GAS TURBINE ENGINE AIR INTAKE | DESIGN REQUIRMENTS FOR SUBSONIC AND SUPERSONIC INTAKES | MODULE 14
8.6 هزار بار بازدید -
3 سال پیش
-
The engine air intake provides
The engine air intake provides a relatively distortion free, high energy supply of air in the required quantity to the face of the compressor. A uniform and steady airflow is necessary to avoid compressor stall and excessive internal engine temperature at the turbine. The high energy enables the engine to produce an optimum amount of thrust. Normally the air intake duct is considered to be an airframe part but the duct itself is so important that when considering engine performance it must be included in any discussion on the complete engine
Let us discuss the design requirements for engine air intakes. There are basically three requirements that the air intake must fulfill.
1. The air intakes must recover as much of the total pressure of the free air streams as possible and deliver this pressure to the face of the engine compressor with the minimum loss.
2. It must deliver the air uniformly with as little turbulence and pressure variation as possible.
3. As far as the aircraft itself is concerned it should keep aerodynamic drag to a minimum.
Air intakes are designed either subsonic or supersonic configuration. Those that maintain optimum airflow condition up to high subsonic speeds are called subsonic intakes whereas those which are also required to operate efficiently at aircraft speeds exceeding Mach one are called Sonic intakes
For a typical gas turbine engine the velocity of the air flow at the compressor inlet is normally less than 0.5 MC this ensures high compressor efficiency so while designing the air intake our main goal is to bring the speed of the air at 0.5 Mac at the face of the compressor. we will see how this requirement is fulfilled for both subSonic and super Sonic configuration
The aircraft which fly in the subsonic regions needs to have a subsonic intakes. The subsonic intakes are designed as a divergent duct. So that when the air enters the engine air inlet at point a it will be around 0.75 Mac.
Now recall that whenever a subsonic flow passes through a divergent duct as that area of the duct increases the pressure increases and the velocity decreases Hence when the air has reached point B the velocity of the air flow has been reduced to 0.5 Mac this ensures high compressor efficiency.
The aircraft which fly above speed of sound needs to have a Sonic intakes.the Sonic intakes are divided into 2 portion the first portion constitutes are convergent duct while the second portion constitutes a divergent duct.
When the airflow enters the point a it has a speed of 1.5 Mac now we need to reduce the speed first to make it subsonic. for this the Sonic intakes utilizes a convergent duct. now recall that Whenever there is a Sonic flow through a convergent duct, as the area of the duct decreases ,the pressure of the air flow
increases and the velocity of the air flow decreases so that when the air flow reaches the point B its speed has been reduced to 0.9 Mac. Now here is an important thing to remember at this point, the air flow has become subsonic, now if we continue using the convergent duct then instead of decreasing the speed of the subsonic flow the speed will be increased since we know that a subsonic flow through a convergent duct increases the speed so at this point in order to decrease the speed of a subsonic flow we will use a divergent that ahead of point B.
As the air flows from point B to C the area of the dark increases and the pressure of the airflow increases as well but the velocity starts decreasing .at Point C at the face of the compressor the airflow has reached 0.5 Mac this ensures high compressor efficiency.
#ENGINEAIRINTAKE #GASTURBINEENGINE #AVIATIONSTUDIES #THEHASHACADEMY
Let us discuss the design requirements for engine air intakes. There are basically three requirements that the air intake must fulfill.
1. The air intakes must recover as much of the total pressure of the free air streams as possible and deliver this pressure to the face of the engine compressor with the minimum loss.
2. It must deliver the air uniformly with as little turbulence and pressure variation as possible.
3. As far as the aircraft itself is concerned it should keep aerodynamic drag to a minimum.
Air intakes are designed either subsonic or supersonic configuration. Those that maintain optimum airflow condition up to high subsonic speeds are called subsonic intakes whereas those which are also required to operate efficiently at aircraft speeds exceeding Mach one are called Sonic intakes
For a typical gas turbine engine the velocity of the air flow at the compressor inlet is normally less than 0.5 MC this ensures high compressor efficiency so while designing the air intake our main goal is to bring the speed of the air at 0.5 Mac at the face of the compressor. we will see how this requirement is fulfilled for both subSonic and super Sonic configuration
The aircraft which fly in the subsonic regions needs to have a subsonic intakes. The subsonic intakes are designed as a divergent duct. So that when the air enters the engine air inlet at point a it will be around 0.75 Mac.
Now recall that whenever a subsonic flow passes through a divergent duct as that area of the duct increases the pressure increases and the velocity decreases Hence when the air has reached point B the velocity of the air flow has been reduced to 0.5 Mac this ensures high compressor efficiency.
The aircraft which fly above speed of sound needs to have a Sonic intakes.the Sonic intakes are divided into 2 portion the first portion constitutes are convergent duct while the second portion constitutes a divergent duct.
When the airflow enters the point a it has a speed of 1.5 Mac now we need to reduce the speed first to make it subsonic. for this the Sonic intakes utilizes a convergent duct. now recall that Whenever there is a Sonic flow through a convergent duct, as the area of the duct decreases ,the pressure of the air flow
increases and the velocity of the air flow decreases so that when the air flow reaches the point B its speed has been reduced to 0.9 Mac. Now here is an important thing to remember at this point, the air flow has become subsonic, now if we continue using the convergent duct then instead of decreasing the speed of the subsonic flow the speed will be increased since we know that a subsonic flow through a convergent duct increases the speed so at this point in order to decrease the speed of a subsonic flow we will use a divergent that ahead of point B.
As the air flows from point B to C the area of the dark increases and the pressure of the airflow increases as well but the velocity starts decreasing .at Point C at the face of the compressor the airflow has reached 0.5 Mac this ensures high compressor efficiency.
#ENGINEAIRINTAKE #GASTURBINEENGINE #AVIATIONSTUDIES #THEHASHACADEMY
3 سال پیش
در تاریخ 1400/03/13 منتشر شده
است.
8,693
بـار بازدید شده