METHOD FOR A COMBUSTOR NOZZLE
A method for supplying fuel to a combustor includes flowing a working fluid through a nozzle, injecting the fuel into the nozzle, and mixing the fuel with the working fluid to create a fuel and working fluid mixture. The method further includes swirling the fuel and working fluid mixture, sensing flame holding in the nozzle, and reducing the swirl in the fuel and working fluid mixture. A method for supplying a working fluid to a combustor includes flowing the working fluid through a nozzle and swirling the working fluid flowing through the nozzle. The method further includes sensing flame holding in the nozzle and reducing the swirl of the working fluid flowing through the nozzle.
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This application is a continuation of prior pending U.S. patent application Ser. No. 12/755,747, filed Apr. 7, 2010 entitled “System and Method for a Combustor Nozzle”, the entirety of which is incorporated herein in its entirety for all purposes. Any disclaimer that may have occurred during prosecution of the above-referenced application(s) is hereby expressly rescinded.
FIELD OF THE INVENTIONThe present invention generally involves a combustor. In particular, the present invention describes and enables a nozzle for a combustor and a method for responding to flame holding conditions in the nozzle.
BACKGROUND OF THE INVENTIONCombustors are commonly used in many fauns of commercial equipment. For example, gas turbines typically include one or more combustors that mix fuel with a working fluid to generate combustion gases having a high temperature, pressure, and velocity. Many combustors include nozzles that premix the fuel with the working fluid prior to combustion. Premixing the fuel with the working fluid prior to combustion allows for leaner fuel mixtures, reduces undesirable emissions, and/or improves the overall thermodynamic efficiency of the gas turbine.
During normal combustor operations, a combustion flame exists downstream from the nozzles, typically in a combustion chamber at the exit of the nozzles. Occasionally, however, an event referred to as “flame holding” occurs in which a combustion flame exists upstream of the combustion chamber inside the nozzles. For example, conditions may exist in which a combustion flame exists near a fuel port in the nozzles or near an area of low flow in the nozzles. Nozzles are typically not designed to withstand the high temperatures created by flame holding, and flame holding may therefore cause severe damage to a nozzle in a relatively short amount of time.
Various methods are known in the art for preventing or reducing the occurrence of flame holding. For example, flame holding is more likely to occur during the use of higher reactivity fuels or during the use of higher fuel-to-working-fluid ratios. Flame holding is also more likely to occur during operations in which the fuel-working fluid mixture flows through the nozzles at lower velocities. Combustors may therefore be designed with specific safety margins for fuel reactivity, fuel-to-working-fluid ratios, and/or fuel-working fluid mixture velocity to prevent or reduce the occurrence of flame holding. While the safety margins are effective at preventing or reducing the occurrence of flame holding, they may also result in reduced operating limits, additional maintenance, reduced operating lifetimes, and/or reduced overall thermodynamic efficiency. Therefore, a nozzle, a combustor, and/or a method for operating the combustor to respond to flame holding would be desirable.
BRIEF DESCRIPTION OF THE INVENTIONAspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.
One embodiment of the present invention is a method for supplying fuel to a combustor that includes flowing a working fluid through a nozzle, injecting the fuel into the nozzle, and mixing the fuel with the working fluid to create a fuel and working fluid mixture. The method further includes swirling the fuel and working fluid mixture, sensing flame holding in the nozzle, and reducing the swirl in the fuel and working fluid mixture.
Another embodiment of the present invention is a method for supplying a working fluid to a combustor that includes flowing the working fluid through a nozzle and swirling the working fluid flowing through the nozzle. The method further includes sensing flame holding in the nozzle and reducing the swirl of the working fluid flowing through the nozzle.
In a still further embodiment, a method for supplying a working fluid to a combustor includes flowing the working fluid through a nozzle and sensing flame holding in the nozzle. The method further includes at least one of increasing the mass flow rate of the working fluid flowing through the nozzle, decreasing a tangential velocity of the working fluid flowing through the nozzle, or increasing an axial velocity of the working fluid flowing through the nozzle.
Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.
A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying Figures, in which:
Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention.
Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
Various embodiments of the present invention include an active device that minimizes or prevents damage to a nozzle or combustor caused by flame holding. When flame holding occurs, the active device reduces the swirling of fuel and working fluid flowing through the nozzle. The reduced swirling of fuel and working fluid in the nozzle in which flame holding is occurring allows that nozzle to “borrow” additional working fluid from adjacent nozzles, thus increasing the axial velocity and/or mass flow rate of the fuel and working fluid mixture to effectively push the combustion flame out of the nozzle. In addition, assuming a constant fuel mass flow rate, the increased mass flow rate working fluid reduces the ratio of fuel-to-working-fluid. The reduced fuel-to-working-fluid ratio further aids to extinguish or remove the combustion flame from the nozzle. When flame holding no longer exists, the active device returns to its previous position to impart swirling to or allow swirling of the fuel and working fluid flowing through the nozzle.
By responding to flame holding, the active device may provide an increase in margins before the onset of flame holding or allow for less restrictive operating limits during normal operations. For example, the ability of the active device to respond to flame holding may allow for the use of fuels with higher reactivity, less restrictive design limitations on the location of fuel injection, and fewer forced outages caused by flame holding. As a further example, the active device may allow for reduced nozzle velocities during normal operations, resulting in reduced pressure losses across the nozzle and increased thermodynamic efficiency.
As shown in
The combination of the angle of the vanes 40 and/or the curvature of the bimetallic guides 46 determines the direction, mass flow rate, axial velocity, and angular velocity of the fuel and working fluid mixture. For example, as shown in
Referring to
In each situation illustrated in
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
Claims
1. A method for supplying fuel to a combustor, comprising:
- a. flowing a working fluid through a nozzle;
- b. injecting the fuel into the nozzle;
- c. mixing the fuel with the working fluid to create a fuel and working fluid mixture;
- d. swirling the fuel and working fluid mixture;
- e. sensing flame holding in the nozzle; and
- f. reducing the swirl in the fuel and working fluid mixture.
2. The method as in claim 1, further including increasing the mass flow rate of the working fluid through the nozzle.
3. The method as in claim 1, further including decreasing a tangential velocity of the fuel and working fluid mixture.
4. The method as in claim 1, further including decreasing a fuel-to-working-fluid ratio in the fuel and working fluid mixture.
5. The method as in claim 1, further including increasing an axial velocity of the fuel and working fluid mixture.
6. The method as in claim 1, further comprising swirling the fuel and working fluid mixture with a bi-metallic guide.
7. The method as in claim 1, further comprising changing a curvature of a bi-metallic guide to reduce the swirl in the fuel and working fluid mixture.
8. A method for supplying a working fluid to a combustor, comprising:
- a. flowing the working fluid through a nozzle;
- b. swirling the working fluid flowing through the nozzle;
- c. sensing flame holding in the nozzle; and
- d. reducing the swirl of the working fluid flowing through the nozzle.
9. The method as in claim 8, further including increasing the mass flow rate of the working fluid flowing through the nozzle.
10. The method as in claim 8, further including decreasing a tangential velocity of the working fluid flowing through the nozzle.
11. The method as in claim 8, farther including increasing an axial velocity of the working fluid flowing through the nozzle.
12. The method as in claim 8, further including decreasing a fuel-to-working-fluid ratio in the nozzle.
13. The method as in claim 8, further comprising swirling the working fluid with a bi-metallic guide.
14. The method as in claim 8, further comprising changing a curvature of a bi-metallic guide to reduce the swirl of the working fluid.
15. A method for supplying a working fluid to a combustor, comprising:
- a. flowing the working fluid through a nozzle;
- b. sensing flame holding in the nozzle; and
- c. at least one of increasing the mass flow rate of the working fluid flowing through the nozzle, decreasing a tangential velocity of the working fluid flowing through the nozzle, or increasing an axial velocity of the working fluid flowing through the nozzle.
16. The method as in claim 15, further including reducing the swirl of the working fluid flowing through the nozzle.
17. The method as in claim 15, further including decreasing a fuel-to-working-fluid ratio in the nozzle.
18. The method as in claim 15, further comprising swirling the working fluid with a bi-metallic guide.
19. The method as in claim 15, further comprising changing a curvature of a bi-metallic guide.
20. The method as in claim 15, further comprising sensing flame holding in the nozzle with a bi-metallic guide.
Type: Application
Filed: Sep 26, 2011
Publication Date: Jan 19, 2012
Applicant: General Electric Company (Schenectady, NY)
Inventor: Jason Thurman Stewart (Greenville, SC)
Application Number: 13/245,019
International Classification: F23K 5/00 (20060101);