Patent ID: 12228080

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Reference will now be made to the drawings wherein like reference numerals identify similar structural features or aspects of the subject disclosure. For purposes of explanation and illustration, and not limitation, a partial view of an embodiment of a system in accordance with the disclosure is shown inFIG.1and is designated generally by reference character100. The systems and methods described herein can be used to monitor for degradation in engine fuel nozzles and the accompanying fluid pathways.

In some engine applications, a flow divider valve (FDV) is used to distribute flow between primary and secondary nozzles, and bias flow more heavily towards the primary (lower flowing) nozzles during an engine start. By tracking either (1) the delta pressure between the primary and secondary lines, regulated by the FDV, or (2) the position of the FDV at a similar condition each flight, it can be determined if a change in plumbing or nozzle effective flow areas has occurred. This can be done via BIT (built in test) check each flight at a similar ground start/idle conditions, and if pressures or valve position exceeds a limit, a fault can be issued.

The system100includes a burn flow line102and an FDV104in fluid communication with the burn flow line102to split flow from the burn flow line102to a primary line106and to a secondary line108for supplying fuel to a set of primary engine nozzles110and to a set of secondary engine nozzles112, respectively. A sensor is operatively connected to the FDV to produce a feedback signal indicative of flow split between the primary line106and the secondary line108. A controller114is operatively connected to receive the feedback signal from the senor, compare the feedback signal to a stored flow split value for a mismatch, and output an alert message116upon detecting the mismatch.

The sensor can include a pressure sensor118operatively connected to detect pressure differentials between: a first pressure port line120, and a second pressure port line122in fluid communication with a point in the secondary line downstream from the FDV. The first pressure port line120is in fluid communication with a point in the primary line106downstream from the FDV104(i.e. downstream of where the primary line106branches off of the burn line102upstream of the FDV104). The second pressure port line122is in fluid communication with a point in the secondary line108downstream from the FDV104. The pressure sensor118can include a differential pressure transducer in fluid communication with each of the first pressure port line120and the second pressure port line122. Based on the pressure difference at the pressure sensor118required to achieve the desired flow split from flight to flight, the controller114can detect changes in this pressure differential to detect coke build up and issue the alert116as needed.

The FDV104includes a sliding piston member124configured to split flow between the primary line106and the secondary line108based on position of the sliding piston member124within the FDV104. The sensor in the system100(in addition to or in lieu of the pressure sensor118) can be a position sensor126operatively connected to the sliding piston124to produce the feedback signal based on position of the sliding piston member124within the FDV104. The position sensor126can include a linear variable differential transformer (LVDT). Based on the position of the sliding piston member124required to achieve the desired flow split from flight to flight, the controller114can detect changes in this position to detect coke build up and issue the alert116as needed.

An equalization bypass valve (EBV)128is in fluid communication with the burn flow line102, operatively connected to control position of the sliding piston member124of the FDV104. The FDV104has an FBV inlet130in fluid communication with the burn flow line102, and an outlet132connected in fluid communication with a first feeder line134of the secondary line108. The EBV128has an EBV inlet136in fluid communication with the burn flow line102, and an outlet138connected in fluid communication with a second feeder line140of the secondary line108. The FDV104and the EBV128are in parallel with one another. The EBV128includes an EBV piston142operatively connected to control the FDV104by changing position of the EBV piston142, i.e. the EBV128moves the FDV104since one or the other must open to its respective feeder line134,140because flow must go to the secondary fuel nozzle line108. A pressure equalization solenoid144is operatively connected to control hydraulic pressure acting on the EBV piston142to control the FDV104, e.g. using input pressures PF and PD. InFIG.1the solenoid144is shown deenergized and the EBV128is closed.

An equalization orifice145in the primary line106is connected in fluid communication to throttle flow from the burn flow line102into the primary line106. The controller114is operatively connected to the pressure equalization solenoid144to control the FDV104. The controller114is configured to control the FDV104to bias flow to the primary line106for an initial portion of an engine startup sequence, and to bias more flow to the secondary line108after the initial portion of the engine startup sequence. The controller114includes a memory146and is configured to read a previous feedback signal from the memory146wherein the previous feedback signal relates to a prior engine startup sequence, i.e. to a prior flight. The controller114is configured to store into the memory a current feedback signal obtained during a current engine startup sequence for use in comparison with a future feedback single to be obtained in a future engine startup sequence, i.e. for use in future flights. The controller114is configured to monitor the feedback signal from the sensor118and/or126each time an engine is operated and to detect a trend in the feedback signal indicative of a change in fuel nozzle performance over time.

A method includes starting up a gas turbine engine148and monitoring a feedback signal indicative of a fuel split between a primary line106feeding a set of primary engine nozzles110and a secondary line108feeding a set of secondary engine nozzles112. The method includes outputting an alert116for taking action in response to the feedback signal being mismatched with an expected flow split and shutting down the gas turbine engine148, and servicing the engine148to correct the flow split if there was an alert116. The expected flow split for the controller can be derived from a previous feedback signal from a previous startup sequence or flight of the gas turbine engine. The method can include storing the feedback signal from a current flight for use in a future operation of the gas turbine engine.

Systems and methods as disclosed herein provide potential benefits including the following. Coking of fuel nozzles changes the restriction in the fuel system and can also change the distribution of burn flow going into the engine combustor. Systems and method as disclosed herein allow for some monitoring of these degraded components which can indicate the need for engine servicing.

The methods and systems of the present disclosure, as described above and shown in the drawings, provide for monitoring for degradation in engine fuel nozzles and the accompanying fluid pathways. While the apparatus and methods of the subject disclosure have been shown and described with reference to preferred embodiments, those skilled in the art will readily appreciate that changes and/or modifications may be made thereto without departing from the scope of the subject disclosure.