Determination of a signal indicative of shaft power

• US 9,273,614 B2
• Filed: 09/01/2006
• Issued: 03/01/2016
• Est. Priority Date: 09/12/2005
• Status: Active Grant

• Current Assignee: Industrial Turbine Company (UK) Limited (Siemens AG)
• Original Assignee: Industrial Turbine Company (UK) Limited (Siemens AG)
• Inventors: Fletcher, Paul, Rebhi, Betka, Perez, Vincent, Doke, Robert, Martis, Dan
• Primary Examiner(s): SUNG, GERALD LUTHER
• Application Number:
  US11/514,766
• Publication Number:
  US 20070125090A1
• Time in Patent Office: 3,469 Days
• Field of Search: 60/392.7, 607/73, 607/94
• US Class Current: 1/1
• CPC Class Codes: F02C 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F02C 9/54 by throttling the working fluid, by adjusting vanes
• CPC Class Codes: F05D 2260/80 Diagnostics
• CPC Class Codes: F05D 2270/02 to control rotational speed (n)
• CPC Class Codes: F05D 2270/304 Spool rotational speed

Abstract

A gas turbine engine provides mechanical shaft power. Two parameters relating to engine operation are sensed that are representative of two different pressures, two different temperatures, or a pressure and a temperature associated with the engine. A value representative of the shaft power is determined during engine operation as a function of these two parameters. This value may be used for engine monitoring including making one or more adjustments to operational aspects of the engine, regulating/controlling engine function, and/or providing one or more power indicators.

Claims

1. A method, comprising:

providing a gas turbine engine structured to rotate a shaft to generate mechanical power;

sensing a gas pressure of a working gas within the gas turbine engine during gas turbine engine operation;

determining a signal representative of a computed estimate of mechanical power provided by rotation of the shaft, the computed estimate formulated as a function of the gas pressure and a temperature, the temperature within the computed estimate used to compensate for gas turbine engine variation over time in the function; and

controlling the gas turbine engine operation in accordance with the signal;

wherein the function comprises the relationship (T20/Tref)^A*(P30/Pamb), wherein

T20 represents a detected inlet temperature of a compressor of the gas turbine engine or an ambient temperature detected proximate the gas turbine engine or within a plenum of the gas turbine engine;

Tref represents a reference ambient temperature;

“

A”

represents an experimentally derived value corresponding to the gas turbine engine;

P30 represents the gas pressure detected at a discharge of a compressor of the gas turbine engine or at an entry of a combustor of the gas turbine engine; and

Pamb represents an ambient air pressure detected proximate the gas turbine engine or within a plenum of the gas turbine engine.

2. The method of claim 1, wherein the signal corresponds to a number, and further comprising:

detecting a turbine inlet temperature of the gas turbine engine; and

included in the determining of the signal, calculating the number from the function, the function including a further relationship (T44/T20)^B as a factor of the function, wherein

T44 represents the detected turbine inlet temperature of the gas turbine engine;

“

B”

represents an experimentally derived value corresponding to the gas turbine engine; and

the further relationship being selected to correct for the gas turbine engine variation over time.

3. The method of claim 2, further comprising:

detecting the ambient pressure represented by Pamb; and

included in the determining of the signal, calculating the number from the function wherein the relationship (P30/Pamb) corresponds to an uncorrected mechanical power.

4. The method of claim 1, wherein the controlling of the gas turbine engine operation includes one or more of:

changing a variable geometry of the gas turbine engine in response to the signal;

adjusting a fuel control device of the gas turbine engine in response to the signal; and

indicating engine power output with an indicator responsive to the signal.

5. A method, comprising:

operating a gas turbine engine with a rotatable shaft structured to provide mechanical shaft power;

sensing a first gas pressure within the gas turbine engine during an operation of the gas turbine engine;

determining a value that approximates the shaft power of the gas turbine engine in accordance with a relationship between the first gas pressure and a second gas pressure; and

in response to the value, performing one or more adjustments to alter the operation of the gas turbine engine;

wherein the relationship comprises P30/Pamb, wherein

P30 represents the first gas pressure and is detected at a discharge of a first compressor of the gas turbine engine or at an entry of a combustor of the gas turbine engine; and

Pamb represents the second gas pressure and is an ambient air pressure detected proximate the gas turbine engine or within a plenum of the gas turbine engine.

6. The method of claim 5 further comprising:

detecting two temperatures represented by T44 and T20;

wherein the relationship further comprises (T44/T20)^B as a factor, wherein

T44 represents a temperature of a working gas detected at a discharge of a first turbine of the gas turbine engine or at an inlet of a second turbine of the gas turbine engine downstream from the first turbine;

T20 represents a detected inlet temperature of a second compressor of the gas turbine engine or a detected ambient temperature; and

“

B”

represents an experimentally derived value corresponding to the gas turbine engine.

7. The method of claim 6, wherein the factor (T44/T20)^B compensates the value for a variation in a wear condition of the gas turbine engine.

8. The method of claim 6, wherein the gas turbine engine includes two or more compressors, two or more turbines, and a controller;

and wherein the method further includes;

monitoring of the operation of the gas turbine engine with the controller including one or more of;

changing a variable geometry of the gas turbine engine;

adjusting a fuel control valve of the gas turbine engine;

and providing an engine power indicator.

9. The method of claim 5, wherein the one or more adjustments include one or more of:

changing a variable geometry of the gas turbine engine;

controlling a fuel control valve of the gas turbine engine;

and changing an engine power indicator.

10. A method, comprising:

providing a gas turbine engine structured to provide mechanical shaft power;

sensing parameters relating to gas turbine engine operation;

calculating a signal representative of the shaft power provided by rotation of the shaft during the gas turbine engine operation, the calculating including mathematically interrogating a function of the parameters; and

monitoring the gas turbine engine operation with the signal; and

controlling the gas turbine engine operation in accordance with the signal;

wherein the function corresponds to the relationship θ

^A*(P1/P2)*(T1/T2)^B;

wherein P1 corresponds to a first one of the parameters and represents a discharge pressure of a first compressor, P2 corresponds to a second one of the parameters and represents ambient pressure, T1 corresponds to a third one of the parameters and represents a turbine inlet temperature, T2 corresponds to a fourth one of the parameters and represents an inlet temperature of a second compressor, θ

is a temperature compensation factor for temperature T2, and A and B are constants based on design of the gas turbine engine.

11. The method of claim 10, wherein θ

is a function of T2 and a constant.