How do you slow down supersonic air?
For a supersonic aircraft, the inlet must slow the flow down to subsonic speeds before the air reaches the compressor. Some supersonic inlets, like the one at the upper right, use a central cone to shock the flow down to subsonic speeds.
What if airflow goes supersonic onto compressor or at any part of engine?
Supersonic airflow through the front of the jet engine would create shock waves to form across the fan and compressor blades, which would not only destroy the normal flow through the engine, but would also cause destructive vibrations and oscillations which could rapidly destroy the engine.
How does a jet engine work at supersonic speed?
When a jet airplane is flying faster than Mach 1—beyond the speed of sound—the air entering the engines is moving supersonically as well. But no turbojet engine compressor—the rotating disks and blades at the face of the engine that compress the air before it is mixed with fuel—is capable of handling supersonic air flow.
How does a compressor blade work in supersonic flow?
A compressor blade works best in subsonic flow. Supersonic flow introduces additional drag sources which should be avoided if efficiency is important. Thus, the intake has to slow down the air to a Mach number between 0.4 and 0.5.
How are jet engines able to run at high speeds?
Due to the high flight speeds, compression is possible by a cascade of shocks, so no moving turbomachinery is needed in ramjets and scramjets. All jets decelerate air in their intake in order to increase air pressure. This compression heats the air, and in order to achieve a combustion which produces thrust, this heating must be restricted.
How does an inlet work in a jet engine?
But no turbojet engine compressor—the rotating disks and blades at the face of the engine that compress the air before it is mixed with fuel—is capable of handling supersonic air flow. The job of an engine inlet is to slow incoming air to subsonic speeds before it passes through the engine.