System for injecting a liquid fuel into a combustion gas flow field

Abstract

A system for injecting a liquid fuel into a combustion gas flow field includes an annular liner that defines a combustion gas flow path. The annular liner includes an inner wall, an outer wall and a fuel injector opening that extends through the inner wall and the outer wall. The system further includes a gas fuel injector that is coaxially aligned with the fuel injector opening. The gas fuel injector includes an upstream end and a downstream end. The downstream end terminates substantially adjacent to the inner wall. A dilution air passage is at least partially defined by the gas fuel injector. A liquid fuel injector extends partially through the dilution air passage. The liquid fuel injector includes an injection end that terminates upstream from the inner wall.

Description

FIELD OF THE INVENTION[0001]The present invention generally involves a system for supplying fuel to a combustor. In particular, the invention relates to a system for increasing penetration of a axially staged liquid fuel into a combustion gas flow field.BACKGROUND OF THE INVENTION[0002]A gas turbine generally includes a compressor section, a combustion section having a combustor and a turbine section. The compressor section progressively increases the pressure of the working fluid to supply a compressed working fluid to the combustion section. The compressed working fluid is routed through and / or around an axially extending fuel nozzle that extends within the combustor. A fuel is injected into the flow of the compressed working fluid to form a combustible mixture. The combustible mixture is burned within a combustion chamber to generate combustion gases having a high temperature, pressure and velocity. The combustion gases flow through one or more liners or ducts that define a hot g...

AI Technical Summary

Benefits of technology

The present invention relates to a system for injecting liquid fuel into a combustion gas flow field in a gas turbine, and a gas turbine including such a system. The system includes an annular liner with a fuel injector opening and a gas fuel injector that is aligned with the opening. The gas fuel injector extends partially through a dilution air passage defined by the annular liner. A liquid fuel injector extends through the dilution air passage and the inner wall of the liner. The gas turbine also includes a system for injecting a liquid fuel into a combustion gas flow field downstream from the axially extending fuel nozzle. The liquid fuel injectors are positioned within a dilution air passage and the plenum of the gas fuel injector. The technical effects of the invention include improved combustion efficiency and reduced emissions.

Problems solved by technology

However, higher combustion gas temperatures may increase the disassociation rate of diatomic nitrogen, thereby increasing the production of undesirable emissions such as oxides of nitrogen (NOX) for a particular residence time in the combustor.

One challenge with injecting a liquid fuel into the combustion gas flow field using existing LLI or axial fuel staging systems is that the momentum of the combustion gases generally inhibits adequate radial penetration of the liquid fuel into the combustion gas flow field.

As a result, local evaporation of the liquid fuel occurs along an inner wall of the liner at or near the fuel injection point, thereby resulting in a high temperature zone and high thermal stresses.

However, this approach creates a bluff body in the combustion gas flow field that results in the formation of a high temperature recirculation zone downstream from the bluff body.

In addition, this approach exposes the fuel injectors to the hot combustion gases which may impact the mechanical life of the component and lead to fuel coke buildup.

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