In a Jet Engine what are those rings that appear in the flame coming out the back.?

Answer 1

They are shockwaves that result from the supersonic flow that is exiting the engine nozzles. The properties of the shockwaves will be dependant on the mass flow rate through the engine and configuration of the nozzle.

The "rings" are not the afterburners - the afterburners are the fuel injectors & igniters that re-light the exhaust gases once the extra fuel has been dumped into them.

Try searching "supersonic flow theory" to find out how it all works.

Answer 2

Those would be the afterburners, only found on military aircraft these days, except Concorde did have them too. Basically they are a way of getting extra thrust from the engine without actually having a bigger engine. Fuel is pumped into the exhaust of the engine which ignites and provides thrust similar to a rocket engine. The downside is the amount of fuel required is immense, an afterburner on can empty the fuel tanks in a matter of minutes so they are really only used during take-off or in certain combat situations, or to get the aircraft over the sound barrier where the drag increases incredibly until the aircraft gets faster than the speed of sound. The rings in it are basically shock waves where subsonic and supersonic flow mix. Hopefully that answers your question.

Answer 3

This is an interesting question. My theory would be, and I'm interested to see if I'm right, that the rings are the effect of the flames, being under tremendous pressure, coming out in such a concentrated form. I presume that, without it, the circles you see would be jagged like a normal flame, so they are probably parts of the flame that are either chemical or temperature, may both I suppose, markers. Physics forces them to appear as a ring. If magnified, I would presume they look like jagged rings.

Answer 4

Afte burner presure bands

Answer 5

I feel like I missed the boat on this one.....
Afterburners.

Answer 6

after burners i think your on about