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
  • F01D5/20—Specially-shaped blade tips to seal space between tips and stator
• • 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
• • 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
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
  • Y02T50/00—Aeronautics or air transport
  • Y02T50/60—Efficient propulsion technologies, e.g. for aircraft

Definitions

• the invention relates to a turbine blade with a bracket arranged in the tip region of the blade and projecting beyond the blade profile, according to the preamble of claim 1.
• gap losses occurring between the blade tip and the blade cover take on considerable dimensions and thus lead to a significant loss in efficiency.
• the cause of these gap losses is the pressure difference between the pressure side and the suction side in the tip area of the blade, as a result of which the working fluid overflows.
• This overflow can be reduced by increasing the friction losses between the blade tip and the blade cover, which leads to a reduction in the gap losses and thus to an increase in efficiency.
• a known measure which aims to reduce the gap losses and to increase the reliability of the turbine blade, is the arrangement of a rib or bracket (so-called minishroud or winglet) projecting laterally over the blade profile in the tip region of the blade (Okapuu, lecture “Aerodynamic design of first stage turbines for small aero engines ", held as part of the Lecture Series 1987-07 of” von Karman Institute for Fluid Dynamics ", on” Small High Pressure Ratio Turbines ", June 15-18, 1987, p. 1-4 and Fig. 1-4).
• minishroud or winglet projecting laterally over the blade profile in the tip region of the blade
• the invention tries to avoid all these disadvantages. It is based on the object of achieving a further improvement in the efficiency of a turbine blade which is equipped with a console which is arranged in the tip region of the blade and projects beyond the blade profile.
• the console is formed only in a partial area of a defined surface area of the pressure side.
• this defined surface area represents the area of the pressure side which is enclosed by an imaginary chord which lies on the pressure side of the airfoil both in the area of the entry edge and in the area of the exit edge.
• both wedge angles of the airfoil i.e. the entry and exit angles are kept small. This results in a pointed blade geometry, which in turn ensures that high Mach numbers in the leading edge area and dead water areas in the leading edge area of the blade are avoided. Ultimately, a further improvement in efficiency is achieved with a guaranteed reduction in gap losses.
• the sub-area of the pressure side carrying the console is advantageously formed between two points lying on the pressure side of the airfoil and spaced apart therefrom, the first point being arranged in the area of the leading edge and the second point in the area of the trailing edge, and the imaginary chord being arranged at both points is present. It has proven to be particularly useful between the first point and the console and between the second Point and the console form a distance ai, a 2 , which corresponds approximately to a blade thickness di, d 2 in the corresponding area of the blade.
• the console is at a greater distance from the leading edge or the leading edge of the airfoil, so that its wedge angle can be further reduced.
• the console has a maximum height h ma ⁇ above the pressure side in a range from 30 to 40% of the chord length I of the airfoil.
• the height of the bracket decreases continuously both in the direction of the leading edge and in the direction of the trailing edge of the airfoil.
• the maximum height h ma ⁇ of the bracket corresponds approximately to a blade thickness d 3 , as is formed in an area of the blade blade adjacent to the bracket and facing away from the blade tip. It is also advantageous if the console is wave-shaped.
• Figure 1 is a pressure side view of the blade.
• FIG. 2 shows a section through the rotor blade, along the line II-II in FIG. 1;
• FIG. 3 shows a section through the moving blade, along the line III-III in FIG. 1. Only the elements essential for understanding the invention are shown. The other components of the exhaust gas turbine, including the blade cover, are not shown, for example
• the turbine blade shown in FIG. 1, designed as a moving blade 1, consists of a blade root 2, a platform 3 and an airfoil 4.
• the platforms of adjacent turbine blades of the turbine wheel, not shown, bear directly against one another and thus form the inner boundary of the flow channel, which is directed outwards from one Blade cover, also not shown, is completed.
• the blade 4 has an entry edge 5, an exit edge 6, a suction side 7, a pressure side 8 and a blade tip 9 (FIG. 2).
• a console 10 is arranged, which extends only over a partial area 11 of the entire pressure side 8.
• This partial area 11 is part of a surface area 13 of the pressure side 8 enclosed by an imaginary chord 12 the chord 12 in the region of the leading edge 5 of the airfoil 4 at a first point 14 and in the region of the trailing edge 6 of the airfoil 4 at a second point 15 It is therefore smaller than the surface area 13 enclosed by the chord 12 (FIG. 3)
• a distance ai is formed between the first point 14 and the bracket 10, which corresponds approximately to the blade thickness di in this area of the airfoil 4.
• a distance a 2 is also formed between the second point 15 and the bracket 10, which in turn is approximately the blade thickness d 2 corresponds in this area of the airfoil 4
• the console 10 has a maximum height h ma ⁇ above the pressure side 8, which corresponds approximately to a blade thickness d 3 , which is formed in an area of the blade blade 4 which is adjacent to the console 10 but faces away from the blade tip 9 (FIG. 2).
• This maximum height h ma ⁇ is arranged at a distance b from the leading edge 5, which is 30 to 40% of the chord length I of the airfoil 4 (Fig. 3).
• the height of the bracket 10 decreases continuously both in the direction of the leading edge 5 and in the direction of the trailing edge 6 of the airfoil 4.
• the height of the console 10 is reduced in both directions in such a way that an undulating outer contour is formed over the chord length I.
• bracket 10 is formed only in a partial area 11 of the pressure side 8 and is offset inwards relative to the contact points of the tendon 12 on the pressure side 8 and because its height decreases continuously in the direction of both blade edges, both wedge angles of the turbine blade 1, ie both the Entry angle cc> ⁇ and the exit angle ⁇ 2 , compared to the solutions known from the prior art, are kept small.
• this pointed blade geometry improves the flow in the area of the leading edge 5 of the blade 4 and thus reduces the Mach numbers. Also due to the pointed blade geometry, the formation of dead water areas is prevented in the area of the trailing edge 6 of the airfoil 4. In this way, a further improvement in the efficiency can be achieved, the required reduction in the gap losses being guaranteed.
• the wave-shaped outer contour of the console 10 enables optimum flow guidance to be achieved.
• a bracket can also be arranged on the suction side 7 (not shown), as a result of which the risk of overflow is further reduced and the flow guidance in this area can also be improved with the appropriate design.
• a console 10 can be used not only with moving blades, but also with guide blades.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Turbine Rotor Nozzle Sealing (AREA)

Priority Applications (4)

Applications Claiming Priority (2)

Publications (1)

Family

ID=7902198

Family Applications (1)

Country Status (8)

Cited By (2)

Families Citing this family (27)

Citations (2)

Family Cites Families (11)

• 1999
  • 1999-03-24 DE DE19913269A patent/DE19913269A1/de not_active Withdrawn
• 2000
  • 2000-03-21 TW TW089105125A patent/TW440653B/zh not_active IP Right Cessation
  • 2000-03-23 KR KR1020017011778A patent/KR100717559B1/ko not_active Expired - Fee Related
  • 2000-03-23 JP JP2000606874A patent/JP4511053B2/ja not_active Expired - Fee Related
  • 2000-03-23 US US09/937,321 patent/US6565324B1/en not_active Expired - Lifetime
  • 2000-03-23 WO PCT/CH2000/000172 patent/WO2000057029A1/de not_active Ceased
  • 2000-03-23 DE DE50003443T patent/DE50003443D1/de not_active Expired - Lifetime
  • 2000-03-23 EP EP00908908A patent/EP1163425B1/de not_active Expired - Lifetime
  • 2000-03-23 CN CNB008054304A patent/CN1237258C/zh not_active Expired - Fee Related

Patent Citations (2)

Non-Patent Citations (1)

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