Patent Application
20140037438
The subject matter disclosed herein relates to the art of turbomachines and, more particularly to a turbine shroud for a turbomachine.
Many turbomachines include a compressor portion linked to a turbine portion through a common compressor/turbine shaft or rotor and a combustor assembly. The compressor portion guides compressed air flow through a number of sequential stages toward the combustor assembly. In the combustor assembly, the compressed air flow mixes with a fuel to form a combustible mixture. The combustible mixture is combusted in the combustor assembly to form hot gases. The hot gases are guided to the turbine portion through a transition piece. The hot gases expand through the turbine portion rotating turbine blades to create work that is output, for example, to power a generator, a pump, or to provide power to a vehicle. In addition to providing compressed air for combustion, a portion of the compressed airflow is passed through the turbine portion for cooling purposes.
According to one aspect of the exemplary embodiment; a turbine shroud includes a body having an upstream edge, a downstream edge, and first and second side edges that collectively define a flowpath surface. A first interface member is arranged on the upstream edge at the first side edge. The first interface member includes a first edge portion having a first end portion that extends at a first non-perpendicular angle relative to the upstream edge and the first side edge out from the flowpath surface to a second end portion, and a second edge portion that extends from the second end portion of the first edge portion to the first side edge. A second interface member is arranged on the upstream edge at the second side edge. The second interface member includes a first edge section having a first end section that extends at a second non-perpendicular angle relative to the upstream edge and the second side edge into the flowpath surface to a second end section, and a second edge section that extends from the second end section of the first edge section to the second side edge.
According to another aspect of the exemplary embodiment, a turbomachine includes a turbine portion having a casing defining hot gas path and a plurality of turbine blades rotatably mounted in the turbine portion along the hot gas path. Each of the plurality of turbine blades includes a tip portion. At least one turbine shroud is mounted to the casing and spaced from the tip portion of each of the plurality of turbine blades. The at least one turbine shroud includes a body having an upstream edge, a downstream edge, and first and second side edges that collectively define a flowpath surface. A first interface member is arranged on the upstream edge at the first side edge. The first interface member includes a first edge portion having a first end portion that extends out at a first non-perpendicular angle relative to the upstream edge and the first side edge from the flowpath surface to a second end portion, and a second edge portion that extends from the second end portion of the first edge portion to the first side edge. A second interface member is arranged on the upstream edge at the second side edge. The second interface member includes a first edge section having a first end section that extends into at a second non-perpendicular angle relative to the upstream edge and the second side edge the flowpath surface to a second end section, and a second edge section that extends from the second end section of the first edge section to the second side edge.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
With reference to
Turbine portion 6 includes a housing 18 that encloses a plurality of turbine stages 25. Turbine stages 25 include a first turbine stage 26, a second turbine stage 27, a third turbine stage 28, and a fourth turbine stage 29 that define a hot gas path 30. First turbine stage 26 includes a first plurality of vanes or nozzles 33 and a first plurality of rotating components in the form of blades or buckets 34. Buckets 34 are mounted to a first rotor member (not shown) that is coupled to shaft 12. Second turbine stage 27 includes a second plurality of vanes or nozzles 37 and a second plurality of blades or buckets 38. Buckets 38 are coupled to a second rotor member (also not shown). Third turbine stage 28 includes a third plurality of vanes or nozzles 41 and a third plurality of blades or buckets 42 that are coupled to a third rotor member (also not shown). Fourth turbine stage 29 includes a fourth plurality of vanes or nozzles 45 and a fourth plurality of blades or buckets 46 that are coupled to a fourth rotor member (not shown). Of course it should be understood that the number of turbine stages may vary.
Housing 18 includes a casing 50 having an outer casing portion 60 and an inner casing portion 64. A thrust collar 65 extends from outer casing portion 60 towards inner casing portion 64, and a stop member 75 extends from inner casing portion 64 toward outer casing portion 60. Stop member 75 acts upon thrust collar 65 to limit axial movement of inner casing portion 64 during operation of turbomachine 2. At this point, it should be understood that the exemplary embodiments may be incorporated into a turbomachine having one or more casings.
Inner casing portion 64 includes a plurality of shroud support elements 80-83. Each shroud support element 80-83 includes a pair of hook elements such as shown at 84 on shroud support element 80, that support a respective plurality of stationary turbine shrouds 86-89. Turbine shrouds 86-89 provide a desired clearance between inner casing portion 64 and tip portions (not separately labeled) of corresponding ones of buckets 34, 38, 42, and 46. Turbine shrouds 86-89 are arranged in a ring circumscribing corresponding ones of turbine stages 25-29. At this point, reference will be made to
Turbine shroud 87 includes a body 100 having an upstream edge 104 and a downstream edge 105. A first side edge 106 extends between upstream edge 104 and downstream edge 105. A second side edge 107 extends between upstream edge 104 and downstream edge 105 opposite to first side edge 106. Upstream edge 104, downstream edge 105 and first and second side edges 106 and 107 collectively define a flowpath surface 110. Turbine shroud 87 is also shown to include first and second hooks 111 and 112 arranged on body 100 opposite to flowpath surface 110. First and second hooks 111 and 112 cooperate with shroud support element 80 to secure turbine shroud 87 to inner casing portion 64. Turbine shroud 87 may also be attached to outer casing portion 60 in accordance with other aspects of the exemplary embodiment.
In accordance with an exemplary embodiment, turbine shroud 87 includes a first interface member 114 arranged at upstream edge 104 at first side edge 106 and a second interface member 118 arranged at upstream edge 104 at second side edge 107. First and second interface members 114 and 118 interface with adjacent turbine shrouds as will be discussed more fully below in order to reduce losses of hot gases from hot gas path 30 and to prevent detrimental effects of hot gas ingestion inside a cooler turbine component.
First interface member 114 includes a first edge portion 124 and a second edge portion 125 that form a projection or tab 126. Tab 126 projects circumferentially outwardly from first interface member 114. First edge portion 124 includes a first end portion 130 that extends from upstream edge 104 to a second end portion 131. First edge portion 124 extends circumferentially outwardly from turbine shroud 87 at a non-perpendicular angle relative to upstream edge 104 and first side edge 106. In accordance with one aspect of the exemplary embodiment, the non-perpendicular angle is about the same as an exit velocity angle of hot gases passing from an upstream stage. In accordance with another aspect of the exemplary embodiment, the non-perpendicular angle is about ±20° of the exit velocity angle of the hot gases from the upstream stage. It should be understood that the non-perpendicular angle may vary and need not fall within the limits described above. Second edge portion 125 includes a first end 134 that extends from second end portion 131 to a second end 135 that joins with first side edge 106. Second edge portion 125 extends substantially parallel to upstream edge 104.
Second interface member 118 includes a first edge section 140 and a second edge section 141 that form a recess 146 in flowpath surface 110. First edge section 140 includes a first end section 150 that extends from upstream edge 104 into flowpath surface 110 to a second end section 151. First edge section 140 extends at a non-perpendicular angle relative to upstream edge 104 and second side edge 107. The non-perpendicular angle of first edge section 140 is generally complementary to the non-perpendicular angle of first edge portion 124. Second edge section 141 includes a first end 157 that extends from second end section 151 to a second end 158 that terminates at second side edge 107. In this manner, second interface member 118 is generally complementary to first interface member 114.
As shown in
In accordance with an exemplary embodiment, first interface member 114 cooperates or nests within a second interface member 194 provided on adjacent turbine shroud 192 to form an angled slashface interface 200. Angled slash face interface 200, due to a near perpendicular orientation relative to upstream gas velocity, creates an elevated pressure area that substantially prevents gas flow from penetrating axially between adjacent turbine shrouds. The elevated pressure area also reduces coolant leakage between seal slots. In addition, the axial position of forward end 180 of second sealing portion 173 creates a relatively higher local static pressure of leakage coolant passing by end gap 198. The relatively higher static pressure reduces coolant loss to hot gas path 30.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
