Gas turbine engine with large diameter forward fan.
Air from the tips of these fan blades is by-passed around the outside of the engine, where as air from the centre is added to the normal jet efflux to provide high propulsive efficiency.
The compressed air is mixed with the fuel, burned, and expanded through the turbine. The turbine generates the power to rotate the shaft and drive the compressor.
The hot exhaust gases exiting from the turbine and compressed bypass air are mixed and expanded through an exhaust nozzle to produce the thrust.
Fuel can be added and burned downstream of the turbine to increase the thrust further.