Power plants – Combustion products used as motive fluid – Combustion products generator
Reexamination Certificate
1998-04-03
2001-04-17
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combustion products generator
C060S748000
Reexamination Certificate
active
06216466
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention concerns a fuel-injection arrangement for a combustor of a gasturbine engine, and in particular a fuel-injection arrangement enabling reliable performance at low load conditions of said engine.
Provision is made in gas turbine engines to inject fuel into a region upstream of the main combustor region of the engine for mixing with air and eventual burning in the main combustor region.
FIG. 1
shows part of a gas-turbine engine comprising a combustion chamber
10
, a fuel-inlet head
12
and a radial swirler
14
disposed therebetween. The swirler
14
, which is commonly used in gas turbine engines as a mixing device to mix fuel and air for supply to the combustion chamber, is configured as illustrated in
FIGS. 2
a
and
2
b
and comprises a series of vanes
16
equally spaced around a circumference of the swirler, the vanes forming a corresponding series of passageways
18
for the flow of mixing air
20
through the swirler from a radially outer to a radially inner region thereof.
The vanes are shaped and disposed such as to impart to the incoming air a tangential component, whereby the air is caused to “swirl” around the longitudinal axis
22
of the swirler, the air also being caused to exit the swirler at a downstream region thereof and enter the combustion chamber
10
(see arrows
21
).
Along the trailing-edge region
24
of the vanes
16
—i.e. trailing-edge in terms of air flow through the vane arrangement—are conventionally disposed a series of fuel outlets
26
fed from a fuel inlet conduit
28
connected to the fuel head
12
. The outlets or holes
26
are of uniform diameter and are evenly spaced axially along the trailing edge. Use of such holes evenly spaced along at least most of the length of the trailing edge promotes better mixing of fuel and air by making for a uniform distribution of the fuel along the axial length of the swirler.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a fuel injection arrangement for a gas turbine combustor, comprising at least one series of fuel-injection outlets arranged in spaced-apart relationship, referred to a longitudinal axis of said combustor, in a pre-chamber region of said combustor upstream of a main-chamber region thereof, said series of outlets being such as to provide, in use, a longitudinal variation in a radial component of momentum of fuel jets exiting said outlets. The variation in radial component of momentum preferably takes the form of a variation in a radial component of velocity, which may achieved by arranging for the outlets in the series to be of varying size.
The outlets may be smallest in an axially upstream portion of said pre-chamber region and the variation in outlet size in said series may be monotonic referred to said longitudinal axis.
Said variation may be a continuous variation or alternatively a stepped variation. It may be linear over at least a part of said series of outlets.
The outlets, which may be substantially equally spaced, may be configured such that a direction of fuel jets exiting said outlets is substantially radial.
The outlets may be disposed in a swirler portion of said pre-chamber region, and/or they may be disposed in an intermediate portion of said pre-chamber region between a swirler portion thereof and said main-chamber region. In the former case, where said swirler portion comprises a plurality of vanes, said series of outlets may be incorporated into each of at least some of said vanes at a trailing edge thereof. In the latter case, the outlets may be disposed in a wall of said intermediate portion. Alternatively, the outlets may be provided in fuel posts situated in said pre-chamber region.
REFERENCES:
patent: 2618982 (1952-11-01), Nathan
patent: 5943866 (1999-08-01), Lovett et al.
patent: 1 215 443 (1966-04-01), None
patent: 0 747 636 A2 (1996-12-01), None
patent: 2 255 628 (1992-11-01), None
Casaregola Louis J.
European Gas Turbines Limited
Kirschstein et al.
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