Explanations: Fuel Metering Systems Flashcards
What does it mean to trim a turbine engine fuel control?
Engine trimming is a procedure in which the fuel control on a gas turbine engine is adjusted to cause the engine to produce the required EGT or EPR at a specified RPM.
What is EEC?
Electronic engine control. An electronic fuel control for a gas turbine engine. The EEC senses the power-lever angle (PLA), engine RPM, bleed valve, and variable stator vane position, and the various engine pressures and temperatures. It meters the correct amount of fuel to the nozzles for all flight conditions, to prevent turbine over-speed and over-temperature.
How does the active clearance control (ACC) maintain compressor and turbine blade clearances?
The ACC directs cooling air through the passages in the engine case to control engine case temperatures, and thus the expansion of the case.
What is fuel specific gravity?
The ratio of the mass of a fuel to a mass of the same volume of water.
A fuel with a lower SG weighs less than a fuel with a higher SG.
What is heat energy content, relating to different turbine engine fuels?
The amount of heat energy released when a fuel is burned.
How is heat energy content and the specific gravity of a fuel related?
The higher the SG of a fuel, the more mass of fuel per unit volume, which typically results in higher energy content per unit volume.
How does one obtain a true temperature reading of engine inlet air?
Hang a thermometer in the shade of the nose wheel well until its temperature stabilizes to find the actual ambient temperature.
How does the automatic mixture control compensate for change in the air density due to temperature and altitude changes?
As either altitude or temperature increases, the air becomes less dense, and the AMC decreases the amount of fuel metered to the engine to keep the fuel/air mixture ratio constant.
What does “at rated power” mean?
maximum power output of an engine.
