuration may be such that it is divided from the vicinity of the back plate surface of the high-pressure impeller portion 19H, that is, from the vicinity of the surface formed by the back plate 31H. In other words, the centrifugal impeller 15 may have a split / separate structure in which the high pressure impeller portion 19Hp and the low pressure impeller portion 19Lp that can be separated from the vicinity of the back plate surface of the high pressure impeller portion 19Hp are combined and integrated. In FIG. 1B, the broken line in the figure shows an example of the dividing surface BL of the high-pressure impeller portion Hp and the low-pressure impeller portion Lp, and the alternate long and short dash line B in the drawing indicates the axis center of the assembly bolt B Is shown.

<Second Embodiment>
A second embodiment of the multi-pressure centrifugal turbomachine according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to embodiment mentioned above, and the detailed description is abbreviate | omitted.
In this embodiment, shrouds are additionally provided on the high-pressure impellers 19H and 59H of the above-described embodiment. Note that the centrifugal impeller 15 of the present embodiment may have either an integral structure or a divided / separate structure.

In the following description, a shroud 41 is provided on the entire blade relative to the high-pressure impeller 19H of the centrifugal compressor C shown in FIG.
Moreover, in the modification shown in FIG. 8, the shroud 41 is provided in the latter half (outlet side) with respect to the high pressure impeller 19H.

The multi-pressure centrifugal turbomachine such as the centrifugal compressor C configured as described above has the same effects as the above-described embodiment.
Since the shroud 41 is additionally provided in the high pressure impeller 19H, the shroud 41 increases the strength of the blade particularly when the load acting on the blade of the high pressure impeller 19H is large. It is effective in improving Such a shroud 41 is effective not only in the centrifugal pump CP that pressurizes a liquid having a high flow density, but also in the various double-pressure centrifugal turbomachines described above.

  In the centrifugal compressor C and the centrifugal blower, when the flow rate is low and the specific speed is low, the blade height near the impeller outlet (the outlet width at the outlet) is lower than the blade inlet, and the shroud clearance (blade tip and casing and The gap) increases for the blade height. For this reason, there is a problem that the leakage loss increases and the efficiency is reduced, but in order to prevent this efficiency reduction, a configuration in which the shroud 41 is provided is effective.

In the double pressure centrifugal turbomachine described in the first embodiment, in any of the centrifugal pump CP, the centrifugal blower, and the centrifugal compressor C, a static pressure as shown in FIG. 9 is provided on the back surface of the high pressure impellers 19H and 59H. Distribution occurs. That is, as shown in FIG. 9, a static pressure distribution such as a shroud surface (shown by a solid line) is generated from the back surface (shown by a broken line) of the high pressure impeller back plates 31H and 71H and the centrifugal impeller inlet. When the R1 impeller outlet static pressure becomes a common value and the radius becomes smaller, the static pressure on the back surface of the back plate becomes higher than the static pressure on the shroud surface.
The pressure difference between the static pressure distribution on the back surface of the plate and the static pressure distribution on the shroud surface becomes a thrust force that presses the centrifugal impeller 15 in the axial direction. This pressure difference is indicated by hatching, and the larger the hatch area, the greater the thrust force.

The reason why the pressure on the back of the back plate is higher than the pressure on the shroud surface is that the fluid flowing in the back plate back gap is almost half of the back plate between the rotating back plate and the stationary casing. This is because it rotates at a speed and a pressure distribution is generated by the centrifugal force of the swirl.
On the other hand, the flow pressure in the inter-blade flow path of the impeller has no turning speed at the impeller inlet, and rotates at a speed of 60 to 80% of the impeller turning speed at the impeller outlet. . Therefore, the radial gradient of the static pressure distribution along the shroud is larger than that on the back surface of the back plate, and as described above, the impeller outlet static pressure with the exit radius R1 has a common value. The static pressure on the back surface is higher than the static pressure on the shroud surface.
As a result, a static pressure difference occurs between the back surface of the back plate and the shroud surface at each radius, and this static pressure difference becomes a force that pushes the impeller in the axial direction, that is, a “thrust force”.

Moreover, there are outlets for the low pressure impellers 19L and 59L on the back plate surfaces of the high pressure impeller back plates 31H and 71H. However, the outlet pressures of the low pressure impellers 19L and 59L are determined by increasing the pressure by the through-flow passages 33 and 73 and the low pressure impeller, and are separated by a leak prevention mechanism (not shown) provided in the gap between the partition wall 37 and the low pressure impeller. Therefore, the static pressure becomes independent from the high pressure impeller outlet.
Accordingly, the outlet pressures of the low pressure impellers 19L and 59L are determined independently of the pressure distribution on the back plate surfaces of the high pressure impellers 19H and 59H. Therefore, as shown in FIG. Discontinuity occurs in the distribution.

  In the centrifugal pump CP that handles liquids and the centrifugal blower and centrifugal compressor C that handles high-density gas (such as chlorofluorocarbon), the absolute value of this thrust force is large, and therefore a large thrust bearing that can withstand this thrust force (thrust bearing) Etc.). As a result, the bearing loss increases, the life of the thrust bearing is shortened when the load capacity of the thrust bearing is small, and the load capacity is exceeded by the thrust bearing alone. Installation of a so-called “balance piston”) is indispensable, which may cause problems in performance, life, and structure, such as a complicated structure.

  The thrust force described above is a portion where the radius of the impeller changes, and the force in the region near the impeller outlet where the radius of the impeller outlet is large and the area is large is large. For this reason, by installing the shroud 41 at the blade tip in the region where the radius changes in the high pressure impellers 19H and 59H, as shown in FIG. Since the distribution can be made almost equal to the distribution (indicated by a broken line), and as a result, the thrust force can be reduced, the above-described performance, life and structural problems can be improved.

<Third Embodiment>
A third embodiment of the multi-pressure centrifugal turbomachine according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the part similar to embodiment mentioned above, and the detailed description is abbreviate | omitted.
The centrifugal impeller of the present embodiment is provided with a low-pressure impeller outlet in the middle of the shroud surface of the high-pressure impeller, and guides the flow flowing out from the discharge port to the low-pressure side outlet.

Below, the case where it applies to the centrifugal impeller 15A of the centrifugal compressor C shown in FIG. Note that the centrifugal impeller 15A of the present embodiment may be either an integral structure or a divided / separate structure as illustrated in FIG.
The illustrated centrifugal impeller 15A is a low pressure opening in the middle of the high pressure impeller 19H of the blade 19A, that is, at a position closer to the flow path inlet 21 in the axial direction than the high pressure outlet flow path 23H communicating with the high pressure side compressor outlet 29H. An outlet channel 23L is provided. The low-pressure outlet channel 23L communicates with the low-pressure compressor outlet 29L, and a diffuser 25L and a scroll 27L are provided on the downstream side thereof.

As a result, the arrangement of the high-pressure outlet flow path 23H and the low-pressure outlet flow path 23L is opposite to the centrifugal compressor of the above-described embodiment in the axial direction, and the low-pressure outlet flow path 23L and the high-pressure flow from the flow path inlet 21 side in the axial direction. The outlet channels 23H are arranged in this order.
With such a configuration, in the high pressure impeller 19H of the blade 19A, the low pressure outlet channel 23L is provided in the middle of the shroud surface, so that part of the fluid pressurized by the centrifugal impeller 15A is being pressurized. After flowing out from the low pressure outlet channel 23L, the pressure is further increased by the high pressure impeller 19H.

Thus, a part of the fluid flowing out from the low pressure outlet flow path 23L is guided to the low pressure side compressor outlet 29L via the diffuser 25L and the scroll 27L.
In this case, it is desirable that the high-pressure impeller 19H has a blade shape in which the blade height can be lowered from the downstream of the low-pressure outlet flow path 23L and further pressure can be increased downstream thereof. That is, in FIG. 11, it is desirable that the blade height H on the upstream side of the low-pressure outlet channel 23L is set higher than the blade height h on the downstream side (H> h). The flow of the fluid flowing out from the high pressure outlet passage 23H of the high pressure impeller 19H is guided to the high pressure side compressor outlet 29H via the diffuser 25H and the scroll 27H.

The centrifugal turbomachine such as the centrifugal compressor of the present embodiment configured as described above includes one fluid inlet to be pressurized, and the centrifugal impeller rotating in the casing includes one fluid inlet and two fluid outlets. And two outlets for the pressurized fluid are provided, so that a double-pressure centrifugal turbomachine having a 1-impeller 2-pressure configuration is obtained. That is, the above-described multi-pressure centrifugal turbomachine can pressurize the fluid with one impeller installed on the same power shaft and supply the fluid with two different pressures and flow rates.
The general features of the centrifugal compressor, the centrifugal blower, and the centrifugal impeller of the centrifugal pump are the same as those of the above-described embodiment.

Also, the centrifugal impeller of this embodiment may have a configuration in which a shroud 41 is provided at the blade tip of the high-pressure impeller 19H, as in the second embodiment described above.
In this case, a shroud 41 may be provided over the entire length of the high-pressure impeller 19H and the blades 19A excluding the position of the low-pressure outlet flow path 23L as in the first modification shown in FIG. 13, or as shown in FIG. In addition, the shroud 41 may be provided only in the high pressure impeller portion from the low pressure outlet channel 23L to the high pressure outlet channel 23H. Furthermore, as shown in FIG. 18, the shroud 41 may be provided only at the blade tip of the blade 19A on the upstream side of the low-pressure outlet channel 23L.

Since such a shroud 41 increases the strength of the blade particularly when the load acting on the blade of the high-pressure impeller 19H is large, as in the above-described embodiment, it is effective in improving reliability and durability. is there. The installation of such a shroud 41 is effective not only in the centrifugal pump CP that pressurizes a liquid having a high flow density, but also in general multi-pressure centrifugal turbomachines such as the centrifugal compressor C.
Further, in the configuration example of the second modification shown in FIG. 14, only the high-pressure impeller portion from the low-pressure outlet channel 23L to the high-pressure outlet channel 23H having a large leakage loss is the same as the relationship of FIGS. 7 and 8 described above. Since the shroud 41 is installed, it is effective in reducing leakage loss.

In addition, the configuration examples shown in FIGS. 13 and 14 are effective in reducing the thrust force in any case, similarly to the configuration examples shown in FIGS. 7 and 8.
FIG. 15 shows the static pressure distribution on the shroud surface and the back plate surface of the centrifugal compressor C shown in FIG. In this case, as described in the above-described embodiment, the thrust force is large because the static pressure on the back surface of the back plate is high and the static pressure on the shroud surface is low. Therefore, by installing the shroud 41, the pressure on the shroud surface becomes substantially equal to the pressure on the back surface of the back plate, and this thrust force can be reduced.

In FIG. 15, the static pressure distribution of the shroud and the back plate surface has a low-pressure outlet channel 23L in the middle portion of the shroud on the shroud surface and becomes constant in that portion, but the static pressure continuously increases as the radius further increases. It has a static pressure distribution that increases.
On the other hand, the back surface of the back plate is a space sandwiched between approximately two disk surfaces from the high pressure outlet channel 23H to the vicinity of the rotation axis, and the static pressure continuously decreases during this time.

  FIG. 16 shows the static pressure distribution of the centrifugal compressor C of the embodiment shown in FIG. In this case, the shroud 41 is installed and separated by a leak prevention mechanism (not shown) installed at the inner diameter end of the shroud 41, so that the pressure in the portion corresponding to the outlet radius R2 of the low pressure outlet passage 23L is reduced. Same as 15. However, at other radii, the pressure distribution is in a radial equilibrium inside the shroud clearance. Therefore, compared to the case of FIG. 15, the pressure on the shroud surface is a radial equilibrium with respect to the static pressure of R2 in Ri to R2. In R2 to R1, the thrust is almost equal to the static pressure on the back surface of the back plate, so that the thrust force can be reduced.

Further, as in the third modification shown in FIG. 18, a beneficial effect can be obtained even when the shroud 41 is provided only at the blade tip of the centrifugal impeller 15 </ b> A on the upstream side of the low pressure outlet channel 23 </ b> L.
As shown in FIG. 17, when the shroud 41 is not provided at the inlet of the centrifugal impeller 15A, the flow at the tip of the blade is caused by a leakage flow from the tip of the blade (see arrow f in the figure). Accumulates. Further, when the low flow velocity region reaches the low pressure outlet channel 23L, the outlet pressure of the low pressure impeller 19L does not reach the expected pressure, and the low pressure outlet channel 23L is closed. The expected flow rate may not be obtained from 23L.

  As an improvement method in such a case, by providing a shroud 41 in the upstream portion of the low pressure outlet flow path 23L, leakage loss at the inlet of the centrifugal impeller 15A is reduced, accumulation in a low flow velocity region is prevented, and the low pressure impeller 19L It is possible to improve the problem of an increase in the loss of the flow flowing out of the gas and a reduction in the flow rate.

Moreover, you may attach the shroud 41 mentioned above so that it may demonstrate below.
For example, in the configuration example of the fourth modification shown in FIG. 20, in the centrifugal compressor C shown in FIG. 11, the shroud 41 is installed between the low pressure outlet channel 23L and the high pressure outlet channel 23H. The shroud 41 protrudes into the flow path from the outlet radius R2 of the low pressure impeller 19L to a smaller outlet radius R3 so that the inner diameter side forms the back plate of the low pressure impeller 19L.
In order to branch the flow of the low-pressure impeller 19L and the flow of the high-pressure impeller 19H in the respective directions at the acute-angled branch portion, the shroud 41 is provided with an inner extension portion.

That is, in the centrifugal impeller 15A of this embodiment, the low-pressure impeller 19L and the high-pressure impeller 19H on which the shroud 41 is installed are the low-pressure impeller back plate surface, and the portion constituting the upstream end of the shroud 41 installed on the high-pressure impeller 19H. It is divided into an impeller having a configuration in which the low pressure impeller 19L and the high pressure impeller 19H are combined.
Further, in the configuration example shown in FIG. 20, the inner diameter side of the shroud 41 of the high pressure impeller 19H is projected so as to constitute the back plate of the low pressure impeller 19L. For example, as in the fifth modification shown in FIG. Except for the impeller outlet portion of the shroud portion installed at the tip of the blade, the outlet radius R2 of the low pressure impeller 19L and a radius portion equal to or less than the partial shroud of the high pressure impeller 19H having a larger radius may be used.

  In the configuration example shown in FIG. 11, the low-pressure outlet channel 23L has a back plate surface that faces the upstream in the axial direction constituting the high-pressure outlet channel 23H of the high-pressure impeller 19H and becomes a disc or a conical surface. Not. For this reason, since there is no part which has the effect | action which guides a flow to the low pressure outlet flow path 23L, as shown by the arrow f1 in FIG. There is a concern that the effect of causing the flow to flow out is smaller than that of the high pressure outlet channel 23H, and the expected flow rate cannot be obtained from the low pressure impeller 19L.

Therefore, by installing a back plate surface having a back plate effect at the low pressure channel outlet 23L of the low pressure impeller 19L so as to protrude into the channel, the effect of guiding the flow to the low pressure outlet channel 23L is increased, and the low pressure The flow flowing out to the outlet flow path 23L and the flow flowing out to the high pressure impeller 19H can be branched by the structure provided with the back plate surface described above. As a result, it is possible to reliably obtain the flow rate flowing out from the low pressure impeller 19L and the flow rate flowing out from the high pressure impeller 19H.
Moreover, the low pressure impeller 19L and the high pressure impeller 19H are divided by the back plate surface of the low pressure impeller 19L, and the centrifugal impeller 15A having a structure in which these are combined can easily manufacture this structure.

According to each embodiment mentioned above, it becomes a double pressure type centrifugal turbomachine which one centrifugal turbomachine can supply a plurality of (two or more) pressure levels. As a result, when applied to various plants that require multiple pressure levels in the same working fluid, various devices such as centrifugal turbomachines and electric motors necessary for the plant configuration can be reduced, and the device configuration can be simplified. It becomes possible.
Examples of plants to which the double pressure centrifugal turbomachine of this embodiment can be applied include the following.

(1) Booster pump for power recovery cycle of exhaust energy discharged from high temperature and high pressure fluid from various industrial plants (2) System for obtaining power via thermal cycle such as power source for ships and vehicles Exhaust heat recovery cycle booster pump (3) Power recovery cycle booster pump for binary cycle power generation using medium and low temperature heat sources such as geothermal and OTEC (4) Factory and plant pressure sources, multiple flow supply devices Plant and equipment in the case where pumps and blowers that supply pressure and a plurality of flow rates are used Note that the present invention is not limited to the above-described embodiment, and may be changed as appropriate without departing from the scope of the invention. Can do.

DESCRIPTION OF SYMBOLS 1 Double pressure type centrifugal turbomachine 3 Electric motor 5 Fluid supply source 7A-7C Plant 11,51 Casing 13,53 Rotating shaft 15,15A Centrifugal impeller 17,57 Hub 19,59 Centrifugal impeller blade 19H, 59H High pressure impeller 19L, 59L Low pressure impeller 21, 61 Channel inlet 23H, 63H High pressure outlet channel 23L, 63L Low pressure outlet channel 25H, 25L Diffuser 27H, 27L, 67H, 67L Scroll 29H High pressure side compressor outlet 29L Low pressure side compressor outlet 31H, 71H (High pressure side Back plate 31L, 71L (of low pressure side impeller) Back plate 33, 73 Through passage 35H High pressure splitter blade 35L Low pressure splitter blade 41 Shroud 55 Centrifugal pump impeller 69H High pressure side pump outlet 69L Low pressure side pump outlet C Centrifugal compressor CP centrifuge Pump

Claims (8)

  One centrifugal impeller that rotates in the casing includes one fluid inlet that introduces fluid in the axial direction, and a plurality of fluid outlets that discharge the pressurized fluid radially outward at different pressures. A multi-pressure centrifugal turbomachine characterized by discharging pressurized fluid radially outward at a plurality of different pressures.   The fluid outlet is arranged so that the discharge pressure decreases sequentially from the fluid inlet toward the downstream side in the axial direction, and the centrifugal impeller passes through the back plate of the high pressure side impeller adjacent to the low pressure side impeller. The double-pressure centrifugal turbomachine according to claim 1, wherein the centrifugal turbomachine is a double-pressure centrifugal machine.   The multi-pressure centrifugal turbomachine according to claim 1, wherein the fluid outlet has a low pressure side having a low discharge pressure disposed in the middle of the shroud surface of the centrifugal impeller.   The multi-pressure centrifugal turbomachine according to any one of claims 1 to 3, wherein the centrifugal impeller includes a shroud provided in at least a part of a blade length.   The centrifugal impeller includes a high-pressure impeller that discharges a pressurized fluid radially outward from the fluid outlet at a high pressure, and a low-pressure impeller that discharges the pressurized fluid radially outward from the fluid outlet at a low pressure. The double-pressure centrifugal turbomachine according to any one of claims 1 to 4, wherein   The multi-pressure type of claim 5, wherein the centrifugal impeller forms a back plate of the low-pressure impeller, and an upstream end of the high-pressure impeller protrudes inward from an outlet radius of the low-pressure impeller. Centrifugal turbomachine.   7. The centrifugal impeller has a split / separate structure in which a high pressure impeller portion and a low pressure impeller portion separable from the vicinity of a back plate surface of the high pressure impeller portion are combined and integrated. The double pressure centrifugal turbomachine according to any one of the above. The back plate surface of the low pressure impeller has a structure of being divided and assembled on the back plate surface of the low pressure impeller so that the shroud upstream end of the high pressure impeller protrudes toward the flow path side. The double-pressure centrifugal turbomachine according to any one of 6.

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