C1 - Manage the operation of propulsion plant machinery
Operating a steam turbine propulsion unit at medium speed, in an area with extremely cold seawater, and the main circulating pump providing full cooling water flow to the condenser will ______.
Reduce plant efficiency due to excessive condensate depression
Increase plant efficiency due to increased condensate recirculation
Decrease plant efficiency due to higher attainable vacuum
Increase effectiveness of the air ejectors due to the increased main condensate temperature
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?
To cool the walls of the flame tube
To cool down the exhaust gas for NOx emission reduction
To cool down the exhaust gas for SOx emission reduction
To add excess air to the primary air stream
The vanes 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 rotor. However, at reduced 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?
Compressor is provided with adjustable blades
Compressor is provided with diaphragm nozzles
Compressor is provided with increased number of blades
Compressor is provided with suction nozzles
Some vessel are equipped with a water lubricated stern tube .When at sea , operating under normal conditions , the water service valve from the ship`s saltwater system to the bearing should be_______.
Closed, and only slight leakage permitted across the shaft packing
Open and no leakage permitted across the shaft packing
Open, and only slight leakage permitted across the shaft packing
Closed and no leakage permitted across the shaft packing
What is the function of boiler variable capacity pressure in atomizing fuel burners?
Provide wide range of combustion
Maintain constant fuel temperature
Maintain constant fuel pressure
Maintain smoke clear atomization
What is the cause of insufficient combustion air supply to a boiler furnace?
Low superheater temperature
High superheater temperature
Sputtering fires
High stack temperature
Due to the continuous combustion which occurs in the combustion chamber of a gas turbine, steps are taken to ensure that temperatures do not become too high. How is this usually dealt with?
Supplying considerable excess air above that required for complete combustion
Installing high capacity exhaust fans in the engine room
Providing appropriately sized insulation and cladding materials around the unit
Installing high capacity air supply blowers in the engine room
When preparing to get underway and the jacking gear has been disengaged, the main turbine rotor should NOT be allowed to remain stationary for more than 3 minutes because________.
Uneven heating from gland seal steam can cause distortion of the rotor
The turbine drains line can fill with condensate
With no motor movement, the journal bearings may overheat due to reduced lube oil flow
Main condenser vacuum will drop rapidly without steam flow through the main unit
The designed function of fixed blades in an impulse turbine is to _______.
Change the direction of steam flow
Equalize pressure differences
Prevent steam turbulence
Decrease steam velocity
During the Gas Turbine Engine operation, how you can control the speed of the power turbine?
Vary the speed of the gas generator
Throttle the fuel oil line
Vary the fuel inlet
Throttle the air intake
The distance made by the propeller through the water in one revolution per minute multiplied by its pitch is called_______.
Engine speed
Ship speed
Pitch
Slip
Gland sealing steam is used on propulsion turbines to prevent_______.
Air leakage into the turbine
Overheating of the labyrinth packing
Reversed steam flow at interstage bleeds
Steam leakage through the casing drains
How is oil pressure maintained when starting or stopping a mediumsized turbine?
By providing an electric-driven auxiliary lube oil pump
By providing a non-return valve to keep the pressure in the line
By engaging the higher gear ratio to increase the lube oil pump speed
By operating the hand pump to keep the required lube oil pressure
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?
Recuperator
Air heater
Attemperator
Economizer
What should be the position of the water service valve when a vessel equipped with a water lubricated stern tube is at sea under normal condition?
Closed, and only slight leakage permitted across the shaft packing
Closed, and no leakage permitted across the shaft packing
Open, and no leakage permitted across the shaft packing
Open, and only slight leakage permitted across the shaft packing
What you need to do to optimize spark for ignition of the GasTurbine Engine?
Ensure that the capacitor discharges a spark of very hig energy
Ensure that the igniter discharges a spark of very high voltage
Ensure that the capacitor discharges a spark of very high current
Ensure that the igniter discharges a spark of very high current
In a single-shaft gas turbine, where does the combustion products expand to a pressure almost corresponding to atmospheric pressure?
Gas turbine
Combustion chamber
Gas chamber
Exhaust manifold
In a "D" type marine boiler operating under constant load, which of the following conditions could cause the superheated steam temperature to rise above normal?
Low feedwater temperature
DFT excessive vapor pressure
High feedwater temperature
Insufficient combustion air
Precautions to be observed prior to starting a turbine driven cargo pump, should include ________.
Checking the manual trip device for proper operation
Observing the operation of the overspeed trip
Assuring that the turbine casings drains are wired closed
Open all governor oil relay drains
The Gas Turbine Engine (GTE) when compared to other types of engines, offers bunch of advatages. What is the GTE greatest asset?
High power - to - weight ratio
High torque - to - weight ratio
High Power - to - length ratio
High efficient to weight ratio
When the engine is running, what part in a large,slow speed diesel engine carry most of the tension?
Tie rod
Column
Entablure
Bed plate
The operating speed of a turbocharger is directly dependent upon which of the following?
Engine load
Engine speed
Atmospheric pressure
Intake manifold pressure
In a gas turbine, the primary stream of air passes the primary combustion zone into which finelyatomized fuel is injected. Where does the secondary stream of air passes?
Around the primary combustion zone and continues into its rearmost part
Joins the primary air stream to increase the excess air
Goes back to the suction side of the air compressor
Around the exhaust manifold and continuous to the atmosphere
What are the reasons why compressor in the ship service refrigeration system is short cycling on the high pressure cutout switch? .
Condenser is getting insufficient cooling water flow
Discharge valves are leaking excessively
System is low on refrigerant
Discharge valves are leaking slightly
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?
Single-shaft gas turbine
Split-shaft gas turbine
Free-turbine version
Split-compressor gas turbine
To raise the vacuum on the main turbine unit, you should________.
Admit gland sealing steam to the turbine glands
Pump the main condenser hotwell dry
Start the lube oil pump after starting the jacking gear
Warm up and drain the main steam lines
What would be the cause of over speeding of the diesel engine driving an electric generator?
Damage to windings
Excessive exhaust temperature
Low voltage trip to trip
Reverse power trip to trip
Which of the gas turbine plant configurations used by a passenger vessel known to operate close to the optimum efficiency at different vessel speeds, with consequent benefits in fuel economy?
Combined gas turbine and gas turbine propulsion system
Combined diesel and gas turbine propulsion system
Combined gas turbine or gas turbine propulsion system
Combined diesel or gas turbine propulsion system
The high rotational speed of the gas turbine is not the best speed for a ship's propeller, which is most efficient at around 100 rpm. What is the remedy for this?
Coupling of a reduction gear box
Installing a clutch mechanism
Installing a speed governor at the power turbine
Installing another lower output gas turbine geared to the shaft
To improve the efficiency of the gas turbine installation, what component is mounted in its exhaust system that enables part of its heat content to be used before it is blown out into the atmosphere?
Heat exchanger
Nozzle
Exhaust distributor
Exhaust draft fan
A diesel engine is operating under normal load with low firing pressures and high exhaust temperatures. What is the most probable cause of this condition?
A restricted exhaust manifold
He fuel rack being too far out
A missing air intake filter
The fuel rack being too far in
From the statements given below, choose the one which is most accurate in relation to the operation of water-tube boiler and fire-tube boilers.
Water-tube boilers are more efficient and generally contain less water than fire-tube boilers.They are prone to major damage when run dry during operation
A firetube boiler does not require a non-return valve in the feed water line
A watertube boiler can tolerate a short period of time without any water when the boiler is operating
A firetube boiler has a much better capability to work at higher steam pressure
If "wet steam" is supplied to the air ejectors of a low pressure evaporator, what will be the outcome if mixtures of steam passes through the nozzles?
Cause the potential level of kinetic energy to be partially converted to thermal energy
Improve overall vacuum
Cause the existing level of thermal energy to be totally converted to kinetic energy
Cause the level of thermal energy to be converted to potential energy
What type of thermodynamic gas turbine built up of a gas generator to power the compressor and a gas power turbine connected to the ship's propulsion?
Split-version gas turbine
Combined-shaft gas turbine
Single-shaft gas turbine
Compressor-powered gas turbine
The first step in breaking vacuum on a main turbine unit should be to _______.
Secure the steam to the main air ejector
Secure the system to the gland seal steam
Stop the main circulating pump
Stop the main condensate pump
What needs to maintain during operation for a more power, more efficient and longer life engine?
Higher turbine inlet temperature
Higher turbine outlet temperature
Lower turbine inlet temperature
Lower turbine outlet temperature
Why is the installation of steam separator required in the steam line before the steam turbine?
To prevent rapid blade wear from erosion due to presence of water
To avoid water hammering in the steam line
To remove any solid particles or debris from the steam
To keep the steam at saturation temperature state
In a boiler where the drum water level is automatically controlled, which of the following conditions listed below could cause erratic variations in the water level?
High total dissolved solids content and foaming in the drum
Low pH boiler water value
Inability to maintain or correct high feedwater temperature
Uncontrolled fluctuating deaerator water level
How do both the impulse and reaction turbines make use of the pressure and thermal or internal energy of the steam from the boiler?
By allowing the steam to expand progressively through several stages
By maximizing the steam quantity at the turbine entry while minimizing the gland and bled steam pressures
By allowing some of the steam to condense under vacuum in the condenser
By allowing all the throttle valves to be fully open for maximum power
To stop the rotor of a main turbine while underway at sea, you should _______.
Admit astern steam to the turbine after securing the ahead steam
Tighten stern tube packing gland
Apply the prony brake
Secure all steam to the turbine
To optize the combination of low power maneuvering and high power operation, which of the gas turbine plant configurations should be use?
Combined diesel or gas turbine propulsion system
Combined gas turbine and gas turbine propulsion system
Combined diesel and gas turbine propulsion system
Combined gas turbine or gas turbine
What is the designated gas turbine type for use on ship's propulsion?
Turboshaft
Turbofan
Turbojet
Turboprop
When a high pressure turbine is operating at high speed, the pressure of the steam leaking through the shaft gland packing may be slightly higher than the pressure of the gland sealing system. In this situation, the excess steam is directed to the ______.
Gland exhaust condenser
Main condenser
Excess steam condenser
Auxiliary exhaust system
Why is it important to maintain good vacuum in a main turbine unit while operating astern?
To maintain proper temperatures in the ahead stage
To limit the amount of time necessary to operate astern
To prevent the ahead element from operating backwards
To reduce wind age loss in the astern section
What would be the result if steam turbine nozzles on the turbo generator are clogged with deposits?
It may prevent the turbine from developing full power
It will damages the turbines thrust bearings
The turbo-generator load will decrease
Turbine blades will be impinged and may cause pitting corrosion
Why does the main propulsion shaft turning gear usually connects to the free end of the high-speed high pressure pinion ?
Because the greatest gear ratio between the turning gear motor output and bull gear can be obtained
Because the lubricating oil from the high - speed pinion can easily supply the turning gearshigh
Because the arrangement allows for the use of a muff tuff coupling for flexibility and smooth engagement
Because the turning gears are double reduction worm type and cannot make with the low pressure high-speed pinion
How is force imparted when steam is applied to the blade of the steam turbine?
When there is a change of direction of steam across the blade
When considerable number of nozzles are put into service
When steam leaves the nozzle and starts entering the blade
When there is no change of direction of steam across the blade
With vacuum up and the main propulsion turbine standing by while awaiting orders, it is necessary to roll the unit alternately ahead and astern every five minutes to________.
Reduce the possibility of warping the turbine rotors
Warm the astern guarding valve and the low lube oil pressure throttle tip
Slowly bring the lube oil and bearings to operating temperature
Distribute the glang sealing steam evenly through out the glands
In a gas turbine, where does the continuous combustion of atomized fuel oil takes place, in the same way as in an oil burner of a steam boiler?
Combustion chamber
Turbine
Fuel intake pipe
Burner
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