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
  • F04D29/66—Combating cavitation, whirls, noise, vibration or the like; Balancing
  • F04D29/68—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers
  • F04D29/681—Combating cavitation, whirls, noise, vibration or the like; Balancing by influencing boundary layers especially adapted for elastic fluid pumps
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
  • F01D—NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES
  • F01D5/00—Blades; Blade-carrying members; Heating, heat-insulating, cooling or antivibration means on the blades or the members
  • F01D5/12—Blades
  • F01D5/14—Form or construction
  • F01D5/141—Shape, i.e. outer, aerodynamic form
  • F01D5/145—Means for influencing boundary layers or secondary circulations
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S415/00—Rotary kinetic fluid motors or pumps
  • Y10S415/914—Device to control boundary layer

Definitions

• Blade grid for turbine and turbine comprising such a blade grid
• the present invention relates to a grid of blades for a turbine comprising, on the one hand, a series of blades arranged between a ceiling and a floor, thus defining a series of channels traversed by the fluid supplying the turbine, each channel being limited by the upper surface of a dawn and the lower surface of the neighboring dawn, the floor and the ceiling, and, on the other hand, at least one communication pierced in the ceiling and / or at least one communication pierced in the floor, each communication opening at one end into a channel and at the other end at a point located downstream of said grid.
• a grid of blades is described in German Patent No. 893,649.
• the slippage generates a whirl of counterclockwise direction at the ceiling of the channel and in the opposite direction to the floor for an observer placed downstream of the grid of blades.
• German Patent No. 893,649 that the communications opening into the channel have a mouth located in the middle part of the ceiling at equal distance between the upper surface of the dawn and the lower surface of the neighboring dawn limiting the channel.
• This communication is of fairly large diameter (relative to the dimensions of the channel) to allow suction of the boundary layer.
• the suction of this boundary layer makes it possible to greatly reduce the disturbances but it does not reduce the secondary losses by the same amount; indeed the sucked fluid no longer works in the channels from which it was sucked and it disturbs the fluid in the channels of the next grid in which it is reinjected.
• only a small part of the boundary layer is sucked in to prevent it from slipping and thus making the fluid of the boundary layer useful.
• the blade grid according to the invention is characterized in that for each communication the end opening into the channel is located in the vicinity of the lower surface of the blade limiting said channel at the neck of this channel.
• This point being connected by communication to a point located downstream of the grid (therefore at reduced pressure) the pressure at this point decreases, which reduces the skid of the boundary layer, thus making it useful for working in the channel considered.
• the blade grid does not have a ceiling (in the case of certain movable blades) or a floor (in the case of certain fixed blades), communications are then provided only in the floor
• the invention also relates to a turbine comprising a fixed blade grid followed by a movable blade grid, each of the blade grids comprising a series of blades arranged between a ceiling and a floor thus defining a series of channels traversed speak fluid supplying the turbine, each channel being limited by the upper surface of a blade and the lower surface of the neighboring blade, the floor and the ceiling, the fixed blade grid comprising for each blade at least one communication pierced in the ceiling and opening at one end into a channel and at the other end at a point located downstream of said grid, said turbine comprising at the level of the movable blade grid sealing wipers surrounding the ceiling of said grid, characterized in that for each communication the end opening into the channel is located in the vicinity of the lower surface of the blade limiting said channel at the neck of this channel, and therefore at the point of the channel which is at maximum pressure.
• the invention also relates to a turbine comprising a movable blade grid followed by a fixed blade grid, each of the blade grids comprising a series of blades arranged between a ceiling and a floor thus defining a series of channels traversed by the fluid supplying the turbine, each channel being limited by the upper surface of a blade and the lower surface of the neighboring blade, the floor and the ceiling, the movable blade grid comprising for each blade at least one pierced communication in the floor and opening at one end into a channel and at the other end at a point downstream of said grid, said turbine comprising at the level of the fixed blade grid sealing wipers surrounded by the floor of said grid, characterized in that, for each communication, the end opening into the channel is located in the vicinity of the lower surface of the blade limiting said channel at the neck of this channel, and therefore at the point of the channel which is at maximum pressure.
• FIG. 1 shows a part of the blade grid of a conventional turbine.
• FIG. 2 shows an axial section of a turbine comprising the grids of blades according to the invention.
• FIG. 3 shows a cross section seen from above of a movable blade grid according to the invention.
• FIG. 4 shows a cross section seen from below of a fixed vane grid according to the invention.
• FIG. 1 there are shown two blades A and B which are part of a crown and whose foot is fixed on a floor 1 and the head on a ceiling 2.
• the floor and the ceiling are usually cylindrical or frustoconical surfaces.
• the lower surface of dawn B, the upper surface of dawn A and the floor and ceiling define a channel 3.
• each movable vane grid 4 is located between two fixed vane grids 5.
• the direction of flow of the fluid is indicated by the arrow F.
• the movable grids 4 are integral with the rotor 6 while the fixed grids 5 and 5 ′ are integral with the stator 7.
• the fixed grids 5 are provided with sealing wipers 8 which reduce leaks between rotor 6 and fixed grids 5.
• the stator 7 is provided with sealing wipers 9 which reduce the leaks between the stator 7 and the ceiling 12 of the movable grid 4.
• the movable blade grid 4 comprises for each blade a communication 13 hollowed out in the floor 11 between a point located in the vicinity of the lower surface of the blade and at the level of the neck 10 of the channel limited by said lower surface and a point located downstream of the blade grid 4 (see Figures 2 and 3).
• the movable grid 4 also includes, for each blade, a communication 14 hollowed out in the ceiling 12 between a point located in the vicinity of the lower surface of the blade and at the level of the neck of the channel bounded by said lower surface and which ends downstream of grid 5 (see figure 2).
• the neck or constriction of the canal is the region of the canal where the distance between upper and lower surfaces is minimal.
• the fixed blade grid comprises for each blade a communication 23 hollowed out in the floor 21 which starts from a point located in the vicinity of the lower surface of the blade at the neck of the channel limited by said lower surface and which ends downstream of grid 5 (see figure 2).
• the fixed blade grid also includes, for each blade, a communication 24, hollowed out in the ceiling 22, between a point located in the vicinity of the lower surface of the blade at the neck 20 of the channel limited by said lower surface and a point located downstream of grid 5 (see Figures 2 and 4).
• the leakage of fluid through the communications 24 serves to supply the leakage of fluid between the wipers 9 and the ceiling 12 of the following movable grid 4 and preferably the flow rate of the communications 24 is chosen to be less than or equal to the leakage flow rate between the wipers 9 and the ceiling 12.
• the fluid leakage through the communications 13 serves to supply the fluid leakage between the wipers of the next fixed grid and the rotor and preferably the flow rate of the communications 13 is chosen to be less than or equal to the leakage rate between wipers and rotor .

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Turbine Rotor Nozzle Sealing (AREA)
• Structures Of Non-Positive Displacement Pumps (AREA)

Priority Applications (1)

Applications Claiming Priority (2)

Publications (1)

Family

ID=9213364

Family Applications (1)

Country Status (7)

Cited By (3)

Families Citing this family (12)

Citations (3)

Family Cites Families (4)

• 1978
  • 1978-10-05 FR FR7828459A patent/FR2438155A1/fr active Granted
• 1979
  • 1979-10-04 US US06/196,792 patent/US4335995A/en not_active Expired - Lifetime
  • 1979-10-04 WO PCT/FR1979/000089 patent/WO1980000728A1/fr unknown
  • 1979-10-04 DE DE7979901211T patent/DE2966029D1/de not_active Expired
  • 1979-10-04 JP JP50162079A patent/JPS55500786A/ja active Pending
• 1980
  • 1980-04-22 EP EP79901211A patent/EP0020433B1/fr not_active Expired
  • 1980-12-15 BE BE1/10074A patent/BE886657A/fr not_active IP Right Cessation

Patent Citations (3)

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