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US 5,915,917 AGranted
Compressor stall and surge control using airflow asymmetry measurement
AssigneeUnited Technologies Corporation
InventorsKevin M. Eveker, Daniel L. Gysling, Carl N. Nett, Hua O. Wang
Life of this patent
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Abstract
A technique for controlling compressor stall and surge is disclosed. In a gas turbine engine, static pressure asymmetry is sensed at a plurality of locations along the circumference of the compressor inlet. Time rate of change of the mass flow in the compressor is also estimated using pressure measurements in the compressor. A signal processor uses these signals to modulate a compressor bleed valve responsive to the level of flow property asymmetry, the time rate of change of the annulus average flow to enhance operability of the compressor.
Claims32
A controller for a compressor, characterized by:
- first means for sensing fluid flow properties in a fluid flow path around a compressor flow axis to produce first signals that manifest circumferential asymmetry of said fluid flow;
- second means for providing a second signal that manifests the time rate of change of the mass flow of said fluid in the flow path;
- signal processing means comprising means for a providing a first processor signal from said first signals with a value that manifests the magnitude of said circumferential asymmetry;
- and for adding said first processing signal with said second signal to produce a control signal;
- and
- third means for modifying said fluid flow as function of the magnitude of said control signal.
3 more elements
A controller for a compressor, characterized by:
- a plurality of first probe means each for producing one of a plurality a first flow signals that manifests static pressure at an individual circumferential locations around compressor flow axis;
- second probe means for providing a second flow signal that manifests the time rate of change of the mass flow of said liquid in the flow path;
- signal processing means comprising means for providing an asymmetry signal from said first flow signals with a value that manifests the magnitude of circumferential asymmetry around said compressor flow axis;
- for a providing a first processor signal that manifests the square of said value;
- and for producing a control signal that manifests the sum of said first processor signal and said second signal;
- and
- means for reducing the value of said first asymmetry signal by altering the magnitude of mass flow in the compressor as function of the magnitude of said control signal.
4 more elements
A gas turbine engine, characterized by;
- first means for sensing airflow in a flow path around a compressor flow axis in the inlet to a compressor stage of the engine to produce a plurality of static pressure signals for different circumferential locations around the airflow path;
- second means for providing a second signal that manifests a rate of change of the mass flow of said airflow;
- signal processing means comprising means for providing an asymmetry signal from said static pressure signals, said asymmetry signal having a value manifesting the magnitude of circumferential asymmetry of said airflow around said axis;
- for providing a first processor signal that manifests the square of said asymmetry signal;
- and for adding said first processor signal with said second signal to produce a control signal;
- and
- third means for modifying said mass flow as function of the magnitude of said control signal to reduce the value of said asymmetry signal.
4 more elements
A gas turbine engine having a rotary compressor with a compressor inlet and an engine control, characterized by:
- a plurality of static pressure sensors located around the circumference of the compressor inlet each providing a static pressure signal for its location;
- a total pressure sensor for providing a total pressure signal manifesting average total flow in the compressor;
- said engine control comprising a signal processor for receiving each static pressure signal and said total pressure and for providing a flow asymmetry signal that manifests the first Fourier spatial coefficient for the flow asymmetry manifested by said static pressure signals;
- for providing a first processor signal that manifests the square of said asymmetry signal;
- for providing a time rate of change signal manifesting the time rate of change of said total pressure signal;
- and for providing a control signal that manifests the sum of said first processor signal and said time rate of change signal;
- and
- a compressor bleed valve for discharging compressor flow as function of the magnitude of said control signal to reduce the magnitude of said first signal.
5 more elements
A gas turbine engine having a rotary compressor with a compressor inlet and an engine control, characterized by:
- a plurality of static pressure sensors located around the circumference of the compressor inlet each providing a static pressure signal for its location;
- a total pressure sensor for providing a total pressure signal manifesting average total flow in the compressor;
- said engine control comprising a signal processor for receiving each static pressure signal and said total pressure and for providing a flow asymmetry signal that manifests the first Fourier spatial coefficient for the flow asymmetry manifested by said static pressure signals;
- for storing a first value representing a desired magnitude for said flow asymmetry signal;
- for providing a first processor signal that manifests the square of said asymmetry signal;
- for providing a second processor signal that manifests the difference between said asymmetry signal and said first value;
- for providing a derivative signal manifesting the time rate of change of said total pressure signal;
- for integrating said second processor signal to produce an integration signal;
- for providing a control signal that manifests the sum of said first processor signal, said derivative signal and said integration signal;
- and
- a compressor bleed valve for discharging compressor flow as function of the magnitude of said control signal to reduce the magnitude of said first signal.
8 more elements
A method of controlling compressor fluid flow in a rotary compressor characterized by:
- sensing compressor fluid flow static pressure at locations along the circumference of the fluid flow to produce first flow signals;
- sensing axial mass flow to produce a second flow signal that manifests a time rate of change of the mass flow of said fluid in the flow path;
- providing a first processor signal from said first signals with a value that manifests the magnitude of circumferential asymmetry of said fluid flow around said axis;
- adding said first processor signal with said second signal to produce a control signal;
- and
- reducing the value of said first processor signal by altering the magnitude of said mass flow as function of the magnitude of said control signal.
3 more elements
A stall and surge controller for a compression system, the compression system including a compressor with a flow path disposed about a flow axis, the controller including:
- means for monitoring the flow through the compressor comprising:
- means for sensing circumferential asymmetry of the fluid flowing within the flow path of the compressor to produce a parameter a that corresponds to the amount of asymmetry;
- and
- means for sensing perturbations in the time rate of change of mass flow throughout the flow path of the compressor to produce a parameter d that corresponds to the size of the perturbation;
- and actuation means for modifying the flow field within the flow path of the compressor responsive to the sum of a and d according to the control law comprising:
- A=k.sub.1 .alpha.+k.sub.2 .delta.
- where A corresponds to the amount of flow disruption produced by the actuation system, k.sub.1 is a predetermined gain for the asymmetry parameter .alpha., and k.sub.2 is a predetermined gain for the time rate of change of mass flow perturbation parameter .delta..
4 more elements
Dependencies are inferred from the claim text.