Power plants – Combustion products used as motive fluid – Combustion products generator
Patent
1997-07-28
1999-07-06
Thorpe, Timothy S.
Power plants
Combustion products used as motive fluid
Combustion products generator
60752, F02C 306, F23R 3010
Patent
active
059184671
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates to a heat shield for a combustion chamber, particularly for an annular combustion chamber of a gas turbine, having a passage opening for a fuel injector, by way of which fuel as well as combustion air arrives in the combustion chamber while forming a swirl, as well as having a plurality of effusion holes where their central axes are inclined toward the heat shield surface and by way of which the cooling air can penetrate from the rear in order to apply a film of cooling air to the hot surface.
A heat shield provided in the head of a combustion chamber is conventionally used for protecting the dome-shaped combustion chamber head area or the front plate provided therein as well as the fuel injector itself from the effect of the hot gas situated in the combustion chamber and from an excessive heat radiation. In order to be able to carry out this function, the heat shield itself must be cooled. For this purpose, the conventional heat shields have so-called effusion holes so that cooling air can penetrate from the rear in order to apply a cooling air film to the hot surface of the heat shield.
However, because it is not always possible to sufficiently cool all vulnerable zones of the heat shield according to the state of the art, an object of the invention is to provide measures for achieving an improved heat shield cooling.
For achieving this object, a surface sector is assigned to each corner area of the heat shield which extends into this corner area. The central axes of the effusion holes in these surfaces sectors are oriented in parallel to one another and essentially toward the assigned corner area and, in sections, extend approximately in the same direction as the fuel combustion air swirl in this sector. The surface sectors are separated from one another by one transition zone respectively having effusion holes whose central axes extend essentially in parallel to one another. The surface sectors, together with the transition zones, form the total surface of the heat shield.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings wherein:
FIG. 1 is a top view of the hot surface of a heat shield according to the present invention; and FIG. 2 is a similar view which explains the orientation of the central axes of the effusion holes.
DETAILED DESCRIPTION OF THE DRAWINGS
The heat shield 1 is arranged conventionally in the head of a gas turbine annular combustion chamber and has the hot surface 1a shown in top view. Conventionally, this heat shield has a central passage opening 2 for a burner which is bounded by a surrounding collar 3. The swirl 4 is generated by the fuel injector and under which fuel as well as combustion air is discharged from the fuel injector into the combustion chamber in a generally known manner.
Furthermore, the heat shield 1 has a plurality of effusion holes 5 by way of which cooling air can arrive from the cold rear of the heat shield, and through the heat shield, in the gas turbine combustion chamber situated on the viewer's side of FIGS. 1 and 2. These effusion holes 5 are drilled diagonally; that is, the central axes 6 of the effusion holes 5 are not disposed perpendicularly on the surface 1a of the heat shield 1 but are inclined with respect to the surface 1a. This measure, which is known per se, has the effect that at least a portion of the cooling air flow penetrating the heat shield 1 by way of the effusion holes 5 is applied as a cooling air film to the hot surface 1a of the heat shield 1 which results in an intensive cooling. The central axes 6 of the individual effusion holes 5 are inclined in different manners, as illustrated in the perpendicular projections of the central axes 6 onto the surface 1a illustrated in FIGS. 1 and 2, which, in particular, is also the result of the elliptical shape of the otherwise cir
REFERENCES:
patent: 5129231 (1992-07-01), Becker et al.
patent: 5271219 (1993-12-01), Richardson
patent: 5307637 (1994-05-01), Stickles et al.
patent: 5323602 (1994-06-01), Defever
BMW Rolls-Royce GmbH
Kim Ted
Thorpe Timothy S.
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