Turbine blade tip clearance system

A method for adjusting a clearance between blade tips of turbine and a shroud assembly spaced radially outward of the blade tips and comprising the steps of:

• heating a shroud assembly of a turbine engine with a first stream of fluid directed along a first fluid passageway from an outlet of a compressor section of the turbine engine, the first fluid passageway extending to the shroud assembly;
• closing the first fluid passageway to stop said heating step with a first valve positioned along the first fluid passageway, wherein said closing step occurs passively and directly in response to a first predetermined level of pressure of the first stream of fluid;
• wherein the first fluid passageway extends to and is in fluid communication with an interior region of the shroud assembly to direct the first stream of fluid into the interior region, the first fluid stream flows through the interior region of the shroud assembly to thermally expand and contract the shroud assembly to adjust the clearance between the blade tips and the shroud assembly;
• and
• wherein said closing step is further defined as occurring when power production of the turbine engine increases from a period of relatively low power production.

A method for adjusting a clearance between blade tips of turbine and a shroud assembly spaced radially outward of the blade tips and comprising the steps of:

• heating a shroud assembly of a turbine engine with a first stream of fluid directed along a first fluid passageway from an outlet of a compressor section of the turbine engine, the first fluid passageway extending to the shroud assembly;
• closing the first fluid passageway to stop said heating step with a first valve positioned along the first fluid passageway, wherein said closing step occurs passively and directly in response to a first predetermined level of pressure of the first stream of fluid;
• wherein the first fluid passageway extends to and is in fluid communication with an interior region of the shroud assembly to direct the first stream of fluid into the interior region, the first fluid stream flows through the interior region of the shroud assembly to thermally expand and contract the shroud assembly to adjust the clearance between the blade tips and the shroud assembly;
• opening a second fluid passageway to direct a second stream of fluid to the shroud assembly from an inter-stage portion of the compressor section to cool the shroud assembly;
• and
• wherein said opening step is further defined as occurring only when power production of the turbine engine increases from relatively low power production.

A turbine engine comprising:

• a multi-stage compressor section;
• a turbine section having a plurality of turbine blades spaced from said multi-stage compressor section along a centerline axis;
• a shroud assembly supporting a plurality of blade tracks in radially spaced relation to said turbine blades and defining an annular chamber encircling an axis;
• a first fluid passageway in fluid communication with an outlet of said multi-stage compressor section and extending to said annular chamber of said shroud assembly to direct a first stream of fluid to said shroud assembly;
• a first valve positioned along said first fluid passageway and moveable between open and closed configurations, said first valve being biased to said open configuration and moved to said closed configuration passively and directly by a first predetermined level of pressure of the first stream of fluid;
• a second fluid passageway in fluid communication with an inter-stage portion of said multi-stage compressor section and extending to said annular chamber to direct a second stream of fluid to said annular chamber;
• a second valve positioned along said second fluid passageway and moveable between open and closed configurations, said second valve moved to said open configuration passively and directly by a second predetermined level of pressure of the second stream of fluid;
• wherein said first fluid passageway extends to and is in fluid communication with said annular chamber of said shroud assembly to direct said first stream of fluid into said annular chamber, said first fluid stream flows through said annular chamber of said shroud assembly to thermally expand and contract said shroud assembly to adjust the clearance between the blade tips and the blade tracks;
• and
• wherein said first and second valves are positioned in circumferentially-spaced relation to one another about said centerline axis.

A turbine engine comprising:

• a multi-stage compressor section;
• a turbine section having a plurality of turbine blades spaced from said multi-stage compressor section along a centerline axis;
• a shroud assembly supporting a plurality of blade tracks in radially spaced relation to said turbine blades and defining an annular chamber encircling an axis;
• a first fluid passageway in fluid communication with an outlet of said multi-stage compressor section and extending to said annular chamber of said shroud assembly to direct a first stream of fluid to said shroud assembly;
• a first valve positioned along said first fluid passageway and moveable between open and closed configurations, said first valve being biased to said open configuration and moved to said closed configuration passively and directly by a first predetermined level of pressure of the first stream of fluid;
• a second fluid passageway in fluid communication with an inter-stage portion of said multi-stage compressor section and extending to said annular chamber to direct a second stream of fluid to said annular chamber;
• a second valve positioned along said second fluid passageway and moveable between open and closed configurations, said second valve moved to said open configuration passively and directly by a second predetermined level of pressure of the second stream of fluid;
• a supplemental cooling system communicating with said second fluid passageway to cool the second fluid stream by directing additional fluid to the second fluid stream;
• and
• wherein said first fluid passageway extends to and is in fluid communication with said annular chamber of said shroud assembly to direct said first stream of fluid into said annular chamber, said first fluid stream flows through said annular chamber of said shroud assembly to thermally expand and contract said shroud assembly to adjust the clearance between the blade tips and the blade tracks.