GAD TURBINE ASSEMBLY – Air – DGCA Question Bank For Politics

#1. The effect on the temperature and pressure of the gases as they pass across the turbine is:

Their temperature decreases and their pressure rises.

Both their temperature and pressure increase.

Both their temperature and pressure decrease.

Their temperature increases and their pressure falls.

#2. Nozzle guide vanes are fitted before the turbine:

To increase the velocity of the airflow.

To decrease the velocity of the gas flow therefore increasing its pressure.

To increase the velocity of the gas flow therefore reducing its pressure.

To increase the temperature of the gas flow.

#3. One reason for shrouding turbine blades is:

To reduce “creep” which may occur in the blades.

To improve efficiency and reduce vibration.

To enable thinner blades to be used.

To minimise blade end erosion.

#4. The blades are usually attached to the turbine disc by a “Fir Tree” root. A tight fit is ensured during operation:

By the action of centrifugal force.

By thermal expansion of the disc.

By blade compression loads and thermal expansion.

By torque loading and thermal expansion.

#5. The main contributory factors which cause creep in turbine blades are:

High temperature and tensile loading.

High rpm and torque loading.

High rpm and high gas speeds.

High temperature and high gas speeds.

#6. A free power turbine:

Has a clutch between the compressor and the power output shaft.

Has no mechanical connection with the other turbine or compressor shafts.

Has a direct drive with a free wheel unit.

Comes free with every 2,000 gallons of AVTUR.

#7. The mixture of impulse and reaction blade shape in the average turbine blade is such that:

The inner half is impulse and the outer half is reaction.

The inner half is reaction and the outer half is impulse.

The leading edge is reaction and the trailing edge is impulse.

The trailing edge is reaction and the leading edge is impulse

#8. Blade creep is:

Movement of the turbine blades around the turbine disc.

Temporary expansion due to temperature change.

Temporary elongation due to centrifugal forces.

Permanent elongation due to heat and centrifugal force.

#9. The net operating temperature of a gas turbine engine is limited by:

The materials from which the combustion chamber is constructed.

The amount of fuel which can be fed into the combustion chamber.

The ability of the compressor to pass sufficient air rearwards.

The materials from which the nozzle guide vanes and the turbine blades are constructed.

#10. The impulse-reaction blade is twisted along its length so that:

There is a greater angle at the base than at the tip.

The gas flow is accelerated through the turbine.

The gas does equal work along the whole of its length

The gas flow is decelerated through the nozzle guide vanes.

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