考题
If the engine does not start on air, it may be due toA.low compression of the fuel pumpsB.incorrect timing of fuel pumpsC.the starting air valves stuckD.air-locks in fuel oil pipeline
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When the fuel oil is burning in the combustion chamber, it _____.A.gives up large amount of heatB.gives off large amount of heatC.gives up large amount of steamD.gives off large amount of steam
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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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题干材料:Due to the large amount of heat picked up by the air in boiler and engine rooms, it would be impracticable to maintain ambient conditions within the comfort zone by air conditioning or any other means. The normal practice is to provide copious mechanical ventilation; in boiler rooms, the quantity is equated to the combustion requirements, while in a motor ship engine room the supply may be 25-50% in excess of the requirements of the engines.The axial flow fan is particularly suited to handle these large air volumes at the moderate pressures required, while of course the “straight-through” flow feature places it at an advantage over the centrifugal fan.The increasing adoption of automation, with the provision of a separate control room makes less significant the fact that comfort conditions cannot be maintained in the engine room all the time.问题:Which of the following devices should be taken to maintain ambient conditions of the boiler and machinery space?A.air compressorB.air coolerC.air-conditioning plantD.mechanical ventilation plantIn a motor vessel, the air quantity which the engine room need is_______ of the requirements of the engines.A.less than 25-50%B.more than 125-150%C.more than 25-50%D.less than 125-150%According to this passage, which of the following statements is true?A.In boiler and machinery spaces, there is the air conditioningB.In the boiler rooms the requirement of air volume should meet 25-50% of combustion requirementC.To maintain the comfort zone in the separate control room the air conditioning plant should be fittedD.The comfort conditions can be maintained in the engine room all the timeAt the middle pressure and large air quantity,_________ is more suitable.A.an axial flow fanB.a radial flow blowerC.a centrifugal fanD.an auxiliary blower请帮忙给出每个问题的正确答案和分析,谢谢!
考题
A bypass line provided around a waste heat auxiliary boiler in a diesel engine exhaust system, may be used to avoid boiler ______.A.corrosion at low engine loadsB.erosion at high engine loadsC.overload at high engine loadsD.scaling at all exhaust temperatures
考题
According to this passage, which of the following statements is true?A.In boiler and machinery spaces, there is the air conditioning.B.In the boiler rooms the requirement of air volume should meet 25-50% of combustion requirement.C.To maintain the comfort zone in the separate control room the air conditioning plant should be fitted.D.The comfort conditions can be maintained in the engine room all the time.
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单选题When the fuel oil is burning in the combustion chamber, it ().A
gives up large amount of heatB
gives off large amount of heatC
gives up large amount of steamD
gives off large amount of steam
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单选题Due to the large amount of heat picked up by the air in boiler and engine rooms, it would be () to maintain ambient conditions within the comfort zone by air conditioning.A
possibleB
necessaryC
practicableD
impracticable
考题
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The power developed by a large slow-speed main propulsion diesel engine is dependent upon the ()A
quantity of air it takes in and retains in the cylinders during a given time periodB
proportion of trapped air that is utilized in the combustion processC
thermodynamic efficiency of the engine cycleD
all of the above
考题
单选题The burning of the fuel adds more heat to the air charge, causing it to expand and force the engine piston to do work on the crankshaftWhat does “it” mean in this sentence?()A
the burningB
the fuelC
the air chargeD
the engine piston
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单选题The crew was unable to()access to the engine room due to the extreme heat.A
maintainB
retainC
gainD
contain
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单选题When would the available energy of the exhaust gases of a two-stroke/cycle diesel engine be insufficient to drive an exhaust gas turbocharger, resulting in the incorrect amount of air for combustion?()A
During operation at low speedB
During operation at rated speed, but low power outputC
During accelerationD
All of the above
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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
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单选题Cold weather starting of a diesel engine is more difficult than warm weather starting due to()A
use of low viscosity oil in cold weatherB
increased moisture content of inlet air in cold weatherC
increased drag of pistons and bearings due to increased oil viscosityD
higher compression pressures reached due to smaller clearances existing in the engine during cold weather
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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The is employed to warm up a large diesel engine before its starting()A
hot airB
hot boiler waterC
cylinder waterD
hot seawater
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单选题As for a diesel engine, lack of combustion air may be due to ().A
fouling turbineB
fuel pump faultsC
lubrication failureD
excessive cooling
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单选题A large two-stroke/cycle direct reversing diesel engine is to be reversedPrior to the admission of starting air you must ()A
line up the engine fore restarting with light diesel oilB
reposition the fuel injection camC
change the intake and exhaust valve cam positionsD
place the starting cam in the intermediate position
考题
单选题If the engine does not start on air, it may be due to ()A
low compression of the fuel pumpsB
incorrect timing of fuel pumpsC
the starting air valves stuckD
air-locks in fuel oil pipeline
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
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单选题The feed water to the boiler will comprise ().A
condensateB
a small amount of make-up feedC
A and BD
None of the above
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单选题One of the main purposes of refractories in a boiler furnace is to()A
help preheat the air for the furnacesB
help preheat the feedwaterC
protect economizer from excessive heatD
prevent excessive furnace heat losses
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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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单选题As for a oil-fired boiler too much air would indicated by ().A
yellowish flameB
golden yellow flameC
milky flameD
brilliant white flame
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单选题Explosions do occur () caused by the ignition of oil or vapour gaining access from compressors or defective engine starting valves.A
in boiler drumsB
in refrigerating plantsC
in starting air pipesD
in air coolers