For a subsonic airflow, in a divergent duct the…
-
A
static pressure decreases, velocity increases and static temperature increases.
-
B
static pressure increases, velocity decreases and static temperature decreases.
-
C
static pressure increases, velocity decreases and static temperature increases.
-
D
static pressure decreases, velocity increases and static temperature decreases.
Refer to figure.
The intake geometry is designed to take full advantage of the ram effect. It captures the required air mass flow and delivers it to the compressor at the correct design speed. That’s why the intake is slightly divergent in order to reduce the airflow’s velocity (=dynamic pressure) and increase the static pressure and temperature just before the fan and compressor’s first stages.
Caution, the total pressure (and temperature) will remain constant - it is only a trade of dynamic pressure for static pressure. Compression (=increase in static pressure) is a process where heat is released, which explains why the temperature behaves in the same way through a divergent duct as pressure. This geometry is also called the ‘pitot intake’, and it has thick, smoothly rounded lips to prevent flow separation under any flight conditions/maneuvers.
- In simple words, when moving through a Divergent Duct the velocity of the air decreases but pressure and temperature increase.
Your Notes (not visible to others)
This question has appeared on the real examination, you can find the related countries below.
-
Austro Control
Use Keyboard Shortcuts
