Dilution holes with ridge feature for gas turbine engines

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:

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 passage in the plurality of passages spirals through a solid portion of the ridge axially and circumferentially about the dilution hole,

each passage in 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 passage in the plurality of passages is spaced apart circumferentially an adjacent passage in the plurality of passages, and

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.

2. The grommet of claim 1 , wherein the grommet further comprises a bell-mouth comprising a second fillet, wherein the inlet opens through one of the bell-mouth or the second fillet.

3. 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).

4. The grommet of claim 3 , wherein the annular geometry comprises a thickness between 100 thousandths of an inch (2.5 mm) and 500 thousandths of an inch (1 cm).

5. 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 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 passage in the plurality of passages spirals through a solid portion of the ridge axially and circumferentially about the dilution hole,

each passage in 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 passage in the plurality of passages is spaced apart circumferentially an adjacent passage in 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.

6. The combustor liner of claim 5 , wherein:

the inner diameter of the annular geometry is between ⅛ inch (3 mm) and 1 inch (25 mm), and

the outer diameter of the annular geometry is between ¼ inch (6 mm) to 1.5 inches (38 mm).

7. 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 passage in the plurality of passages spirals through a solid portion of the ridge axially and circumferentially about the dilution hole,

each passage in 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 passage in the plurality of passages is spaced apart circumferentially an adjacent passage in 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.

8. The gas turbine engine of claim 7 , wherein:

the inner diameter of the annular geometry or the elliptical geometry is between ⅛ inch (3 mm) and 1 inch (25 mm), and

the outer diameter of the annular geometry or the elliptical geometry is between ¼ inch (6 mm) to 1.5 inches (38 mm).