GAS TURBINE COMBUSTION CHAMBER – Air – DGCA Question Bank For Politics

#1. The ratio of air to kerosene to give the greatest heat release during combustion is:

45 : 1.

130 : 1.

12.5 : 1.

15 : 1.

#2. One advantage of an annular combustion chamber system is that:

The diameter of the engine is reduced.

There is unrestricted airflow at maximum r.p.m.

There are no flame propagation problems.

The air casing area is greater.

#3. Of the total airflow entering the combustion chamber the percentage that is mixed with the fuel and burnt is:

10%

40%

20%

60%

#4. The combustion chamber drain valve is closed:

By combustion chamber gas pressure.

By a return spring.

By 12th stage compressor air pressure.

During a blow out cycle.

#5. A cannular combustion system is:

A set of flame tubes, each of which is mounted in a separate air casing.

A set of flame tubes enclosed in a common air casing.

One common flame tube enclosed in a common air casing.

Superior to the annular system because it only requires one igniter.

#6. It is necessary to have a combustion drain system:

To prevent pressure build up in the combustion chamber.

To allow moisture content in the fuel to drain away.

To allow any unburnt fuel to drain after shut down or a wet start.

To prevent the igniters becoming wetted by excess fuel.

#7. The purpose of the tertiary airflow created in the combustion chamber is to:

Reduce the gas temperature and cool the flame tube.

Form a toroidal vortex, which anchors and stabilises the flame.

Reduce the gas temperature and cool the burner head.

Ensure complete combustion of the fuel.

#8. A re-light envelope:

Shows the flame stability limits.

Shows airspeed and altitude limitations for an in-flight restart.

Shows fuel / air mixture limitations for an in-flight restart.

Contains the in flight re-start igniter plugs.

#9. Swirl vanes in the combustion chamber:

Increase the velocity of the airflow.

Reduce the velocity of the airflow.

Prevent compressor stall.

Help to stabilize combustion.

#10. The air entering the combustion chamber is divided; a small percentage is used in combustion, the rest:

Is syphoned off for airframe anti-icing purposes.

Is used only for cooling the gases before they exit the combustion chamber.

Is used to reduce the oil temperature and cool the turbine blades.

Is used to cool both the gases exiting the chamber and the walls of the air casing.

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