Patent Application
20130187339
The present application and the resultant patent relate generally to gas turbine engines and more particularly relate to a near flow path seal with axially flexible arms.
Generally described, a gas turbine includes a main flow path intended to confine a main working fluid therein, i.e., the hot combustion gases. Adjacent turbine rotor structural components may be provided with a cooling fluid therein that is independent of the main working fluid. Sealing device thus may be used to shield the rotor components from direct exposure to the main working fluid driving the turbine, Such sealing devices also prevent the cooling fluid from escaping with the main working fluid. Typical sealing devices, however, may reduce the efficiency and performance of the turbine due to leakage. For example, leakage in sealing devices such as inter-stage seals may require an increase in the amount of parasitic fluid needed for cooling purposes. The use of the parasitic cooling fluid decreases the overall performance and efficiency of the gas turbine engine.
There is thus a desire for an improved turbine flow path seal, particularly for use in-between stages. Preferably such a flow path seal may effectively shield rotor components with reduced leakage and without sacrificing overall gas turbine engine efficiency and output.
The present application and the resultant patent thus provide a near flow path seal for use in a gas turbine engine. The near flow path seal includes a base, a pair of arms extending from the base, and a curved indentation positioned between the pair of arms.
The present application and the resultant patent further provide a near flow path seal for a gas turbine. The near flow path seal may include a separated base, a pair of arms extending from the separated base in a fork-like configuration, and a curved indentation positioned between the pair of arms.
The present application and the resultant patent further provide a near flow path seal for a gas turbine. The near flow path seal may include a base, a pair of arms extending from the base in a parallel orientation with the first arm being higher than the second arm, and a curved indentation positioned between the pair of arms.
These and other features and improvements of the present application and the resultant patent wilt become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.
Referring now to the drawings, in which like numerals refer to like elements throughout the several views,
The gas turbine engine 10 may use natural gas, various types of syngas, and/or other types of fuels, The gas turbine engine 10 may be any one of a number of different gas turbine engines offered by General Electric Company of Schenectady, New York, including, but not limited to, those such as a 7 or a 9 series heavy duty gas turbine engine and the like. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.
Generally described, the near flow path seal 75 may include a pair of arms: a first arm 85 and a second arm 90. The arms 85, 90 may extend from a seal base 95. The arms 85, 90 and the seal base 95 may form a substantially “T” shaped configuration. This T-shaped configuration may be very stiff in the axial direction (i.e., the direction of the shaft 45) with correspondingly high axial spring rates.
Generally described, the arms 85, 90 of the near flow path seal 75 may deflect outwardly due to centrifugal force and contact the buckets 60, 65 to provide sealing. The near flow path seal 75 also may be subject to axial loading due to rotor gravity sag. This rotor gravity sag loading may be resisted by the friction loading about the bucket 60, 65. The near flow path seal 75 thus may be intended to “stick” to the buckets 60, 65 by generating more friction loading than that induced by rotor gravity sag loading. In addition to the steady loading conditions generated by centrifugal force, resisting such rotor gravity sag loading also may induce an alternating load condition on the arms 85, 90 of the near flow path seal 75. As such, this T-shaped configuration may be relatively stiff and may require substantial mass to accommodate these conflicting forces.
As an alternative, a split flow path seal 380 also may be used. The split flow path seal 380 may be similar to the near flow path seal 300 described above but a split base 390. The split base 390 may be completely separated into the form of two distinct halves, a first half 400 and a second half 410, so as to reduce the stress thereabout. The halves 400, 410 then may be connected as desired. The first arm 110 thus may be formed with the first half 400 and the second arm 120 may be formed with the second half 410, Other components and other configurations also may be used herein.
The near flow path seals 100, 200, 300 described herein thus provide flexible arms 110, 120. The axially flexible arms 110, 120 may tolerate gross axial deflections without inducing large alternating stresses due to rotor gravity sag loading and the like. The arms 110, 120 may be axially flexible with correspondingly low axial spring rates. As such, the near flow path seals 100, 200, 300 may result in a reduced risk of slippage at the bucket interfaces as well as associated fretting-wear failure. In other words, contact stresses may be reduced so as to improve the durability of the bucket interface. Lower alternating stresses also may increase the margin of safety of high cycle fatigue failure and the like. The near flow path seals 100, 200, 300 thus may require relatively less mass. The near flow path seals 100, 200, 300 described herein thus provide adequate sealing and improved overall durability with little to no added component costs.
It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.
