PRESSURE REGULATED PISTON SEAL FOR A GAS TURBINE COMBUSTOR LINER

1 . A seal assembly to seal a gas turbine hot gas path flow at an interface of a combustor liner and a downstream component in a gas turbine, the seal assembly comprising:

a piston ring seal housing having defined therein a cavity; and

a piston ring disposed within the cavity of the piston ring seal housing and circumferentially about the combustor liner, the piston ring responsive to a regulated pressure to secure sealing engagement of the piston ring and an outer surface of the combustor liner, the piston ring including at least one arcuate seal ring segment.

2 . A seal assembly as claimed in claim 1 , wherein the downstream component is a stage one turbine nozzle.

3 . A seal assembly as claimed in claim 1 , wherein one of the piston ring seal housing or the piston ring is rotated relative to the other of the piston ring seal housing or the piston ring.

4 . A seal assembly as claimed in claim 1 , wherein the piston ring seal housing includes one or more sectional through-slots in a wall of the piston ring seal housing to provide for a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component.

5 . A seal assembly as claimed in claim 4 , wherein the piston ring seal housing includes one or more sectional through-slots in a front wall of the piston ring seal housing to provide for the flow therethrough of an inner flow of the high-pressure (P high ) bypass airflow.

6 . A seal assembly as claimed in claim 4 , wherein the piston ring seal housing includes one or more sectional through-slots in at least one of an aft wall and a radially outermost wall of the piston ring seal housing to provide for a flow therethrough of an outer flow of the high-pressure (P high ) bypass airflow.

7 . A seal assembly as claimed in claim 1 , wherein the piston ring includes one or more bumps extending from an upstream surface to provide for a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component.

8 . A seal assembly as claimed in claim 1 , wherein the piston ring seal housing includes one or more bumps extending from a front wall to provide for a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component.

9 . A seal assembly as claimed in claim 1 , wherein the piston ring includes one or more channels extending into an upstream surface to define a conduit for a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component.

10 . A seal assembly as claimed in claim 1 , wherein the piston ring housing includes one or more channels extending into a front wall to define a conduit for a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component.

11 . A seal assembly as claimed in claim 1 , wherein the piston ring further includes a cockle spring disposed circumferentially thereabout and exerting a radially inward force on the piston ring.

12 . A gas turbine comprising:

a combustor liner;

a stage one nozzle disposed downstream of the combustor liner;

a piston seal assembly defined at an interface of the combustor liner and the stage one nozzle to seal a gas turbine hot gas path flow, the piston seal assembly comprising:

a piston ring seal housing having defined therein a cavity; and

a piston ring disposed within the cavity of the piston ring seal housing and circumferentially about the combustor liner, the piston ring responsive to a regulated pressure to secure sealing engagement of the piston ring and an outer surface of the combustor liner, the piston ring including at least one arcuate seal ring segment.

13 . A gas turbine as claimed in claim 12 , wherein one of the piston ring seal housing or the piston ring is rotated relative to the other of the piston ring seal housing or the piston ring during a takeoff condition.

14 . A gas turbine as claimed in claim 12 , wherein the piston ring seal housing includes one or more sectional through-slots in a front wall to provide for a flow therethrough of high-pressure (P high ) bypass airflow exiting an upstream component to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring.

15 . A gas turbine as claimed in claim 12 , wherein the piston ring includes one or more bumps extending from an upstream surface to channel a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring.

16 . A seal assembly as claimed in claim 12 , wherein the piston ring seal housing includes one or more bumps extending from front wall to channel a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring.

17 . A seal assembly as claimed in claim 12 , wherein the piston ring includes one or more channels extending into an upstream surface to channel a flow therethrough of a high-pressure (P high ) bypass airflow exiting an upstream component to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring.

18 . A seal assembly as claimed in claim 12 , wherein the piston ring housing includes one or more channels extending into a front wall to channel a flow therethrough of a high-pressure (P high ) flow exiting an upstream component to the cavity and wherein the high-pressure (P high ) flow exerts a radial force on the piston ring.

19 . A gas turbine system, the system comprising:

a compressor section;

a combustor section coupled to the compressor section, the combustor section comprising an annular combustor liner defining an annular combustion chamber coaxial with a longitudinal axis;

a turbine section coupled to the combustor section, the turbine section comprising a stage one turbine nozzle positioned at the downstream end of the annular combustor liner;

a piston seal assembly defined at an interface of the annular combustor liner and the stage one nozzle to seal a gas turbine hot gas path flow, the piston seal assembly comprising:

a piston ring seal housing having defined therein a cavity; and

a piston ring disposed within the cavity of the piston ring seal housing and circumferentially about the combustor liner, the piston ring responsive to a regulated pressure to secure sealing engagement of the piston ring and an outer surface of the combustor liner, the piston ring including at least one arcuate seal ring segment.

20 . A gas turbine system as claimed in claim 19 , wherein one of the piston ring seal housing or the piston ring is rotated relative to the other of the piston ring seal housing or the piston ring during a takeoff condition.

21 . A gas turbine system as claimed in claim 19 , wherein the seal assembly includes at least one of:

one or more sectional through-slots in at least one of a front wall, an aft wall and a radially outermost wall of the piston ring seal housing to provide for a flow therethrough of high-pressure (P high ) bypass airflow exiting the compressor section to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring;

one or more bumps extending from at least one of an upstream surface of the piston ring and a front wall of the piston ring seal housing to channel a flow therethrough of the high-pressure (P high ) bypass airflow exiting the compressor section to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring; and

one or more channels extending into at least one of an upstream surface of the piston ring and a front wall of the piston ring seal housing to channel a flow therethrough of the high-pressure (P high ) bypass airflow exiting the compressor section to the cavity and wherein the high-pressure (P high ) bypass airflow exerts a radial force on the piston ring.