Electronic Fuel Control for GE-T58 Gas Turbine

Replace a mechanical fuel controller for a gas turbine engine with an electronically controlled fuel controller that will measure EGT, turbine speeds, TPS, and thermocouple readings. Develop a programmed controller that will respond to these readings and output fuel to nozzles and stator vane actuator. The fuel to nozzles and stator vane actuator will be controlled via 2 and 4 way valves, respectively. The valves will be packed within an aluminum manifold and be able to bolt into the proper location on the engine.

Background
The GE-T58 currently uses a complex mechanical fuel control that provides kerosene to the stator actuator and the fuel nozzles. This unit is extremely difficult to service and tune. The rebuild costs have been estimated around $15,000.00, while only a few places have the proper equipment to perform this service.

Deliverables
The electronic fuel control will be packaged within a sealed aluminum manifold. Inside this manifold will be industrial off the shelf valves, hoses, fittings, and hydraulic controller. The aluminum manifold will have flanges to attach the existing fuel pump and tach generator. The unit will be a bolt on replacement with minor adjustments.

Specifications

 * •Programmed hydraulic controller
 * •Read type K thermocouples for Exhaust Gas Temperature (EGT)
 * •Read intake air temperature with thermistor
 * •Read Throttle Position Sensor (TPS) (0-5V)
 * •Read turbine 1 (N1) and turbine 2 (N2) speed


 * •2 way hydraulic valve
 * •Supply fuel to 16 fuel nozzles
 * •Control using Pulse Width Modulation (PWM)
 * •Vary PWM using controller inputs
 * •Governing feature to close valve at N2 speed of 105%


 * •4 way hydraulic valve
 * •Supply fuel to stator vane actuator
 * •Open and close compressor guide vanes
 * •Supply correct quantity of fuel for timing of compressor guide vanes
 * •Supply voltage of 10V

GE-T58 Gas Turbine

 * •7 stages of compressors, first 3 are stationary
 * •Stator vane actuator which controls first 3 compressors
 * •2 stages of turbines, N1 and N2
 * •16 fuel nozzles to combustion chamber
 * •Fuel pump is powered by N1
 * •Tach generator outputs N2 speed: 4200 rpm (tach) = 100% (N2)
 * •8 thermocouple EGT readings

Electric Hydraulic Controller

 * •Understanding block diagrams
 * •Gaining knowledge of electrical systems

2 Way Hydraulic Valve

 * •Gaining knowledge of PWM

4 Way Hydraulic Valve

 * •Application of fluid mechanics for timing

Thermodynamic Analysis
A gasifier turbine cycle was used to analyze the GE-T58 gas turbine. The knowns were given from previous dynamometer runs.



• A energy balance was used to solve for the unknowns

$$ \sum(W_{in}+Q_{in})-\sum(W_{out}-Q_{out})+m_{dot}*(h_{in}-h_{out})=dE_{sys}/dt$$

• Knowledge of the gasifier turbine shaft being connected to the compressors

$$ W_{gasifier}=W_{compressors}$$

• Calculating compressor efficiency

$$\eta_{compressors}=(h_{1}-h_{2s})/(h_{1}-h_{2})$$

$$h_{2s}=h(P_{2},s_{1})$$

• Neglect pressure drop through combustion chamber

$$P_{2}=P_{3}$$

Document Archives
[[media:ElectronicFuelControl_GE-T58_ExpoPoster.pdf|Engineering Expo Poster]]

[[media:ElectronicFuelControl_GE-T58_FinalReport.pdf|Final Design Report]]

[[media:ElectronicFuelControl_GE-T58_ExpoPresentation.pdf|Engineering Expo Presentation]]