EP3805572A1 - Diffuseur, turbocompresseur radial - Google Patents

Diffuseur, turbocompresseur radial Download PDF

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Publication number
EP3805572A1
EP3805572A1 EP19201593.1A EP19201593A EP3805572A1 EP 3805572 A1 EP3805572 A1 EP 3805572A1 EP 19201593 A EP19201593 A EP 19201593A EP 3805572 A1 EP3805572 A1 EP 3805572A1
Authority
EP
European Patent Office
Prior art keywords
diffuser
dfr
contour
flow
leading edge
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP19201593.1A
Other languages
German (de)
English (en)
Inventor
Lutz Keferstein
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Siemens AG
Original Assignee
Siemens AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Siemens AG filed Critical Siemens AG
Priority to EP19201593.1A priority Critical patent/EP3805572A1/fr
Publication of EP3805572A1 publication Critical patent/EP3805572A1/fr
Withdrawn legal-status Critical Current

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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D29/00—Details, component parts, or accessories
    • F04D29/40—Casings; Connections of working fluid
    • F04D29/42—Casings; Connections of working fluid for radial or helico-centrifugal pumps
    • F04D29/44—Fluid-guiding means, e.g. diffusers
    • F04D29/441—Fluid-guiding means, e.g. diffusers especially adapted for elastic fluid pumps
    • F04D29/444—Bladed diffusers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2240/00—Components
    • F05D2240/10—Stators
    • F05D2240/12—Fluid guiding means, e.g. vanes
    • F05D2240/121—Fluid guiding means, e.g. vanes related to the leading edge of a stator vane
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/70—Shape
    • F05D2250/71—Shape curved
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2250/00—Geometry
    • F05D2250/70—Shape
    • F05D2250/71—Shape curved
    • F05D2250/713—Shape curved inflexed

Definitions

  • the invention relates to a diffuser of a radial turbo compressor, the diffuser extending annularly around a central axis, the diffuser having an inflow which is formed along at least a first section of the flow for an at least largely radial flow by means of a process fluid during operation, the Diffuser has stationary guide vanes, which divides the diffuser at least along a radial section into individual circumferential segments, the guide vanes extending in the direction of flow from an entry edge to an exit edge in the axial center along a mean chord length, the diffuser in the area of the first section has a first diffuser delimitation contour on a first axial side and a second diffuser delimitation contour on a second axial side, the guide vanes extending transversely thereto along at least part of the extent in the direction of flow extend from the first diffuser delimiting contour to the second diffuser delimiting contour along a blade height.
  • the diffuser according to the invention is designed bladed. With regard to the blading, a distinction is made between low solidity diffusers [LSD] with low blade overlap (with guide blades that are relatively far apart in the circumferential direction in relation to their radial extent) and channel diffusers - also known as aerodynamic diffusers [AE diffusers] .
  • a diffuser according to the invention is preferably designed as an LSD.
  • Diffusers for radial machines are already from the EP 2 650 546 A1 known. It is proposed there to arrange the guide vanes of the diffuser in an inclined shape in a standing diffuser arranged behind the impeller (dihedral vanes). With the LSD in particular, this aerodynamic measure is intended to achieve a reduced pressure loss.
  • the fin guide vanes In the case of a combined use of fin guide vanes and guide vanes which - unlike the fin guide vanes - extend over the entire axial channel height of the diffuser, the fin guide vanes being upstream of the other guide vanes, it is disadvantageous that the fin guide vanes in the area of their axial end in Flow channel can trigger separation phenomena in the flow. In addition, it is disadvantageous that the rib guide vanes can cause a dead water area extending over part of the channel height downstream, so that in an axial view the flow pattern through the diffuser can also become less uniform through the use of the rib guide vanes, so that positive effects in aerodynamic terms at least to be partially repealed.
  • the invention has set itself the task of providing a more uniform flow guidance and at the same time offering the advantage that a separate flow guidance on the part of a cover disk side of the diffuser offers - as is done for example by means of rib guide vanes provided upstream.
  • radial, axial, tangential or circumferential direction relate to the initially defined axis around which the diffuser extends in an annular manner. In the case of a turbo compressor or a radial turbo compressor, this axis is coaxial with the axis of rotation of the rotor.
  • the invention understands a profile center line to be an imaginary line that extends through the center of a blade profile.
  • the blade profile is understood as a two-dimensional shape.
  • the profile center line can be constructed in this two-dimensional form, for example by connecting the center points of all inscribed circles by means of a line - the profile center line.
  • the diffuser is defined axially by diffuser boundary contours.
  • the term “diffuser delimitation contours” is not to be understood here in such a way that the diffuser delimitation contours always have an axial surface normal. Rather, this term is intended to mean that the diffuser delimiting contours in any case have a radial extent and - even if they have an oblique course with respect to the radial or axial - delimit the diffuser in the axial direction.
  • Another advantageous development of the invention provides that the axial distance between diffuser delimitation contours widens in the radial direction.
  • the diffuser is a flow-conducting component of the stator, which is located downstream of the impeller outlet.
  • the flow rate of the process fluid is delayed in the diffuser, so that a pressure build-up results in accordance with Bernoulli's principles.
  • the diffuser effect results from the radial increase in the cross-sectional area through which the flow passes.
  • a change in the diffuser channel width which usually results from the axial extent of the clear width of the diffuser.
  • the diffuser can also extend in a manner deviating from the radial direction. Most diffusers extend largely radially.
  • the diffuser channel width is limited by diffuser delimitation contours provided on both sides. In the case of a purely radially extending diffuser without axial expansion, the diffuser delimitation contours also run purely radially.
  • the impeller is usually constructed with a wheel disc that connects the impeller to the shaft with a shaft-hub connection.
  • the side that does not have the axial suction of the impeller is referred to here as the hub side.
  • the other opposite axial side is referred to as the housing side. In the case of impellers that have a cover disk on the housing side, this housing side is also often referred to as the cover disk side.
  • the invention understands a blade height as the extension of the blade perpendicular to the main flow direction. If one follows a - for the main flow direction - representative flow thread through the arrangement of the invention, for example through the diffuser, then this extends Flow filament essentially perpendicular to the direction of the blade height. If this flow thread extends approximately centrally through the arrangement, it will be approximately 50% of the blade height.
  • stationary guide vanes to mean guide vanes that are firmly connected to the stator and cannot be moved relative to the rest of the stator for the purpose of changing fluidic conditions during operation.
  • These guide vanes divide the diffuser at least along a radial section into individual circumferential segments. Such a division does not generally take place by means of purely radially extending guide vanes, but is provided by means of guide vanes extending obliquely to the radial. In the area of the curved leading edge, such a segment division does not exist over the entire axial channel width.
  • the invention provides, however, that the guide vanes extend at least in radial sections over the entire width of the channel and that circumferential segments are thereby separated from one another.
  • the peripheral segments of claim 1 or the set of patent claims are conceptually synonymous with flow channels between the guide vanes of the diffuser which extend essentially from radially inward to radially outward or are flowed through along this direction.
  • the invention understands an average chord length to be a mean value of the chord length averaged over the axial height of the guide vane.
  • the chord length is the length of the profile chord - that is, an imaginary connecting line between the profile nose and the profile trailing edge or the leading edge of the guide vane and the trailing edge. Since the profile according to the invention is not constant over the vane height, the terminology of the invention refers to a mean chord length averaged over the height of the guide vane.
  • the special feature of the invention is that the curved leading edge of the guide vane is what comes out of the impeller Exiting process fluid leads significantly earlier or further upstream on the cover disk side than on the wheel disk side or on the hub side. Furthermore, the invention ensures a steady transition between the early acceptance of the process fluid on the cover disk side by the flow guidance of the guide vane and the later or more downstream acceptance of the process fluid by the guide vane on the hub side. This smooth transition through the curved leading edge ensures a more harmonious or uniform flow development overall, so that the flow losses in the area are reduced and the flow is less prone to detachment.
  • the invention understands the attribute “curved” to mean a “non-angular” course, that is to say a course with a continuous curvature course.
  • the terms “curved”, “non-angular profile” and “continuous curvature profile” are synonymous for the invention. As a rule, and preferably, it is an arcuate profile with changing curvature.
  • the invention therefore proposes that on the first axial side, the leading edge of the guide vanes is essentially offset upstream along the direction of flow by an offset, the offset being at least 30% of the axial guide vane height or the axial channel width of the diffuser. According to the invention, an even more uniform flow can often be achieved if the offset is at least 50% of the axial diffuser channel width.
  • the offset is at least 20% of the mean chord length of the guide vanes.
  • An offset of at least 30% of the mean chord length of the guide vanes makes sense aerodynamically.
  • the design of the tangential projection of the leading edge is particularly useful if it has at least one turning point in the area of the axial channel width of the diffuser.
  • the arrangement according to the invention is particularly expedient and aerodynamically efficient when an angle between the tangents on a tangential projection of the leading edge and a tangential projection of the first diffuser boundary contour is at least 45 °, preferably at least 75 °.
  • An advantageous development provides that the angle between the tangent on a tangential projection of the leading edge and a tangential projection of the second diffuser boundary contour is at least 45 °, preferably at least 75 °.
  • the design of the curved leading edge according to the invention is particularly expedient if the point of inflection of the tangential projection of the leading edge is arranged closer to the first diffuser delimiting contour than to the second diffuser delimiting contour. In this case, it makes sense, in the event that there are several turning points of this type, that this criterion is applicable for at least one turning point.
  • the invention also relates to a radial turbo compressor with a diffuser of the design according to the invention.
  • FIG. 1 shows a centrifugal compressor RTC with a diffuser DFR and an impeller IMP arranged upstream of the diffuser DFR.
  • the impeller IMP and the diffuser DFR extend annularly along a circumferential direction CDR of an axis X with an axis of rotation ROT.
  • the impeller IMP is fastened in a specific axial position to a shaft SHT which is rotatably mounted about the axis of rotation ROT or the axis X arranged coaxially to the axis of rotation ROT.
  • the impeller IMP has a wheel disk H, impeller blades BLD and a cover disk SHR, the impeller blades BLD being attached between the wheel disk H and the cover disk SHR, forming flow channels.
  • a process fluid PFL is sucked in axially and deflected outwards in the radial direction, where it exits the rotating impeller IMP during operation and enters a static diffuser DFR.
  • the process fluid PFL flows from the diffuser DFR into a collecting spiral VOL. From there, the process fluid PFL from the radial turbo compressor RTC is fed to units located downstream in a manner not shown.
  • FIGS 2-4 show schematically that in the Figure 1 with II designated detail, whereby different variants of this detail are shown.
  • the guide vane VNS shown of the diffuser DFR each has a curved leading edge LDG according to the invention.
  • a maximum chord length XCL is indicated in each of the figures, and the minimum chord length YCL is also indicated. Schematically drawn between these two extremes Values is a mean chord length MCL.
  • An offset between the leading edge LDG on the first axial side and the leading edge LDG on the second axial side is indicated according to the invention with an offset DCL.
  • the inlet edge LDG which is offset upstream by the offset DCL on the first axial side, guides the process fluid entering the diffuser DFR a little further upstream, so that the inhomogeneity of the process fluid flowing out of the impeller IMP over the axial channel width is better taken into account.
  • the guide vane VNS extends at least over a partial section axially over the entire channel width with an axial guide vane height AVH.
  • the tangential projection of the leading edge LDG has at least one turning point WP, which is preferably closer to the first diffuser delimiting contour DC1 than to the second diffuser delimiting contour DC2.
  • An angle ⁇ between tangents on a tangential projection of the leading edge LDG and a tangential projection of the first diffuser boundary contour DC1 is preferably at least 75 ° ( Figure 3 ), particularly preferably at least 90 ° ( Figures 2 , 4th ).
  • the angle ⁇ means the angle between the two tangents that defines the free space between the first diffuser boundary contour DC1 and the leading edge LDG of the guide vane VNS and not the angle that is within the solid or the material of the guide vane VNS.
  • a second angle ⁇ located on the opposite, second diffuser delimiting contour DC2 preferably has the same conditions as in FIG Figures 2, 3 shown.
  • Figure 5 shows an in Figure 3 section illustrated as VV, which shows schematically the arrangement of the guide vanes VNS in the diffuser DFR.
  • the guide vanes VNS extend from a leading edge LDG up to a trailing edge TRG, with a chord length CDL or a mean chord length MCL or, depending on the arrangement of the section along the axial height AVH, a minimum chord length YCL or a maximum chord length XCL are characteristic for the respective profile.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)
EP19201593.1A 2019-10-07 2019-10-07 Diffuseur, turbocompresseur radial Withdrawn EP3805572A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
EP19201593.1A EP3805572A1 (fr) 2019-10-07 2019-10-07 Diffuseur, turbocompresseur radial

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
EP19201593.1A EP3805572A1 (fr) 2019-10-07 2019-10-07 Diffuseur, turbocompresseur radial

Publications (1)

Publication Number Publication Date
EP3805572A1 true EP3805572A1 (fr) 2021-04-14

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EP19201593.1A Withdrawn EP3805572A1 (fr) 2019-10-07 2019-10-07 Diffuseur, turbocompresseur radial

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EP (1) EP3805572A1 (fr)

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3781128A (en) * 1971-10-12 1973-12-25 Gen Motors Corp Centrifugal compressor diffuser
US4850795A (en) 1988-02-08 1989-07-25 Dresser-Rand Company Diffuser having ribbed vanes followed by full vanes
JPH03134298A (ja) * 1989-10-20 1991-06-07 Hitachi Ltd 遠心圧縮機の羽根付デイフユーザ
EP0446900A1 (fr) 1990-03-14 1991-09-18 Hitachi, Ltd. Compresseur à écoulement mixte
EP1873402A1 (fr) * 2006-06-26 2008-01-02 Siemens Aktiengesellschaft Turbocompresseur avec un compresseur radial
EP2650546A1 (fr) 2010-12-10 2013-10-16 Hitachi, Ltd. Turbomachine centrifuge
WO2019057413A1 (fr) 2017-09-20 2019-03-28 Siemens Aktiengesellschaft Dispositif pouvant être parcouru par un flux
WO2019057412A1 (fr) 2017-09-20 2019-03-28 Siemens Aktiengesellschaft Dispositif pouvant être parcouru par un flux
WO2019057414A1 (fr) 2017-09-20 2019-03-28 Siemens Aktiengesellschaft Dispositif pouvant être parcouru par un flux

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3781128A (en) * 1971-10-12 1973-12-25 Gen Motors Corp Centrifugal compressor diffuser
US4850795A (en) 1988-02-08 1989-07-25 Dresser-Rand Company Diffuser having ribbed vanes followed by full vanes
JPH03134298A (ja) * 1989-10-20 1991-06-07 Hitachi Ltd 遠心圧縮機の羽根付デイフユーザ
EP0446900A1 (fr) 1990-03-14 1991-09-18 Hitachi, Ltd. Compresseur à écoulement mixte
EP1873402A1 (fr) * 2006-06-26 2008-01-02 Siemens Aktiengesellschaft Turbocompresseur avec un compresseur radial
EP2650546A1 (fr) 2010-12-10 2013-10-16 Hitachi, Ltd. Turbomachine centrifuge
WO2019057413A1 (fr) 2017-09-20 2019-03-28 Siemens Aktiengesellschaft Dispositif pouvant être parcouru par un flux
WO2019057412A1 (fr) 2017-09-20 2019-03-28 Siemens Aktiengesellschaft Dispositif pouvant être parcouru par un flux
WO2019057414A1 (fr) 2017-09-20 2019-03-28 Siemens Aktiengesellschaft Dispositif pouvant être parcouru par un flux

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