Patent Description:
In one example, a combustor of a gas turbine engine may be configured to burn fuel in a combustion area. Such configurations may place substantial heat load on the structure of the combustor (e.g., heat shield panels, combustor shells, etc.). Such heat loads may dictate that special consideration is given to structures, which may be configured as heat shields or panels, and to the cooling of such structures to protect these structures. Excess temperatures at these structures may lead to oxidation, cracking, and high thermal stresses of the heat shields panels.

<CIT> discloses a combustion liner for an engine including a shell having an impingement slot disposed therethrough and a panel having an effusion cooling hole disposed therethrough. A length of the impingement slot is longer than a width of the impingement slot, the length and the width configured to create turbulent airflow within a flow channel and minimize particulate matter accumulation.

<CIT> discloses a component for a gas turbine engine including a gas path wall having a first surface and a second surface, wherein at least one cooling hole extends through the gas path wall from an inlet in the first surface through a transition to an outlet in the second surface, and cusp features are formed on the transition.

According to a first aspect there is provided a combustor for use in a gas turbine engine as claimed in claim <NUM>.

The nonaxisymmetric shape of each of the plurality of impingement apertures extends from the outer surface to the inner surface through the combustor shell.

According to a second aspect there is provided a gas turbine engine as claimed in claim <NUM>.

The foregoing features and elements may be combined in any of the various possible combinations without exclusivity, unless expressly indicated otherwise.

The following descriptions should be considered to be exemplary.

The detailed description explains embodiments of the present disclosure, together with advantages and features, by way of example with reference to the drawings.

In one disclosed embodiment, the engine <NUM> bypass ratio is greater than about ten (<NUM>:<NUM>), the fan diameter is significantly larger than that of the low pressure compressor <NUM>, and the low pressure turbine <NUM> has a pressure ratio that is greater than about five (<NUM>:<NUM>). The geared architecture <NUM> may be an epicyclic gear train, such as a planetary gear system or other gear system, with a gear reduction ratio of greater than about <NUM>:<NUM>. It should be understood, however, that the above parameters are only exemplary of one embodiment of a geared architecture engine and that the present disclosure is applicable to other gas turbine engines including direct drive turbofans.

The fan section <NUM> of the engine <NUM> is designed for a particular flight condition--typically cruise at about <NUM> Mach and about <NUM>,<NUM> feet (<NUM>,<NUM> meters).

Referring now to <FIG>, with continued reference to <FIG>, the combustor section <NUM> of the gas turbine engine <NUM> is shown. The combustor <NUM> of <FIG> is an impingement film float wall combustor. It is understood that while an impingement film float wall combustor is utilized for exemplary illustration, the embodiments disclosed herein may be applicable to other types of combustors for gas turbine engines including but not limited to double pass liner combustors, float wall combustors, and combustors with single wall liners.

As illustrated, a combustor <NUM> defines a combustion chamber <NUM>. The combustion chamber <NUM> includes a combustion area <NUM> within the combustion chamber <NUM>. The combustor <NUM> includes an inlet <NUM> and an outlet <NUM> through which air may pass. The air may be supplied to the combustor <NUM> by a pre-diffuser <NUM>. Air may also enter the combustion chamber <NUM> through other holes in the combustor <NUM> including but not limited to quench holes <NUM>, as seen in <FIG>.

Compressor air is supplied from the compressor section <NUM> into a pre-diffuser <NUM>, which then directs the airflow toward the combustor <NUM>. The combustor <NUM> and the pre-diffuser <NUM> are separated by a dump region <NUM> from which the flow separates into an inner shroud <NUM> and an outer shroud <NUM>. As air enters the dump region <NUM>, a portion of the air may flow into the combustor inlet <NUM>, a portion may flow into the inner shroud <NUM>, and a portion may flow into the outer shroud <NUM>.

The air from the inner shroud <NUM> and the outer shroud <NUM> then enters the combustion chamber <NUM> by means of one or more impingement apertures <NUM> in the combustor shell <NUM> and one or more effusion apertures <NUM> in the heat shield panel <NUM>, as shown in <FIG> and <FIG>. The impingement apertures <NUM> and effusion apertures <NUM> may include nozzles, holes, etc. The air may then exit the combustion chamber <NUM> through the combustor outlet <NUM>. At the same time, fuel may be injected into the combustion chamber <NUM> through the primary and/or secondary orifices of a fuel injector <NUM> and a pilot nozzle <NUM>, which may be atomized and mixed with air, and then ignited and burned within the combustion chamber <NUM>. The diffuser case <NUM> defines the inner shroud <NUM> and the outer shroud <NUM>. The combustor <NUM> is housed within the diffuser case <NUM> between the inner shroud <NUM> and the outer shroud <NUM>.

The combustor <NUM>, as shown in <FIG>, includes multiple heat shield panels <NUM> that are attached to one or more combustor shells <NUM> (See <FIG>). The heat shield panels <NUM> may be arranged parallel to the combustor shell <NUM>. The combustor shell <NUM> includes a radially inward combustor shell 600a and a radially outward combustor shell 600b defined the combustion chamber <NUM> therebetween. The combustor shell <NUM> also includes a forward combustor shell 600c extending between the radially inward combustor shell 600a and the radially outward combustor shell 600b. The forward combustor shell 600c further bounds the combustion chamber <NUM> on a forward end 300a of the combustor <NUM>. The radially inward combustor shell 600a and the radially outward combustor shell 600b extend circumferentially around the longitudinal engine axis A. The radially inward combustor shell 600a is located radially inward from the radially outward combustor shell 600b.

The heat shield panels <NUM> can be removably mounted to the combustor shell <NUM> by one or more attachment mechanisms <NUM>. In some embodiments, the attachment mechanism <NUM> may be integrally formed with a respective heat shield panel <NUM>, although other configurations are possible. In some embodiments, the attachment mechanism <NUM> may be a threaded mounting stud or other structure that may extend from the respective heat shield panel <NUM> through the interior surface to a receiving portion or aperture of the combustor shell <NUM> such that the heat shield panel <NUM> may be attached to the combustor shell <NUM> and held in place. The heat shield panels <NUM> partially enclose a combustion area <NUM> within the combustion chamber <NUM> of the combustor <NUM>.

Referring now to <FIG>, with continued reference to <FIG> and <FIG>, a heat shield panel <NUM> and combustor shell <NUM> of the combustor <NUM> (see <FIG>) that may be used within the gas turbine engine <NUM> (see <FIG>). Combustors <NUM> of gas turbine engines <NUM>, as well as other components, experience elevated heat levels during operation. Impingement and convective cooling of heat shield panels <NUM> of the combustor <NUM> may be used to help cool the combustor <NUM>. Convective cooling may be achieved by air that is channeled between the heat shield panels <NUM> and a combustor shell <NUM> of the combustor <NUM>. Impingement cooling may be a process of directing relatively cool air from a location exterior to the combustor <NUM> toward a back or underside of the heat shield panels <NUM>.

Thus, heat shield panels <NUM> are utilized to face the hot products of combustion within a combustion chamber <NUM> and protect the combustor shell <NUM> of the combustor <NUM>. The heat shield panels <NUM> are supplied with cooling air through the impingement apertures <NUM> and other dilution passages which deliver a high volume of cooling air into a hot flow path. The cooling air may be air from the compressor of the gas turbine engine <NUM>. The cooling air impinges upon a back side (i.e., second surface <NUM>) of the heat shield panel <NUM> that faces the combustor shell <NUM> inside the combustor <NUM>. The cooling air may contain particulates, which may build up on the heat shield panels <NUM> overtime, thus reducing the cooling ability of the cooling air. Embodiments disclosed herein seek to address particulate adherence to the heat shield panels <NUM> in order to maintain the cooling ability of the cooling air.

The heat shield panel <NUM> and the combustor shell <NUM> are in a facing spaced relationship. The heat shield panel <NUM> includes a first surface <NUM> oriented towards the combustion area <NUM> of the combustion chamber <NUM> and a second surface <NUM> opposite the first surface <NUM> oriented towards the combustor shell <NUM>. The combustor shell <NUM> has an inner surface <NUM> and an outer surface <NUM> opposite the inner surface <NUM>. The inner surface <NUM> is oriented toward the heat shield panel <NUM>. The outer surface <NUM> is oriented outward from the combustor <NUM> proximate the inner shroud <NUM> and the outer shroud <NUM>.

The combustor shell <NUM> includes a plurality of impingement apertures <NUM> configured to allow airflow <NUM> from the inner shroud <NUM> and the outer shroud <NUM> to enter an impingement cavity <NUM> located between the combustor shell <NUM> and the heat shield panel <NUM>. Each of the impingement apertures <NUM> extend from the outer surface <NUM> to the inner surface <NUM> through the combustor shell <NUM>. Each of the impingement apertures <NUM> fluidly connects the impingement cavity <NUM> to at least one of the inner shroud <NUM> and the outer shroud <NUM>. Conventionally, these impingement apertures <NUM> have been circular in shape ( see.

The heat shield panel <NUM> includes one or more effusion apertures <NUM> configured to allow airflow <NUM> from the impingement cavity <NUM> to the combustion area <NUM> of the combustion chamber <NUM>. Each of the effusion apertures <NUM> extends from the second surface <NUM> to the first surface <NUM> through the heat shield panel <NUM>. Airflow <NUM> flowing into the impingement cavity <NUM> impinges on the second surface <NUM> of the heat shield panel <NUM> and absorbs heat from the heat shield panel <NUM>.

As seen in <FIG>, particulate <NUM> can accompany the airflow <NUM> flowing into the impingement cavity <NUM>. Particulate <NUM> may include but is not limited to dirt, smoke, soot, volcanic ash, or similar airborne particulate known to one of skill in the art. As the airflow <NUM> and particulate <NUM> impinge upon the second surface <NUM> of the heat shield panel <NUM>, the particulate <NUM> begins to collect on the second surface <NUM>, as seen in <FIG>. Particulate <NUM> collecting upon the second surface <NUM> of the heat shield panel <NUM> reduces the cooling efficiency of airflow <NUM> impinging upon the second surface <NUM> and thus may increase local temperatures of the heat shield panel <NUM> and the combustor shell <NUM>. Particulate <NUM> collection upon the second surface <NUM> of the heat shield panel <NUM> may potentially create a blockage <NUM> to the effusion apertures <NUM> in the heat shield panels <NUM>, thus reducing airflow <NUM> into the combustion area <NUM> of the combustion chamber <NUM>. The blockage <NUM> may be a partial blockage or a full blockage.

Embodiments disclosed herein seek to reduce the amount of particulate adhering the second surface <NUM> of the heat shield panel <NUM> by adjusting the shape of the impingement apertures <NUM> to disturb vorticities that are conventionally generated by impingement apertures <NUM> that are circular in shape, which helps better disperse particulate <NUM>.

Referring now to <FIG>, with continued reference to <FIG>, a heat shield panel <NUM> and a combustor shell <NUM> of the combustor <NUM>, are illustrated in accordance with an embodiment of the present disclosure. The combustor shell <NUM> of <FIG> comprises one or more impingement apertures <NUM> that have nonaxisymmetric shapes (i.e., not axisymmetric in shape). Axisymmetric may be defined as being symmetric about an axis and thus nonaxisymmetric may be defined as not symmetric about an axis or in other words not axisymmetric.

<FIG> illustrates an impingement aperture <NUM> that is axisymmetric in shape. The impingement aperture <NUM> of <FIG> is circular in shape and is axisymmetric about a longitudinal axis B of the impingement apertures <NUM>. <FIG> illustrates that the impingement aperture <NUM> is axisymmetric in shape because a single plane 307a may be rotated <NUM> degrees around the longitudinal axis B to form the axisymmetric shape. This differs from an impingement aperture <NUM> that is nonaxisymmetric in shape (as in <FIG> and <FIG>) because the nonaxisymmetric shape cannot be formed by a single plane 307a rotated <NUM> degrees around the longitudinal axis B.

The impingement aperture <NUM> of <FIG> is crescent-shaped and is nonaxisymmetric about a longitudinal axis B of the impingement aperture <NUM>. The impingement aperture <NUM> extends from the outer surface <NUM> to the inner surface <NUM> through the combustor shell <NUM>. In an embodiment, the nonaxisymmetric shape of the impingement aperture <NUM> extends from the outer surface <NUM> to the inner surface <NUM> through the combustor shell <NUM>.

An impingement aperture <NUM> that is nonaxisymmetric in shape may have two or more walls 307b that form the impingement aperture <NUM> by extending from the outer surface <NUM> to the inner surface <NUM> through the combustor shell <NUM> (see <FIG>). An impingement aperture <NUM> that is axisymmetric in shape typically only has one wall 307b that forms the impingement aperture <NUM> by extending from the outer surface <NUM> to the inner surface <NUM> through the combustor shell <NUM> (see <FIG>). An impingement aperture <NUM> that is nonaxisymmetric in shape may also have only one wall 307b that forms the impingement aperture <NUM> by extending from the outer surface <NUM> to the inner surface <NUM> through the combustor shell <NUM>. For example, an impingement aperture <NUM> that is nonaxisymmetric in shape and only has one wall 307b may be oval-shaped, as illustrated in <FIG>. In an embodiment, the impingement aperture <NUM> is oval-shaped.

While the impingement apertures <NUM> of <FIG> are crescent-shaped, it is understood that the impingement apertures <NUM> may have any other nonaxisymmetric shapes. Some other examples of nonaxisymmetric shapes are illustrated in <FIG>.

An impingement aperture <NUM> that is nonaxisymmetric in shape may be formed by combining various intersecting shapes (e.g., <FIG>, and <FIG>). In an embodiment, a shape of the impingement aperture <NUM> is composed of two or more intersecting shapes, as illustrated in <FIG> and <FIG>. The two or more intersecting shapes may be circles or any other shape. Additionally, a shape of the impingement aperture <NUM> may also be composed of two or more intersecting shape shapes that are different, such as, for example, a circle and a square. The two-or more shapes may be in aligned in an arc 307c. For example, the crescent-shape may be formed by three intersecting circles in an arc 307c, as illustrated in <FIG>. The impingement aperture <NUM> of <FIG> has a shape of two intersecting circles and is nonaxisymmetric about a longitudinal axis B of the impingement aperture <NUM>. It is understood that while the two intersecting circles are different sizes in <FIG>, the two intersecting circles may also be the same size.

Advantageously, manufacturing is eased when the nonaxisymetric shape is formed by intersecting circles. The nonaxisymetric shape may be formed by various manufacturing methods, including but not limited to laser drilling or a water jet.

The impingement aperture <NUM> of <FIG> in accordance with the invention is comma-shaped and is nonaxisymmetric about a longitudinal axis B of the impingement aperture <NUM>. The impingement aperture <NUM> is comma-shaped. The impingement aperture <NUM> of <FIG> is star-shaped and is nonaxisymmetric about a longitudinal axis B of the impingement aperture <NUM>. In an embodiment, the impingement aperture <NUM> is star-shaped. It is understood that while the star-shape of the impingement aperture <NUM> of <FIG> is a four-point star, the star-shape may have any number of points. The impingement aperture <NUM> of <FIG> is oval-shaped and is nonaxisymmetric about a longitudinal axis B of the impingement aperture <NUM>. In an embodiment, the impingement aperture <NUM> is oval-shaped.

The impingement aperture <NUM> of <FIG> is arc-shaped and is nonaxisymmetric about a longitudinal axis B of the impingement aperture <NUM>. In an embodiment, the impingement aperture <NUM> is arc-shaped. The arc shape of <FIG> is formed by three-intersecting shapes aligned in an arc 307c. In an embodiment, the arc shape of <FIG> is formed by three-intersecting circles aligned in an arc 307c.

Impingement apertures <NUM> that are axisymmetric in shape direct air in an impingement jet in the form of circular vortex rings towards the second surface <NUM> of the heat shield panel <NUM> for impingement cooling. These vortices concentrate particulate near the second surface <NUM> of the heat shield panel <NUM> and in particular near a stagnation region of the impingement jet where particulate can agglomerate due to small local velocities along surface. This may inadvertently lead to build up of particulate <NUM> on the second surface <NUM> of the heat shield panel <NUM>(see <FIG>). Advantageously, by utilizing impingement apertures <NUM> that are nonaxisymmetric in shape, the vortices that are formed break up rapidly and the cooling airflow <NUM> hits the second surface <NUM> of the heat shield panel <NUM> in a non-uniform or variable manner, thus particulate <NUM> is dispersed better on the second surface <NUM> of the heat shield panel <NUM> by dispersing in non-uniform or variable manner.

Technical effects of embodiments of the present disclosure include shaping impingement apertures of combustor lines in an nonaxisymmetric shape to eliminate consistent vortices from the impingement apertures and promote dispersion of particulate.

Claim 1:
A combustor (<NUM>) for use in a gas turbine engine (<NUM>), the combustor comprising:
a heat shield panel (<NUM>) having a first surface (<NUM>), a second surface (<NUM>) opposite the first surface (<NUM>), and a plurality of effusion apertures (<NUM>) extending from the second surface (<NUM>) to the first surface (<NUM>); and
a combustor shell (<NUM>) having an inner surface (<NUM>) and an outer surface (<NUM>) opposite the inner surface (<NUM>), the inner surface (<NUM>) of the combustor shell (<NUM>) and the second surface (<NUM>) of the heat shield panel (<NUM>) being in a facing spaced relationship defining an impingement cavity (<NUM>) therebetween, wherein the combustor shell (<NUM>) comprises a plurality of impingement apertures (<NUM>) that have a nonaxisymmetric shape, each of the impingement apertures (<NUM>) extending from the outer surface (<NUM>) to the inner surface (<NUM>) through the combustor shell (<NUM>), and each of the plurality of impingement apertures (<NUM>) are configured to disperse particulate (<NUM>) on the second surface (<NUM>) of the heat shield panel (<NUM>), characterised in that:
each of the plurality of impingement apertures (<NUM>) is comma-shaped,
wherein the comma shape is defined by one curved wall (307b) and one linear wall (307b), the linear wall (307b) extending from a first end of the curved wall (307b) to a second end of the curved wall (307b) and the curved wall (307b) and linear wall (307b) extend from the outer surface (<NUM>) to the inner surface (<NUM>) through the combustor shell (<NUM>).