Abstract: A combustion-gas supply system and a combustion-gas supply method thereof, a device equipped with a turbine engine, and a fracturing system are provided. The combustion-gas supply system includes a main pipeline and a multi-functional pipeline; the main pipeline includes a first sub-pipeline and a second sub-pipeline; the first sub-pipeline includes a first gas intake pipe, a first gas supply valve and a first gas outlet pipe arranged in sequence; the second sub-pipeline includes a combustion-gas supply valve and a gas supply pipe, the first gas outlet pipe is connected with the combustion-gas supply valve, the gas supply pipe is configured to be connected with a turbine engine, the multi-functional pipeline includes a second gas intake pipe, a second gas supply valve and a second gas outlet pipe arranged in sequence, and the second gas outlet pipe is communicated with the first gas outlet pipe.

Abstract: A gas turbine engine includes a core having a compressor section with a first compressor and a second compressor, a turbine section with a first turbine and a second turbine, and a primary flowpath fluidly connecting the compressor section and the turbine section. The first compressor is connected to the first turbine via a first shaft, the second compressor is connected to the second turbine via a second shaft, and a motor is connected to the first shaft such that rotational energy generated by the motor is translated to the first shaft. The gas turbine engine includes a takeoff mode of operation, a top of climb mode of operation, and at least one additional mode of operation. The gas turbine engine is undersized relative to a thrust requirement in at least one of the takeoff mode of operation and the top of climb mode of operation, and a controller is configured to control the mode of operation of the gas turbine engine.

Abstract: A computing system for an unducted rotor engine with a variable pitch vane assembly in aerodynamic relationship with an unducted rotor assembly, including a sensor-based controller configured to execute a first set of operations and a model-based controller configured to execute a second set of operations. The first set of operations includes obtaining a first signal corresponding to a commanded low spool speed; obtaining a second signal indicative of a pitch angle corresponding to thrust output from the unducted rotor assembly and variable pitch vane assembly; generating a pitch feedback signal corresponding to a commanded adjustment to the pitch angle based at least on one or both of a variable blade pitch angle or a variable vane pitch angle. The second set of operations include obtaining a desired thrust output via a throttle input; determining, at least via a power management block, a commanded thrust output signal; receiving the commanded thrust output signal; and generating an output signal.

Abstract: A method to attenuate noise associated with operation of a gas turbine engine during a fracturing operation may include connecting an inlet of a first elongated plenum to an exhaust duct of the gas turbine engine. The method further may include connecting a noise attenuator to a distal end of the first elongated plenum. The noise attenuator may include first and second silencer hoods. The method also may include pivoting the first and second silencer hoods from stowed positions to operative positions so that the second silencer hood in combination with the first silencer hood define a second elongated plenum positioned to receive exhaust gas via the first elongated plenum and the exhaust duct. The first elongated plenum and the second elongated plenum may increase an effective length of the exhaust duct and may reduce sound emission associated with operation of the gas turbine engine.

Abstract: Apparatus, systems, and methods store energy by liquefying a gas such as air, for example, and then recover the energy by regasifying the liquid and combusting or otherwise reacting the gas with a fuel to drive a heat engine. The process of liquefying the gas may be powered with electric power from the grid, for example, and the heat engine may be used to generate electricity. Hence, in effect these apparatus, systems, and methods may provide for storing electric power from the grid and then subsequently delivering it back to the grid.

Abstract: A fuel system can include a total flow line configured to receive a total flow and a primary flow line connected to the total flow line. The primary flow line can be in fluid communication with one or more primary fuel nozzles of a nozzle assembly. The fuel system can include a secondary flow line connected to the total flow line in parallel with the primary flow line, the secondary flow line in fluid communication with a plurality of secondary flow nozzles of the nozzle assembly. The fuel system can include a flow split system configured to control a flow split between a primary flow of the primary flow line and a secondary flow of the secondary flow line.

Abstract: Systems and methods for controlling fuel flow to an engine during start are provided. Fuel is caused to be injected into a combustor of the engine according to a first fuel schedule defining a minimum fuel flow limit required to achieve light-off of the engine, the minimum fuel flow limit set at an initial value. Following light-off of the engine, at least one operating parameter of the engine is monitored. Based on the at least one operating parameter, occurrence of flameout in the engine is detected. In response to detecting occurrence of flameout in the engine, the minimum fuel flow limit is increased from the initial value to a first value to obtain an adjusted fuel schedule, and fuel is caused to be injected into the combustor according to the adjusted fuel schedule.

Abstract: An apparatus for transporting a turbine engine with a transportation fixture including a turbine engine jig having mounts for securing the turbine engine, a rotor with a drive shaft rotationally supported by a bearing, the method includes supplying a lubricant to the bearing and rotating the drive shaft while the turbine engine is in transport.

Abstract: Herein provided are methods and systems for reducing an acoustic signature of a gas turbine engine. An acceleration command for the engine is received. In response to receiving the acceleration command: a fuel flow to the engine is increased for a first predetermined time period; subsequent to the first predetermined time period, the fuel flow to the engine is reduced for a second predetermined time period; and subsequent to the second predetermined time period, the fuel flow to the engine is increased for a third time period.

Abstract: A gas turbine engine shut-down system includes a pump configured to draw a flow of fuel from a source, a fuel nozzle configured to receive the flow of fuel from the pump, a fuel shut-off valve in fluid communication with the pump, a recirculation circuit for circulating excess fuel to a location upstream of the pump; a solenoid valve in communication with the pump and the recirculation circuit; and a fuel-bypass valve. The fuel-bypass valve includes a first opening connected to the fuel pump, a second opening connected to the fuel shut-off valve, a third opening connected to the recirculation circuit, a fourth opening connected to the solenoid valve, and a piston disposed within the fuel-bypass valve and movable between a plurality of positions.

Abstract: A flow divider valve for a gas turbine engine fuel supply system is provided. The flow divider valve is configured, whenever fuel pressure at its inlet port is between a first predetermined pressure and a second predetermined pressure, to supply the fuel to a start nozzle manifold outlet port at a substantially constant flow rate, and to direct any fuel flow in excess of the substantially constant flow rate to a run nozzle manifold outlet port.

Abstract: The speed of a high-pressure turbine of a gas turbine engine may be determined using known centrifugal pump affinity relationships for a fuel pressure apparatus, fuel pressure apparatus input and output pressures, and gear ratios for a mechanical linkage between the high-pressure turbine and the fuel pressure apparatus. The technique avoids wear-related variations in gas pressure based measurements and also applies to fuel pressure apparatus using both single pump and multiple pump configurations.

Abstract: A jet pump (14) is inserted between the low-pressure pump and a high-pressure fuel pump (16). A fuel metering unit (20) includes a metering valve (22) which delivers a regulated fuel flow to a feed line (30), and a bypass valve (24) which diverts to a primary intake (14a) of the jet pump the excess fuel flow supplied by the high-pressure pump. An overspeed protection unit (50) includes a control element (54) of the bypass valve (24) which causes said to fully open in the event of an overspeed of the engine. A shutoff and pressurization checkvalve (42) is mounted on the feed line and controlled by a servo-valve (44) having a high-pressure port (44a) brought to the high fuel pressure, a low-pressure port brought to the pressure of the primary intake (14a) of the jet pump and an output setting the pressure in a control chamber (42a) of the shutoff valve (42) to a value between those prevailing at the high pressure and low pressure ports.

Abstract: The present invention provides a gas turbine combustion system capable of minimizing unburned content of a gas fuel under all load conditions from partial load to rated load. A gas turbine combustion system includes: a plurality of gas fuel burners 32, 33; an IGV 9 that adjusts a flow rate of air to be mixed with a gas fuel; and a control system 500 that temporarily reduces an air flow rate from a reference flow rate to a set flow rate by outputting a signal to the IGV 9 when a combustion mode is switched from a partial combustion mode in which the gas fuel is burned with part of the gas fuel burners 32, 33 to a full combustion mode in which the gas fuel is burned with all of the gas fuel burners 32, 33.

Abstract: Method for conditioning a power supply for starting a jet engine having an electrical starting system with an auxiliary power unit in parallel with a DC power supply.

Abstract: An object is to reduce a fluctuation in the gas-turbine output in a nozzle switching period. In the nozzle switching period during which a first nozzle group that has been used is switched to a second nozzle group that is going to be used, the amounts of fuel supplied through the first nozzle group and the second nozzle group are adjusted by using at least one adjustment parameter registered in advance, the adjustment parameter registered in advance is updated according to the operating condition of the gas turbine, and the updated adjustment parameter is registered as an adjustment parameter to be used next.

Abstract: A fuel system comprises a first, variable displacement fuel pump operable to supply fuel through a metering valve to an engine, a control servo operable to control the operation of the first pump, a pressure drop control valve (PDCV) responsive to a pressure drop across the metering valve, a second fuel pump, and a spill valve movable between an open position in which substantially all of the fuel supplied by the second fuel pump is returned to an inlet side thereof, and a closed position, or partially closed position, wherein a proportion of the fuel supplied by the second pump is delivered to the engine.

Abstract: A method of sensing a reduction in fuel screen area in a fuel system. The method includes detecting an engine shutdown, initiating an electronic engine control (EEC) built in test, shifting a metering valve from a first position to a second position, determining a travel time of the metering valve, and sensing a reduction in fuel screen area based on the travel time of the metering valve.

Abstract: The present invention provides a method and apparatus for starting an engine which can decrease the amount of compressed air consumed by air motors and can lessen an increase in a size of a compressed air tank and an increase in a size of an air compressor, and in a method of starting an engine using a plurality of air motors, the number of air motors being operative is decreased before the engine can start increasing its engine speed for itself, at starting. That is, during increasing of the engine speed of the engine at the starting, the number of air motors being operative is decreased from, for example, two to one.

Abstract: A method of starting a gas turbine engine by use of a start sequence is provided. Turbine speed and fuel delivery are coordinated so as to provide a fuel/air mixture at an ignition device allowing a successful ignition. If a successful ignition has not occurred by end of the start sequence the gas turbine engine is purged and the start sequence is repeated after the purging of the gas turbine engine.

Abstract: A system for starting a gas turbine engine includes an engine controller and a fuel controller. The engine controller varies the engine speed between a minimum start speed and a maximum start speed until light-off of the engine occurs. The fuel controller operates a fuel command to vary fuel provided to a combustion chamber of the engine until light-off of the engine occurs.

Abstract: A method for controlling fuel flow to a gas turbine engine during starting includes monitoring acceleration of the gas turbine engine to determine actual acceleration value, and calculating a fuel flow rate for a setpoint acceleration using the actual acceleration value as a factor. The method further includes commanding the calculated fuel flow for the setpoint acceleration to the gas turbine engine.

Abstract: A reduce electric power consumption when an electric motor starts an engine and the time required to start the engine. Engine start control is implemented as follows. The RPM of the engine is increased to an RPM (R1) by the electric motor. Fuel is supplied to the engine of which RPM has reached to the RPM (R1) and further increases in the RPM are detected. If a further increase in the RPM is not detected, the supply of electric power to the electric motor is temporarily stopped. If the RPM has decreased to a RPM (R2), the supply of fuel to the engine is interrupted and also the supply of electric power to the electric motor is resumed. If a further increase in the RPM is detected or if the RPM has not decreased to the RPM (R2), it is determined that the engine has been started.

Abstract: A fuel system for an auxiliary power unit includes a mechanical fuel pump, an electric fuel pump, and a controller. The mechanical fuel pump provides fuel flow to the auxiliary power unit and has an output dependent upon an operational speed of the auxiliary power unit. The electric fuel pump provides fuel flow to the auxiliary power unit, and is located in flow series with the mechanical fuel pump. The controller causes the electric fuel pump to provide fuel flow during starting of the auxiliary power unit.

Abstract: A method is described for the start-up of a gas turbine comprising the phases of effecting a preliminary purging cycle of the discharge duct (28) of the turbine (20), establishing a predetermined minimum value (FSR1) for the flow of gaseous fuel entering the combustor (14) for a period of time which is adequate for effecting a first attempt at ignition and effecting a first attempt at ignition, effecting an intermediate purging cycle of the discharge duct (28), interrupting the flow of gaseous fuel to the combustor (14), and progressively increasing the value (FSRn) of the flow of gaseous fuel entering the combustor (14), effecting further attempts at ignition until the mixture of air/gaseous fuel has been ignited and the consequent start-up of the turbine (20), or until a predetermined maximum value (FSRmax) of the flow of gaseous fuel has been reached.

Abstract: A system for controlling NOx emissions and combustion pulsation levels of a gas turbine having a gas turbine combustion system, having a single combustion chamber and multiple burners, includes a cascade structure having a first and second control level (1, 2), the first level (1) having a device to control NOx emissions and generate combustion pulsation target levels based on the difference between measured and target NOx emission levels, and the second level (2) having a device to control pulsation levels and generate a ratio (?) of fuel flow to different types of burners or to different stages of each burner. The fuel flow ratio (?) is based on the difference between the measured and generated target pulsation levels. The control system enables the operation of a gas turbine to meet NOx emission requirements, while maintaining combustion pulsation levels within limits that ensure improved lifetime of the combustion system.

Abstract: A fuel divider system includes a housing assembly and a flow passage network having an inlet, a primary outlet, and a secondary outlet. A fuel divider piston is slidably disposed within the housing assembly and movable between a flow biasing position and a flow equalizing position. A control chamber is fluidly coupled to the flow passage network and fluidly communicates with the piston. An inlet chamber, at least partially defined by the piston and the housing assembly, is fluidly coupled to the inlet. At least one channel is provided through the piston and configured to cooperate with the flow passage network to port the FD control chamber to: (i) the fuel pressure at the secondary outlet when the FD piston is in the flow biasing position, and (ii) the fuel pressure within the inlet chamber when the FD piston is in the flow equalizing position.

Abstract: In operating a gas turbine, there can be a difference between the desired heating value of the fuel and the actual needs of the fuel for the supplied fuel to be ignited. In one aspect, fuel parameters related to the molecular weight of the fuel such as specific gravity and pressure drop are determined. Ignitability of the fuel is calculated based on the fuel parameters and adjusted as necessary to bring the fuel's ignitability to designed values. The fuel's ignitability can be calculated without actually igniting the fuel and also without direct knowledge of the fuel's calorific value or its composition.

Abstract: A flow equalizing override assembly is provided for use in conjunction with a gas turbine engine (GTE) and a fuel divider system. In one embodiment, the flow equalizing override assembly includes a housing assembly, a fuel divider (FD) valve, a remotely-actuatable valve, and a controller. The FD valve includes: (i) a piston slidably disposed within the housing assembly and movable between a default position and a flow equalizing position, and (ii) a control chamber defined by the piston and the housing assembly. The remotely-actuatable valve is fluidly coupled to the control chamber and is configured to selectively adjust the fuel pressure therein. The controller is configured to command the remotely-actuatable valve to adjust the pressure within the control chamber such that the piston moves from the default position to the flow equalizing position after ignition of the GTE.

Abstract: An example method of fuel delivery to a turbomachine includes reaching a light-off speed of a turbomachine and delivering fuel to a combustor of the turbomachine at a first rate. The method also increases the rate of the delivery. The combustor achieves light-off at a fuel flow rate on or in-between the first rate and a second rate that is greater than the first rate. An example turbomachine fuel delivery assembly includes a fuel delivery component and a controller configured to adjust the fuel pump to increase a rate of fuel delivery from a fuel supply to a combustor of a turbomachine.

Abstract: A centrifugal pump driven by mechanical coupling with an engine has a low pressure inlet receiving fuel from a fuel circuit of an aircraft, a high pressure outlet connected to a regulator circuit for regulating the flow rate of fuel supplied to the engine, and an assistance pump unit that is electrically controlled, having an inlet connected to the aircraft fuel circuit and an outlet connected to the flow rate regulator circuit so as to deliver, via its outlet, fuel that is at a predetermined minimum pressure, the pressure of the fuel supplied to the regulator circuit being the higher of the pressures delivered by the centrifugal pump and the assistance pump unit.

Abstract: An object of the present invention is to provide a method of starting and stopping a gas turbine and a start-and-stop control device, which are capable of solving a problem of a failure in normally igniting a fuel gas due to a purge gas (nitrogen gas) remaining in a fuel gas pipe and thereby igniting the fuel gas stably.

Abstract: A method and algorithm are provided to operate a gas turbine at baseload in an emission compliant capable mode to avoid combustion dynamics while operating with cold fuel and hot fuel combustion hardware. The method includes performing a gas turbine operational sequence such as a startup to an emission compliant capable mode. A gas fuel temperature is measured. The gas turbine is operated in the emissions compliant capable mode according to a designated fuel split for avoiding combustion dynamics when a temperature for a gas fuel is below a designated value. A determination is made whether a modified wobbe index for the gas fuel is below an emissions compliant value. An alarm is activated if the modified wobbe index is below the emissions compliant value to notify the operator of a potential emissions shift.

Abstract: Methods and systems for delivering fuel in a gas turbine engine are provided. The system includes a plurality of can annular combustors that includes at least a first set of combustors of the plurality of can annular combustors and at least a second set of combustors of the plurality of can annular combustors wherein each set of combustors is supplied by a separately controllable respective fuel delivery system. The method includes supplying fuel at a first fuel schedule to the first set of combustors and supplying fuel at a second fuel schedule to the second set of combustors during a first mode of operation wherein the second fuel schedule is different than the first fuel schedule, and supplying fuel at the second fuel schedule to the first and second sets of combustors during a second mode of operation.

Abstract: Compensation is provided for a fuel demand signal of a gas turbine controller during transition between operating modes. The compensation adjusts fuel demand to account for combustion efficiency differences between the starting and ending operating mode that otherwise can lead to severe swings in combustion reference temperature and lean blowout.

Abstract: Systems and methods for controlling the startup of a gas turbine are described. A gas discharge component may be configured to discharge gas from a compressor component associated with the gas turbine. A fuel control component may be configured to control a fuel flow provided to a combustor component associated with the gas turbine. A drive component may be configured to supply a rotational force to a shaft associated with the gas turbine. At least one control device may be configured to (i) direct the gas discharge component to discharge gas from the compressor component, (ii) direct the fuel control component to adjust the fuel flow, and (iii) direct the drive component to rotate the shaft.

Abstract: System, methods and apparatus for dynamic control of mixing of diluent and fuel at desired diluent-to-fuel ratios to obtain low level of undesirable emissions in a combustion system are described.

Abstract: Embodiments of the present invention employ a closed loop controls philosophy that actively determines the air-to-fuel ratio of turbomachine throughout the start-up process. This closed loop controls philosophy provides many benefits. This philosophy performs the ignition process while the turbomachine is operating at a purge speed and eliminates the associated coast down period. Reduces or eliminates the warm-up timer. The philosophy may also increase the acceleration rate of the turbomachine to the primary operating speed. These benefits may reduce the overall start-up time of the turbomachine. Furthermore, by actively controlling the air-to-fuel ratios during the start-up processes, the turbomachine may be operated on a nearly optimal and repeatable schedule. These benefits may reduce thermal transients, possibly extending parts life; reduce variations in start-up times, and possibly increasing combustor margin.

Abstract: A method and apparatus for distributing control of multiple engines amongst the engines in a power generation system that has a central controller, comprises the steps of: receiving aboard each engine from the central controller a control signal representative of a desired fuel flow; metering fuel at a fuel metering point aboard each engine; sensing at least one parameter aboard each engine proximate the fuel metering point that is representative of fuel flow; adjusting the fuel metering aboard each engine to cause the sensed parameter to correlate to the desired fuel flow; and transmitting a monitoring signal from each engine to the central controller that is representative of the adjusted fuel metering.

Abstract: An aspect of the invention is directed towards a method and device for optimizing a light-up procedure of a gas turbine engine. An aspect of the method comprises repeating an engine start attempt with amended light-up parameter values or range of light-up parameter values, where the values are amended by a predefined scheme including recording the light-up parameter value or the range of light-up parameter values of each start attempt together with the light-up success rate achieved in the respective start attempts, and optimizing the light-up parameter value or range of parameter values by analyzing the recorded data after the start attempts have been finished. An aspect of the device is to provide a control unit that implements the inventive method.

Abstract: A fuel control method for a gas turbine with a combustor being formed of at least two groups of a pluralities of main nozzles for supplying fuel, and that supplies fuel from the main nozzles of all groups upon ignition of the combustor (S1), and supplies fuel from three main nozzles of a group A during subsequent acceleration of the gas turbine (S3). Because fuel is injected from a small number of the main nozzles during acceleration, the fuel flow rate per one main nozzle is increased, thereby increasing the fuel-air ratio (fuel flow rate/air flow rate) in a combustion region and improving the combustion characteristics. Accordingly, the generation of carbon monoxide and unburned hydrocarbon is reduced, whereby no bypass valve is required and manufacturing costs are reduced.

Abstract: A method and apparatus for measuring a start fuel flow to a pilot nozzle of a fuel system of a gas turbine engine using pressure differential between fuel passages leading to fuel nozzles.

Abstract: In a turbo-engine system, oil is circulated by means of a positive-displacement pump directly driven by the output shaft. The pump output pressure is monitored to trigger fuel injection when the turbine reaches sufficient speed during the start-up sequence.

Abstract: In one embodiment, an ecology valve (EV) fuel return system includes a housing assembly, an ecology valve, and a fuel routing assembly. The ecology valve includes an EV piston slidably disposed within the housing assembly for movement between a fuel storage position and a fuel return position, a fuel storage chamber defined by the EV piston and the housing assembly, and an EV control chamber defined by the EV piston and the housing assembly. The fuel routing assembly, which is fluidly coupled to the EV control chamber and to the fuel storage chamber, is configured to route fuel: (i) from the fuel storage chamber to a fuel supply system when a gas turbine engine (GTE) is in a start-up mode, and (ii) from the first fuel manifold and from the EV control chamber to the fuel storage chamber when the GTE is in a shut-down mode.

Abstract: A flow equalizing override assembly is provided for use in conjunction with a gas turbine engine (GTE) and a fuel divider system. In one embodiment, the flow equalizing override assembly includes a housing assembly, a fuel divider (FD) valve, a remotely-actuatable valve, and a controller. The FD valve includes: (i) a piston slidably disposed within the housing assembly and movable between a default position and a flow equalizing position, and (ii) a control chamber defined by the piston and the housing assembly. The remotely-actuatable valve is fluidly coupled to the control chamber and is configured to selectively adjust the fuel pressure therein. The controller is configured to command the remotely-actuatable valve to adjust the pressure within the control chamber such that the piston moves from the default position to the flow equalizing position after ignition of the GTE.

Abstract: A gas turbine engine arrangement (1) comprises a first gas turbine engine (10), a second gas turbine engine (70), a differential gearbox (57) and an electrical generator (112). The differential gearbox (57) has a first input drive (54), a second input drive (78) and an output drive (110). The output drive (110) of the differential gearbox (57) is arranged to drive the electrical generator (112) via an external, accessory, gearbox (56). The external, accessory, gearbox (56) drives other accessories (116, 120). The first gas turbine (10) is arranged to drive the first input drive (54) of the differential gearbox (57) and the second gas turbine engine (70) is arranged to drive the second input drive (78) of the differential gearbox (57). The electrical generator (112) and accessories (116, 120) are driven at a constant frequency speed/frequency.

Abstract: A method for determining a target exhaust temperature for a gas turbine including: determining a target exhaust temperature based on a compressor pressure condition; determining a temperature adjustment to the target exhaust temperature based on at least one parameter of a group of parameters consisting of specific humidity, compressor inlet pressure loss and turbine exhaust back pressure; and adjusting the target exhaust temperature by applying the temperature adjustment.

Abstract: In a gas-turbine engine control system having a first control channel inputting the outputs of sensors to calculate and output a first command value indicative of a quantity of fuel to be supplied to the engine and a second control channel inputting the outputs of the sensors to calculate and output a second command value similarly indicative of the quantity of fuel, the second control channel calculates and outputs the second command value using the first command value so long as the instruction to switch the outputs is not generated, while calculates and outputs the second command value, without using the first command value, when the instruction to switch the outputs is generated. With this, immediately after switching to the second command value, the second command value is made substantially equal to and not greatly different from the preceding first command value.

Abstract: An event-driven starter controller regulates the speed of a gas turbine engine based on detected events. The event-driven starter controller is used to supply motive force to the gas turbine engine, prior such that the gas turbine engine is able to ignite (i.e., achieve light-off). In particular, in response to engine speed reaching a defined threshold, the event-driven starter controller causes the speed of the starter motor to ramp or increase through a defined range of speeds suitable for engine light-off (i.e, light-off window). Upon reaching an upper threshold of the light-off window, the event-driven starter controller causes the speed of the starter motor to decrease through the range of speeds suitable for engine light-off. If at any time during the light-off window the event-driven starter controller detects a successful light-off condition, the event-driven starter controller causes the speed of the gas turbine engine to increase toward a second threshold.

Abstract: A method of controlling fuel flow to a combustor (18) of a gas turbine engine (10) during startup of the engine includes determining a relationship between Cv and valve position for a flow control valve (e.g., 24) in a fuel supply (20) to the combustor as a function of at least one real time parameter of fuel (30) in the fuel supply. The method also includes determining a value of the at least one parameter of the fuel before initiating a flow of the fuel to the combustor, and then calculating a first actual Cv value for the flow control valve at a target flow rate using the determined value of the parameter. The method then includes positioning the flow control valve to a first position corresponding to the actual Cv value based upon the determined relationship between Cv and valve position, and initiating the flow of fuel to the combustor through the flow control valve.