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DUAL MIXER LLI INJECTOR VIA FUEL LEAK AIR PURGE

IP.com Disclosure Number: IPCOM000235896D
Publication Date: 2014-Mar-28
Document File: 5 page(s) / 306K

Publishing Venue

The IP.com Prior Art Database

Abstract

The present invention proposes a technique for reducing flame holding in gas turbines. The proposed technique introduces secondary stage of mixing which protects injector vanes and injector exit from flame holding. The technique directs leak in fuel pipe through a separate shield covering only a fuel pipe into a main injector path. The proposed technique curbs the flame holding risk in late lean injection (LLI) injectors with segmented air shield. The technique reduces flame holding risk by providing a separate path for injectors and fuel pipe. By using the proposed technique, any leak is communicated in the fuel pipe via a separate air shield and the flow back is introduced in to the injector wall.

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DUAL MIXER LLI INJECTOR VIA FUEL LEAK AIR PURGE

BACKGROUND

The present invention relates generally to gas turbines and more particularly to reduced flame holding in gas turbines.

In general, fuel pipes protected against fuel leak is clubbed under the same hood as late lean injection (LLI). As a result, vanes of the LLI suffer from recirculation zones which are potential flame holding regions.

Figure 1 depicts conventional LLI injector air inlet.

Figure 1

As illustrated in the above figure, recirculation is found with uneven flow distribution and flame holding risk.

A conventional technique includes a bypass air injection which blows separation regions. A mesh is connected around the injector vanes to uniform the flow and design iteration on an air shield to aerodynamically feature in the flow into the vanes.

Another conventional technique includes a late lean fuel injection nozzle for a gas turbine. The late lean fuel injection nozzle has an outer air supply having relatively large inner diameter and an outlet at a distal end. The outer air supply tube supplies air to a combustion chamber and fuel injection tube having relatively smaller diameter enters a distal end portion of the outer supply tube. The fuel injection tube extends within the first outer air supply tube substantially to the outlet.

However, the flame holdings are not reduced by the above mentioned conventional techniques. 

Therefore there is a need in the art to reduce flame holdings in gas turbines.

BRIEF DESCRIPTION OF THE DRAWINGS

Figure 1 depicts conventional LLI injector air inlet.

Figure 2 depicts proposed design of LLI injector air inlet.

Figure 3 depicts proposed design of LLI injector air inlet (dual mixer)

DETAILED DESCRIPTION

The present invention proposes a technique for reducing flame holding in gas turbines.

The proposed technique introduces secondary stage of mixing which protects injector vanes and injector exit from flame holding. The technique directs leak in fuel pipe through a separate shield covering only a fuel pipe into a main injector path.

The proposed technique curbs the flame holding risk in late lean injection (LLI) injectors with segmented air shield. The technique reduces flame holding risk by providing a separate path for injectors and fuel pipe. By using the proposed technique, any leak is communicated in the fuel pipe via a separate air shield and the flow back is introduced in to the injector wall. Consequently, the technique mitigates flame holding risks both in injector as well as in injector vanes. Further, downsizing the conventional air shield...