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单选题
A waste heat boiler is installed on some diesel propelled vessels to （）.
A
provide steam for emergency propulsion
B
provide steam for the turbo-generator
C
heat the waste water tanks
D
steam for warming engines
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单选题Before shutting off the fuel supply to stop a medium or high–speed diesel engine, why is it necessary to allow the engine to idle for a few minutes?（）A
To prevent internal damage form local overheatingB
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To let the waste heat boiler reduce its rate of steam generation
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reduce exhaust gas temperatureD
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单选题Which of the following items is necessary for all waste heat boiler installations, regardless of design or manufacturer? （）A
Control of evaporationB
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单选题Which of the devices listed is installed on a diesel engine to isolate some of the crankshaft vibrations caused by rotational and reciprocating forces?（）A
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单选题The over-speed trip device installed in some diesel engines is automatically actuated by（）A
spring forceB
hydraulic pressureC
centrifugal forceD
mechanical linkage
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单选题An exhaust gas bypass is installed on a waste heat boiler in order to （）.A
bypass exhaust gas at high loads to prevent excessive back pressureB
bypass a portion of the exhaust gas at peak loads for better efficiencyC
recycle exhaust gas to the turbochargerD
minimize moisture condensation in the boiler gas passages at low loads
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单选题The diesel engine exhaust gas bypass, as fitted with some waste heat boilers, is installed to （）A
prevent engine back pressure at heavy loadsB
increase total engine efficiency at low loadsC
prevent boiler corrosion at low engine loadsD
improve engine fuel consumption at any load
考题
单选题The rate of heat transfer in a water-tube auxiliary boiler can be increased by （）.A
operating the boiler at less than normal water levelB
installing fins on the firesides of water-tubesC
increasing the amount of excess air to the burnersD
treating the boiler water with chemical oxygen scavengers
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单选题Which of the following statements represents the function of the compression rings installed at the top of a diesel Engine piston?（）A
Control the amount of lube oil burned in the combustion chamberB
Transmit heat from the piston to the cylinder linerC
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考题
单选题The purpose of designing some waste heat boilers with sinuous fire tubes, is to（）A
increase exhaust gas velocity through the boilerB
reduce accumulations of carbon deposits on the heat transfer surfacesC
eliminate exhaust gas pulsations and noiseD
increase the rate of heat transfer to the waterside
考题
单选题Diesel engine waste heat boiler construction is usually of the fire-tube or（）A
cyclone furnace boiler typeB
dry back boiler typeC
water-tube typeD
critical circulation boiler type
考题
单选题Generating tubes in waste heat boilers are finned to （）.A
reduce gas flow turbulenceB
prevent exhaust gas corrosionC
increase the rate of combustionD
increase the rate of heat transfer
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单选题The maximum pressure developed by a waste heat boiler is determined by the main engine exhaust （）.A
gas compositionB
gas temperatureC
pressureD
timing
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单选题Which one is not the normal operation for boiler shutdown?（）A
Carry out soot blowing if permissibleB
Change fuel supply to diesel oilC
Close steam stop valves on boiler when pressure is reducedD
Drain boiler empty when it has cooled down
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space limitations prevent separately run pipesB
the engines are small auxiliary unitsC
they are arranged to prevent gas backflow to each engineD
a waste heat boiler is installed
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单选题Fins are installed on the fireside of water-tubes used in waste boiler to（）A
decrease the velocity of gases flowing past the tubesB
increase the rate of heat transferC
reduce accumulations carbon depositsD
direct the flow of gases
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单选题The interior of some diesel engine saltwater heat exchangers are protected from corrosion by the use of（）A
aluminum platesB
lead cathodesC
copper baffle platesD
sacrificial zincs
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单选题In motor ship, （） is often used to recover some of the heat carried in the exhaust gases from the main engine.A
an diesel oil heaterB
a waste heat boilerC
a fresh water generatorD
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单选题Fins are installed on the generating tube surfaces in waste heat boilers to （）.A
prevent soot fires in the exhaust systemB
prevent exhaust gas erosion of the tubesC
increase the velocity of exhaust gas flowD
increase the rate of heat transfer
考题
单选题The PRIMARY function of a waste heat boiler is to （）.A
reduce engine exhaust noiseB
reduce engine back pressureC
recover heat which otherwise would be lostD
increase turbocharger efficiency
考题
单选题Excessive alkalinity of the water in an auxiliary boiler can cause （）.A
caustic embrittlement of the boiler metalB
acidic corrosion of the boiler metalC
hard scale deposits on the boiler tubesD
etching of the heat exchange surfaces
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单选题Sacrificial zinc anodes are used on the saltwater side of diesel engine heat exchangers to（）.A
reduce electrolytic action on heat exchanger metalsB
keep heat transfer surfaces shiny and cleanC
prevent rapid accumulation of marine growthD
provide a protective coating on heat exchanger surfaces
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单选题Valve cages are used on some large diesel engines to （）A
reduce wear on the valve stemB
permit the use of alloy valve seat materialsC
reduce heat transfer from the valve seatD
facilitate valve removal for servicing
考题
单选题A SECONDARY function of a waste heat boiler is to （）.A
reduce engine exhaust noiseB
reduce engine back pressureC
increase engine cycle efficiencyD
increase turbocharger efficiency
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