Contents
What is pressure recovery aerodynamics?
An increase in fluid velocity leads to a drop in local pressure. As fluid velocity slows down, local pressure increases; i.e. there is pressure recovery. If decrease in fluid velocity is accompanied by an increase in turbulent flow, there will be an increase in heat loss at the expense of pressure recovery.
What is the importance of compressor inlet screens?
Compressor Inlet Screens To prevent the engine from readily ingesting any items that can be drawn in the intake, a compressor inlet screen is sometimes placed across the engine air inlet at some location along the inlet duct.
What does spillage drag on an inlet mean?
Spillage drag, as the name implies, occurs when an inlet “spills” air around the outside instead of conducting the air to the compressor face. The amount of air that goes through the inlet is set by the engine and changes with altitude and throttle setting.
What happens when air spills over the cowl lip?
As the air spills over the external cowl lip, the air accelerates and the pressure decreases. This produces a lip suction effect that partially cancels out the drag due to spilling. Inlet aerodynamicists account for this effect with a correction factor K that multiplies the theoretical spillage drag. Typical values of K range from .4 to .7.
When does spillage drag occur in a compressor?
Spillage drag, as the name implies, occurs when an inlet “spills” air around the outside instead of conducting the air to the compressor face.
What is the correction factor for an inlet?
This produces a lip suction effect that partially cancels out the drag due to spilling. Inlet aerodynamicists account for this effect with a correction factor K that multiplies the theoretical spillage drag. Typical values of K range from .4 to .7. But for a given inlet the value is determined experimentally.