# US 7,412,320 B2 · Detection of gas turbine airfoil failure > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,412,320 B2 - Document ID: US7412320B2 - Status: Granted - Kind: B2 - Application number: 11/135,114 - Filed: 2005-05-23 - Published: 2006-11-23 - Granted: 2008-08-12 - Earliest claimed: 2005-05-23 - Assignees: Siemens Power Generation, Inc. - Inventors: Hans-Gerd Johann Brummel - Web page: https://patentgrep.com/patent/US7412320B2 ## CPC - F01D 21/12: responsive to temperature - F01D 5/189: {the insert having a tubular cross-section, e.g. airfoil shape} - F01D 21/003: {Arrangements for testing or measuring (for measuring vibrations G01H)} - F01D 21/14: responsive to other specific conditions - F05D 2260/201: by impingement of a fluid - F05D 2270/301: Pressure - F05D 2270/3015: differential pressure - F05D 2270/303: Temperature - F05D 2270/3032: excessive temperatures, e.g. caused by overheating - F05D 2300/611: Coating - F01D: NON-POSITIVE DISPLACEMENT MACHINES OR ENGINES, e.g. STEAM TURBINES (machines or engines for liquids F03; non-positive displacement pumps F04D) - F05D: INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS ## Abstract A system and method for early detection of a failure of a gas turbine engine airfoil (10), such as but not restricted to a burn through of the airfoil outer skin (12). A sensor (52) provides a signal (54) responsive to a condition of fluid flowing through an outer cooling chamber (24) of the airfoil. A detected change in the condition of the fluid is correlated to a failure of the airfoil, which for example can be detected by measuring the static fluid pressure. An increase in the static pressure of fluid in the outer cooling chamber may indicate a breach in the region of the leading edge of the airfoil. A decrease in the static pressure of fluid in the outer cooling chamber may indicate a breach along other portions of the profile of the airfoil outer skin. Both pressure and temperature parameters of the fluid may be measured and coincident changes thereof correlated to a condition of failure of the airfoil. ## Claims ### Claim 1 A method of detecting a failure of an airfoil of a gas turbine engine, the airfoil comprising an outer skin having an outer surface defining an airfoil shape and an inner surface, an impingement structure spaced from the inner surface to define an outer cooling chamber between the inner surface and the impingement structure and an inner cooling chamber, and impingement holes in the impingement structure for directing a cooling fluid from the inner cooling chamber into the outer cooling chamber and against the outer skin inner surface, the method comprising: measuring a parameter responsive to a condition of a fluid flowing through the outer cooling chamber without measuring any parameter of cooling fluid in the inner cooling chamber; and correlating a change in the measured parameter to a failure of the outer skin. ### Claim 2 (depends on 1) The method of claim 1, further comprising measuring the parameter as a static fluid pressure within the outer cooling chamber. ### Claim 3 (depends on 1) The method of claim 1, further comprising: measuring the parameter as a fluid pressure within the outer cooling chamber; correlating an increase in the fluid pressure to a failure of the outer skin along a leading edge of the airfoil. ### Claim 4 (depends on 1) The method of claim 1, further comprising: measuring the parameter as a fluid pressure within the outer cooling chamber; correlating a decrease in the fluid pressure to a failure of the outer skin. ### Claim 5 (depends on 1) The method of claim 1, wherein the step of measuring a parameter comprises: measuring a fluid pressure within the outer cooling chamber; and measuring a fluid temperature within the outer cooling chamber. ### Claim 6 (depends on 5) The method of claim 5, further comprising correlating a coincident decrease in the fluid pressure and increase in the fluid temperature to a failure of the outer skin proximate a leading edge of the airfoil. ### Claim 7 (depends on 1) The method of claim 1, further comprising measuring the parameter responsive to flow through the outer cooling chamber as a fluid velocity within the outer cooling chamber. ### Claim 8 (depends on 7) The method of claim 7, further comprising measuring fluid velocity within the outer cooling chamber by disposing a hot wire anemometer in the outer cooling chamber. ### Claim 9 (depends on 1) The method of claim 1, further comprising measuring the parameter responsive to flow through the outer cooling chamber as a difference between a static fluid pressure in the outer cooling chamber and a static fluid pressure at a second location within the gas turbine engine. ### Claim 10 (depends on 1) The method of claim 1, further comprising measuring the parameter responsive to flow through the outer cooling chamber as a difference between a static fluid pressure in the outer cooling chamber and a static fluid pressure within an outer cooling chamber of a second airfoil within the gas turbine engine. ### Claim 11 (depends on 1) The method of claim 1, further comprising measuring the parameter responsive to flow through the outer cooling chamber as a difference between a static fluid pressure in the outer cooling chamber and an average static fluid pressure within an outer cooling chamber of a plurality of other airfoils within the gas turbine engine. ### Claim 12 (depends on 1) The method of claim 1, further comprising measuring the parameter responsive to flow through the outer cooling chamber as a difference between a static fluid pressure in the outer cooling chamber and a static fluid pressure within a combustor shell of the gas turbine engine. ### Claim 13 An apparatus for detecting a failure of an airfoil of a gas turbine engine, the airfoil comprising an outer skin having an outer surface defining an airfoil shape and an inner surface, an impingement structure spaced from the inner surface to define an outer cooling chamber between the inner surface and the impingement structure and an inner cooling chamber, and impingement holes in the impingement structure for directing a cooling fluid front the inner cooling chamber into the outer cooling chamber and against the outer skin inner surface, the apparatus comprising: a sensor providing a signal responsive to at least one of a temperature and a rate of flow of a fluid flowing through the outer cooling chamber of the airfoil; a storage device staring a computer code for correlating changes in the signal to a condition of failure of the airfoil; a central processing unit operative with the computer code to correlate a change in the signal with the condition of failure of the airfoil; and an output device providing an indication of the condition of failure. ### Claim 14 (depends on 13) The apparatus of claim 13, further comprising: a first sensor providing a first signal responsive to a pressure of the fluid flowing through the outer cooling chamber of the airfoil; a second sensor providing a second signal responsive to a temperature of the fluid flowing through the outer cooling chamber of the airfoil; and the central processing unit operative with the computer code to correlate a change in the first signal coincident with a change in the second signal with the condition of failure. ### Claim 15 (depends on 13) The apparatus of claim 13, further comprising no sensor detecting a condition of a fluid flowing through the inner cooling chamber of the airfoil. ### Claim 16 A vane monitoring system for a gas turbine engine comprising: a plurality of stationary vanes, each vane comprising an inner cooling chamber and an outer cooling chamber, the outer cooling chamber comprising an outer skin of the vane, the vane monitoring system comprising; a plurality of sensors providing a respective plurality of signals responsive to a respective condition of fluid flowing through the respective outer cooling chamber of a plurality of the vanes; a controller responsive to the plurality of signals to detect a change in the condition of the fluid flowing through the outer cooling chamber of one of the vanes compared to a corresponding condition of the fluid flowing through the outer cooling chamber of another of the vanes resulting from a breach of the outer skin of the one of the vanes; and an alarm signal output by the controller in response to the change in condition exceeding a predetermined value. ### Claim 17 (depends on 16) The vane monitoring system of claim 16, further comprising; the sensors each comprising a pressure transducer measuring fluid pressure in the respective outer cooling chambers; and the controller responsive to a change in a difference between a measured pressure in one of the outer chambers compared to a measured pressure in another of the outer chambers. ### Claim 18 (depends on 16) The vane monitoring system of claim 16, further comprising: the sensors each comprising a pressure transducer measuring fluid pressure in the respective outer cooling chambers; and the controller responsive to a change in a difference between a measured pressure in one of the outer chambers compared to an average of measured pressures in a plurality of others of the outer chambers.