Thrust may decrease due to reduction of density, weight of fuel flow, Engine RPM, Amount of air bleed from the compressor. Then to have more thrust during take off, sharp manoeuvres, the required thrust must be obtain. This method is using in gas turbine engines.
According to this formula we can see that Thrust can be increase by increasing weight and changing the velocity equation. Further more increasing v2 factor
Alcohol (methyl or ethyl) is additional source of fuel and gives small thrust. It may not pass the central part of the combustion chamber because it has low combustion efficiency. Water alone may produce high thrust per pound than water alcohol mixture.( high latent heat of vaporisation & reduce the temp: )Water and alcohol mixture may, keep turbine temperature and may restored & lower the freezing point of waterDemineralized water to prevent deposits build up on compressor blades.
Principle of This method may vaporizing the liquid cooling air.( Increase the Density & Mass). If water is only used, need more fuel to be burned. Higher turbine temperatures may result in increased thrust.Increase mass flow through the turbine to compressor, may result decreased temperature and pressure drop across the turbine, then increased pressure at the exhaust nozzle.
𝑊𝑎 water mass, 𝑊𝑓 Alcohol MassThermal shock due to cooling effect.𝑊_𝑎 water mass, 𝑊_𝑓 Alcohol MassThermal shock due to cooiing effect.
3. In ram air operation Air is used but in this system fuel is used.4. 50% of thrust increased due to heat is increased. But direct fuel is used this may cause to higher fuel consumption. Then this system only use in akeoff, climb, and maximum bursts of speed.The advantage of this system is it will act only after the turbine, then the heat limitation on turbine can be avoided.5. Variable area exhaust nozzles may wide open when after burning conditions on to provide sufficient area to exit gas stream to avoid back pressure.
After the turbine operation will carry out then no effects on engine due to heat.During “Cold Operation” restriction may occur at burner due to flame holders and fuel spray bar.To have control in high thrust
Screech liner is to reduce noise.
Extra quantity of fuel is injected into one of the chamber, the resultant hot gases will ignites the afterburner fuel.Pilot light is fed fuel and ignited on its own, it will ignite the afterburner.Similar to spark plug
Augmentation System are used to generate more thrust at small time. These applications either water injection or aftrburner may change according to the application.In military aircrafts these system are using in quick manuevors and ta have short take off.Civil Air crafts use to have short take of with heavy payload.
THRUST AUGMENTATION 1
AIMAim of this presentation is give a briefintroduction about the thrust augmentation ingas turbine engines.2
Use in Turbo Jets and Turbo fan engine types.Periodically increase in thrust.Much similar to Ramjet operationPrinciple of Afterburning is increasing exit air velocity.Cooperated with variable area exhaust nozzles.10
Specific RequirementsLarge Temperature RiseLow Dry LossWide Temperature Modulation11