Patent Application
20130170960
The subject matter disclosed herein relates to turbines. More particularly, the subject matter relates to reducing fluid flow between components of turbines.
In a gas turbine, a combustor converts chemical energy of a fuel or an air-fuel mixture into thermal energy. The thermal energy is conveyed by a fluid, often compressed air from a compressor, to a turbine where the thermal energy is converted to mechanical energy. In some turbine embodiments, leakage of fluid between components into the compressed hot air causes a reduced power output and lower efficiency for the turbine. Leaks of fluid may be caused by thermal expansion of certain components and relative movement between components during operation of the gas turbine. Accordingly, reducing fluid leaks between components can improve efficiency and performance of the turbine.
According to one aspect of the invention, a turbine assembly includes a stator and a rotor adjacent to the stator. The turbine assembly also includes a passage formed in a member coupled to the rotor to form a fluid curtain between the rotor and stator, wherein the fluid curtain reduces a flow between the stator and rotor.
According to another aspect of the invention, a method for reducing fluid flow between turbine components includes flowing a hot gas across a stator and flowing the hot gas across a rotor adjacent to the stator. The method also includes flowing a cooling air flow through radially inner portions of the stator and rotor and flowing a fluid from a member on the rotor to the stator to reduce leaking of the flow of cooling air and the flow of hot gas between the stator and rotor.
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.
In an aspect, the combustor 104 uses liquid and/or gas fuel, such as natural gas or a hydrogen rich synthetic gas, to run the engine. For example, fuel nozzles 110 are in fluid communication with an air supply and a fuel supply 112. The fuel nozzles 110 create an air-fuel mixture, and discharge the air-fuel mixture into the combustor 104, thereby causing a combustion that heats a pressurized gas. The combustor 104 directs the hot pressurized exhaust gas through a transition piece into a turbine nozzle (or “stage one nozzle”) and then a turbine bucket, causing turbine 106 rotation. The rotation of turbine 106 causes the shaft 108 to rotate, thereby compressing the air as it flows into the compressor 102. The turbine components or parts are configured to allow for thermal expansion and relative movement of the parts while hot gas flows through the turbine 106. By reducing flow of a fluid that is cooler than the hot gas, turbine efficiency is improved. Specifically, reducing leakage of fluid into the hot gas path or compressed gas flow increases the volume of hot gas flow along the desired path, enabling more work to be extracted from the hot gas. Methods, systems and arrangements to reduce fluid leakage between turbine parts, such as stators and rotors, are discussed in detail below with reference to
As used herein, “downstream” and “upstream” are terms that indicate a direction relative to the flow of working fluid through the turbine. As such, the term “downstream” refers to a direction that generally corresponds to the direction of the flow of working fluid, and the term “upstream” generally refers to the direction that is opposite of the direction of flow of working fluid. The term “radial” refers to movement or position perpendicular to an axis or center line. It may be useful to describe parts that are at differing radial positions with regard to an axis. In this case, if a first component resides closer to the axis than a second component, it may be stated herein that the first component is “radially inward” of the second component. If, on the other hand, the first component resides further from the axis than the second component, it may be stated herein that the first component is “radially outward” or “outboard” of the second component. The term “axial” refers to movement or position parallel to an axis. Finally, the term “circumferential” refers to movement or position around an axis. Although the following discussion primarily focuses on gas turbines, the concepts discussed are not limited to gas turbines and may apply to other rotating machinery, such as steam turbines.
Referring now to
The fluid curtain 222 may be formed by a fluid flow from any suitable fluid source, such as the fluid source 218 (e.g., air, water or other coolant) for temperature control of turbine components. The depicted formation of fluid curtain 222 between the rotor 202 and stator 204 provides improved performance by increasing the amount of work available to be extracted from the hot gas flow 228 while also providing a low maintenance seal or barrier that will not wear out or need replacement.
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.
