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
  • F05D2220/00—Application
  • F05D2220/40—Application in turbochargers
• • 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
  • F05D2250/30—Arrangement of components
  • F05D2250/32—Arrangement of components according to their shape
  • F05D2250/324—Arrangement of components according to their shape divergent
• • 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
  • F05D2250/50—Inlet or outlet
  • F05D2250/52—Outlet

Definitions

• the invention relates to the field of turbomachines, it relates to a diffuser of a centrifugal compressor, a centrifugal compressor with such a diffuser and an exhaust gas turbocharger with a centrifugal compressor with such a diffuser.
• Radial compressors are used inter alia in exhaust gas turbochargers for charging internal combustion engines.
• the compressor wheel of the centrifugal compressor gives the incoming air flow a rotational movement, as a result of which a pressure field builds up due to the centrifugal forces with radially outwardly increasing pressure.
• the always relatively high exit velocity of the air flow from the compressor wheel requires a delay in the diffuser to keep the flow velocities in the spiral plenum (spiral) low, thereby reducing the wall friction losses and improving the efficiency of the compressor stage as a whole.
• the diffuser of the centrifugal compressor also called radial diffuser, is generally designed as a parallel-walled annular space. This annular space closes radially to the compressor wheel outlet.
• the annular space is usually limited by two annular plates which are perpendicular or approximately perpendicular to the axis of rotation of the shaft of the compressor.
• a stator with circumferentially arranged vanes profiled vanes, wedge vanes or circular vanes for flow guidance
• the efficiency of the diffuser can be increased.
• An example of a bladed diffuser is shown in DE102008044505.
• Important parameters of the radial diffuser are the narrowest cross-sectional area (throat) between two adjacent vanes, the area ratio of the channel exit / channel entry (AR) and the ratio of the channel length to the entrance width (LWR).
• the object of the present invention is to optimize the diffuser of a centrifugal compressor in such a way that, despite a great deal of delay, the flow instabilities do not occur.
• this is achieved by a strong enlargement of the area through which flows through in the inlet region of the diffuser section.
• the flow is granted more space even before the actual diffuser channel, resulting in an early delay and corresponding pressure build-up.
• This reduces the speed of the flow in the subsequent subcomponents of the compressor with correspondingly reduced flow losses.
• the strong deceleration with the associated strong build-up of pressure in the space in front of the bladed diffuser part and in the half-bladed diffuser area has a positive effect on the map width.
• the strong enlargement of the flow cross-section in front of the bladed diffuser / in the inlet region of the bladed diffuser takes place by a circumferential recess in the lateral diffuser wall (parallel-walled or with divergence).
• This circumferential recess is preferably produced by turning off the lateral diffuser wall.
• the return can be on both side walls or only on one of the side walls. It can be done in one or more stages.
• the return can also be designed as a ramp.
• the return lies in an area between the impeller outlet and the narrowest cross section (throat) between two adjacent blades.
• the area thus obtained in the throat allows, in particular for shallow diffuser blade angles, an increased flow delay in the region of the diffuser inlet in combination with reduced false flow losses.
• the diffuser angle and area of the throat can be adjusted independently of each other.
• a certain throat area can be achieved at very shallow diffuser vane angles, resulting in favorable, loss-reduced inflow conditions near the surge line.
• FIG. 1 is a schematic representation of a conventional exhaust gas turbocharger, wherein the compressor side is shown with a bladed radial diffuser in more detail than the turbine side,
• Fig. 3 shows a detail of the compressor side of an inventive design
• Fig. 5 shows a detail of the compressor side of an inventively designed
• FIG. 7 shows a detail of the compressor side of a diffuser formed according to the invention with shroud side ramped and hub-side multi-step recess in the housing wall.
• Fig. 1 shows an exhaust gas turbocharger with a schematically illustrated exhaust gas turbine 50, which is acted upon by a gas inlet 51 with exhaust gases of the supercharged by the exhaust gas turbocharger internal combustion engine.
• the energy contained in the exhaust stream is converted in the turbine rotational energy for driving the connected via the shaft 30 to the impeller of the turbine compressor wheel.
• the compressor wheel comprises a hub 10 and a plurality of blades 1 1 arranged on the hub.
• the shaft 30 is rotatably mounted in a bearing housing 40.
• the compressor wheel in turn is arranged in the adjacent to the bearing housing 40 compressor housing 2.
• the compressor housing comprises in the illustrated embodiment an outer part, the outer compressor housing 22 and an inserted inner part, the inner compressor housing 20.
• the different parts of the compressor housing limit the flow channel for the air masses to be compressed .
• the air to be compressed is fed in the axial direction of the compressor wheel.
• Area of the blades of the compressor wheel, the flow channel through the hub 10 and the inner compressor housing 20 is limited.
• the flow undergoes a change of direction from the axial to the radial direction.
• the flow enters the region of the diffuser, which forms the flow section 23 from the outlet compressor wheel up to the collecting space 24 in the outer compressor housing.
• the collecting space is spirally formed, wherein at the broad end of the spiral, the air flow leaves the compressor in the direction of the intercooler or the air inlet of the internal combustion engine.
• the diffuser region is essentially an annular cavity, which is bounded on both sides by an annular surface-shaped wall.
• shroud disorderen (blade tip side) wall portion 21 and the hub-side wall portion 41st The two wall sections 21 and 41, which extend from the Verdicherradaustritt to the mouth in the spiral-shaped collecting space, extend in the illustrated embodiment perpendicular to the marked shaft axis.
• the shroud-side wall region or the hub-side wall region or both wall regions can deviate from the strictly radial direction, resulting in a slightly diverging wall course.
• the diffuser area may be bladed with a plurality of circumferentially disposed vanes 25.
• These vanes are generally formed as profiled vanes, wedge blades or circular arc shaped vanes for flow guidance. They may be regularly or irregularly distributed and arranged at the same or differing radial height and be formed identically or differently shaped. Between two adjacently arranged guide vanes, there is in each case a location with the narrowest cross-section, which is referred to in the jargon as Throat.
• FIGS. 2 to 7 show various embodiments of diffusers with an enlargement of the flow channel cross-section according to the invention.
• Fig. 2 and 3 show unilaterally arranged recesses of different configuration
• Fig. 4 to 7 show two-sided arranged recesses of different design.
• the hub-side housing wall with the wall portion 41 delimiting the diffuser is in alignment with the outlet of the compressor wheel, so that there is no flow cross-sectional widening on the hub side.
• the recess 21 1 is formed as a rectangular step which extends at an angle of approximately 90 ° to the housing wall.
• the angle can also be sharper, so that the return fails in the form of an oblique ramp.
• Such a ramp-shaped return has the embodiment of FIG.
• the one-sided cross-sectional widening is arranged on the hub side, that is to say in the wall section 41 associated with the bearing housing.
• the flow channel 231 at the exit of the compressor wheel expands due to the hub-side recess 402 in the flow direction on the cross-sectional widened flow channel section 232 before and in the region of the vanes 25 of the diffuser.
• the angle may also be less acute up to 90 °, so that the return in the form of a steeper ramp or even a right-angled step fails.
• 4 and 5 show the two-sided execution of the above-described one-sided cross-sectional widening. First with two-sided, right-angled recess 21 1 and 401, then with double-sided ramped jump 212 and 402.
• the described one-sided or two-sided recesses may each also be composed of a plurality of radially spaced sub-steps, wherein the sub-stages may each have the same or different angles to the housing wall.
• a correspondingly formed, double-sided cross-sectional widening with multi-level recesses 213 and 403 is shown in FIG.
• the differently formed, two-sided recesses can also be combined with each other, as indicated in Fig. 7.
• the illustrated combination of hub-side, multi-level recess 403 and shroud wornem, ramped return 212 is to be understood only as a possible combination. All possible combinations are conceivable and protected by the following claims.
• the cross-sectional widening recesses arranged on both sides they can be arranged at the same radial height, so that a single cross-sectional widening results in the flow direction in the sum.
• the two-sided recesses may be arranged at different radial heights, so that a total of two consecutive cross-sectional enlargements, or in the case of multistage or ramped recesses results in a larger cross-sectional widening continuously over a larger portion.
• the respective recesses in the flow direction are arranged clearly in front of the entry edges 251 of the guide vanes.
• the cross-sectional widenings are particularly effective when they are carried out in front of the narrowest points between two adjacently arranged guide vanes.
• the recesses are arranged at a radial height which is smaller than the radial height of this narrowest point between two adjacently arranged guide vanes (throat). LIST OF REFERENCE NUMBERS
• Multi-stage recess for expanding the diffuser cross-section (Shroud side) 22 External compressor housing (spiral housing)

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)
• Supercharger (AREA)

Applications Claiming Priority (2)

Publications (1)

Family

ID=58054146

Family Applications (1)

Country Status (6)

Families Citing this family (4)

Family Cites Families (9)

• 2016
  • 2016-02-19 DE DE102016102924.6A patent/DE102016102924A1/de not_active Withdrawn
• 2017
  • 2017-02-17 CN CN201780024823.XA patent/CN109072939A/zh active Pending
  • 2017-02-17 KR KR1020187026833A patent/KR20180120704A/ko active Search and Examination
  • 2017-02-17 WO PCT/EP2017/053629 patent/WO2017140852A1/de active Application Filing
  • 2017-02-17 JP JP2018543725A patent/JP2019505728A/ja not_active Withdrawn
  • 2017-02-17 EP EP17705636.3A patent/EP3417176A1/de not_active Withdrawn

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