Variable geometry hysteresis control for a gas turbine engine
First Claim
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1. A method, comprising:
- operating a gas turbine engine including a variable geometry mechanism with a number of vanes, a controller controlling the variable geometry mechanism according to a hysteresis band and operating to vary working fluid flow area between the vanes over a range from a first extreme to a second extreme, one of the first extreme and the second extreme defining a greater flow area than another of the first extreme and the second extreme;
within the range, selecting a desired state of the variable geometry mechanism different than a current state of the variable geometry mechanism to provide a desired flow area closer to the first extreme than the current state; and
transitioning the variable geometry mechanism from the current state to the desired state in response to said selecting by adjusting the variable geometry mechanism from the current state to an interim state with a corresponding flow area closer to the first extreme than the desired state, and subsequently adjusting the variable geometry mechanism from the interim state to the desired state to regulate hysteresis of the variable geometry mechanism.
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Abstract
One embodiment of the present application is a gas turbine engine with a compressor that includes a variable geometry mechanism to vary working fluid flow area. A desired state of this mechanism is selected different than a current state to change the amount of flow area. The mechanism has a hysteresis band corresponding to a difference between increasing the flow area to reach the desired state and decreasing the flow area to reach the desired state. To control operation of the mechanism within this hysteresis band, a determination is made whether the desired state corresponds to a greater flow area or a lesser flow area relative to the current state.
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Citations
17 Claims
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1. A method, comprising:
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operating a gas turbine engine including a variable geometry mechanism with a number of vanes, a controller controlling the variable geometry mechanism according to a hysteresis band and operating to vary working fluid flow area between the vanes over a range from a first extreme to a second extreme, one of the first extreme and the second extreme defining a greater flow area than another of the first extreme and the second extreme; within the range, selecting a desired state of the variable geometry mechanism different than a current state of the variable geometry mechanism to provide a desired flow area closer to the first extreme than the current state; and transitioning the variable geometry mechanism from the current state to the desired state in response to said selecting by adjusting the variable geometry mechanism from the current state to an interim state with a corresponding flow area closer to the first extreme than the desired state, and subsequently adjusting the variable geometry mechanism from the interim state to the desired state to regulate hysteresis of the variable geometry mechanism. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A method, comprising:
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operating a gas turbine engine including a compressor with a variable geometry mechanism, a controller controlling the variable geometry mechanism according to a hysteresis band, the variable geometry mechanism including a number of vanes, and operating to vary flow area for working fluid passing between the vanes; selecting a desired state of the variable geometry mechanism different than a current state of the variable geometry mechanism to change the flow area; and controlling hysteresis of the variable geometry mechanism in response to said selecting by one of increasing or decreasing the flow area from the current state to an interim state followed by another of increasing or decreasing the flow area from the interim state to the desired state. - View Dependent Claims (9, 10, 11)
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12. A method, comprising:
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operating a gas turbine engine including a compressor and a controller, the compressor including a variable geometry mechanism that is controlled by the controller according to a hysteresis band and operates to vary an amount of flow area for a working fluid passing through the compressor; selecting a desired state of the variable geometry mechanism different than a current state of the variable geometry mechanism to change the amount of flow area, the variable geometry mechanism having a hysteresis band corresponding to a difference between increasing flow area to reach the desired state and decreasing flow area to reach the desired state; and determining whether the desired state corresponds to a greater flow area or lesser flow area relative to the current state to control operation of the variable geometry mechanism within the hysteresis band. - View Dependent Claims (13, 14, 15, 16, 17)
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Specification