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Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?
A.Baffle plates that have been bent during prior removal
B.Leaks m the cooler tube nest
C.Operating the engine while maintaining a high sea water outlet temperature
D.A punctured sea water strainer supplying cooling water to the heat exchanger
参考答案
更多 “ Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?A.Baffle plates that have been bent during prior removalB.Leaks m the cooler tube nestC.Operating the engine while maintaining a high sea water outlet temperatureD.A punctured sea water strainer supplying cooling water to the heat exchanger ” 相关考题
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If the coolant temperature of a closed cooling water system for a diesel enginegradually increases, the trouble usually is( ).A.a broken shaft on the freshwater pumpB.an excessive accumulation of scale in the heat exchangerC.an incorrect thermostatic element operating rangeD.lube oil in the cooling water
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In a diesel engine closed freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the __.A.suction pressure regulatorB.thermostatic bypass valveC.sea water temperatureD.water level in the expansion tank
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The purpose of treating the cooling water of the diesel engine is to______. I、 resist the scale formation in the cooling chamber II、lubricate the engine part II III、increase thermal capacity IV、 resist corrosionA.I + IIB.II + IIIC.III + IVD.I + IV
考题
第二组The only attention that heat exchanger should require is to ensure that the heat transfer surfaces remain substantially clean and the flow passages generally clear of obstruction. Indication that undue fouling is occurring is given by a progressive increase in the temperature difference between the two fluids, over a period of time, usually accompanied by a noticeable rise in pressure loss at a given flow.Fouling on the sea-water side is the most usual cause of deterioration in performance. The method of cleaning the sea water-side surfaces depends on the type of heat exchanger. With shell-and-tube heat exchangers, the removal of the header covers or, m the case of the smaller heat exchangers, the headers themselves, will provide access to the tubes. Obstructions, dirt, scale etc., can then be removed, using the tools provided by the heat exchanger manufacturer. Flushing through with fresh water is recommended before a heat exchanger is returned to service. In some applications, such as piston oil cooling, progressive fouling may take place on the outside of the tubes. Most manufactures recommend a chemical flushing pr6cess to remove this in situ~ without dismantling the heat exchanger.Plate heat exchangers may be cleaned by unclamping the stack of plates and mechanically cleaning the surface of each plate as recommended by the manufacturers. The plate seals may require replacement from time to time and here the manufacturers instructions should be closely followedBy which of the following indication, can we conclude that the lube oil-sea water heat exchanger is unduly fouled?A.the heat exchanger lube oil inlet temperature loweringB.the heat exchanger sea-water outlet pressure riseC.the heat exchanger temperature difference between lube oil and sea water increasingD.the heat exchanger pressure difference between sea water inlet and outlet decreasing
考题
Which of the following conditions could contribute to the cracking of a diesel engine cylinder head?A.Leaking seal ringB.Insufficient heat transfer from the exhaust valvesC.Blocked cooling water passages to the headD.Excessive scavenging air provided to the engine
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The purpose of treating the cooling water of the diesel engine is to____. I、 resist the scale formation in the cooling chamber II、 lubricate the engine part III、 increase thermal capacity IV、 resist corrosionA.I +IIB.II + IIIC.III + IVD.I +IV
考题
Prolonged operation of a diesel engine with a closed cooling water system, at lower than normal designed operating temperatures can ______.A.increase power outputB.decrease lube oil viscosityC.eliminate fuel knockD.cause sulfuric acid formation
考题
单选题Which of the following conditions could contribute to the cracking of a diesel engine cylinder head?（）A
Leaking seal ringB
Insufficient heat transfer from the exhaust valvesC
Block cooling water passages to the headD
Excessive scavenging air provided to the engine
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单选题Lube oil accumulating in the cooling water system of a diesel engine will result in （）A
lube cooler failureB
poor heat transferC
mechanical lubricator failureD
camshaft seizure
考题
单选题The device allowing for the change in volume of the cooling water in a propulsion diesel engine closed cooling system is the （）.A
fresh water expansion tankB
sea water expansion tankC
thermostatic expansion valveD
jacket water cooler accumulator
考题
单选题The expansion tank for a diesel engine closed cooling system is designed to maintain a constant head on the system and （）.A
reduce water temperatureB
reduce water turbulenceC
provide an air cushionD
allow for an increase in water volume as the engine warms up
考题
单选题The highest pressure in any closed diesel engine freshwater cooling system is at the （）.A
jacket water outletB
expansion tank inletC
heat exchanger inletD
cooling water pump outlet
考题
单选题Which of the following factors tends to increase scale formation on the saltwater side of a heat exchanger used in a diesel engine cooling water system?（）A
Baffle plates that have been bent during prior removalB
Leaks in the cooler tube nestC
Operating the engine while maintaining a high sea water outlet temperatureD
A punctured sea water strainer supplying cooling water to the heat exchanger
考题
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
考题
单选题The purpose of treating the cooling water of the diesel engine is to（） Ⅰ. resist the scale formation in the cooling chamber Ⅱ.lubricate the engine part Ⅲ.increase thermal capacity Ⅳ.resist corrosionA
Ⅰ+ⅡB
Ⅱ+ⅢC
Ⅲ+ⅣD
Ⅰ+Ⅳ
考题
单选题In any diesel engine closed freshwater cooling system, the lowest pressure exists at the （）.A
jacket water outletB
cooling water pump outletC
heat exchanger outletD
expansion tank atmospheric vent
考题
单选题If the jacket water temperature in an auxiliary diesel engine cooling system is lower than normal, the probable cause is （）A
air binding of the engine cooling systemB
a cracked water cooled exhaust manifoldC
blockage in the heat exchangerD
faulty operation of the thermostat
考题
单选题Which of the following problems can cause fluctuating pressures in the closed cooling system of a main propulsion diesel engine?（）A
Defective temperature controls in the systemB
Cavitation in the cooling water pumpC
Opened vent in the cooling systemD
Restricted water passages in the engine
考题
单选题On which of the following heated surfaces of a flash type evaporator would you be more likely to find soft scale formation?（）A
Feed-water heater internal tube surfacesB
Internal distillate cooler tubesC
Flash chamber vertical surfacesD
Distilling condenser tubes
考题
单选题A faulty thermostatic bypass valve, in a diesel engine cooling system, can result in （）A
excessive time required for warming-upB
excessive freshwater corrosionC
scale formation on the saltwater sideD
saltwater mixing with the freshwater
考题
单选题In a diesel engine cooling system, the high temperature alarm contact maker will be activated on excessively high water discharge temperature from the （）A
raw water pump dischargeB
expansion tank outletC
cooling water heat exchangerD
outlet engine jacket water outlet
考题
单选题Which of the following statements is correct concerning diesel engine cooling water systems?（）A
Each engine must have its own engine driven cooling water pump capable of providing cooling for all ranges of operationB
propulsion engines with bores exceeding 200 mm are to be fitted with a means to display the cooling water temperature of each cylinderC
At least two independent sea suctions are to be provided for supplying water to the engine jackets or to the heat exchangersD
Suitable strain are to be fitted between the circulating pumps and heat exchangers when sea water is used for direct cooling
考题
单选题Temperature control valves installed in the jacket cooling water system of a diesel engine modulates the rate of water flow through the （）.A
cooling water pumpB
nozzle cooling passagesC
cylinder jacketsD
heat exchanger
考题
单选题In the process of the stand-by, warm-up the engine usually through give preheat of which parts of the diesel engine?（）A
cooling water of the cooling systemB
fuel of the FO systemC
LO of the LO systemD
cooling water of the cooling system and LO of the LO system
考题
单选题In a closed diesel engine freshwater cooling system, the amount of coolant flowing through the heat exchanger is controlled by the （）.A
suction pressure regulatorB
thermostatic bypass valveC
sea water temperatureD
water level in the expansion tank
考题
单选题Which of the following faults would allow lube oil to enter the cooling system of a diesel engine?（）A
Excessive valve train lubricationB
Leaking standby oil cooler coreC
Excessive lube oil pressureD
Excessive lube oil in the system
考题
单选题Which of the following conditions will develop if the flow of ‘raw’ cooling water to diesel engine is obstructed?（）A
Air will enter the cooling systemB
Carbon will plug the water cooled exhaust manifoldsC
The jacket water temperature will riseD
The lube oil viscosity will increase
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