This invention is directed generally to transitions in turbine engines between combustors and turbine vane assemblies for directing exhaust gases into the turbine vane assemblies and, more particularly, to devices for cooling turbine brackets used to attached transitions in turbine engines.
Typically, gas turbine engines operate at high temperatures that may exceed 2,500 degrees Fahrenheit. During operation, turbine engines expose turbine vane assemblies, transitions, and other components to these high temperatures. As a result, these components must be made of materials capable of withstanding such high temperatures. Typically, transition sections are coupled to a blade ring or other component of a turbine vane assembly. The transition sections are often attached using a bracket. During operation, the bracket is heated on one edge by the transition and cooled on another edge by cooling gases. As a result, a large temperature differential is developed in the transition bracket as the end of the bracket coupled to the transition becomes very hot and the other end opposite the end coupled to the transition is cooled with cooling gases. This large temperature differential often causes premature failure of the transition brackets or transitions, or both, in turbine engines. Thus, a need exists for a system for attaching transitions to turbine vane assemblies in a turbine engine that reduces the likelihood of premature failure of the attachment system.
This invention relates to a heat shield for a transition bracket in a can-annular combustion system of a turbine engine, whereby the transition bracket is used to couple a transition to a blade ring or other component of a turbine blade assembly to direct combustion exhaust gases from a combustor to a turbine blade assembly. The heat shield insulates the transition bracket from the cooling gases so that the bracket is not exposed to large temperature differentials, and therefore is not as susceptible to premature failure.
The heat shield may be formed from an elongated body configured to be coupled to an outer surface of a transition. In at least one embodiment, the elongated body may be tubular and have a generally teardrop shaped cross section. The elongated body may include a top surface and a bottom surface. The elongated body may include an opening in the bottom surface configured to receive a transition bracket rib attached to a transition and an opening in a top surface enabling a transition bracket to protrude through the elongated body. The elongated body may have a cross-section formed from a top portion having a generally hemispherical shape and two sides extending from the top portion toward each other. The two sides may extend generally toward each other and may include flared ends that extend generally away from each other and away from a longitudinal axis. The heat shield may also include first and second end attachments for closing the ends of the elongated body. The first and second end attachments may include slots for receiving the transition bracket rib.
The heat shield may be attached to an outer surface of a transition in a turbine engine. The heat shield may be attached to the transition bracket rib using an interference fit by placing the body over the transition bracket rib so that the transition bracket rib rests within the opening between the two sides forming the elongated body. In other embodiments, the heat shield may be attached to the transition using welds or other such connections. Once the heat shield is in place, the transition bracket may protrude through the heat shield. The transition bracket may include apertures or other devices for attaching the transition bracket to a blade ring or other component of a turbine vane assembly.
During operation of a turbine engine, the transition directs exhaust gases from a combustor into a turbine blade assembly. As a result, the transition becomes very hot as does one edge of the transition bracket. The other edge of the transition bracket remains cool due to its exposure to cooling gases. The heat shield insulates the transition bracket from the cooling gases, and thus, the transition bracket maintains a relatively consistent temperature throughout the bracket.
An advantage of this invention is that the heat shield enables a transition bracket to maintain a relatively even temperature throughout the bracket, or at least, enables a transition bracket to reduce the temperature differential in the bracket relative to conventional systems, such that the likelihood of premature failure of a transition or a transition bracket, or both, is substantially reduced relative to conventional designs.
These and other embodiments are described in more detail below.
The accompanying drawings, which are incorporated in and form a part of the specification, illustrate embodiments of the presently disclosed invention and, together with the description, disclose the principles of the invention.
As shown in
As shown in
The heat shield 10 may also include a first end attachment 36 and a second end attachment 38 for closing the open ends of the elongated body 16, as shown in
A transition bracket 12 may extend from the elongated body 16 so that the bracket 12 extends generally through a top surface 44 of the elongated body 16. In at least one embodiment, as shown in
The heat shield 10 may be installed on a transition bracket rib 34 by sliding the elongated body 16 onto the transition bracket rib 34 so that the transition bracket rib 34 and the transition bracket 12 protrude through the opening 31. The first and second sides 22, 26 may extend from the top portion 20 such that a width of the opening 31 is narrower than a width of the transition bracket rib 34, thereby creating an interference fit when the elongated body 16 is inserted onto the transition bracket rib 34. The transition bracket 12 attached to the heat shield 10 may be coupled to a blade ring or other component of a turbine blade assembly so that exhaust gases produced during operation of a turbine engine may be directed into the turbine blade assembly via the transition 14. These gases heat the transition 14, the transition bracket rib 34, and the transition bracket 12. However, the heat shield 10 insulates the transition bracket 12 and the transition bracket rib 34 from the cooling gases surrounding the transition 14. As a result, the transition bracket 12 and the transition bracket rib 34 maintain an even or relatively even temperature across its height and thus, is less likely to fail prematurely.
The foregoing is provided for purposes of illustrating, explaining, and describing embodiments of this invention. Modifications and adaptations to these embodiments will be apparent to those skilled in the art and may be made without departing from the scope or spirit of this invention.
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Number | Date | Country | |
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20060162314 A1 | Jul 2006 | US |