PP 10

The correct sequence of events to sustain operation in a gas turbine engine is Intake. Compression, expansion, exhaust. Intake, expansion, compression.

What principle of Bernoulli applies to the intake and exhaust ducting in a gas turbine. Divergent ducting, decreasing velocity & increasing pressure. Convergent ducting, increasing velocity & decreasing pressure.

The most often used type of cooling and relieving thermal stresses on a turbine wheel is?. Bleed air onto the wheel surface. Increasing fuel spray onto the wheel surface.

What is referred to as blade profile?. Where the ends of the compressor blades are thinner to prevent damage should the blades contact the housing. The curvature of blades to increase compression efficiency.

What effect on the performance on the gas turbine engine will a dirty compressor cause?. Engine light off but low acceleration. Engine fails to light off entirely.

What is the purpose of the diffuser?. Decrease velocity and increase pressure direct the airflow into the combustion chamber. Increase velocity and decrease pressure before the turbine.

What is the purpose of the variable stator blades?. Reduce the possibility of stalls. Increase exhaust gas temperature.

What is the purpose of a blow in door?. To let more air into the plenum chamber for ground ops. To restrict airflow into the engine during high-altitude ops.

How does a torque indicate system pressure?. Shaft HP. Compressor discharge pressure.

What is the proper starting sequence for a turbine engine?. Airflow, ignition, fuel. Ignition, fuel, airflow.

What are the characteristics of a labyrinth seal?. Pressurized by a light film of air. Sealed by heavy oil lubrication.

Carbon seals are used for?. Spring loaded to hold carbon rings against the rotating shaft. Preventing air leakage from turbine blades.

What bearings are usually used to absorb loads in the compressor of a turbine?. Ball bearings. Tapered roller bearings.

What is the procedure for cracks in swirl vanes in the combustion chamber-rejection. Loose swirl vanes can be silver braized. Loose swirl vanes must be welded with TIG process.

What is the most efficient combustion can used in a centrifugal type compressors. Multiple chamber or cam. Annular reverse flow.

What is the purpose of the bleed valve?. Reduce of possibility of stall. Increase turbine inlet temperature.

Labyrinth seals are made of. Circumferential grooves. Interlocking metal teethe.

What is the basic difference between turbo prop and turbo jet engines. Tuebo Prop Engines have more turbine stages. Turbo jet engines have more compressor stages.

Drain valves in gas turbine engines are for. Preventing fuel build up in combustion area after shutdown. Increasing fuel flow during start.

What are stator blades?. Blades between rows of compressor blades. Blades on the turbine output shaft.

What is the purpose of the pre-swirl vanes in combustion liner?. Better atomization of the fuel-air mixture. Cooling the outer liner walls.

What is the prime advantage of a centrifugal flow compressor over axial flow?. Less weight & ease of manufacture – centrifugal Low frontal area – axial. Higher compression ratios than axial flow compressors.

What is an impeller of a centrifugal flow compressor made of?. Forged aluminum alloy. Cast stainless steel.

What is outer layer on an insulation blanket made of?. Stainless steel. Titanium mesh.

A stage comprises of what in an axial flow compressor. Rotor and stator. Stator only.

In a turbo jet engine with a triple row turbine where are the longest blades. At the rear of the turine section. At the front of the turbine section.

What is the operating principle of a torque indicating system. The twisting action on power transmitting device. The temperature variation in the exhaust.

What are the last chance filters in an oil system?. Filter located just before the spray nozzles. Filter located after the oil tank vent.

The calorific value of JP-4 IS 18,730. The value of JP1 IS 18,590. Jp4 has a greater range. JP1 has a greater range.

What is the principle of a fuel-oil heat exchanger?. Cools the oil & heats the fuel. Heats the oil & cools the fuel.