CN1039087A

CN1039087A - Improve the device of performance of centrifugal compressors

Info

Publication number: CN1039087A
Application number: CN89104525A
Authority: CN
Inventors: 卡尔-海因茨·罗尼
Original assignee: Asea Brown Boveri AG Switzerland
Current assignee: ABB Schweiz Holding AG; ABB AB
Priority date: 1988-06-29
Filing date: 1989-06-29
Publication date: 1990-01-24
Also published as: KR900000600A; KR970005863B1; CN1012698B; PL159958B1; DE58903001D1

Abstract

A kind ofly comprise by stablizing the device that impeller stream in inlet region improves its performance when the small flow in centrifugal compressor: be positioned at the circumferential slot type cinclides (5) of compressor inlet (6), at flow direction, it reaches impeller (2) with a certain axial width; One stabilizing ring is contained in the cinclides (5), places the front of impeller (2) and in the outside of transmission medium main flow (7); Somely place blade on stabilizing ring (3) cylindrical (4,4a), they are fixed on the inside contour of cinclides (5) successively.

Description

Improve the device of performance of centrifugal compressors

The present invention is about improving the device of performance of centrifugal compressors.

When using turbocompressor, no matter they are centrifugal or axial flow, in order when partial load is worked, to obtain high reliability, that people are just trying hard to obtain is stable, not have the dull negative characteristic of hysteresis with increasing flow, yet higher than more at the design point upward pressure, it is just difficult more to obtain stable characteristic curve under partial load.People have made great efforts to remedy this point, adopt additional stabilizer to improve desired characteristic curve.Because the difference of Blade Design, and when partial load was worked, the architectural difference from laminar flow to turbulent region of variation up to now, did not also sum up the clear and definite technological scheme of a cover, derives a kind of stabilizer easily by it.

Therefore, can't on the science precision, whether can in a compressor, obtain stable characteristic curve fully now by stabilizer.Especially under the situation of centrifugal compressor, can experience this unsatisfied state.

A kind of stabilizer of centrifugal compressor becomes known technology by EP-A1-0229519, and the feature that it has is an inner cover, as the overcoat of impeller, demonstrates radially or accurate warp-wise eyelet.Above-mentioned eyelet is set up contact between at the influent stream pipe with more or less by the blade grid that block in blade-side.Though this eyelet has changed the pumping limit and the stability limit of characteristic aspect, this is to obtain under the loss of sacrificing efficient, and loss in efficiency can reach 4-5%.So adopting this technological scheme to obtain to improve performance owing to the unstability that occurs is desired on small flow under particular job pattern is impossible substantially.Here other very important factor is, the stablizing effect that this is minimum must be to obtain under the prerequisite of out-of-proportion high loss in efficiency.

Therefore, the objective of the invention is the performance when can predetermined precision improving small flow by stablizing inlet region impeller stream for centrifugal compressor provides a kind of new device.

Advantage of the present invention is based on such fact: as long as centrifugal compressor transmits full flow.This device nature running; Only when different fluidic structures occur, especially under partial load, only when different fluidic structures occur, especially under partial load, this device just works, it is impossible that the aforementioned segregation phenomenon that the entire portion load zones occurs crossing is become.Worrying " suction " also is avoided, thereby produced stability characteristic (quality).Further advantage of the present invention is based on the following fact: apparatus structure of the present invention is simple, can be used for each centrifugal compressor and let it be technical performance how.In additional claim, will the technological scheme that draw according to purpose of the present invention be described further developing aspect advantage and the convenience.

Purpose of the present invention adopts a kind of device in the centrifugal compressor impeller inlet region to reach.This device comprises a cinclides, and it is positioned the circumferencial direction of centrifugal compressor inlet tube, upstream stretches from the inlet of impeller; A stabilizing ring, it is contained in the above-mentioned cinclides, is placed in the front of impeller and in the outside of transmission medium main flow; Be contained in the some blades on the stabilizing ring excircle, they itself are fixed on the inner loop of cinclides.The present invention also clearly provides the each several part size of this device form with ratio, provides data for realizing purpose of the present invention.

By to following detailed description with reference to accompanying drawing, can be easy to obtain equally also can understand the present invention better to more complete evaluation of the present invention and a lot of attached advantages of discovery, wherein:

Fig. 1 represents to have the centrifugal compressor that makes the improved device of compressor performance;

Fig. 2 represents to have the structurally centrifugal compressor of improved device;

Fig. 3 represents this device size situation.

Referring now to accompanying drawing,, wherein in institute's drawings attached, same reference number is represented identical or corresponding parts, and Fig. 1 represents the phantom in the zone of the device that centrifugal compressor provides in order to improve its performance during operation.At the partial load duration of work, this device produces stable impeller stream at entrance region usually.Centrifugal compressor is made up of cover 1 and impeller 2, and the aforementioned stable device is installed in the place ahead of impeller 2, and itself is made up of stabilizer cinclides 5, stabilizing ring 3 and some fins 4.Stabilizer cinclides 5 is made inside channel, from the surface of inlet duct 6, radially be stretched in the cover 1 with a certain degree of depth, upstream stretches certain certain-length at the axial approximately influent stream edge from impeller 2.Stabilizing ring 3 is packed in the stabilizer cinclides 5, and its interior ring surface extends in the extension on inlet duct 6 surfaces.The outer shroud of stabilizing ring 3 and some blades suit, and blade has been filled stabilizer cinclides 5 inside residue width radially, and is fixed on there.The wall thickness of stabilizing ring 3 is along with the intensity of job requirement changes with stability.Consider that from the aerodynamic force aspect wall thickness of stabilizing ring 3 must damage the height of fin 4 unnecessaryly.Therefore, this is a kind of stabilizer deformable body with blade, compares with the structure with blade not, and it can guarantee to reduce hysteresis or the unstability scope plays good action.Though the stabilizer structure itself with blade can not reduce the unstability scope yet, yet the latter's minimizing can not obtain with it.This is relevant with the following fact to a great extent, i.e. circuit volume flow under the partial load state is with respect to the volume flow of compressor transmission, concerning the stabilizer of band blade, than bigger with blade not.These differences derive from the different loss coefficient of stabilizer.Generally speaking, the correct design of stabilizer depends primarily on the correct selection of stabilizing ring 3 external diameters, it must be coordinated with compressor, that is to say that the external diameter at impeller inlet place is under every kind of situation, on optimum, only there is air flow stream seldom to cross stabilizer cinclides 5 on the one hand, the unlikely decline of efficient like this, and on the other hand, big as far as possible air-flow 8 must circulate under partial load.Nature after the external diameter of stabilizing ring 3 is selected, exists relation of interdependence at it with installing between other size of component.

Here, we come interpretation maps 3, and under overload situations, part blast air 9 flows through stabilizer cinclides 5, and flow direction is identical with the direction of main flow 7, and it clashes into impeller 2, is discharged into path 10 as pressurized air then.In stabilizer cinclides 5, part blast air 9 also has reverse twist, and efficient presents the tendency of increase thus.Can see also that from Fig. 1 the structure of being mentioned as an example is to be designed to impeller 2 protrude in the stabilizer cinclides 5 here.The reason of doing like this is, impeller 2 protrudes in the stabilizer cinclides 5 dark more, and the merit that passes on the recycle gas is many more, and the circulation volume flow is big more, and then the stabilization of this device is just big more.The width of fin 4 is transformable as the fin 4a that dots on the airflow direction of circuit partial load air-flow 8, can be envisioned for the whole residue width of stabilizer cinclides 5 in this extension plane.The fin 4a of maximum possible width has pipe effect because of part air-

flow

8,9, thus the stability when helping to increase partial load and overload.

Fig. 2 is the such centrifugal compressor of presentation graphs 1 also, and in order to improve the air-flow in the stabilizer cinclides 5 under partial load, stabilizing ring 3 and fin 4a have had further improvement.Stabilizing ring 3 has imitated structure, and fin 4a has presented maximum extending axially on the direction of partial load air-flow 8, and is further improved by influent stream supporting facility 4b, under partial load, these measures are further improved characteristic curve, although this improvement is less.Fig. 2 also is illustrated in the example that this device stabilization of supposing among Fig. 1 increases, and this increase is stretched into 5 one long distances of stabilizer cinclides and obtained in countercurrent direction by impeller 2a.As shown in Figure 2, structurally can accomplish to make impeller 2a to protrude into stabilizer cinclides 5 interior places fully up to stabilizing ring 3a.

Fig. 3 is as the basis that describes below.As what mention in the description of Fig. 1, the correct design of stabilizer mainly comprises the correct selection of the outside diameter d of stabilizing ring 3.Obviously, if wish from have one in order at entrance region, the work of the centrifugal compressor of device that especially stabilization vane takes turns under partial load guarantees advantage, obviously diameter d must have one to determine ratio to impeller eye external diameter Y.Correct stabilizing ring outside diameter d to the proportional limit of impeller eye external diameter Y in the scope of 1.02-1.05.Other size of component of this device is derived by this initial selected value, and for clarity sake, these size of component are used the ratio of impeller eye external diameter Y is represented later on.

We can summarize relation of plane down:

The stack size S2 of impeller 2 and stabilizer cinclides 5 is 0-0.06 to the ratio of impeller eye external diameter Y.

At the initial edge of stabilizer cinclides 5 with flowing to that the ratio of residue hole S3 and impeller eye external diameter Y is 0.06-0.12 between the initial edge of stabilizing ring 3 on the air current flow direction of impeller 2.

The width B 1 of the fin 4a that the ingress edge of stabilizer cinclides 5 is counted from the flow direction is 0.08-0.22 with the ratio of impeller eye external diameter Y.

Stabilizer cinclides 5 outer diameter D are 1.08-1.21 with the ratio of impeller eye external diameter Y.

The Effective face width B2 of stabilizer cinclides 5, it deducts overlap region size S2 by the overall width of stabilizer cinclides 5 and draws, with the ratio of impeller eye external diameter Y be 0.12-0.26.

The Effective face width B3 of stabilizing ring 3 is 0.06-0.16 with the ratio of impeller eye external diameter Y.

Interval S1 is 0-0.04 with the ratio of impeller eye external diameter Y between the ingress edge of the end edge of stabilizing ring 3 and impeller 2.

At last, in above-mentioned explanation, the outside diameter d of stabilizing ring 3 is 1.02-1.05 with the ratio of impeller eye external diameter Y as.

These very close ratios clearly illustrate, needn't be through laboratory tests in advance, just can determine to be used for to improve the design of the new optimum device of the performance of centrifugal compressor under partial load.

Obviously, according to top introduction, modifications and variations of the present invention are are possible.Therefore, should can be understood as within the scope of the appended claims, with described herein different also may be to implement the present invention.

Claims

1, in a kind of centrifugal compressor impeller inlet region in order to improve the device of the performance of centrifugal compressor when the small flow, it is characterized in that, this device comprises: a cinclides (5), it is positioned at the circumferencial direction of centrifugal compressor inlet tube (6), upstream stretch from the inlet of impeller (2), a stabilizing ring (3) is installed in the above-mentioned cinclides (5), is placed in the front of impeller (2) and in the outside of transmission medium main flow (7); (4,4a), they itself are fixed on the inside chow ring of cinclides (5) to be contained in some blades on stabilizing ring (3) excircle.

2, according to the device of claim 1, it is characterized in that: impeller (2) and cinclides (5) distal-most end imbricate on flow direction, above-mentioned overlapping dimension (S2) is 0-0.06 with the ratio of impeller (2) inlet external diameter (Y).

3, according to the device of claim 1 and 2, it is characterized in that: the interval (S1) between the ingress edge of the end edge of the stabilizing ring on the flow direction (3) and impeller (2) is 0-0.04 with the ratio of the inlet external diameter (Y) of impeller (2).

4, according to the device of claim 1 to 3, it is characterized in that: the external diameter of stabilizing ring (d) is 1.02-1.05 with the ratio of impeller (2) inlet external diameter (Y).

5, according to the device of claim 1 to 4, it is characterized in that: the ratio 0.6-0.16 of the width (B3) of stabilizing ring (3) and the inlet external diameter (Y) of impeller (2).

6, according to the device of claim 1 to 5, it is characterized in that: the spacing (B2) from the ingress edge of cinclides (5) on flow direction to impeller (2) is 0.12-0.26 with the ratio of impeller eye external diameter (Y).

7, according to the device of claim 1 to 6, it is characterized in that: (4, width 4a) (B1) is 0.08-0.22 with the ratio of impeller (2) inlet external diameter (Y) to the fin of counting from the ingress edge of flow direction cinclides (5).

8, according to the device of claim 1 to 7, it is characterized in that: the external diameter (D) of cinclides (5) is 1.08-1.21 with the ratio of the inlet external diameter of impeller (2).