Composite piston ring seal for axially and circumferentially translating ducts
A seal system is provided. The seal system may comprise a first duct having an annular geometry, a second duct overlapping the first duct in a radial direction, and a seal disposed between the first duct and the second duct. The seal may comprise a groove defined by the first duct and a piston configured to slideably engage the groove.
1. A seal system for a gas turbine engine, comprising:
a first duct having an annular geometry and including a first surface exposed to a bypass airflow, wherein the first surface is oriented radially inward;
a second duct coaxial to the first duct and disposed radially outward of the first duct, the second duct including a second surface oriented radially inward and exposed to the bypass airflow, wherein a forward portion of the second surface overlaps an aft portion of the first duct in a radial direction;
a seal disposed between the aft portion of the first duct and the forward portion of the second surface, the seal comprising:
a groove defined by the second duct;
a piston configured to slideably engage the groove; and
a spring disposed in the groove, the spring being located between the piston and a floor of the groove.
2. The seal system of claim 1 , wherein the piston comprises a fibrous material.
3. The seal system of claim 2 , wherein the piston comprises a glass fiber-reinforced polymer (GFRP) or an aramid fiber-reinforced polymer (AFRP).
4. The seal system of claim 1 , further comprising a bumper bonded to the second duct.
5. The seal system of claim 4 , wherein the bumper comprises at least one of a glass fiber-reinforced polymer (GFRP) or an aramid fiber-reinforced polymer (AFRP).
6. The seal system of claim 5 , wherein the bumper comprises the annular geometry.
7. The seal system of claim 5 , wherein the bumper is disposed in a recess in the second duct.
8. The seal system of claim 1 , wherein the piston comprises an elliptical shape.
9. A gas turbine engine, comprising:
a compressor;
a combustor disposed aft of the compressor and in fluid communication with the compressor;
a turbine aft of the combustor and in fluid communication with the combustor;
an inner duct radially outward from the turbine, the inner duct including a first surface exposed to a bypass airflow;
an outer duct radially outward from the inner duct, the outer duct including a second surface exposed to the bypass airflow, wherein a forward portion of the outer duct overlaps an aft portion of the inner duct;
a groove formed aft of the turbine and in the forward portion of the outer duct; and
a piston configured to slideably engage the groove.
10. The gas turbine engine of claim 9 , wherein the piston comprises a fibrous material.
11. The gas turbine engine of claim 10 , wherein the piston comprises at least one of a glass fiber-reinforced polymer (GFRP) or an aramid fiber-reinforced polymer (AFRP).
12. The gas turbine engine of claim 9 , further comprising a bumper bonded to at least one of the outer duct or the inner duct.
13. The gas turbine engine of claim 12 , wherein the bumper comprises at least one of a glass fiber-reinforced polymer (GFRP) or an aramid fiber-reinforced polymer (AFRP).
14. The gas turbine engine of claim 13 , wherein the bumper comprises an annular geometry.
15. The gas turbine engine of claim 14 , wherein the bumper is disposed in a recess in the at least one of the outer duct or the inner duct.
16. The gas turbine engine of claim 14 , wherein the bumper is configured to prevent the piston from contacting a radial surface of the groove.
17. The gas turbine engine of claim 9 , wherein the piston comprises an elliptical shape.
18. The gas turbine engine of claim 9 , further comprising a spring disposed in the groove.
19. The gas turbine engine of claim 10 , wherein the piston is configured to contact a radial surface of the groove prior to the inner duct contacting the outer duct.