Comp 3

Question 1

13. What type of thermodynamic gas turbine composed of an air compressor, combustion chamber, and gas turbine, wherein the energy released by the process is partly used to operate the air compressor?
    A. Free-turbine version
    B. Split-compressor gas turbine.
    C. Single-shaft gas turbine.
    D. Split-shaft gas turbine.

Answer 1

C. Single-shaft gas turbine.

Question 2

14. What is the main reason why the navy and military ships have always been using the marine gas turbine engines?
    A. It has less maintenance.
    B. It occupies less space in the engine room.
    C. The fuel type used is mostly available worldwide.
    D. It can accelerate the speed of a ship by a huge factor.

Answer 2

D. It can accelerate the speed of a ship by a huge factor.

Question 3

15. The gas turbine relies on oil for lubrication of parts. Because of the high temperatures reached by the oil leaving the bearing surfaces ( about 300 degC ), as opposed to the normal 100 degC, what is the preferred type of oil to be used?
    A. EP lubricants.
    B. Mineral oils.
    C. Synthetic oils.
    D. Hydraulic oils.

Answer 3

C. Synthetic oils.

Question 4

16. In a gas turbine, the primary stream of air passes the primary combustion zone into which finely-atomized fuel is injected. Where does the secondary stream of air passes?
    A. Goes back to the suction side of the air compressor.
    B. Joins the primary air stream to increase the excess air.
    C. Around the primary combustion zone and continues into its rearmost part.
    D. Around the exhaust manifold and continuous to the atmosphere.

Answer 4

C. Around the primary combustion zone and continues into its rearmost part.

Question 5

17. In a gas turbine, how is combustion started which ignites fuel/air mixture and then continue to burn under stable conditions?
    A. By the use of a hearing rod.
    B. By high voltage spark.
    C. By heating the compressed air to attain spontaneous ignition.
    D. By injection of highly atomized fuel.

Answer 5

B. By high voltage spark.

Question 6

18. In the 4-stroke cycle engine, what happens basically during compression stroke?
    A. The fuel injector injects fuel to the cylinder.
    B. The oil pump delivera fuel to the fuel injector.
    C. The intake and exhaust valve opens.
    D. Both intake and exhaust valves close.

Answer 6

D. Both intake and exhaust valves close

Question 7

19. As part of a survey of a main steam boiler , it is necessary to check the condition of the steam drum. What would be the preferred method for checking the drum shell thickness in such a situation?
    A. Use magnetic particle inspection.
    B. Use dye penetrant tester.
    C. Drill a test hole in the shell to accurately measure the thickness.
    D. Use ultrasonic thickness instrument.

Answer 7

D. Use ultrasonic thickness instrument.

Question 8

20. The designed function of fixed blades in an impulse turbine is to ______?
    A. Decrease steam velocity.
    B. Change the direction of steam flow.
    C. Equalize pressure differences.
    D. Prevent steam turbulence.

Answer 8

B. Change the direction of steam flow.

Question 9

21. In a single-shaft gas turbine, where does the combustion products expand to a pressure almost corresponding to atmospheric pressure?
    A. Gas turbine.
    B. Combustion chamber.
    C. Exhaust manifold.
    D. Gas chamber.

Answer 9

A. Gas turbine.

Question 10

22. Part of the heat contained in the exhaust from the gas turbine can be used for pre-heating the compressed combustion air to reduce the specific fuel oil consumption. What is the heat exchanger called for this purpose?
    A. Air heater
    B. Economizer
    C. Attemperator
    D. Recuperator

Answer 10

D. Recuperator

Question 11

23. The most important factor in engine performance is the actual power output at the end of the crankshaft available for doing work is known as ______.
    A. Friction horse power.
    B. Net horse power.
    C. Brake horse power.
    D. Union joints.

Answer 11

C. Brake horse power.

Question 12

24. Due to the continuous combustion which occurs in the combustion chamber of a gas turbine, steps are taken to ensure that temparatures do not become too high. How is this usually dealt with?
    A. Installing high capacity air supply blowers in the engine room.
    B. Providing appropriately sized insulation and cladding materials around the unit.
    D. Supplying considerable excess air above that required for complete combustion.

Answer 12

D. Supplying considerable excess air above that required for complete combustion.

Question 13

25. The canes of air compressor of a gas turbine are designed so that the highest efficiency is achieved at or near the speeds considered normal for the roto. However, at resuced power, the flow conditions will be poor, and efficiency will be lower than the designed point. What can be done to prevent this reduction in efficiency?
    A. Compressor is provided with suction nozzle.
    B. Compressor is provided with diaphragm nozzles.
    C. Compressor is provided with adjustable blades.
    D. Compressor is provided with increased number of blades.

Answer 13

C. Compressor is provided with adjustable blades.

Question 14

26. What is considered as disadvantage of a 4-stroke cycle diesel engine?
    A. The use of scavenge ports.
    B. Fewer power strokes per revolution of the crankshaft.
    C. Higher working temperature of piston and cylinder.
    D. Part of the fuel is burned as the piston is moving.

Answer 14

B. Fewer power strokes per revolution of the crankshaft.

Question 15

27. The secondary air of a gas turbine plant serves two purposes, one of which is to lower the temperature of the gasses from the primary zone to a level acceptable to the materials used in the turbines. What is the other purpose?
    A. To cool the walls of the flame tube.
    B. To cool down the exhaust gas for SOx emission reduction.
    C. To add excess air to the primary air stream.
    D. To cool down the exhaust gas for NOx emission reduction.

Answer 15

A. To cool the walls of the flame tube.