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Q2. Describe with aid of sketches, a turbocharger bearing lubrication system, stating the type of bearing employed and explaining the advantages and disadvantages of the lubricating system described. One of the turbochargers of the main engine on the vessel aboard which you are serving as second engineer has suffered a sudden and unexpected failure. Write a letter to the ship owner/operator concerning the incident and stating the action taken in bringing the turbocharger back into service.

Q1. (a) Explain the types of turbocharging in a marine diesel engine. (8)

(b) What are the reasons that may induce vibration on a main engine turbocharger? (8)

Q9. During normal engine operation, a turbocharger rapidly loses speed and the speed reduction is accompanied by appreciable noise -

A. State with reasons the possible causes.

B. Explain in detail how the engine might be safely operated if the damage caused by this incident is such that the turbocharger cannot function.

C. State with reasons the factors which may limit engine operating speed with the turbocharger out of operation.

Q4. Referring to latest developments in Turbo charger application in marine diesel engines, write short notes on the following:-

(a) Power turbines Generators.

(b) Hybrid Turbo Chargers.

(c) Electro-assist Turbo chargers.

Q8. a) To improve the power-to-weight ratio of an engine, it is necessary to increase the mep. Discuss the importance of turbocharger compression ratio in this regard. Why has it become necessary to introduce two-stage turbocharging?

b) With reference to turbochargers with variable turbine area, explain

i)Which area is varied

ii)Why is it varied

iii)How is it varied.

Q4. Many modern turbochargers use sleeve type bearings for rotor support.

A. Explain the reasons for their preference over the rolling contact bearings;

B. With a sketch describe the lubricating system provided for this type;

C. In a turbocharger with integral type of bearings, describe the procedure for renewing the bearings.

Q8. Sketch and describe a turbocharger-bearing lubrication system. State the type of bearing employed and explain the advantages and disadvantages of the lubricating system described.

Q5. With reference to main turbochargers:

a) Give a reason why binding wire is frequently fitted near the top of the blades

b) Mention one fault that occasionally develops with binding wire in services,

c) Define the cause and identification under running conditions of turbine blade damage

d) State how (c) can be largely avoided.

Q3. Describe, with the aid of sketches, a system of turbo-charging a two-stroke cycle main engine. State the routine attention, which should be given to the turbo-charger. Which parameters are to be recorded during watch keeping? (16)

Q9. a) Draw a simple sketch of turbocharger, describing each component. (8)

b) Describe how compressed air is delivered by the turbocharger to main engine? (4)

c) What arrangement is provided on turbocharged 2-stroke main diesel engine to provide compressed air while starting of main engine. (4)

Q8. With reference to the construction of a turbocharger, sketch and describe

a) The rotor bearing and it's method of lubrication. (6)

b) Labyrinth seal and explain how such a seal work. (6)

c) Impeller and diffuser. (4)

Q7. Describe the following turbocharger cleaning operations.
(a) Turbine side water washing. (6)
(b) Turbine side Dry Cleaning. (5)
(c) Blower side water washing (5)