Patent Application
20130074471
The subject matter disclosed herein relates to turbines. More particularly, the subject matter relates to combustion dynamics control and temperature control of a turbine.
In a gas turbine engine, 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 air from a compressor, to a turbine where the thermal energy is converted to mechanical energy. Several factors influence the efficiency of the conversion of thermal energy to mechanical energy. The factors may include blade passing frequencies, fuel supply fluctuations, fuel type and reactivity, combustor head-on volume, fuel nozzle design, air-fuel profiles, flame shape, air-fuel mixing, flame holding, combustion temperature, turbine component design, hot-gas-path temperature dilution, and exhaust temperature.
For example, high combustion temperatures in selected locations in the turbine engine, such as the combustor, may enable improved combustion efficiency and power production. In some cases, high temperatures may shorten the life and increase wear and tear of certain components.
In addition, effective operation of turbine engines may also involve managing combustion dynamics, i.e., dynamic instabilities in operation. Dynamics are often caused by fluctuations in such conditions as the temperature of exhaust gases and oscillating pressure levels within regions of the turbine, such as within the combustor. High dynamics can limit hardware life and operability of an engine, due to such factors as mechanical and thermal fatigue.
According to one aspect of the invention, a turbine combustor includes an outer member coupled to a wall of the combustor, wherein there is at least one damping hole formed in outer member. The turbine combustor further includes at least one temperature control hole formed in the wall wherein the at least one temperature control hole is formed at an angle with respect to a line perpendicular to a hot gas path in the combustor.
According to another aspect of the invention, a method for temperature control and damping a portion of a combustor includes flowing a treatment fluid through at least one damping hole in an outer member coupled to a wall of the combustor, wherein the outer member forms a resonator cavity that receives the treatment fluid. The method further includes flowing the treatment fluid from the resonator cavity through at least one temperature control hole formed in the wall, wherein the at least one temperature control hole is formed at an angle with respect to a line perpendicular to a hot gas path in the combustor.
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 turbine engine. For example, fuel nozzles 110 are in fluid communication with a fuel supply and pressurized air from the compressor 102. The fuel nozzles 110 create an air-fuel mix, and discharge the air-fuel mix into the combustor 104, thereby causing a combustion that creates a hot pressurized exhaust gas. The combustor 104 directs the hot pressurized exhaust gas through a transition piece into a turbine nozzle (or “stage one nozzle”), causing turbine 106 rotation as the gas exits the nozzle or vane and gets directed to the turbine bucket or blade. The rotation of turbine 106 causes the shaft 108 to rotate, thereby compressing the air as it flows into the compressor 102. In an embodiment, hot gas flow through portions of the turbine, such as the combustor 104, causes wear and thermal fatigue of turbine parts, due to non-uniform temperatures. Controlling the temperature of parts of the combustor 104 can reduce wear and enable higher combustion temperatures, thereby improving performance. In addition, oscillations and vibration due to pressure changes and combustion, i.e. combustion dynamics, can also wear portions of the combustor 104. Combustion dynamics may be controlled and reduced by selected mechanisms, such as resonators, to reduce wear and improve life of the combustor 104. Controlling combustion dynamics of and temperatures of the combustor 104 are discussed in detail below with reference to
The holes 206, 214, 306, 314 may be any suitable geometry and orientation configured to direct fluid flow to portions of the combustors 200, 300. Exemplary geometries of the cross-sectional flow area of the holes may be circular, rectangular, oval, ellipses, rectangles or other suitable shapes. In embodiments, the cooling fluid flow 212, 312 outside the wall 204, 304 of the combustor 200, 300 and between about 400 and about 800 degrees Fahrenheit (F). In addition, temperatures of the combustors 200, 300 inside the walls 204, 304 range from about 2500 to about 3500 degrees F. Therefore, the flow of the cooling fluid 212, 312 to fluid flows 208, 308 and 214, 314 inside the combustors 200, 300 (and along with members 318 for combustor 300) provide improved temperature control and/or cooling to reduce wear for the turbine components. Further, the arrangement of the outer member 202, 302 and holes 206, 306 act as a resonating apparatus to provide damping and control combustion dynamics. In embodiments, the outer members 202, 302 are coupled to walls 204, 302 to form Hemholtz resonators configured to provide damping and control combustion dynamics. In an embodiment, the resonators are tuned to combustion dynamics frequency and are thereby configured to cause damping of combustion dynamics at the selected frequency. Accordingly, the depicted arrangement improves turbine reliability and performance by improving temperature control while controlling combustion dynamics for the exemplary combustors 200, 300. In embodiments the depicted portions of the combustors 200, 300 may be any portion of the combustor, including but not limited to the liner or cap region.
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.
