The present application relates generally to gas turbine engines and more particularly relates to a trailing edge of a first stage nozzle or a transition nozzle configured to promote mixing of respective combustion streams downstream thereof before entry into a first stage bucket of a turbine.
Annular combustors often are used with gas turbine engines. Generally described, an annular combustor may have a number of individual can combustors that are circumferentially spaced between a compressor and a turbine. Each can combustor separately generates combustion gases that are directed downstream towards the first stage of the turbine.
The mixing of these separate combustion streams is largely a function of the free stream Mach number at which the mixing is taking place as well as the differences in momentum and energy between the combustion streams. Practically speaking, the axial distance between the exit of the can combustors and the leading edge of a first stage nozzle is relatively small such that little mixing actually may take place before entry into the turbine.
There is thus a desire to minimize mixing loses. Such reduced mixing loses may reduce overall pressure losses without increasing the axial distance between the combustor and the turbine. Such an improved combustion design thus should improve overall system performance and efficiency.
The present application and the resultant patent thus provide a disruptive surface on a trailing edge of a stage one nozzle or a transition nozzle to promote mixing of respective combustion streams downstream thereof before entry into a first stage bucket of a turbine. For example, in one embodiment, a gas turbine engine may include a combustor including a combustion flow. The gas turbine engine also may include one or more airfoils forming a first stage nozzle or a transition nozzle disposed downstream of the combustor. Moreover, the gas turbine engine may include a flow disruption surface positioned about a trailing edge of the one or more airfoils to promote mixing of the combustion flow.
The present application and the resultant patent further provides a method of limiting pressure losses in a gas turbine engine. The method may include positioning a flow disruption surface on a trailing edge of one or more airfoils of a first stage nozzle or a transition nozzle, generating a number of combustion streams in a number of can combustors, substantially mixing the combustion streams with the flow disruption surface, and passing a mixed stream to a stage one bucket.
The present application and the resultant patent further provides a gas turbine engine. The gas turbine engine may include a number of can combustors forming a number of combustion flows. The gas turbine engine also may include one or more airfoils forming a first stage nozzle or a transition nozzle disposed downstream of the can combustors. Moreover, the gas turbine may include a flow disruption surface positioned about a trailing edge of the one or more airfoils to promote mixing of the combustion flows.
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.
Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale.
Referring now to the drawings, in which like numerals refer to like elements throughout the several views,
The gas turbine engine 10 may use natural gas, various types of syngas, and/or other types of fuels. The gas turbine engine 10 may be anyone of a number of different gas turbine engines such as those offered by General Electric Company of Schenectady, New York and the like. The gas turbine engine 10 may have different configurations and may use other types of components. Other types of gas turbine engines also may be used herein. Multiple gas turbine engines, other types of turbines, and other types of power generation equipment also may be used herein together.
A cooling flow 90 from the compression system 15 or elsewhere may pass through the impingement sleeve 85. The cooling flow 90 may be used to cool the liner 68 and the transition piece 70 and then may be used at least in part in charging the flow of combustion gases 35. A portion of the flow 90 may head towards the aft end 75 and may be used for cooling the first stage nozzle vanes 80 and related components. Other types of cooling flows may be used. The loss of a portion of the cooling flow 90 thus results in a parasitic loss because that portion of the flow 90 is not used for charging the combustion flow 35. Other components and other configurations also may be used herein.
In certain embodiments, as depicted in
The increased uniformity of the temperature and velocity field created by the enhanced mixing of the trailing edge 404 disruption surface 406 of the airfoils 400 of the first stage nozzle and/or the transition nozzle is beneficial to the rotor blade row mechanical and thermal durability downstream thereof. This is particularly beneficial for a low nozzle count or a transition-nozzle configuration. The enhanced mixing is created by the use of spikes, chevrons, lobes, and/or jets disposed about the trailing edge 404 of the airfoils 400 of the first stage nozzle. This enhanced mixing increases the pressure loss relative to unforced mixing. The addition of the flow disruption surface 406 about the trailing edge 404 of the airfoils 400 of the first stage nozzle and/or the transition nozzle minimizes the amount of mixing that takes place within the bucket domain. The additional pressure loss incurred by the enhanced mixing from the trailing edge 404 of the airfoils 400 of the first stage nozzle and/or the transition nozzle is much lower than the mixing loss incurred should the nozzle wake mix in the downstream bucket. Also, the enhanced mixing reduces the wake strength of the nozzle and the high cycle fatigue loads on the bucket, which allows more economical nozzle configurations to be chosen (such as, but not limited to, lower count and/or closer axial nozzle-bucket spacing). Further, the enhanced mixing makes the incoming velocity and thermal flow distributions more uniform, which reduces the gas loads and thermal loads on the bucket, thereby improving the durability of the bucket.
The embodiments of the flow disruption surface described herein are for purposes of example only. Any other the flow disruption surface geometry or other type of flow disruption surface that encourages mixing of the combustion flows may be used herein. Different types of flow disruption surfaces may be used herein together. Other components and other configurations also may be used herein.
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 disclosure as defined by the following claims and the equivalents thereof