WO2012119914A1

WO2012119914A1 - Outlet collecting housing for a radial compressor

Info

Publication number: WO2012119914A1
Application number: PCT/EP2012/053496
Authority: WO
Inventors: Werner Jonen; Christian Woiczinski
Original assignee: Siemens Aktiengesellschaft
Priority date: 2011-03-04
Filing date: 2012-03-01
Publication date: 2012-09-13
Also published as: DE102011005105B4; DE102011005105A1

Abstract

The invention relates to a housing arrangement for a radial compressor and to a method for flow guidance of a flow medium in a radial compressor. Said housing arrangement for the radial compressor has a first, substantially radially aligned annular cavity and a second, substantially axially aligned annular cavity which are connected to one another via a diverting arrangement. A guide grate is arranged in the second, substantially axially aligned annular cavity. In the method for flow guidance of a flow medium in a radial compressor, the flow medium is conducted outward substantially in a radial direction. The flow medium is subsequently diverted substantially into an axial direction and guided onward substantially in the axial direction. As the flow medium flows onward in the substantially axial direction, a swirl is at least partially withdrawn from the flow.

Description

description

Outlet collecting housing for a centrifugal compressor

The invention relates to a housing arrangement for a

Radial compressor and a method for flow guidance of a flow medium in a centrifugal compressor.

Radial compressors are known, for example from EP 1 356 168 Bl.

Such centrifugal compressors consist of a one

Compressor stage forming, rotating about a rotation axis impeller with a - with respect to the axis of rotation of the impeller - axial inlet and a radial outlet. To be compressed gas flows axially into the impeller of

Compressor stage and is then deflected to the outside (radially or in the radial direction), wherein it emerges from the impeller at high speed and twisted.

Kinetic energy of the gas emerging at high velocity and with swirl radially and to be compressed is then (prospectively) potential in a diffuser

Energy converted in the form of pressure.

Such a diffuser is usually formed by two non-rotating, an annular cavity or an annular space forming rings, which annular space radially adjoins the impeller outlet or which rings or annular

Walls / side surface radially adjoin the impeller outlet and are usually perpendicular to the axis of rotation of the impeller or to this at a very obtuse angle.

The gas exiting the impeller is guided radially outward in this annular space between these two annular walls and reaches a collector and / or a spiral. about which the compressed gas is collected and released from the

Radial compressor is discharged.

Such a spiral, also called volute casing, receives continuously by a growing over a circumference of the spiral cross section, the gas to be discharged and leads it into an outlet nozzle, which is usually a piping system for further or discharge of the

Connected compressed gas.

Due to the over the circumference growing cross-section in the spiral, the gas flowing through it is continuously collected. In the subsequent (conical)

The exit diffuser further retards the flow and thus part of its kinetic energy into potential energy, i. in pressure, converted (pressure gain or

Pressure recovery).

To further achieve the highest possible pressure increase or compression of the fluid, several such

Compressor stages are connected in series, wherein for collecting and discharging the compressed gas from the last compressor stage or from one compressor stage to the next compressor stage also such a spiral is used as described.

While usually single-shaft machines are used, in (multi-stage) gear turbo compressors (short in the

Below also only gear compressor) the individual

Grouped around compressor stages around a large gear, wherein a plurality of parallel (pinion) shafts, each one or two - recorded in such as housing structures realized spiral housings - wheels (at free shaft ends of

Pinion shafts arranged turbochargers) wear, of a large, mounted in the housing drive gear, a

Big wheel, to be driven. Such a transmission compressor, a transmission compressor from Siemens called STC-GC, used for air separation, is out

http: / / www. energy. Siemens. com / hg / en / compression-expansion-ventilation / turbo-compressor / gearbox turbo-compressor / stc-gc. htm (available on 18.02.2011).

Such used for flow guidance and pressure recovery in single or multi-stage centrifugal compressors

However, spirals or spiral housing have the disadvantage that they are technically complicated to manufacture.

Furthermore, so-called guide grids are known. Under

Guideways are used in turbomachinery,

understood fixed grid of profiled blades that either swirl a fluid flowing in the turbomachine and thereby reduce pressure (for example, turbines) or withdraw a swirl from the flow medium, thereby increasing a pressure (pressure recovery) (e.g.

Compressor).

It is the object of the invention to provide an arrangement and a method, which in a

Radial compressor allows the highest possible pressure recovery. Also, the invention should be simple and inexpensive to implement, make optimal use of the available space and flexible adaptable to different flows in centrifugal compressors or at different currents in

Be used radial compressors.

The task is accomplished by a housing arrangement for a

Radial compressor and a method for flow guidance of a flow medium in a centrifugal compressor with the features according to the respective independent claim solved.

The housing assembly for the centrifugal compressor has a first, substantially radially oriented, annular Cavity as well as a second, substantially axial

aligned, annular cavity, which are interconnected via a deflection. In the second, substantially axially aligned, annular cavity, a guide grid is arranged.

In the method for flow guidance of a flow medium in a centrifugal compressor, the flow medium is in

Essentially guided in a radial direction to the outside.

Subsequently, the flow medium is deflected substantially in an axial direction and in the substantially

Continued axial direction. In this continuation or further flow of the flow medium in the substantially axial direction of the flow, a swirl is at least partially removed.

This kinetic energy withdrawn from the flow medium is converted into potential energy in the form of pressure, i. a (desired) pressure increase of the flow medium,

transformed. Therefore, it is desirable to withdraw the flow of all possible twist. In other words, after the flow guidance, the flow medium, for example a process gas, should be spin-free.

The terms "radial" and "axial" are according to the invention with respect to an axis of rotation of an impeller of

Radial compressor or the radial compressor stage to

understand. The term "substantially" is to be expressed according to the invention that the direction thus designated permits deviations, which may be in the range of up to 45 °.

Furthermore, according to the invention, the term "aligned" - used for example for the radially oriented, annular cavity or the axially aligned,

annular cavity - in the sense of a flow direction, for example, defined by the cavity or realized flow direction of the flow medium, to understand.

So means under the radial orientation of the radial

aligned cavity such that this cavity

is formed, for example, over a substantially larger compared to its axial extent radial

Extension, that in this cavity a radial

Flow of the flow medium forms or that this cavity is flowed through radially by the flow medium. Accordingly, under the axial orientation of the axially aligned cavity means that this cavity so

is formed, for example, over a much larger compared to its radial extent axial

Extension, that in this cavity an axial

Flow of the flow medium forms or that this cavity is flowed through axially by the flow medium.

The housing arrangement according to the invention and their

Further developments are particularly suitable for the method according to the invention.

In this case, flows through the flow medium, usually a process gas, the first, substantially radially oriented,

annular cavity radially outward, is characterized by the

Deflection deflected in the substantially axial direction and flows through the second, substantially axially aligned, annular cavity in the substantially axial direction. When flowing through this second cavity of the flow using the guide grid, a twist at least in part, if possible, largely to approximately completely, preferably completely removed.

The invention thus uses a (downstream) guide grille known, for example, from a recirculation stage in a multi-stage turbomachine, such as a multistage radial compressor. The Nachleitgitter or its profiling (blading) in this case causes the flow of the depressed by the impeller of the centrifugal compressor twisted and converted into pressure (conversion of kinetic energy into potential).

In this case, however, in the invention, the Nachleitgitter not - as in the known feedback stage - centripetally flows through, but according to the invention in the axial direction.

This proves in the invention of particular

Advantage that of use known, in constructive

Conditions, such as space limitations, difficult

realizable spirals or spiral housings for

Flow control and pressure recovery can be deviated - without having to do without a pressure recovery. Instead, the invention allows by their flow control and their structural design with

Pressure recovery is a solution that uses this efficiently in a restricted space.

Also, the invention allows by their, compared to a spiral flow guide, simpler

Flow guidance of the flow medium a considerable

controlled treatment or management of the flow.

Furthermore, the guide grid according to the invention of the swirling flow flow to remove the swirl and implement this in a pressure increase (pressure recovery), which is a

Spiral or a spiral casing is not able. There remains the swirl - unused for pressure recovery - in the flow.

Furthermore, it proves advantageous in the invention that it allows a flexible adaptation of a centrifugal compressor to different design cases, i. different

Volume flows in the flow medium, allows. Thus, an adaption to a particular one can be achieved by simply adapting the transmission grid

Volumetric flow of the flow medium are completed. The Housing of the centrifugal compressor itself can remain unchanged in each case for a machine size.

For example, over a leading edge angle of a profile used in the guide grid, this can be adapted to the flow or the flow over a channel height or over a height of the second cavity to the leading edge angle.

Also, the invention, in particular in combination with a collecting housing, a structurally advantageous and simpler as well as more economical solution for collecting and discharging a flow medium from a

Radial compressor with pressure recovery dar than a spiral or as a spiral housing. Thus, a frequently cast version of the spiral requires long delivery times. In addition, there are high in a welded spiral

Flow losses, which may be reduced by the simple flow guidance in the invention.

Preferred developments of the invention will become apparent from the dependent claims.

In a preferred embodiment, a radial outlet of an impeller of the radial compressor or a

Compressor stage of the centrifugal compressor connected to a radial inlet of the first, substantially radially oriented, annular cavity. Thus, the accelerated and swirling flow - coming from the impeller - can be discharged radially outward.

In this first, substantially radially oriented, annular cavity, in short, only annular space or diffuser, the accelerated by the impeller flow medium,

For example, a process gas that has a high kinetic

Energy has, due to a radially expanding

Cross section of the diffuser slows down while the

kinetic energy of the flow medium is converted into pressure. For this purpose, it can further be provided that this annulus has an optionally adjustable blading through which the pressure recovery can be increased.

In a further preferred embodiment, it is provided that at an axial outlet of the second, substantially axially aligned annular cavity,

in particular annular, collecting space, in particular with a over a circumference of the annular collecting space constant cross-section, is arranged (concentric arrangement). Also a collection room with changing over the scope

Cross sections is possible (eccentric arrangement). The swirl-free or nearly swirl-free flow coming from the secondary lattice is absorbed in the collecting chamber.

Furthermore, it can be provided that at a predetermined circumferential position of the collecting space an outlet diffuser

(Discharge nozzle), in particular a substantially radially aligned outlet diffuser, with the collecting space

connected is. Preferably, the outlet diffuser is conical.

Also, at a predetermined circumferential position of the

A separation rib may be arranged in the collecting space, which divides a flow entering into the collecting space into two approximately equal flows.

In a further preferred embodiment of this is

Exit diffuser, in particular using a

Outlet flange, connected to a piping system, whereby the compressed flow medium from the

Radial compressor off and can be forwarded. In this case, the flow medium usually has a predetermined or

desired pressure, for example 6 to 8 bar, on. It is also provided that the flow medium with a

predetermined flow velocity from the

Radial compressor off or in the piping system entry. This specification of a flow velocity can be based on structural boundary conditions, such as load limits in the pipeline system.

An adaptation of the flow guidance is preferred

different volume flows in the flow medium using or via the (downstream) guide grille provided.

Thus, it can preferably be provided here that a profile of the guide grid or a Leitgitterbeschaufelung over a leading edge angle of the profile to a flow of a

Flow medium in the second, substantially axially aligned, annular cavity is adapted and / or that the flow over a cross section or a (channel) height of the second, substantially axially aligned, annular cavity is adapted to the leading edge angle of the profile of the guide grid ,

Preferably, the housing assembly can be used in a single or multi-stage radial compressor. Such a multi-stage centrifugal compressor can also as

Gear compressor to be realized.

Although the housing is described with respect to a radial compressor, the invention can be used anywhere

Turbomachines are used, where a flow medium is radially out or to lead into a turbomachine. For example, in radial turbines, where the

Flow direction of the flow medium is then adjusted accordingly. In other words, the flow medium first flows through the second cavity, is then deflected in the radial direction and flows through the first cavity radially inwards.

In figures, embodiments of the invention

illustrated, which are explained in more detail below.

Show it 1 Sketch in section

Centrifugal compressor; 2 Sketch in a sectional view through a

Outlet collecting housing of a centrifugal compressor according to an embodiment;

FIG 3 sketch in section through the

Outlet collecting housing of the centrifugal compressor after

FIG. 2;

FIG 4 sketch in section through a

Outlet collecting housing of a centrifugal compressor according to another embodiment;

5 Sketch in a sectional view through a

6 shows a sketch in section through a

Outlet header of a centrifugal compressor according to another embodiment. Embodiments: Radial compressor and

Outlet header of centrifugal compressors

1 shows a radial compressor 100, whose

Outlet collecting housing 1 according to an imple mentation form in the figures 2 and 3 is shown in more detail.

This radial compressor 100, as shown in FIG 1, has an impeller 10 which rotates about an axis 11 at high speed. The impeller 10 has a hub 12 and radially projecting blades 13th

The - with flow direction 101 - axially flowing gas is rotated by the impeller 10 in rotation and leaves the Impeller 10 in the radial flow direction 101 to the axis 11 and at an obtuse angle to the axis 11 with high

Speed and swirling. The blades 13 are attached to a common back plate 14 of the hub 12. The impeller 10 is located in a housing 15, the wall 16 of the outer contour of the impeller 10 is adjusted. The fan formed by the impeller 10 has an axial inlet 17 and a radial outlet 18 extending around the circumference of the impeller 10. The

Impeller 10 may also be provided with a final cover plate (not shown) on the outer contour.

At the outlet 18 closes as further the FIGS. 2 and 3 show an annular space 2 or diffuser 2, which is firmly connected to the housing 15 and does not rotate.

The annulus or diffuser 2 has a substantially radial support wall 21, to the wings 22nd

(Diffuser paddle), as shown, which direct the flow passing the outlet 18.

The radial support wall 21 of the annular space or diffuser 2 axially spaced apart there is another substantially radial wall 23, whereby the annular space or the diffuser 2 an annular, occasionally with the

Blade 22 occupied, radially aligned cavity or channel forms. The wings 22 extend substantially radially to the axis 11th

The task of the diffuser 2 is that of the

Impeller 10 accelerated gas, which has a high kinetic

Energy has to slow down and put the kinetic energy into pressure. Here, a substantial conversion of the existing swirl into pressure energy only takes place when the diffuser is bladed. As the figures 2 and 3 show, the compressed gas is after flowing through the bladed annulus or diffuser 2, first by means of an arc 4 by 90 ° in Achs- or

Axial direction deflected.

Subsequently, the in an axial annular channel. 3

weiterströmenden gas almost completely removed by a distributed over a circumference of the axial annular channel 3 and adapted to a flow angle of the gas, profiled Nachleitgitter 5 the twist and converted into pressure energy (pressure recovery).

The adaptation takes place via a front edge angle 27 of a radially inner wall 28 of the

Nachleitgitters 5 arranged profile or blade profile 26th

The axial annular channel 3 has an (annular)

Outlet opening 25, through which the compressed and now twist-free gas in an annular cross-section 6, a collecting space 6, occurs.

In the collection chamber 6, the now swirl-free flow

taken and further guided radially outward into the discharge nozzle or conical outlet diffuser 7.

About the outlet diffuser 7, the gas is further via an outlet flange 8 (not shown) in a

Pipe system 9 (not shown) with the desired pressure of for example 6 to 8 bar at desired

Exit speed steered. The gas flow is generally further retarded in the outlet diffuser, which results in a further pressure increase in this component. FIGS. 4 to 6 show further embodiments of the invention

Exit manifold housing 1 of the radial compressor 100. The same components are denoted by the same and, if not described in detail, designed according to the above. According to the outlet header housing 1 shown in FIG. 4, the collecting space 6 is in such a manner with the axial annular channel 3

connected, that the annular outlet opening 25 opens at the radially innermost point of the collecting space 6 into the collecting space 6. Put simply, the gas or the (twist-free) flow enters this directly at the bottom of the collecting space 6. A further radially inward turnout of the flow in the collecting space 6 is not possible. In the collecting chamber 6, the swirl-free flow is absorbed and further out radially into the discharge nozzle or conical outlet diffuser 7.

An embodiment according to FIG 4 is implemented, if presumably still a residual twist after the guide grid 5 is present. It is ensured that the swirl through the guide grille. 5

has been completely withdrawn, a more compact design can be selected according to FIG 2, in which the collecting space 6 is further offset to the axis 11.

FIG. 5 shows a discharge collecting housing 1, in which the

Concentrically, the annular channel formed in the collecting chamber 6 has constant cross-sections around the circumference. In other words, the collecting chamber 6 is arranged concentrically with the axial annular channel 3 (concentric Arrangement).

Furthermore, in the outlet collecting housing 1 according to FIG. 5, a radial separating rib 24 is provided in the collecting space 6, which, as FIG. 5 shows, in the collecting space 6

is arranged that for an approximately equal distribution (about 50% / 50%) of the inflowing into the plenum 6

twist-free flow is provided in a right or left flowing or guided gas flow. About the discharge nozzle or the conical outlet diffuser 7 both streams are discharged radially outward. According to the Austrittsammeigehäuse 1 shown in FIG 6, the collecting chamber 6 is eccentric to the axial annular channel. 3

arranged (eccentric arrangement). This can be easily realized by a jacket plate of the

Collecting space 6 is arranged offset. Here, too, as FIG 6 shows, the collecting space 6, the barrier rib 24 to

Splitting the flow into two approximately equal flows.

A special feature of this radial compressor 100 or its housing 1 according to FIGS. 1 to 6 lies in the use of a secondary lattice known from a return stage, in this case lattice grids 5, together with the collecting housing 6.

The Nachleitgitter 5 in this case causes the flow of the impressed by the impeller 10 and after flowing through the

given case bladed diffuser is still deprived of existing twist (conversion of kinetic into potential energy).

Here, the Nachleitgitter 5 is not - as in the known feedback stage - centripetally flows through, but in the axial direction 101 in the axial annular channel. 3

The used Profi 1 26 of the Nachleitgitters 5 can be adjusted via the leading edge angle 27 to the flow or the flow over the height of the axial annular channel 3 at the leading edge angle 27.

The described flow guide or the described

Housing 1 represents an advantageous alternative to the use of a spiral, if this is due to

difficult to realize constructive conditions.

An adaptation to different design cases

(Different volume flows) in the radial compressor 100 can alone on the adaptation of the Nachleitgitters. 5 be performed while the housing 1 remains the same even for a machine size.

This and the fact that the Nachleitgitter 5 in

Combination with the collecting housing 6 the constructive

simpler (housing) solution to the spiral dars makes the described housing 1 both technically and economically advantageous.

The following are different alternatives of

mentioned embodiment mentioned.

Thus, the described flow guide or the

described housing 1 even in multi-stage

Radial compressors are used. There it can - as described above - for flow guidance behind the last stage of such a multi-stage centrifugal compressor as well as each between two stages of such a multi-stage

Radial compressor can be used.

In this case, such a multi-stage centrifugal compressor can also be a transmission compressor.

Claims

claims

A housing arrangement (1) for a radial compressor (100) with a first, substantially radially aligned,

annular cavity (2)

marked by

a second, substantially axially aligned,

annular cavity (3), which first substantially radially oriented, annular cavity (2) and which second substantially axially aligned, annular

Cavity (3) via a deflection arrangement (4) are interconnected, and arranged in the second, substantially axially aligned, annular cavity (3)

Guide grid (5).

2. Housing arrangement (1) after at least one of

preceding claims,

characterized in that

a radial outlet (18) of an impeller (10) of the

Radial compressor (100) with a radial inlet (19) of the first, substantially radially oriented annular cavity (2) is connected.

3. Housing arrangement (1) after at least one of

preceding claims,

characterized in that

at an axial outlet (25) of the second, substantially axially aligned annular cavity (3) a, in particular annular, collecting space (6), in particular with a over a circumference of the annular collecting space

(6) constant cross section, is arranged.

4. Housing arrangement (1) according to at least the preceding claim,

characterized in that

at a predetermined circumferential position of the collecting space (6) an outlet diffuser (7) (discharge nozzle), in particular a substantially radially aligned outlet diffuser (7), with the collecting space (6) is connected.

5. Housing arrangement (1) according to at least one of the two preceding claims,

characterized in that

at a predetermined circumferential position of the collecting space (6) a separating rib (24) is arranged, which one in the

Plenum entering flow divides into two approximately equal flows.

6. Housing arrangement (1) after at least one of

preceding claims,

characterized in that

the outlet diffuser (7), in particular using an outlet flange (8), is connected to a pipeline system (9).

7. Housing arrangement (1) after at least one of

preceding claims,

characterized in that

a profile (26) of the guide grid (5) via a

Lead edge angle (27) of the profile (26) is adapted to a flow of a flow medium in the second, substantially axially aligned, annular cavity (3) and / or that the flow over a cross section (height) of the second, substantially axially aligned, annular cavity (3) to the leading edge angle (27) of the profile (26) of the guide grid (5) is adapted.

8. Housing arrangement (1) according to at least the preceding claim,

characterized in that

the first substantially radially oriented annular cavity (2) has a blading (22).

9. Housing arrangement (1) after at least one of

preceding claims used in a single or multi-stage centrifugal compressor (100).

10. A method for flow guidance of a flow medium in a radial compressor (100), wherein the flow medium is guided in a radial direction to the outside substantially, characterized in that

the flow medium is then deflected substantially in an axial direction and in the substantially

Axial direction is continued, wherein the flow of a twist is at least partially removed.