Classifications

• • 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
  • F01D5/18—Hollow blades, i.e. blades with cooling or heating channels or cavities; Heating, heat-insulating or cooling means on blades
  • F01D5/187—Convection cooling
• • 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
  • F05D2240/00—Components
  • F05D2240/20—Rotors
  • F05D2240/30—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor
  • F05D2240/303—Characteristics of rotor blades, i.e. of any element transforming dynamic fluid energy to or from rotational energy and being attached to a rotor related to the leading edge of a rotor blade
• • 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
  • F05D2260/00—Function
  • F05D2260/20—Heat transfer, e.g. cooling
  • F05D2260/201—Heat transfer, e.g. cooling by impingement of a fluid
• • 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
  • F05D2260/00—Function
  • F05D2260/20—Heat transfer, e.g. cooling
  • F05D2260/221—Improvement of heat transfer
  • F05D2260/2214—Improvement of heat transfer by increasing the heat transfer surface
  • F05D2260/22141—Improvement of heat transfer by increasing the heat transfer surface using fins or ribs

Definitions

• the invention relates to a turbine blade according to the preamble of claim 1.
• Turbine blades in particular turbine blades for gas turbines, are exposed during operation to high temperatures which rapidly exceed the limit of material stress. This applies in particular to the regions in the vicinity of the flow inlet edge at which the hot process gas flow first of all occurs on the blade profile of the turbine blade. To turbine blades even at high
• Cooling types include convection cooling, impingement cooling and film cooling.
• convection cooling cooling air passes through channels in the interior of the blade and uses the convective effect to dissipate the heat.
• impingement cooling a cooling air flow impinges on the inner blade surface from the inside. In this way, a very good cooling effect is made possible at the point of impact, which, however, is limited only to the narrow area of the point of impact and the closer environment.
• This type of cooling is therefore usually used for cooling the flow inlet edge, which is also referred to as the leading edge, a turbine blade.
• film cooling cooling air is directed out through openings in the turbine blade from the interior of the turbine blade. This cooling air flows around the turbine blade and forms an insulating layer between the hot process gas and the blade surface.
• the described Cooling types are suitably combined depending on the application in order to achieve the most effective blade cooling possible.
• coolants such as turbulators, which are usually provided in the form of ribs
• turbulators which are usually provided in the form of ribs
• the incorporation of fins in the cooling channels causes the flow of cooling air in the boundary layers to be detached and entangled. Due to the forced disruption of the flow, the heat transfer can be increased in the presence of a temperature difference between the cooling channel wall and the cooling air.
• the ribbing constantly causes the flow to form new "reassembly areas" in which a substantial increase in the local heat transfer coefficient can be achieved
• the lifetime of known fins is limited due to the high operating temperatures, which is particularly due to the geometry underlying ribs.
• the thermal stresses associated with the known rib geometries result in internal cracks which can limit the life of the rib and ultimately also the service life of the turbine blade.
• cooling channels are often formed in turbine blades which run parallel to and close to the flow inlet edge, and cooling air is supplied thereto by further cooling channels formed in the blades.
• the convective cooling of the flow inlet edge realized in this way is usually supplemented by impingement cooling of the inner wall of the cooling channel extending near the flow inlet edge in the case of film-sensed blades.
• convective cooling is intensified by turbulators disposed on the inner wall of the cooling duct.
• the invention has for its object to provide a turbine blade, which can be cooled more effectively compared to known solutions both with existing and in the absence of film cooling and has a longer service life.
• the turbine blade has a front edge extending on one side of the turbine blade, wherein the cooling channel is delimited by a wall section relative to the front edge and has at least one cooling element which extends from this wall section into the cooling channel.
• the cooling element does not represent a turbulizer in the conventional sense.
• the generally thermally stressed front edge can thus be cooled very effectively.
• the cooling elements according to the invention which extend from the wall portion into the cooling channel, and in particular cause a strong turbulence of the cooling medium, the heat transfer can be significantly increased at a temperature difference between the wall portion and the cooling medium, along with a substantial increase of the local heat transfer coefficients. Overall, in this way, the heat in the vicinity of the leading edge can be dissipated very effectively, along with a very effective cooling of the leading edge.
• the cooling elements initially impinged by the cooling-cooling medium are designed in the form of pegs or ribs. Pine-shaped or rib-shaped cooling elements cause on the one hand an enlargement of the coolable wall surface and on the other hand after successful
• Impact cooling a very strong turbulence of the cooling medium, for example in the form of cooling air, which are increased by the forced so strong disruption of flow at a temperature difference between a wall of the cooling channel and the cooling medium of the heat transfer, along with a significant increase of the local heat transfer coefficient.
• the thermal stresses which form in the cooling elements during operation of the turbine blade can be kept to a minimum, so that no internal cracks can occur, in particular the thermal stresses are significantly lower than those thermal stresses that form in known turbulators. According to the invention, therefore, the entire voltage situation is improved and it can be a significant increase in the life of the cooling elements over known solutions can be achieved, with the high life of the cooling elements and a long service life and service life of the turbine blade is connected.
• the turbine blade according to the invention can be exposed to known gas higher temperatures compared to known solutions, even if no film cooling is provided. If film cooling is provided, even higher gas temperatures are possible. This in turn gives rise to the possibility of being able to form the turbine blade according to the invention with thinner outer walls.
• the wall section has a wall surface facing the cooling channel, wherein the at least one cooling element or the two or more Cooling elements extend orthogonal to the wall surface or orthogonal to the curved wall surface in the cooling channel inside.
• the inventively provided extent in a direction orthogonal to the wall surface of the cooling channel causes a very effective turbulence of the cooling medium, which is accompanied by a very effective cooling, in particular the leading edge, since according to the invention a substantially perpendicular to the longitudinal extent of the cooling elements directed flow of the cooling elements with the Can be done cooling medium.
• the cooling channel is preferably limited by a wall portion facing the cooling channel having a curved wall surface, wherein two or more cooling elements are provided, wherein the cooling elements have a longitudinal extent extending into the cooling channel, and wherein the two or more cooling elements are directed with their longitudinal extent to the center of the curvature of the wall surface.
• cooling elements which are directed with their longitudinal extent to the center of the curvature of the wall surface, a very effective turbulence of the cooling elements flowing against the cooling medium can be achieved.
• the convection cooling realized by means of the cooling elements can be very effectively combined with impingement cooling, such that the cooling medium flows in a manner onto the cooling elements in such a way that it impinges on the cooling elements, so that a very high cooling effect is achieved in the respective impingement point can be, which causes in conjunction with the provided convection cooling a very effective cooling of the turbine blade according to the invention.
• the at least one cooling element or the two or more cooling elements are integrally formed with the wall portion.
• the cooling elements have different lengths, wherein the length of the individual cooling elements is preferably adapted to a predetermined local cooling requirement.
• Turbine blades generally have a very inhomogeneous temperature distribution during operation, which is associated with large thermal loads acting on the turbine blades, which in particular have a detrimental effect on the service life of the turbine blade.
• an inhomogeneous temperature distribution forming along the radial direction results for the leading edge.
• cooling elements within the preferably adjacent the leading edge extending cooling channel whose cooling capacity is adapted over its length a predetermined cooling demand, for example, for the leading edge in the vicinity of the cooling element, the temperature distribution, for example, at the leading edge, "uniform", According to the invention, correspondingly high cooling is achieved at comparatively hot places by appropriately designed cooling elements and vice versa
• the turbine blade according to the invention can thus be cooled in a manner which counteracts an inhomogeneous temperature distribution, which is advantageous in particular with regard to effective cooling of the leading edge.
• the cooling capacity of each individual peg-shaped cooling element over a suitably designed length is equal to the predetermined local cooling requirement in the environment of
• Cooling element adapted. Cooling elements in the vicinity of which a high cooling requirement exists, according to the invention have a greater length than cooling elements in the environment of the cooling demand is less pronounced. Increasing the length of a single cooling element increases the "swirl area" as well as the surface to be cooled, along with a significant increase in the local heat transfer coefficient.
• a cooling channel partially delimiting the wall portion opposite rear wall is provided in which one or more impingement cooling holes are provided. These are preferably placed and aligned in the back wall so that the cooling air jets flowing through them are directed onto the cooling elements, whereby a particularly efficient cooling of the leading edge can be achieved.
• the distance between the cooling element tip, on the one hand, and the mouth of the impact cooling opening, on the other hand can be kept comparatively small.
• This also applies to a comparatively large outflow cross section of the cooling channel. A disturbance of the impact cooling jets by transverse to the beams, ie along the cooling channel flowing cooling air can thus be safely avoided.
• the invention relates generally to a turbine blade having a leading edge, a cooling channel formed in the turbine blade for carrying cooling air, which extends at least partially along the leading edge, and a number of cooling elements, which are arranged in the longitudinal direction of the cooling channel in this sequentially stationary, each individual cooling element has a cooling capacity which is adapted to a predetermined cooling requirement for the leading edge in the vicinity of the cooling element, and wherein the cooling channel preferably extends parallel to the leading edge through the turbine blade.
• FIG. 1 is a sketch-like cross-sectional view of a turbine blade according to the invention with a Number of arranged in a cooling channel peg-shaped cooling elements and
• FIG. 2 shows a longitudinal section through the turbine blade along a front edge.
• FIG. 1 shows a sketch-like sectional view of a front section of an airfoil of a turbine blade 10 according to the invention, with a flat sectional surface perpendicular to its front edge 12.
• the front edge 12 may also be referred to as a flow inlet edge.
• a cooling channel 14 extending parallel to the front edge 12 (ie, a radially extending channel 14 in the case of axially through-flowed turbines) is formed near the front edge 12, which is delimited by a wall section 24 in relation to the front edge 12.
• peg-shaped cooling elements 18 extend into the cooling channel 14, wherein the cooling elements 18 are directed with their longitudinal extent to the center of the curvature of the wall surface 16.
• openings 22 are formed to supply the cooling channel 14 of further cooling channels (not shown), which are formed in the rear region of the turbine blade 10, cooling air chilling cooling.
• FIG. 2 shows a further sectional illustration of the front section of the turbine blade 10 according to the invention, with a flat sectional surface parallel to the front edge 12.
• the cooling elements 18 formed on the curved wall surface 16 of the cooling channel 14 extend orthogonally from the curved wall surface 16 into the cooling channel 14 2, in the radial direction R, the length of the cooling elements 18 varies. According to the invention, this counteracts the inhomogeneous temperature distribution which forms along the leading edge 12 when the turbine blade 10 is used.
• the frusto-conical cooling elements 18 have a greater length in the middle region than in the edge regions, since, as stated above, by increasing the length of the cooling elements 18, the local heat transfer coefficient and thus the cooling capacity the cooling elements 18 can be increased.
• the impingement cooling comprises the impact of cooling air emerging from the openings 22 on the arched wall surface 16 or the cooling elements 18 in order to locally enable a very good cooling effect there. Since it is provided according to the invention that the cooling elements 18 are directed with their longitudinal extent to the center of the curvature of the wall surface 16, a very effective impingement cooling can be provided, with which, in conjunction with the corresponding convection cooling, a very effective cooling of the turbine blade 10 is provided can be.
• the cooling passage 14 is opened on both sides of the turbine blade 10 to flow the cooling air in two directions out of the cooling passage 14. As a result, a temperature harmonization of the turbine blade 10 is favored, since where cooling air is needed, cooling air is also provided, and the effect of the impingement cooling is not reduced by a cross-flow.
• the cooling elements 18 may also be formed rib-shaped, which extend along the cooling channel 14, ie in the flow direction of the cooling air.
• the surface of the wall surface 16 is significantly increased in order to improve the cooling of the then preferably convectively cooled turbine blade 10. It is conceivable that the height of the ribs due to the aforementioned locally different temperatures at the front edge 12 can be adapted to match.

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• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Priority Applications (6)

Applications Claiming Priority (2)

Publications (1)

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ID=37951488

Family Applications (1)

Country Status (7)

Cited By (2)

Families Citing this family (27)

Citations (7)

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• 2006
  • 2006-11-08 EP EP06023274A patent/EP1921268A1/de not_active Withdrawn
• 2007
  • 2007-09-20 CN CN200780041599.1A patent/CN101535602B/zh not_active Expired - Fee Related
  • 2007-09-20 DE DE502007003044T patent/DE502007003044D1/de active Active
  • 2007-09-20 WO PCT/EP2007/059935 patent/WO2008055737A1/de not_active Ceased
  • 2007-09-20 AT AT07820379T patent/ATE459785T1/de active
  • 2007-09-20 EP EP07820379A patent/EP2087206B1/de not_active Not-in-force
  • 2007-09-20 JP JP2009535648A patent/JP2010509532A/ja active Pending
  • 2007-09-20 US US12/513,742 patent/US8297926B2/en not_active Expired - Fee Related
• 2012
  • 2012-03-02 JP JP2012046594A patent/JP5269223B2/ja not_active Expired - Fee Related

Patent Citations (7)

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