US 5,743,079 AGranted

Turbine engine control system

AssigneeROLLS-ROYCE plc

InventorsPhilip P. Walsh, Nicholas C. Corbett, Arthur L. Rowe

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Abstract

A fuel control system for a premixed lean burn combustor in a combustion turbine engine, the combustor having at least two stages (P,S,T), the control system including; an air flow evaluation module having means utilising an iterative algorithm to derive an accurate value of total air flow to the combustor, the evaluation module further having means dividing the derived total air flow value into the proportions (Mp, Ms, Mt) required by the combustor stages (p,s, t) and outputting signals in parallel representing the air flow to respective combustor stages (p,s,t), and a control module associated with each stage (p,s,t) of the combustor and responsible for setting the fuel demand signal for the associated combustor stage (p,s,t), each control module being adapted to set the fuel demand signal with reference to an appropriate one of said output signals.

Claims24

Dependent claims

A method for regulating fuel flow in a gas turbine engine comprising a compressor section, a combustor section, a turbine section, turbine nozzle guide vanes, fuel inputs and means to measure values for one or more of the parameters:

engine entry pressure, compressor delivery pressure, combustor entry temperature, compressor exit capacity, nozzle guide vane throat temperature, nozzle guide vane throat capacity, fuel flow rate, specific humidity of the air,
wherein the method includes the evaluation of combustor entry air mass flow rate, the method for said evaluation comprising the steps of:
a) estimating a value for the nozzle guide vane throat air mass flow rate;
b) evaluating nozzle guide vane throat temperature;
c) evaluating nozzle guide vane throat pressure;
d) evaluating nozzle guide vane throat capacity;
e) using the values of nozzle guide vane throat temperature, pressure and capacity to calculate nozzle guide vane throat mass flow rate;
(f) taking a value for fuel flow rate and deducting it from the nozzle guide vane throat mass flow rate to give a value for air mass flow rate;
g) comparing the calculated value of the air mass flow rate with the estimated value of the air mass flow rate and checking whether the two values agree within a specified tolerance;
h) if the two values of air mass flow rate do not agree within a specified tolerance making a revised estimate and carrying out steps b) to g) again until the two values of air mass flow rate agree within the specified tolerance;
i) when the two values of air mass flow rate agree within the specified tolerance outputting the calculated value of air mass flow rate to give an output for the combustor entry air mass flow rate where calculated value of air mass flow rate=combustor entry air mass flow rate plus any air flow diverted from the combustor entry air flow.

8 more elements

A fuel control system for a gas turbine engine comprising a compressor section, a combustor section, a turbine section, turbine nozzle guide vanes, fuel inputs and means to measure values for one or more of the parameters:

engine entry pressure, compressor delivery pressure, combustor entry temperature, compressor exit capacity, nozzle guide vane throat temperature, nozzle guide vane throat capacity, fuel flow rate, specific humidity of the air,
wherein the fuel control system includes means to evaluate the combustor entry air mass flow rate, the means for said evaluation comprising:
a) means to estimate a value for the nozzle guide vane throat air mass flow rate;
b) means to evaluate nozzle guide vane throat temperature;
c) means to evaluate nozzle guide vane throat pressure;
d) means to evaluate nozzle guide vane throat capacity;
e) means using the values of nozzle guide vane throat temperature, pressure and capacity to calculate nozzle guide vane throat mass flow rate;
f) means to take a value for fuel flow rate and deduct it from the nozzle guide vane throat mass flow rate to give a value for air mass flow rate;
g) means to compare the calculated value of the air mass flow rate with the estimated value and to check whether the two values of the air mass flow rate agree within a specified tolerance;
h) means to make a revised estimate if the two values of the air mass flow rate do not agree within a specified tolerance;
i) means to give an output for the combustor entry air mass flow rate where calculated value of air mass flow rate=combustor entry air mass flow rate plus any air flow diverted from the combustor entry air flow when the two values of air mass flow rate agree within the specified tolerance outputting the calculated value of air mass flow rate.

8 more elements

Dependencies are inferred from the claim text.