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[start]
[q]The purpose of the inlet or diffuser is to?
[a]Answer:
Reduce the velocity and increase the pressure of the air entering the compressor section (ANA page 107)
[q]What happens to the volume and pressure of the air aft of the diffuser?
[a]Answer:
Volume is decreased, and pressure is increased. (ANA page 107)
[q]What happens to pressure within the combustion chamber?
[a]Answer:
Pressure remains constant within the combustion chamber. The process is essentially a constant pressure with the addition of heat energy. (ANA page 107)
[q]Where is the diffuser located within a typical turbine engine?
[a]Answer:
The diffuser is located aft of the compressor section. (ANA page 107)
[q]The combustion of fuel causes a large change in ______________ and ____________.
[a]Answer:
Temperature, volume (ANA page 107)
[q]Which section is the first section in which work is extracted from the turbine engine process?
[a]Answer:
The turbine section (ANA page 107)
[q]Which section is responsible for furnishing the combustion chamber with specific quantities of high-pressure air?
[a]Answer:
The compressor section (ANA page 107)
[q]The ________ is responsible for increasing the pressure in order for the compressor section to furnish high-pressure air.
[a]Answer:
Diffuser (ANA page 110)
[q]The diffuser converts ________ energy into _______ energy.
[a]Answer:
Kinetic, static-pressure energy (ANA page 111)
[q]The ___________ receives the high pressure discharge from the compressor and introduces approximately one half of this air into the immediate area of fuel spray.
[a]Answer:
The combustion chamber (ANA page 111)
[q]What would happen if the velocity of the air delivered by the compressor was too high?
[a]Answer:
Poor combustion and likelihood of a flameout would occur. The diffuser aids in the reduction of velocity and an increase of pressure. (ANA page 113)
[q]What is the function of the turbine section?
[a]Answer:
The function of the turbine section is to extract energy from the combustion gases and furnish power to drive the compressor and accessory section. (ANA 112)
[q]High-pressure energy from the combustion gases is converted into what type of energy?
[a]Answer:
Kinetic energy (ANA 112)
[q]What type of energy is extracted from the combustion gases by the turbine blades?
[a]Answer:
Mechanical energy (ANA page 113)
[q]Which section is considered the most critical element of a turbojet engine?
[a]Answer:
The turbine section (ANA page 113)
[q]Which section of the turbine engine is subjected to the highest temperatures?
[a]Answer:
The turbine inlet (ANA page 114)
[q]The turbine engine is limited by the turbine inlet ______________.
[a]Answer:
Temperature (ANA page 114)
[q]The function of the tailpipe or exhaust nozzle is to discharge the exhaust gases at __________.
[a]Answer:
The highest possible velocity to produce the greatest momentum change and thrust. (ANA page 114)
[q]Which section of the turbine engine has the highest velocity of airflow?
[a]Answer:
The exhaust section (ANA page 114)
[q]The highest pressure in a turbine engine can be found in which section?
[a]Answer:
The compressor section (ANA page 115)
[q]When at ______, during takeoff for example, an increase in velocity will reduce the velocity change through the engine without a corresponding increase in mass flow, and the available thrust willdecrease.
[a]Answer:
Low velocity; at higher velocity, the beneficial ram helps to overcome this effect, and the available thrust no longer decreases but increases with speed. (ANA page 116)
[q]The turbine engine usually has a strong preference for _______ RPM to produce _____ specific fuel consumption.
[a]Answer:
High, low (ANA page 119)
[q]Which one factor strongly affects the performance of the turbojet engine?
[a]Answer:
Altitude (ANA page 119)
[q]Generally speaking, the specific fuel consumption _________ steadily with altitude until the Tropopause is reached.
[a]Answer:
Decreases (ANA page 121)
[q]The axial flow compressor must operate relatively close to the stall-surge limit to obtain ________.
[a]Answer:
Peak efficiency (ANA page 124)
[q]When considering the operation of a gas turbine engine, what provides the most important restriction to the operation of the turbojet engine?
[a]Answer:
The limiting exhaust-gas temperatures (ANA page 125)
[q]What can cause an attendant breakdown of a stable, steady flow of air through the compressor?
[a]Answer:
An excessive pressure rise required in the compressor (ANA page 126)
[q]What happens during a compressor stall once there is an attendant breakdown of stable air?
[a]Answer:
As a stall occurs, the pressure rise drops and the compressor does not furnish discharge at a pressure equal to the combustion chamber pressure. As a result, a flow reversal and backfire takes place. (ANA 127)
[q]During a compressor stall, what causes an immediate rise in exhaust-gas temperatures?
[a]Answer:
The increase in compressor power required tends to reduce RPM and further reduces airflow and increases fuel flow. (ANA page 126)
[q]What is the recommended method to recover from a compressor stall?
[a]Answer:
Recovery is accomplished by quickly reducing throttle setting, lowering the airplane angle of attack, and increasing airspeed and reducing altitude if high altitude is a contributing factor. (ANA page 126)
[q]What are the three common causes for compressor stalls?
[a]Answer:
1. A malfunctioning fuel control or governing apparatus
2. Power inlet conditions are typical at high angles of attack and sideslip.
3. Very high-altitude flight produces low Reynolds numbers for the compressor. Very high altitudes reduce the maximum pressure ratio of the compressor. (ANA page 126)
[q]What two ramifications does the effect of temperature have on thrust output?
[a]Answer:
1. At takeoff, a high ambient temperature reduces thrust because of low density and low mass flow.
2. Thrust is lost due to reduced mass flow, and fuel flow is reduced further because of the high compressor inlet temperature. (ANA page 128)
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