Exam 3 Flashcards
T/F The Ram Jet engine is the simplest of the jet engines in that it contains no moving parts.
True
What are the four most common types of Jet Propulsions?
Turbinejet, Rocket Jet, Ram Jet, Pulse Jet
Turbine Jet
A type of gas turbine engine which produces thrust through the hot gases exiting the exhaust section of the engine
Rocket Jet
The simplest form of rocket made of metal, or even paper, filled with gunpowder or some other sort of rapid burning mixture of chemicals that rapidly expand when burned. The reaction to the escaping gases pushing out of the back creates thrust
Ram Jet
Simplest form of jet engine. Must be assisted to 250 mph before started. Used as afterburners
Pulse Jet
Operates by a step by step cycle there is a grill of shutters that opens to let air into the combustion chamber, then the hot exhaust gases force close the shutters which moves the gases down the tail pipe to the exhaust then springs force the shutters back open to bring in more air.
Aircraft gas-turbines can generally be classified into what four types?
Turbo Jet and turbofan (thrust producing) turboprop and turboshaft (torque producing engines)
T/F A high-bypass engine does not bypass as much air around the core as a low-bypass engine.
False
The advantages of turbofans are _______, _______ and _________
Greater fuel efficiency , reduced noise, turbojet speeds, turboprop short-field take-off capability
T/F Once combustion occurs, pressure is no longer the driving requirement. It is exit velocity.
True
T/F In a jet engine, the compressor wheels are used to turn the turbine wheels.
False
The amount of force or thrust produced depends on the _____ of the air moved through the engine and the extent to which this air can be ______ and ejected.
Amount of mass, accelerated
A gas-turbine has four major sections:
Compressor, combustion, turbine nozzle
The _____ engine accelerates a smaller volume of air than the turboprop engine but a larger volume than the turbojet engine.
Turbofan
Turbofan engines may be _____-bypass or _______-bypass engines
High or low
The fan diameter of a turbofan is much _______ than a propeller, but there are _______ blades and it has a greater _________.
Smaller, many, exit velocity
A _______ engine is nothing more than a gas-turbine or turbojet engine with a reduction gear mounted in the front or forward end to drive a standard airplane propeller.
Turboprop
The major disadvantages of the turboprop is that it does not deliver
More power/thrust from exhaust gases
When it is necessary to increase velocity and decrease pressure of air in an engine, a ________ duct is used.
Convergent
The inlet area can be controlled by a set of vanes known as the _______ vanes.
Inlet guide vanes
There are two types of compressors with respect to airflow: the ______ type and the type.
Centrifugal and Axial
The centrifugal compressor consists of three main parts: an ________, a _________, and a _________
Impeller diffuser, and compressor manifold
What is the primary purpose of the compressor section in a gas turbine engine?
The primary purpose of the compressor section is to increase the pressure of the air that is entering the engine inlet and to discharge it to the combustor at the proper velocity, temperature, and pressure.
Compressor stall occurs when the rotor blades’ AOA gets too high. This generally occurs under what conditions?
- Turbulent of disrupted airflow to the engine inlet. 2. Excessively rich fuel flow caused by abrupt engine acceleration. 3. Contaminated or damaged compressors. 4. Damaged turbine components, causing loss of power to the compressor. 5. Engine operation above or below designed RPM
The turbine _______ is a series of airfoil-shaped vanes arranged in a ring at the rear of the combustion section of a gas-turbine engine.
Nozzle diaphragm
Turbines come in three types: the ______ turbine, the _______ turbine, and a combination of the two called a _____ _________ turbine
Impulse, reaction, impulse reaction
During most operating conditions, the nozzle exit velocity reaches the speed of sound and th propelling nozzle is said to be _____ - that is, no further increase in velocity can be obtained unless the _______ is increased.
Choked, temperature
The normal function of the exhaust nozzle, or cone, is to control the ______ and _______ of the exhaust gases.
Velocity, temperature
The two most commonly used types of thrust reversers are the _______ system and the _________ system.
Aerodynamic or mechanical blockers
The _______ section of a turbine engine is used to power engine and aircraft accessories such as fuel pumps.
Accessory drive (gearbox)
