Tip clearance radio frequency sensor
AssigneeROLLS-ROYCE plc
InventorsGlen Steven Bishop, Wayne Thomas Padgett, Sr., John Joseph Costello, Geoffrey L. Gatton
Life of this patent
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Abstract
A blade tip sensor may be provided that includes a bridge-network circuit embedded in a composite body such as a ceramic matrix composite body. The bridge-network circuit may include a first resistor-capacitor circuit on a first branch and a second resistor-capacitor circuit on a second branch. Each of the first resistor-capacitor circuit and the second resistor-capacitor circuit includes a corresponding capacitor having a capacitance that depends on a distance between the corresponding capacitor and a blade of a rotor.
Claims16
A tip clearance sensor comprising:
- a ceramic matrix composite body comprising a plurality of ceramic fibers arranged in a plurality of layers and a matrix material in which the ceramic fibers are embedded;
- a bridge-network circuit embedded in the ceramic matrix composite body, the bridge-network circuit comprising a first resistor-capacitor circuit on a first branch and a second resistor-capacitor circuit on a second branch, the first resistor-capacitor circuit and the second resistor-capacitor circuit connected in parallel, wherein each of the first and second resistor-capacitor circuits includes a respective capacitor and a respective resistor connected in series, wherein a portion of the ceramic matrix composite body in which at least one of the ceramic fibers is embedded forms a dielectric of the respective capacitor, and wherein the respective capacitor of each of the first and second resistor-capacitor circuits has a capacitance that depends on a distance between the respective capacitor and a blade of a rotor of gas turbine engine configured to pass by the ceramic matrix composite body;
- and
- a processor configured to determine a blade tip clearance from the capacitance of the capacitors in the first and second resistor-capacitor circuits, which is derivable from a measurement signal received from the bridge-network circuit.
A method to form a blade tip sensor, the method comprising:
- arranging a plurality of ceramic fibers in a plurality of layers to form a porous ceramic preform;
- and
- forming the porous ceramic preform into a ceramic matrix composite body by melt and/or vapor infiltration, wherein a bridge-network circuit is embedded in the ceramic matrix composite body, the bridge-network circuit comprises a first resistor-capacitor circuit on a first branch and a second resistor-capacitor circuit on a second branch, wherein each of the first and second resistor-capacitor circuits includes a respective capacitor and a respective resistor connected in series, and, a portion of the ceramic matrix composite body in which at least one ceramic fiber is embedded forms a dielectric of the respective capacitor, and wherein the respective capacitor of each of the first and second resistor-capacitor circuits has a capacitance that depends on a distance between the respective capacitor and a blade of a rotor of gas turbine engine.
Dependencies are inferred from the claim text.