EP3183427B1 - Profiling of inlet guide vanes of radial compressors - Google Patents

Description

The invention relates to a centrifugal compressor with a distributor.

Compressors or fluid compressing devices are used in various industries for various applications involving compression or compression of (process) fluids, especially (process) gases. Well-known examples of this are turbo compressors in mobile industrial applications, such as in exhaust gas turbochargers or in jet engines, or even in stationary industrial applications, such as gearbox turbo compressors for air separation.

In such - in its operation continuously working - turbo compressor, the pressure increase (compression) of the fluid is effected by an angular momentum of the fluid from entry to exit by a rotating radially extending blades having impeller of the turbo compressor is increased by the rotation of the blades , Here, i. In such a compressor stage, pressure and temperature of the fluid increase while the relative (flow) velocity of the fluid in the impeller decreases. In order to achieve the highest possible pressure increase or compression of the fluid, a plurality of such compressor stages can be connected in series.

As types of turbocompressors, a distinction is made between radial and axial compressors.

In the axial compressor, the fluid to be compressed, for example a process gas, flows in a direction parallel to the axis (axial direction) through the compressor. In the centrifugal compressor, the gas flows axially into the impeller of the compressor stage and then outward (radial, radial direction) distracted. With multi-stage centrifugal compressors, a flow diversion becomes necessary behind each stage.

Such a radial compressor is known from http://de.wikipedia.org/wiki/Verdichter (available on 06.10.2014).

Combined types of axial and radial compressors draw large volume flows with their axial stages, which are compressed to high pressures in the subsequent radial stages.

While mostly single-shaft machines are used, gear compressor compressors, the individual compressor stages are grouped around a large wheel around, with several parallel shafts, each carrying one or two - recorded in spiral housings - wheels are driven by a large drive gear, a large wheel.

Such a gear compressor, a gear turbo compressor from Siemens called STC-GC, used for the air separation, is from http://www.energy.siemens.com/hq/en/compression-expansionventilation/turbo-compressor/transmissionurbo-compressor/stc-gc .htm (available on 06.10.2014).

Another, in this case single-stage geared centrifugal compressor with overhanging open impeller, a transmission turbo compressor from Siemens called STC-GO, used to meet a demand of a metallurgical, fossil and chemical industry, is from http://www.energy .siemens.com / hq / DE / compression-expansion-ventilation / turbo-compressor / single-stage-compressor / stc-go.htm (available on 06.10.2014)

From the EP 2 241 722 A1 is known an axial compressor whose first vane stage has a turning point in the profile profile. From the WO 2005/059313 A2 a turbocharger is known which has an adjustable inlet guide.

In times of increasingly flexible process control in general, requirements such as (control) flexibility and / or performance in turbomachinery in particular are also increasing.

For this purpose, it is known to improve / increase an efficiency and / or control range in turbomachines, to influence the characteristics of turbomachines or even to control turbomachinery in general, such turbomachinery with nozzles, such as - usually adjustable - ( axial impeller) upstream Eintrittsleitapparaten and / or (axial impeller) downstream Austrittsleitapparaten to provide.

Such nozzles usually have a ring-shaped, possibly by means of a (adjustable) mechanics (angle) adjustable blades with profiled, of the (process) fluid flow around / -ten blade blades, which contribute to an optimized flow guidance through the turbomachine.

Such an inlet and outlet guide is, for example, from DE 10 2012 216 656 A1 known. Also, the transmission turbo-compressor STC-GC has an inlet guide (before its first stage).

From the EP 2 241 722 A1 an axial compressor with a guide vane is known, wherein the vane has a turning point in the profile center line or skeleton line. The WO 2005/059313 A2 . WO 2009/086959 A1 and the EP 1790 830 A1 each show a turbocharger with corresponding vanes on the turbine.

For example - in the case of an adjustable Eintrittsleitapparates - so by means of such an adjustable Eintrittsleitapparates the axially (with respect to the impeller axis) entering the turbomachine (process) fluid or its flow in terms of speed and flow direction before hitting the impeller or on the first impeller level depending on a power request the turbomachine is adjusted or regulated by the (angular) adjustment of the blades or the blades of the blade ring of the inlet guide.

However, especially with large angle adjustments of the blades or blades, the fluid flow no longer follows a profile contour of the blades or blades, which is accompanied by flow losses, efficiency losses and so also to restrictions in the (power / flexibility) requirements of the turbomachinery.

The same applies also to outlet nozzles in turbomachinery or local angular adjustments.

The invention has for its object to improve disadvantages of the prior art and to realize a simple and inexpensive way turbomachinery, which are flexibly mobile with high efficiencies.

The object is achieved by a centrifugal compressor with the features of independent claim 1.

The distributor of the centrifugal compressor has at least one blade which has a fluid blade that can be flowed around by a fluid. A curvature of a profile center line (also referred to as a skeleton line) of the airfoil has at least one point of inflection.

Here, under profile - as defined in fluid mechanics (see http://de.wikipedia.org/wiki/Profil (fluid mechanics) , available on 06.10.2014) - the shape of a cross section of a body, here the airfoil, in the flow direction be understood. Under profile center line or skeleton line (also curve line), the connecting line of the in a profile, in this case the airfoil profile, inscribed circle center be understood.

By modifying the profile centerline, i. by the at least one inflection point (or optionally also several inflection points) having curvature of the profile center line of the airfoil, short and simplified - by the at least one inflection point (or possibly more inflection points) having curved profile center line of the airfoil, a blade airfoil surface can be changed so that flow losses in a wide range of adjustment of an (adjustable) blade at an adjustable nozzle can be reduced - without a significant change in a 0 ° position of the airfoil / the blade.

Thus, the performance or performance data of a turbomachine in certain operating points, such as a main guarantee point, can be improved.

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

According to a preferred embodiment, it is provided that the curvature of the profile centerline / skeleton line of the airfoil has exactly one point of inflection. Expressed in a clear and simplified way, the airfoil forms here a profile similar to an S-flapping profile (for wings, for example in winged wings, winglets). The name, "S-blow", comes from the fact that the profiled center line / skeleton line in the rear of the profile "S-shaped" facing up, whereby - here then at the airfoil - the flow - with swirl (which depends on a Formation of the "S-shaped course" or a "S-shaped" upwardly facing profile trailing edge is,) - flows from the airfoil.

Alternatively, it can also be provided that the curvature of the profile center line of the airfoil has two ("double S-stroke"), three ("triple S-stroke") or even more inflection points.

According to a further preferred development, it is provided that a number of turning points and / or a position of the at least one turning point or - in the case of several turning points - the positions of the turning points and / or a strength and / or a curve of the curvature, briefly simplified an expression of the curvature, is dependent on an aerodynamic task, in particular to be provided onflow conditions of the airfoil and / or the impeller. Other profile sizes or geometries, such as profile thickness, tread depth and / or span of the airfoil, can be designed accordingly or depending on the aerodynamic task.

In this context, position (of the point of inflection) can be understood to mean a point of inflection, which is the distance of the at least one inflection point or inflection point projected onto a chord of the airfoil from a leading edge of the airfoil. A relative inflection point reserve is the inflection point reserve based on the length of the profile chord or on the tread depth.

Thus, for example - clearly and / or in simplified terms - for an operating or design point of a fluid machine, for which the diffuser, for example, as its Eintrittsleitapparat, is provided, the adjustment set - and then for local flow conditions (flow of the airfoil under the Verstellwinkel ) the airfoil profile or the characteristic of the curvature of the airfoil and thus also the number of inflection points, the inflection point reserve of the inflection point or the inflection point of the inflection points, the strength of the curvature and / or the curvature are optimized such that the flow of the airfoil - at an assumed adjustment angle - with a certain, intended swirl (to the impeller) flows, but the flow around the blade (at the assumed adjustment angle) takes place without stall.

According to the invention, it is provided that the airfoil is designed such that a profile depth of the airfoil changes over its span (extension of the airfoil from a blade airfoil to a free airfoil end). Clearly and simply said, the airfoil changes its tread depth between its airfoil root and its free airfoil end. For example, such an airfoil may be approximately trapezoidal in its outer dimensions.

In addition, it is provided that the airfoil is designed such that the profile thickness (corresponding to the maximum profile thickness) also changes with the tread depth changing over the span of the airfoil.

Also, it is provided here that changes the profile thickness according to the profile depth change.

In a clear and simplified way, the airfoil scales here (over the span) according to its tread depth (over the span). Relative maximum profile thickness (here is the maximum profile thickness related to the profile depth) and maximum profile curvature and relative maximum profile curvature (here is the maximum profile curvature relative to the tread depth) can remain unchanged in this case (over the span).

In a further development can also be provided that a plurality or a plurality of the blades are arranged in a ring. Put simply, the blades form a guide ring here.

Further, according to the invention, an adjusting device for adjusting the blade - or in the case of several of the, in particular ring-shaped arranged to a guide ring, blades to be provided for the adjustment thereof. For this purpose, a (adjustment) mechanics be provided, which after a prescribed

Kinematik a blade or all blades of a Leitranz can be adjusted. For adjustment itself, a motor unit, such as an electric motor, can be used.

It is further provided according to the invention that the diffuser is a Eintrittsleitapparat (so also arranged or arranged at an inlet of the centrifugal compressor). This is then arranged at an inlet of the radial compressor, that the inflow into the centrifugal compressor (via the inlet guide) takes place axially.

Simplified and clearly expressed, the distributor is arranged in the axial extension of an impeller shaft in the fluid machine or a Leitkranzmittelachse is arranged in the axial extension of the impeller shaft.

Particularly preferably, the distributor can be used in a single or multi-stage centrifugal compressor or a multi-stage radial gear compressor.

The previously given description of advantageous embodiments of the invention contains numerous features, which are given in the individual subclaims partially summarized in several. However, those skilled in the art will conveniently consider these features individually and summarize them to meaningful further combinations.

The features, features and benefits described above of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of one or more Embodiments, which is or will be explained in more detail in connection with the figures.

However, the invention is not limited to the combination of features specified in the exemplary embodiments, not even with regard to functional features. For this purpose, suitable features of each embodiment can also be considered explicitly isolated, removed from one exemplary embodiment, introduced into another exemplary embodiment for its supplementation.

Function / construction identical or identical elements or components have the same reference numerals in the embodiments or figures.

FIG 1

eine Skizze eines Eintrittsleitapparates bei einer Turbomaschine;

FIG 2

eine Skizze einer verstellbaren Schaufel eines Eintrittsleitapparates;

FIG 3

eine Skizze eines Profils einer verstellbaren Schaufel eines Eintrittsleitapparates (Profilschnitt III - III).

Show it

FIG. 1

a sketch of a Eintrittsleitapparates in a turbomachine;

FIG. 2

a sketch of an adjustable blade of a Eintrittsleitapparates;

FIG. 3

a sketch of a profile of an adjustable blade of a Eintrittsleitapparates (profile section III - III).

Exemplary embodiment: Profiling of guide vanes of distributor apparatuses in turbomachines, in particular of inlet distributor apparatus in compressors
FIG. 1 shows a section of a multi-shaft gear compressor 10, for example for the air separation, with a arranged in a volute casing 14 (first) compressor stage 15th

Axial this (first) compressor stage 15 and the impeller 27 is connected upstream - at an axial inlet 16 of this Spiral housing 14, like FIG. 1 1, an inlet guide apparatus 1 (ELA or I (nlet) G (uide) V (ane)) is arranged.

The Eintrittsleitapparat 1 has, as FIG. 1 also illustrates a plurality of annularly arranged, adjustable profiled airfoils 3 having guide vanes 4 (see. 2, FIG. 3 ) on (Leitkranz 13, inlet guide 13).

The control of the transmission compressor 10 is u.a. via the adjustable Eintrittsleitapparat 1, i. by adjusting the blades 4 and their blades 3 (by means of an adjustment mechanism 12), whereby - depending on the adjustment angle of the blades 4 and the blades 3 of the inlet guide 13 - the arrival, flow and outflow of the blades 3 by the operating gas 2 in the Eintrittsleitapparat 1 and thus in sequence the inflow to or flow to the (first) compressor stage 15 and the impeller 27 by the operating gas 2 changes.

Even at large adjustment angles, for example greater than 15 °, or over a wide adjustment of the blades 4 or blades 3 flow losses (no longer the profile contour 17 of the blades 3 following fluid flow / operating gas flow or by a stall of the fluid flow / operating gas flow in the blades 3) to avoid show, in particular the FIG. 3 illustrates the blades 3 a special profiling 23, ie here an S-beating profile 23 (with a simple "S-blow") on.

FIG. 2 shows - representative of all (appropriately trained) blades 4 of the inlet guide 13 of the Eintrittsleitapparats 1 - / the adjustable blade 4 of the inlet guide 13 of the inlet guide 1 of the gear compressor 10th

As FIG. 2 illustrates the adjustable blade 4, the profiled blade 3, which via the adjustment mechanism 12 - here indicated only by a connecting shaft 18 and a pin 24 and plate 25 - (win kel-) is adjustable.

The airfoil 3 is - like FIG. 2 also clarifies - in its outer dimensions substantially trapezoidal, ie the tread depth 8 decreases in the airfoil 3 over the span 9 (extension of the airfoil 3 of the blade airfoil 19 to the free blade end 20) continuously.

Expressed and simplified, the blade 3 changes, here reduced, its tread depth 8 between its Schaufelblattfuß 19 and its free blade end 20 and over its span. 9

According to this (from Schaufelblattfuß 19 to the blade end 20 and over the span 9) decreasing tread depth 8, the entire blade 3 scales with or in his (S-blow) profile 23rd

That is, the profile thickness 11 (corresponding to the maximum profile thickness) decreases over the span 9 of the airfoil 3 in accordance with the decrease in the tread depth 8 (also). Relative maximum profile thickness (here is the maximum profile thickness based on the tread depth 8) and maximum profile curvature and relative maximum profile curvature (here is the maximum profile curvature based on the tread depth 8) remain - over the span 9 of the airfoil 3 - unchanged.

FIG. 3 shows by the section III - III (at FIG. 2 ) marked (flow line) profile section through the blade 3 of the blade 4 of the stator 13 of the inlet guide 1, in short the profile 23 of the blade 3.

As FIG. 3 shows the airfoil 3 and its profile 23 an S-beating profile 23 (with a simple "S-beat") - with a (simple) "S-shaped" curved profile center line 6 or skeleton line 6 - from.

That is, the ("s-shaped") curvature 5 of the profile center line / skeleton line 6 of the airfoil 3 has - in this case - exactly one inflection point 7, the profile center line / skeleton line 6 in the front region of the profile 23, i. in the area of the leading edge 21 of the airfoil 3, "S-shaped" downwards and in the rear region of the profile 23, i. in the region of the trailing edge 22 of the airfoil 3, "S-shaped" facing upward.

The flow around the profile 23 is also dependent (or in particular also influenced) by an expression of the "S-shaped course" or of the "S-beat" in the profile 23, i. et al the course and the magnitude of the curvature 5 as well as the position of the (here one - otherwise also the number of inflection points) inflection point 7 (inflection point reserve 28 (distance of the inflection point 7 - projected onto the chord 26 (chord 26 is straight line of connection between the front chord) 21 and trailing edge 22 of the profile 23) of the airfoil 3 - from a front edge 21 of the airfoil 3).

The expression of the "S-impact" profile 23 of the airfoil 3 (about which the flow conditions in the airfoil 3 can be influenced) is dependent on the aerodynamic task in the inlet guide 1 (optimization on the aerodynamic task (or the operating point)), in particular of the inflow conditions to be provided for the blade 3 and the impeller 27 of the (first) compressor stage 15 (at the operating point).

Is - as exemplified here - for the operating or design point of the compressor 10 a (design) adjustment angle of the blades 4 in the Eintrittsleitapparat 1 of about 15 °, then the "S-blow" profile 23 and its expression for local flow conditions (flow of the airfoil 3 at this (design) adjustment angle) optimized such that the flow of the airfoil 3 -. at this assumed (design) adjustment angle - with a certain, intended swirl (to the impeller 27) flows, but the flow around the blade 3 (at this assumed (interpretation) adjustment angle) without stall or at lower flow losses.

As FIG. 3 shows here - under said aspects - the "S-blow" profile 23 only a weak "S-dash" (ie, only one turning point 7 at low curvature 5 (after "up and down")) with a narrow profile thickness 11 on. The inflection point reserve 28 of the inflection point 7 of the "S-shock" or in the "S-blow" profile 23 of the airfoil 3 is slightly behind, ie in the direction of the profile trailing edge 22, the middle of the chord 26th

Although the invention has been further illustrated and described in detail by the preferred embodiment (s), the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

Claims (4)

1. Centrifugal compressor (10) with a stator (1) which is designed as an inlet stator (1),
   in particular for a compressor (10),
   with at least one vane (4) having a vane
   airfoil (3) around which a fluid (2) can flow,
   with an adjustment device (12) for adjusting the vane (4), characterized in that
   a curvature (5) of a profile centre line (6) of the vane airfoil (3) has at least one inflection point (7),
   wherein the vane airfoil (3) is designed such that a profile depth (8) of the vane airfoil changes over the span (9) of the latter,
   wherein the vane airfoil (3) is designed such that a profile thickness (11) changes along with the profile depth (8) that changes over the span (9) of the vane airfoil (3), such that the profile thickness (11) changes according to the change in profile depth.
2. Centrifugal compressor (10) according to Claim 1, characterized in that
   the curvature (5) of the profile centre line (6) of the vane airfoil (3) has one inflection point (7) or two points of inflection (7).
3. Centrifugal compressor (10) according to at least one of the preceding claims, characterized in that
   a number of points of inflection (7) and/or a position of the at least one inflection point (7) and/or a magnitude and/or a course of the curvature (5) is/are dependent on an aerodynamic specification, in particular on incident flow conditions of the vane airfoil (3) that are to be determined.
4. Centrifugal compressor (10) according to at least one of the preceding claims, characterized by a plurality of the vanes (4) arranged in the form of a ring.

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