WATER ACTIVE TURBINE CLEARANCE CONTROL
A turbine engine assembly includes an active clearance control system that is configured to utilize water that is extracted from the exhaust gas flow to control a clearance between a tip of a rotating blade and a case structure by controlling thermal growth of the case structure. Water extracted by the condenser is also provided to an evaporator system where thermal energy from the exhaust gas flow is utilized to transform water into a steam flow. A portion of water utilized in the active clearance control system is communicated to the evaporator system.
1 . A turbine engine assembly comprising:
a compressor section where an inlet airflow is compressed;
a combustor section where the compressed inlet airflow is mixed with fuel and ignited to generate an exhaust gas flow that is communicated through a core flow path;
a turbine section where expansion of the exhaust gas flow is utilized to generate a mechanical power output;
a condenser where water is extracted from the exhaust gas flow;
an active clearance control system configured to utilize water extracted from the exhaust gas flow to control a clearance between a tip of a rotating blade and a case structure by controlling thermal growth of the case structure; and
an evaporator system where thermal energy from the exhaust gas flow is utilized to transform water extracted from the exhaust gas flow into a steam flow, wherein a portion of water utilized in the active clearance control system is communicated to the evaporator system.
2 . The turbine engine assembly as recited in claim 1 , wherein the active clearance control system includes a cooling passage where a cooling water flow is in thermal communication with the case structure, the cooling passage includes an inlet and an outlet.
3 . The turbine engine assembly as recited in claim 2 , wherein the case structure includes an inner wall spaced radially apart from an outer wall and the cooling passage is at least partially defined within a radial space between the inner wall and the outer wall.
4 . The turbine engine assembly as recited in claim 2 , wherein the passage comprises at least one conduit in thermal contact with the case structure.
5 . The turbine engine assembly as recited in claim 4 , wherein the at least one conduit are disposed about an outer periphery of the case structure.
6 . The turbine engine assembly as recited in claim 2 , further including a control valve configured to proportionally control a flow rate of the cooling water flow to the inlet.
7 . The turbine engine assembly as recited in claim 6 , further including a controller programmed to operate the control valve to adjust the flow rate of the cooling water flow based on at least one of a measured engine temperature or a current engine operating condition.
8 . The turbine engine assembly as recited in claim 1 , wherein the compressor includes a plurality of rotatable compressor blades and the case structure comprises a compressor case.
9 . The turbine engine assembly as recited in claim 1 , wherein the turbine section includes a plurality of rotatable turbine blades and the case structure comprises a turbine case.
10 . The turbine engine assembly as recited in claim 2 , wherein the case structure includes a rib member disposed on a radially outer surface corresponding to a position of a rotating blade and the cooling passage is configured to place a cooling water flow in the thermal communication with the rib member.
11 . The turbine engine assembly as recited in claim 1 , further including a fuel system configured to provide a non-carbon-based fuel to the combustor section.
12 . The turbine engine assembly as recited in claim 1 , further including an intercooling system where a flow of water is utilized for cooling a portion of the compressed inlet flow.
13 . An aircraft propulsion system comprising:
a core engine configured to generate an exhaust gas flow, the core engine including a compressor section, combustor section and a turbine section, wherein the turbine section includes a turbine case structure and a rotatable turbine blade;
a condenser where water is extracted from the exhaust gas flow;
an active clearance control system configured to utilize water extracted from the exhaust gas flow to control a clearance between a tip of the rotatable turbine blade and the turbine case structure by controlling thermal growth of the turbine case structure, wherein the active clearance control system includes a cooling passage where a cooling water flow is placed in thermal communication with the turbine case structure; and
an evaporator system where thermal energy from the exhaust gas flow is utilized to transform water extracted from the exhaust gas flow into a steam flow, wherein a portion of water utilized in the active clearance control system is communicated to the evaporator system.
14 . The aircraft propulsion system as recited in claim 13 , wherein the turbine case structure includes an inner wall spaced radially apart from an outer wall and the cooling passage is at least partially defined within a radial space between the inner wall and the outer wall.
15 . The aircraft propulsion system as recited in claim 13 , wherein the passage comprises at least one conduit disposed about an outer periphery of the turbine case structure.
16 . The aircraft propulsion system as recited in claim 13 , further including a control valve configured to proportionally control a flow rate of the cooling water flow through the cooling passage.
17 . The aircraft propulsion system as recited in claim 16 , further including a controller programmed to operate the control valve to adjust the flow rate of the cooling water flow based on at least one of a measured engine temperature or a current engine operating condition.
18 . A method of operating a gas turbine engine, the method comprising:
generating an exhaust gas flow that is communicated through a core flow path;
expanding the gas flow through a turbine section to generate a mechanical power output;
extracting water from the exhaust gas flow in a condenser;
controlling a clearance between a rotating blade and a fixed case structure by controlling thermal growth of the fixed case structure by selectively providing a water flow in thermal communication with an outer surface of the fixed case structure;
communicating the water flow from the fixed case structure to an evaporator system; and
transforming the water flow to a steam flow with heat from the exhaust gas flow in the evaporator system.
19 . The method as recited in claim 18 , further including monitoring a temperature of the fixed case structure and controlling the water flow in thermal communication with the fixed case structure to maintain a predefined clearance between the rotating blade and an inner surface of the fixed case structure.
20 . The method as recited in claim 19 , proportionally controlling the water flow with a control valve based on at least one of sensed temperature of the fixed case structure and a current engine operating parameter.