Dilution holes with ridge feature for gas turbine engines
A grommet may define a dilution hole in a combustor panel. The grommet may comprise a ridge having a stepped geometry formed about an inner diameter of the grommet, the ridge comprising a passage. The passage may comprise an outlet. The ridge may further comprise a fillet about the inner diameter of the grommet, wherein the outlet is configured to direct a cooling flow circumferentially along the fillet and fill the ridge with the cooling flow.
1 . A grommet having an annular geometry inserted into a dilution hole of a combustor liner, the annular geometry comprising an inner diameter and an outer diameter of the grommet, the grommet being coupled to the combustor liner, wherein the inner diameter of the grommet defines an inner diameter of the dilution hole, the grommet comprising:
a ridge having a step geometry comprising at least one of a sharp geometry, a radial geometry, or a multi-radial geometry, the ridge formed about the inner diameter of the grommet and comprising a plurality of passages, wherein:
a step is defined by the step geometry and a ridge face geometry,
the ridge face geometry comprises the at least one of the sharp geometry, the radial geometry, or the multi-radial geometry,
each of the plurality of passages begins at an inlet disposed on a cold side of the ridge and ends at an outlet on a hot side of the ridge,
the outlet opens through a fillet of the ridge,
each of the plurality of passages is spaced apart circumferentially from an adjacent passage of the plurality of passages,
the plurality of passages are configured to direct cooling flow around the ridge to at least partially fill the ridge with cool air, wherein the fillet is disposed about the inner diameter of the grommet, wherein the outlet is configured to direct the cooling flow radially inward of the fillet and the ridge toward the dilution hole, and
a first of the plurality of passages includes an arc length that is greater than that of a second of the plurality of passages.
2 . The grommet of claim 1 , wherein the inlet of each of the plurality of passages opens through a bell-mouth.
3 . The grommet of claim 2 , wherein each of the plurality of passages is cut across or opens through the fillet.
4 . The grommet of claim 1 , wherein the first of the plurality of passages is disposed circumferentially adjacent to a first set of the plurality of passages on a first side and a second set of the plurality of passages on the second side, each of the first set of the plurality of passages and the second set of the plurality of passages having an arc length that is less than that of the first of the plurality of passages.
5 . The grommet of claim 1 , wherein a cross-sectional area of the inlet of each of the plurality of passages is greater than a cross-sectional area of the outlet of the respective passage of the plurality of passages.
6 . The grommet of claim 1 , wherein a first of the plurality of passages is spaced apart from a second of the plurality of passages on a first side by a first arc length and the first of the plurality of passages is spaced apart from a third of the plurality of passages on a second side by a second arc length, and wherein the second arc length is greater than the first arc length.
7 . The grommet of claim 1 , wherein the inner diameter of the annular geometry is between ⅛ inch (3 mm) and 1 inch (25 mm), the outer diameter is between ¼ inch (6 mm) to 1.5 inches (38 mm).
8 . The grommet of claim 7 , wherein the annular geometry comprises a thickness between 100 thousandths of an inch (2.5 mm) and 500 thousandths of an inch (1 cm).
9 . A combustor liner comprising:
an array of cooling holes defined by the combustor liner; and
a grommet having an annular geometry comprising an inner diameter and an outer diameter of the grommet, the grommet formed integrally with the combustor liner and defining a dilution hole, wherein the inner diameter of the grommet defines an inner diameter of the dilution hole, wherein the grommet comprises:
a ridge having a step geometry comprising at least one of a sharp geometry, a radial geometry, or a multi-radial geometry, the ridge formed about an inner diameter of the grommet and comprising a plurality of passages, wherein:
the ridge projects radially inward from an inner diameter wall of the grommet and defines a step,
the step is defined by the step geometry and a ridge face geometry,
the ridge face geometry comprises the at least one of the sharp geometry, the radial geometry, or the multi-radial geometry,
each of the plurality of passages begins at an inlet disposed on a cold side of the ridge and ends at an outlet on a hot side of the ridge,
the outlet opens through a fillet of the ridge, each of the plurality of passages is spaced apart circumferentially from an adjacent passage of the plurality of passages,
the plurality of passages are configured to direct cooling flow around the ridge to at least partially fill the ridge with cool air,
a first of the plurality of passages includes an arc length that is greater than that of a second of the plurality of passages,
the fillet is disposed about the inner diameter of the grommet, and
the outlet is configured to direct the cooling flow radially inward of the fillet and the ridge toward the dilution hole.
10 . The combustor liner of claim 9 , wherein the inlet of each of the plurality of passages opens through a bell-mouth.
11 . The combustor liner of claim 10 , wherein each of the plurality of passages is cut across or opens through the fillet.
12 . The combustor liner of claim 9 , wherein the first of the plurality of passages is disposed circumferentially adjacent to a first set of the plurality of passages on a first side and a second set of the plurality of passages on the second side, each of the first set of the plurality of passages and the second set of the plurality of passages having an arc length thatis less than that of the first of the plurality of passages.
13 . The combustor liner of claim 9 , wherein a cross-sectional area of the inlet of each of the plurality of passages is greater than a cross-sectional area of the outlet of the respective passage of the plurality of passages.
14 . The combustor liner of claim 9 , wherein a first of the plurality of passages is spaced apart from a second of the plurality of passages on a first side by a first arc length and the first of the plurality of passages is spaced apart from a third of the plurality of passages on a second side by a second arc length, and wherein the second arc length is greater than the first arc length.
15 . A gas turbine engine comprising:
a compressor section configured to compress a gas;
a combustor section aft of the compressor section and configured to combust the gas, wherein the combustor section comprises a combustor liner having a grommet formed integrally with the combustor liner, having one of an annular geometry or an elliptical geometry and defining a dilution hole, the annular geometry or the elliptical geometry comprising an inner diameter and an outer diameter of the grommet, wherein the inner diameter of the grommet defines an inner diameter of the dilution hole; and
a turbine section aft of the combustor section and configured to extract energy from the gas, wherein the grommet comprises:
a ridge having a step geometry comprising at least one of a sharp geometry, a radial geometry, or a multi-radial geometry, the ridge formed about the inner diameter of the grommet and comprising a plurality of passages, wherein:
the ridge projects radially inward from an inner diameter wall of the grommet and defines a step,
the step is defined by the step geometry and a ridge face geometry,
the ridge face geometry comprises the at least one of the sharp geometry, the radial geometry, or the multi-radial geometry,
each of the plurality of passages begins at an inlet disposed on a cold side of the ridge and ends at an outlet on a hot side of the ridge,
the outlet opens through a fillet of the ridge,
each of the plurality of passages is spaced apart circumferentially from an adjacent passage of the plurality of passages,
a first of the plurality of passages includes an arc length that is greater than that of a second of the plurality of passages,
the plurality of passages are configured to direct cooling flow around the ridge to at least partially fill the ridge with cool air,
the fillet is disposed about the inner diameter of the grommet, and
the outlet is configured to direct the cooling flow radially inward of the fillet and the ridge toward the dilution hole.
16 . The gas turbine engine of claim 15 , wherein the inlet of each of the plurality of passages opens through a bell-mouth.
17 . The gas turbine engine of claim 16 , wherein each of the plurality of passages is cut across or opens through the fillet.