POWERPLANT MIDTERM MOD 4

Kerosene

All turbine fuels contain _____________.

Turbine Fuel System

store, transfer, and meter fuel to a turbine engine in the proper amount and at the right pressure

Tanks

Lines

Valves

Pumps

Filter devices

Gauges

Fuel control unit

Fuel nozzles

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TLVP FGFF

A turbine fuel system consists of:

Fuel Heater

is required to eliminate fuel metering problems caused by ice crystals in the fuel.

Crossfeed System

Most large turbine aircraft fuel systems are known as _____.

Engine-Driven Pumps

designed to deliver a continuous supply of fuel to a fuel control unit in quantities that exceed the needs of the engine

Engine-Driven Pumps

are typically gear type pumps with one or two gear elements.

Check Valve

allows flow in one direction only. It is installed at the outlet of each gear element to prevent fuel from draining out of the fuel system when the engine is shut down and to keep fuel from recirculating within a failed gear element.

Pressure Relief Valve

releases excess pressure. It is built into the pump housing to limit pump fuel pressure and provide protection to the fuel system

centrifugal boost pump impeller

dual gear pump elements

check valves

relief valve

A typical engine-driven fuel pump housing for a turbine engine contains a _________.

Fuel Transfer Ejectors

Carburetor of a recipro. Sometimes called jet pumps that are used in some fuel systems to help the primary and/or boost pump scavenge fuel from a fuel tank and to facilitate the transfer of fuel from the main tank to a boost pump sump.

Fuel Heater

is installed to eliminate and prevent the formation of ice cryst

Coarse Mesh Filter

is typically installed between the supply tank and the fuel pump.

Fine Mesh Filter

is placed between the fuel pump and the fuel control unit.

Fuel Filters

Its purpose is to protect the delicate control components within the high pressure fuel pump and the fuel control unit (FCU) from any dirt and contamination.

Water Injection

a means of augmenting engine thrust in a gas turbine engine. In some cases, it may be used to cool the airflow and increase air density.

water and methanol

A typical water injection system uses a mixture of?

Turbine Engine Fuel Metering

must meter fuel to a turbine engine for reliable ground and air operations.

Fuel Control Unit

Fuel Nozzles

Main components of a typical engine fuel metering system.

Fuel Control Unit

monitors several engine operating parameters including power lever position, engine rpm, compressor inlet air temperature and pressure, and burner or compressor discharge pressure.

Fuel Control Unit

meter the correct amount of fuel into the combustion section to obtain an optimum air-to-fuel mixture ratio of 15:1 by weight. This ratio represents 15 pounds of combustor primary air to one pound of fuel.

Hydromechanical Fuel Control Unit

Divided into a fuel metering section and a computing section.

Fuel Metering Section

meter the appropriate amount of fuel to the combustion section at the correct pressure

fuel shutoff valve

To provide a positive means of stopping the flow of fuel to the engine for engine shut down, a _________ is provided downstream from the main metering valve

Computing Section

is responsible for positioning the metering valve to obtain the appropriate power output and control the rate of acceleration and deceleration.

Hydro-Pneumatic

often used on turboprop engines. It utilizes a pneumatic computing section that determines fuel flow rates based on the position of the power lever, N1 rpm, compressor discharge air (P3), and outside air pressure (Po)

Electric Engine Control (EEC)

To obtain precise monitoring and control needed in fuel metering, most modern turbofan engines utilize an ________.

Supervisory EEC

consists of an electronic control and a conventional hydromechanical fuel control unit.

Full-Authority EEC

A full-authority digital engine control, or FADEC, performs virtually all the functions necessary to support engine operation during all phases of flight.

Fuel Nozzles

Sometimes referred to as fuel distributors typically located in the diffuser or inlet of the combustion chamber where they deliver fuel in a specified quantity.

Fuel Nozzles

must mix the fuel with air and vaporize it as it enters the combustion chamber

Atomizing Nozzles

receive fuel from a manifold, mix the fuel with air, and then deliver it to the combustor in an atomized spray patter

Simplex Nozzle

It provides a single spray pattern.

Duplex Nozzle

has two independent discharge orifices; one small and the other large. The types are single-line and dual-line

Spill-Type Nozzle

is basically a Simplex nozzle with a passage leading away from the spin chamber.

Variable-Port Nozzle

also called Lubbock nozzle, it was developed to properly atomize fuel over a wide range

Air-Spray Nozzle

It used in some Rolls Royce engines. This type of atomizing nozzle differs from other nozzles in that there are openings in back of the nozzle that allow primary combustion airflow to aerate the fuel spray.

Vaporizing Nozzles

pre-mixes the primary air and fuel in a vaporizing tube instead of delivering the fuel directly to the primary air in the combustor.

Cane-Shaped Vaporizers

one outlet vaporizing nozzle

T-Shaped Vaporizers

two outlets vaporizing nozzle

Nozzle Malfunctions

anytime an internal passage or air bleed hole becomes plugged, a distorted spray pattern or incomplete atomization

Pressurization & Dump Valve

It is frequently incorporated into fuel metering systems which utilize dual line duplex nozzles.

Drain Valves

Fuel that is dumped during engine shutdown must be either dumped into a separate storage tank or sent through a recovery system.

control replacement or occasional field adjustments

Turbine engine fuel control repairs in the field consist of _________.