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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 level
B
installing fins on the firesides of water-tubes
C
increasing the amount of excess air to the burners
D
treating the boiler water with chemical oxygen scavengers
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更多 “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” 相关考题
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
单选题One advantage of dry cylinder liners used in a diesel engine is the（）A
lower thermal expansion rates than wet linersB
greater heat transfer rate than wet linersC
greater wear resistance than wet linersD
procedure to replace dry liners is simpler than for wet liners
考题
单选题What is NOT a function of the steam drum of a marine water-tube boiler（）.A
Receives saturated steam from the generating tubesB
Serves as a reservoir of boiler feed waterC
Holds internal fittings for separation of moisture from steamD
Collects steam exhausted from the turbines
考题
单选题In readying an auxiliary water-tube boiler for a routine hydrostatic test, which of the following procedures should be undertaken prior to filling the boiler with fresh water?（）A
The safety valve escape piping should be disconnected from the valve body and a blank insertedB
The boiler vent valves should be openedC
All hand-hole/manhole covers should be tightened up as much as possible to preclude any leaksD
All of the above
考题
单选题In the event of a flame failure in an auxiliary water-tube boiler, you must（）A
relight the boiler immediately to prevent loss of steam pressureB
relight the fire off the brickwork as the bricks are cherry redC
purge the furnace of any combustible gases before attempting to relight the fireD
speed up the feed pump to prevent dry firing when the burner flame is reestablished
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
考题
单选题In readying an auxiliary water-tube boiler for a routine hydrostatic test, which of the following procedures should be undertaken prior to filling the boiler with fresh water?（）A
The safety valve escape piping should be disconnected from the valve body and a blank insertedB
The boiler vent valves should be openedC
All handhole/manhole covers should be tightened up as much as possible to preclude any leaksD
All of the above
考题
单选题Bottom blow valves are installed on auxiliary water-tube boilers to （）A
remove suspended and precipitated solids from the boiler waterB
completely drain the boiler in an emergency situationC
prevent hardened scale deposits in the water drumD
remove floating impurities from the oily water surface
考题
单选题Which of the statements listed concerning heat transfer is correct?（）A
Heat is always transferred at a constant rateB
Heat transfer rate increases as temperature difference increasesC
The rate of heat transfer is not affected by temperature differenceD
The high temperature region is known as a heat sink
考题
单选题The rate of heat transfer from a hot region to a cold region is affected most by the （）.A
size of the heat sinkB
temperature difference between the regionsC
size of the heat sourceD
total heat of the system
考题
单选题Which of the following statements is correct concerning heat transfer?（）A
Heat is given off from a high temperature region known as a heat sinkB
Heat transfer rate is affected most by the size of the heat sink involvedC
Heat transfer rate is affected most by the temperature difference between the heat source and the heat sinkD
Heat transfer by radiation will occur only by mass motion of a fluid substance
考题
单选题The rate of heat transfer between the hot and cold fluids passing through a shell-and-tube type heat exchanger will （）.A
remain constant along the tubes lengthB
be greatest in a single pass counter flow heat exchangerC
remain constant throughout the heat exchangerD
vary from section to section through out the heat exchanger
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The water in an auxiliary boiler should be tested daily for （）.A
dissolved oxygenB
chloridesC
sludgeD
dissolved nitrogen
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The fuel supply system to an automatic auxiliary boiler, will be automatically shutdown if the boiler （）A
salinity is abnormally highB
steam demand is too highC
water level is abnormally lowD
feedwater flow is low
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
考题
单选题The fuel oil supply system to an automatic auxiliary boiler, will automatically shutdown if the boiler （）A
steam demand is highB
salinity is highC
safety valve simmersD
burner flame is extinguished
考题
单选题Exhaust pipes for separate diesel engines can be combined only when （）A
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
考题
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
考题
单选题A （） boiler is an auxiliary boiler sometimes included in a steamships installation for supplying steam to auxiliaries in port.A
monkeyB
donkeyC
waste heatD
main
考题
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Which of the lists forms of heat transfer, if any, is illustrated by the flow of combustion gases through a boiler?（）A
Natural convection onlyB
Forced convection onlyC
Both natural convection and forced convectionD
None
考题
单选题The boiler water alkalinity in a coil-type auxiliary boiler should be maintained at the pH recommended by the boiler manufacturer to（）A
precipitate silica from solutionB
reduce corrosion in the heating coilC
prevent clogging and erosion in the coilD
maintain zero water hardness
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
考题
单选题Bottom blow valves are installed on auxiliary water-tube boilers to （）A
completely drain the boiler in an emergencyB
prevent sludge from forming in the drumC
remove floating impurities from the boiler water surfaceD
remove settled solids from the water drum
考题
单选题If the feed pump for an auxiliary boiler fails to deliver the feed water to the boiler, the cause maybe （）.A
high steam pressure in the boilerB
abnormally high feed water temperatureC
abnormally high boiler water temperatureD
steam demand exceeding feed pump capacity
考题
单选题Before an auxiliary boiler is shutdown for an extended period of time, the water in the boiler should have a pH value of （）.A
10B
7C
4D
1
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