Chapter 4. Turbojet engine with afterburner

The power of turbojet engine can be increased by installation of afterburner between turbine and nozzle. The afterburner provides the additional energy to the gases before nozzle. It increases the exit gases speed from nozzle and thrust.  Usually, turbojet engines with afterburner are supplied with converging/diverging nozzle as such aircrafts are designed for supersonic flights. The turbojet engine with afterburner (ab) is shown in Fig. 4.1.

Fig. 4.1. Scheme of turbojet engine with afterburner.

The calculation of turbojet engine with afterburner is identical to the regular turbojet engine until a turbine section (Chapter 3(4)).

4 (ab). The total pressure after afterburner is

where  is the pressure losses in the afterburner.

The relative fuel consumption in the afterburner is

where the enthalpies   and    can be found from the empirical curves [1]. The lower heating value of kerosene is .
5. The disposable pressure ratio at the nozzle is

If the pressure is fully discharged in the nozzle the normalized gas speed from nozzle is

or by using gas dynamic function:

6. The specific thrust is

and the specific fuel consumption is

The thrust is

7. The effective efficiency of cycle is

where  is an effective work of cycle that can be found from

The flying efficiency is

The total efficiency is