Patent Application
20110000215
The present application relates generally to gas turbine engines and more particularly relates to a full combustor can flow conditioner so as to provide a more uniform incoming air velocity to the combustor nozzles.
In a gas turbine, operational efficiency increases as the temperature of the combustion gas stream increases. Higher gas stream temperatures, however, may produce higher levels of nitrogen oxide (NOx), an emission that is subject to both federal and state regulation in the U.S. and subject to similar types of regulation abroad. A balancing act thus exists between operating the gas turbine in an efficient temperature range while also ensuring that the output of NOx and other types of emissions remain below the mandated levels.
New combustion concepts are exploring the use of a number of very small nozzles in the combustor. These small nozzles or other types of combustion nozzles may utilize more of the combustor cap space so as to reduce emissions and also to permit the use of highly reactive types of syngas and other fuels. To minimize the emissions and the potential for flashback with the alternative fuels, it may be desirable to have as uniform an airflow velocity distribution about the nozzles as possible. Current combustion designs, however, generally result in a non-uniform air velocity profile upstream of the combustion zone.
There is thus a desire to provide a uniform airflow velocity distribution about the combustor and the combustor cap. Preferably such a uniform airflow should provide both reduced emissions as well as improving the overall performance of the gas turbine engine.
The present application thus provides a combustor for a gas turbine engine. The combustor may include a combustor can with a number of nozzles therein and a flow conditioner positioned around the combustor can. The flow conditioner may include a number of apertures therein.
The present application further provides a combustor for a gas turbine engine. The combustor may include a combustor can with a number of mini-tube nozzles therein and a flow conditioner positioned around the combustor can. The flow conditioner may include a cylinder with a number of apertures therein.
The present application further provides a combustor for a gas turbine engine. The combustor may include a combustor can with a number of mini-tube nozzles therein and a flow conditioner positioned around the combustor can. The flow conditioner may include a plate with a number of apertures therein.
These and other features and improvements of the present application will 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 numbers refer to like elements throughout the several views,
The gas turbine engine 10 may use natural gas, various other types of syngas, and other types of fuels. The gas turbine engine may be a 9FBA heavy duty gas turbine engine offered by General Electric Company of Schenectady, N.Y. The gas turbine engine 10 may have other configurations and may use other types of components. Other types of gas turbine engines may be used herein. Multiple gas turbine engines 10, other types of turbines, and other types of power generation equipment may be used herein together.
Air from the compressor 12 thus flows through the cooling flow path 28 between the combustion liner 24 and the flow sleeve 26 and then reverses into the combustor can 15. The air then flows through the interior flow path 22 defined between the end cover 18 and the cap member 20. As the air passes through mini-tube nozzles 23 of the cap member 20, the air is mixed with a flow of fuel from a fuel path 30 and is ignited within a combustion chamber 32. The combustor 14 shown herein is by way of example only. Many other types of combustor 14 designs and combustion methods may be used herein.
As the airflow approaches the nozzles 23 of the cap member 20 through the interior flow path 22, there may be a large velocity distribution variance across the cap member 20. These variances may be particularly an issue given the use of a large number of the small mini-tube nozzles 23 as opposed to the use of a few larger nozzles. Such velocity variances may impact on emission levels and other types of combustion dynamics.
The flow conditioner 110 may be mounted off the end cover 18, off of the flow sleeve 26, or otherwise positioned upstream of the interior flow path 22. Mounting via the end cover 18 may provide for ease of fit or mounting via the flow sleeve 26 may provide for ease of construction. Air advancing along the cooling flow path 28 may pass through the apertures 140 of the cylinder 130 and into the interior flow path 22 towards the mini-tube nozzles 23 of the cap member 20. Forcing tile airflow through the number of apertures 140 provides a more uniform velocity through the flow conditioner 120. The use of the flow conditioner 120 thus may provide air flow with a more uniform velocity to the nozzles 23 of the cap member 20. The shape of the flow conditioner 10 and the apertures 140 also may be optimized to provide a diffuser effect to enhance pressure recovery of the air as it exits the flow sleeve 26.
The use of the flow conditioners 120, 220, 300 as a cylinder 130, a plate 230, or a screen/mesh 310 is by way of example only. Many other configurations may be used to reduce the velocity variances in the airflow and otherwise normalize the airflow as it enters the nozzles 23. Likewise, a diffuser effect may enhance the pressure recovery of the air as it exits the flow sleeve 26.
It should be apparent that the foregoing relates only to certain embodiments of the present application and that 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.
This invention was made with government support under Contract No. DE-FC26-05NT42643, awarded by the U.S. Department of Energy (“DOE”). The United States has certain rights in this invention.
