Unit 16 - Prime Movers & Engines (Ch. 68-72)
How many basic types of turbines are there? A) 2 B) 3 C) 4 D) 5 E) 6
A) 2 impulse and reaction
A steam engine will have the steam supply to the cylinder shut off once the piston has traveled _____ of its stroke. A) 25% to 35% B) 75% to 90% C) 15% to 20% D) 55% to 65% E) 90% to 95%
A) 25% to 35%
Explain how the exhaust gases are discharged from the cylinder of a two-stroke cycle spark ignition engine.
At the bottom of the downward stroke, the exhaust port is uncovered and the expanding gasses are allowed to escape. At the same time, the fuel-air mixture entering the cylinder removes remaining exhaust gases (scavenging).
Large internal combustion engines achieve cooling by use of: A) evaporation. B) air cooling. C) water jackets. D) condensers. E) refrigerants.
C) water jackets.
Approximately ___________________ of the power produced by a gas turbine is used to drive the turbine compressor.
Two-Thirds
Steam turbine governors: A) prevent the turbine from over speeding B) regulate the speed of the turbine automatically C) Should be checked annually by the boiler inspector D) Are driven by the generator shaft E) Are not required for reaction turbines
b
Reaction turbines: A) have bucket shaped blades B) have a pressure drop through the moving and stationary blades C) are used for high pressures only D) have a pressure drop in the moving blades only E) have little axial thrust
b
Steam engines are still used today for? A) For fast rotational speed B) For reversal of rotational direction C) For driving gas engines D) For its low cost
b
Turbine thrust bearings are fixed to the casing and prevent axial movement of the spindle by contacting a component on the shaft known as a ____________________________. A) shaft sleeve B) labyrinth C) collar D) shroud E) diaphragm
c
Two of the more important methods of classifying a steam turbine are by the stationary steam passages and the: A) Casing passages B) Exhaust passages C) Rotor passages D) Inlet passages E) Oil passages
c
With a steam turbine, a large amount of lubricating oil is supplied to the bearings because: A) There is a large amount of friction between the bearings and the shaft. B) Steam turbine bearings are very fragile. C) Heat is removed from the bearings by the circulating oil. D) The oil is also used for operating the hydraulic governor.
c
A "heat engine" is an operating cycle that uses a working fluid to convert: A) Thermal energy to chemical energy B) Chemical energy to mechanical energy C) Thermal energy to electrical energy D) Mechanical energy to electrical energy E) Thermal energy to mechanical energy
e
A large reaction turbine will have A) no thrust bearings B) steam pressure dropping in only the moving sections C) blades which are basically symmetrical in cross-section D) never more than 5 stages E) steam pressure dropping through moving and stationary sections
e
A simple gas turbine is one without reheaters or: A) Starting motors B) Shafts C) Compressors D) Combustors E) Regenerators
e
A two-cycle gasoline engine: A) Has more moving parts than a four cycle B) Produces twice as much power as a four cycle C) Must have two cylinders D) Requires exhaust valves E) Is of more simple construction than a four cycle
e
Biological fouling in recirculating cooling water towers is caused by algae, _____ and bacteria growth. A) Flora B) Fauna C) Micro-organisms D) Biological E) Fungi
e
Clean air flows into a gas turbine regenerator from: A) Before the compressor B) After the combustion chamber C) Between the turbine and combustion chamber D) Between the turbine and atmosphere E) Downstream of the compressor
e
In a four-stroke cycle gasoline engine, each cylinder is fitted with two or more __________________ valves held closed by _____________________________.
poppet, springs
There are two basic types of steam turbine categorized by the type of blade used. These are _______________ turbines and ________________ turbines.
reaction turbines impulse turbines
remove
remove
Sulphuric acid is added to reduce _____________________ in cooling tower water.
scaling
Before entering the steam chest of a steam engine (or turbine) the steam flow is regulated to control the engine speed by a ________________________ valve.
throttle valve
Which of the following are heat engines? *(choose all that are correct)* 1. Steam turbine 2. Gasoline engine 3. Wind Mill 4. Jet engine 5. Steam power plant 6. Gas turbine 7. 2 stroke engine
2, 4, 5, 6, 7
In cold climates, ice formation in cooling tower can be dealt with be: *(choose all that are correct)* 1. slowing the fans down. 2. spray the unit with glycol. 3. reversing the fans. 4. reversing the flow of cooling water.
1 & 3 slowing the fans down. reversing the fans.
Which of the following are disadvantages of gas turbines? 1. high noise levels. 2. low thermal efficiency. 3. slow and difficult start-up. 4. cannot burn solid fuels. 5. low power to weight ratio.
1, 2 & 4 high noise levels. low thermal efficiency. cannot burn solid fuels.
Which steam plant functions do gas turbines replace? *(choose all that are correct)* 1. boilers. 2. steam turbines. 3. boiler feedwater pump. 4. control system.
1, 2, 3 boilers, steam turbines, boiler feedwater pump.
Impulse turbines: *(choose all that are correct)* 1. have a velocity increase through the nozzles. 2. blades have the angle of inlet the same as the outlet. 3. could have more than one set of blades. 4. are used for low pressure steam only. 5. may not require a thrust bearing.
1, 2, 3, & 5 1. have a velocity increase through the nozzles. 2. blades have the angle of inlet the same as the outlet. 3. could have more than one set of blades. 5. may not require a thrust bearing.
Which of the following are prime movers? *(choose all that are correct)* 1. Steam turbine 2. Gasoline engine 3. Wind Mill 4. Jet engine 5. Steam power plant 6. Gas turbine 7. 2 stroke engine
1, 2, 3, 4, 6, 7
Chemical methods used to prevent biological fouling in cooling towers include: *(choose all that are correct)* 1. oxidizing chemicals. 2. strong acids. 3. heavy metals. 4. non-heavy metals. 5. non-oxidizing chemicals.
1, 3, 5 oxidizing chemicals. heavy metals. non-oxidizing chemicals.
Some of the characteristics which make the gas turbine a better choice over other prime movers are: *(choose all that are correct)* 1. low maintenance 2. minimum cooling water 3. high thermal efficiency 4. rapid start-up and loading
1,2,4
State the cause of each of the following problems associated with cooling towers: 1. Deposit of Airborne Particles 2. Scaling 3. Corrosion 4. Biological Fouling 5. Wood Deterioration
1. *Deposit of Airborne Particles:* dust in atmospheric air that becomes entrained in cooling tower water. 2. *Scaling:* hardness forming salts in the cooling water consisting of calcium and magnesium compounds. 3. *Corrosion:* pH level below 8.5 and dissolved oxygen (since the water is constantly circulated through the tower dissolved oxygen is high) 4. *Biological Fouling:* algal, fungal, and bacterial growth 5. *Wood Deterioration:* delignification due to attack by chlorine and alkaline solutions and biological attack of wood cellulose.
List 6 steps required in the shutdown of a large condensing turbine.
1. As the load is being taken off, regulate the supply of steam to the glands, to conform to the new conditions. 2. Start the auxiliary oil pump. Where the control is automatic, check its operation later as the turbine comes to rest. 3. When the order to stop the machine is received, the stop valve may be closed gradually or tripped by hand. Once a week (or at specific intervals) the operation of the emergency governor should be checked. 4. See that the bearings are receiving a proper supply of oil while the machine slows down. 5. Shut off the supply of steam and water to the glands. 6. When the machine has stopped, shut off the water supply to the oil coolers and stop the auxiliary oil pump.
List 5 steps that should be followed when starting up a typical steam engine: 1. _____________________________________ 2. _____________________________________ 3. _____________________________________ 4. _____________________________________ 5. _____________________________________
1. Ensure there are no tools or debris around the engine where it could cause damage. 2. Check the steam chest and cylinder drains to be sure they are open and clear of all water. 3. Open the separator drain on the steam line to empty it of water OR see that the trap is operating properly if equipped. 4. When water ceases to flow through the drain valves, open the stop valve slightly until steam blows freely through the drains. This allows cooled steam that condenses to drain. 5. Never open a steam valve suddenly to avoid the risk of water hammer.
List four factors the affect the rate of heat transfer in a cooling tower: 1. ________________________________________ 2. ________________________________________ 3. ________________________________________ 4. ________________________________________
1. RELATIVE VELOCITY of both the air and water during contact. 2. AREA of water surface in contact with air. 3. LENGTH of contact time between air and water. 4. DIFFERENCE between inlet water temperature and inlet of air wet bulb temperature (relative humidity or air).
List seven advantages of a steam turbine over a steam engine or diesel engine.
1. more reliable operation. 2. simple design. 3. low maintenance costs. 4. no cylinder lubrication required. 5. less space required. 6. lighter foundations required. 7. reduced vibration.
On a steam engine, what is the purpose of a flywheel? *(choose all that are correct)* 1. prevents over-speed. 2. dampens speed fluctuations. 3. allow direction rotation to change. 4. it carrier the engine over "dead center".
2 & 4 dampens speed fluctuations. it carrier the engine over "dead center".
What fire extinguishing media are fitted in gas turbine automatic fire suppression systems? *(choose all that are correct)* 1. dry chemical. 2. halon. 3. water. 4. carbon dioxide.
2 & 4 halon & carbon dioxide.
The different methods of stating a gas turbine are: *(choose all that are correct)* 1. sequential 2. manual 3. semi-automatic 4. automatic
2, 3, 4 2. manual 3. semi-automatic 4. automatic
When warming up a turbine: *(choose all that are correct)* 1. the turbine condenser is under full vacuum. 2. the warm up is done slowly. 3. the turbine is slow rotated. 4. the warm up must be done so warping is prevented.
2, 3, 4 2. the warm up is done slowly. 3. the turbine is slow rotated. 4. the warm up must be done so warping is prevented.
The turbine overspeed trip: *(choose all that are correct)* 1. prevents the turbine from vibrating 2. prevents the turbine exceeding the maximum rated speed 3. is operated by a spring loaded pin in the rotating blades 4. will close the steam stop valve 5. should be tested before the turbine is placed in service
2, 4, 5
Why are gas turbines suited for standby duties such as fire pumps and emergency generators? A) Because they can be started and loaded quickly. B) Because their installed cost is low. C) Because they have a high power to weight ratio. D) Because the have minimal cooling water characteristics. E) Because of their high thermal efficiency.
A) Because they can be started and loaded quickly.
A gasoline engine is a heat engine. What is its working fluid? A) Gasoline/Air mixture. B) Glycol. C) Air. D) Gasoline. E) Glycol/Water Mix.
A) Gasoline/Air mixture. ch. 72. - pg. 79
Four cycle engine lubrication is usually: A) forced by pump. B) by gravity oilers. C) by the scoop method. D) by the dip tube method. E) by grease fittings.
A) forced by pump.
The output power of a gas turbine is directly related to the: A) mass of gas passing through the turbine per second. B) temperature at the turbine inlet. C) mass of the unit. D) slippage between the turbine and compressor. E) turbine exhaust temperature.
A) mass of gas passing through the turbine per second.
In a dry cooling tower: A) there is no contact between the air and water. B) forced draft fans are used. C) airflow and waterflow are in the same direction. D) airflow is created by induction. E) induced draft fans are required.
A) there is no contact between the air and water.
The purpose of a spark plug is: A) to ignite the fuel air mixture in a gasoline engine. B) to produce power from the compression stroke. C) to preheat the engine. D) to raise the ignition point of the fuel. E) to ignite the air in the cylinder.
A) to ignite the fuel air mixture in a gasoline engine.
Natural draft cooling towers operate most effectively in large open spaces and: A) where wind is relatively constant. B) where relative humidity is high. C) where a large body of water is nearby. D) require a windbreak. E) must not be in direct sunlight.
A) where wind is relatively constant.
A closed cycle gas turbine: A) will use the same working fluid over again. B) must use a cooler before the regenerator. C) starts with the exhaust valve closed. D) is a self-starting type gas turbine. E) does not need a combustion chamber.
A) will use the same working fluid over again.
A gas turbine compressor is usually: A) downstream of the turbine. B) a dynamic axial design. C) driven by a motor. D) downstream of the combustion chamber. E) a centrifugal type.
B) a dynamic axial design.
An example of a prime mover is: A) an electric generator. B) a steam turbine. C) a centrifugal pump. D) an air compressor. E) a boiler.
B) a steam turbine.
The combustion chamber of a basic gas turbine: A) is water cooled. B) burns fuel with compressed air. C) rotates as shaft speeds. D) is heated between the load turbine and the compression turbine. E) increases the pressure of the compressed air.
B) burns fuel with compressed air.
Gas turbines are ideal when considering: A) long warm-up periods. B) emergency power generation. C) automotive power. D) cooling water pump operation. E) good thermal efficiency.
B) emergency power generation.
The purpose of a generator is to: A) clean the exhaust gases. B) improve the efficiency of the turbine. C) increase the temperature in the combustion chamber. D) lower the temperature in the combustion chamber. E) recirculate the exhaust gases back through the compressor.
B) improve the efficiency of the turbine.
The exhaust steam from a steam turbine is more acceptable for process than the exhaust from a steam engine because: A) it is super saturated steam with lots of energy. B) it is free of lubricating oils. C) it can be used without lowering the efficiency of the turbine as compared to a steam engine. D) it is made from cleaner boiler water than what can be used by steam engines. E) steam engines use too much energy from the steam and leave the system at risk of condensing too much steam and causing water hammer.
B) it is free of lubricating oils.
A single device which converts a natural source of energy into mechanical motion is a/an: A) steam plant B) prime mover C) heat engine D) alternator E) electic motor
B) prime mover
An essential auxiliary in a gas turbine installation is a/an? A) air heater. B) starting motor. C) air dehumidifier. D) generator. E) pump.
B) starting motor.
In a compression ignition engine the fuel is ignited by: A) an electric spark. B) the compressed air temperature. C) the atomized fuel. D) a cross-combustor. E) compressed air pressure.
B) the compressed air temperature.
What might improper or poor fuel injection be cause by? A) piston blowby from worn out piston rings. B) worm or choked injector orifices. C) poor cylinder compression. D) high cylinder exhaust temperatures. E) clogged air ports.
B) worm or choked injector orifices.
Diesel engine governing is accomplished by: A) varying the fuel quality. B) carburetion. C) varying the fuel quantity. D) fuel atomizing air quality. E) fuel atomizing air pressure.
C) varying the fuel quantity.
how many "ports" does a simple 2-stroke spark ignition engine have: *(choose all that are correct)* A) 1 B) 2 C) 3 D) 4 E) 5
C) 3 1. Intake port to the crankcase 2. Intake port to the cylinder 3. Exhaust port from the cylinder.
Internal combustion engines used to drive gas compression machinery and which burn natural gas operate on the ________ cycle. A) Rotary B) Two-stroke C) Two-stroke or four-stroke D) Four-stroke
C) Two-stroke or four-stroke
Diesel engine governing is accomplished by: A) Varying the load on the engine. B) Carburetion. C) Varying the fuel quantity delivered per power stroke. D) Modulating the volume of the atomizing air. E) Modulating the pressure of the atomizing air.
C) Varying the fuel quantity delivered per power stroke.
The combustion chamber of a gas turbine: A) increases the pressure of the compressed air. B) is heated between the load turbine and the compression turbine. C) burns fuel with excess air. D) is water cooled. E) rotates at shaft speed.
C) burns fuel with excess air.
The shrouding installed on the blades of a steam turbine serves to: A) expand the steam by creating a vacuum behind the shroud. B) cool the blade tips. C) confine the steam to the blades & stiffen the blades. D) protect the blades from suspended solids in the steam. E) stop the steam flow in the event of an emergency.
C) confine the steam to the blades & stiffen the blades.
Excessive wind velocities in a natural draft cooling tower may cause: A) rotation reversal of the fan. B) under-cooling of the water. C) high water drift or losses. D) over-cooling of the water. E) louvers to become broken
C) high water drift or losses.
The great majority of steam turbine governors utilise the: A) hydraulic system principle. B) pneumatic system principle. C) mechanical centrifugal principle. D) lever principle. E) bimetal expansion principle.
C) mechanical centrifugal principle.
In order to move the throttling valve in a large steam turbine, a governing system uses a __________________. A) linkage B) speeder C) relay D) pilot valve E) controller
C) relay ??????????? find source chapter 69 figure 22
Ignition of the fuel in a diesel engine is achieved by means of: A) a precisely timed glow plug. B) the injector delivery valve pressure. C) the heat of compression. D) the fuel injector nozzle. E) a spark plug.
C) the heat of compression.
Cooling towers are divided into two classes depending on what? A) the type of fans used. B) the direction of airflow. C) the method used to create air circulation. D) the degree of cooling provided. E) the type of fill used.
C) the method used to create air circulation.
What is the purpose of the nozzles in a turbine? A) to create kinetic momentum. B) to direct the steam onto the shaft. C) to increase steam velocities. D) to lower steam velocities. E) to crease a pressure rise.
C) to increase steam velocities.
Air trapped in a cylinder of a typical compression ignition engine is heated to about ______C to ______C and its pressure increased to about ______kPa to ______ kPa A) 400C to 500C B) 450C to 570C C) 500C to 620C D) 540C to 650C And E) 1500 kPa to 3200 kPa F) 1700 kPa to 3400 kPa G) 2800 kPa to 4200 kPa H) 2200 kPa to 3900 kPa
D & G 540C to 650C & 2800 kPa to 4200 kPa
What type of rotor(s) is/are used in large steam turbines? A) Reaction. B) Impulse. C) Reaction and Cross-flow. D) Impulse and Reaction. E) Impulse and Condensing.
D) Impulse and Reaction. ch. 69 - pg. 16
Diesel engines require: A) a spark plug in each cylinder. B) a carburetor. C) a magneto. D) a fuel injector. E) an ignition distributor.
D) a fuel injector.
The reciprocating motion of a steam engine is converted to rotary motion: A) at the end of the piston stroke. B) in the steam cylinder. C) by the camshaft. D) at the crankshaft. E) via the valve gear. F) via the valve eccentric.
D) at the crankshaft.
An injection nozzle is used to __________ the fuel in a diesel engine. A) eject B) mix C) ignite D) atomize E) aspirate
D) atomize
Dissolved and suspended solids can build up in a closed cooling tower system as the water evaporates. This build-up is controlled by: A) adding chemicals to remove the dissolved solids. B) treating the water supply to remove dissolved solids. C) scraping the scale from the cooling tower components on a regular basis. D) bleeding a portion of the water from the system continuously.
D) bleeding a portion of the water from the system continuously.
In a venturi type cooling tower, how is airflow created? A) by mechanical induction. B) by forced draft. C) by wind. D) by spray nozzles. E) by crossflow.
D) by spray nozzles.
How are microbial organisms most effectively killed in a cooling tower water system? A) by injecting chemicals once per month. B) by constantly changing chemicals. C) be feeding the biocides daily at low doses. D) by using multiple biocides. E) by temporarily raising the concentration of the chemicals to a high level.
D) by using multiple biocides. **needs to be confirmed
The process of vaporization of gasoline for use in an internal combustion engine, is known as? A) combustion. B) convection C) oxidation D) carburetion E) priming
D) carburetion
Most turbine over-speed trips operate by: A) shutting down the turbine. B) mechanical force. C) centripetal force. D) centrifugal force. E) kinetic energy.
D) centrifugal force.
The stationary passage of reaction turbines is the: A) shaft. B) rotor. C) shroud ring. D) fixed blade. E) dummy piston.
D) fixed blade.
Whenever feasibly possible, when checking bearings on running pieces of equipment it is wise to: A) observe the temperature on a thermometer B) smell the normal odors of the running bearing C) check the oil quality leaving each. D) get accustomed to normal running temperature and vibration by feel. E) check the oil quality leaving each.
D) get accustomed to normal running temperature and vibration by feel.
A cross-flow mechanical draft cooling tower: A) does not require free diffusion at the outlet. B) has higher power requirements. C) has a smaller footprints. D) has a low pressure drop. E) may be located below the level of the system it serves.
D) has a low pressure drop. **needs confirmation
A steam piston: A) moves fastest at the end of its stroke. B) can never have steam applied to either side. C) is lubricated by the crankcase oil by splash method. D) has greater driving force on it at the beginning of its stroke. E) never requires lubrication.
D) has greater driving force on it at the beginning of its stroke.
The internal combustion 4-stroke engine power sequence is: A) compression -> intake -> power -> exhaust B) power -> compression -> exhaust ->intake C) exhaust -> intake -> power -> compression D) intake -> compression -> power -> exhaust E) compression -> power -> intake -> exhaust
D) intake -> compression -> power -> exhaust
A steam turbine's exhaust can often supply a process with steam because: A) processes always require a lower steam pressure. B) processes never require the high steam temps that turbines do. C) turbines exhaust steam is always dry and saturated. D) it is free of oil. E) the steam will be at a temperature above the initial temperature.
D) it is free of oil.
A routine inspection of an operating steam engine should cover first and foremost: A) drive belts B) steam quality C) steam temperatures D) lubricators E) engine speed
D) lubricators
Scaling is not even as severe in towers when compared to boilers because: A) a tower does not evaporate. B) there are not as many dissolved solids in tower water. C) pressure is not as high as in a boiler. D) temperatures are not as high as in a boiler. E) water is constantly aerated.
D) temperatures are not as high as in a boiler.
What will happen if only one type of biocide is used to control biological fouling in a cooling tower. A) you will have to change to a non-oxidizing chemical. B) scaling will increase. C) heat transfer raters will decrease. D) the organisms will become immune to the biocide. E) the biocide injection rate will have to be increased over time.
D) the organisms will become immune to the biocide.
A 4-stroke spark ignition engine: A) operates best at high RPMs. B) has on power stroke every rotation. C) has low torque at low speeds. D) theoretically has half the power of a 2-stroke engine of the same size and speed. E) has poorer cylinder scavenging the a 2-stroke engine.
D) theoretically has half the power of a 2-stroke engine of the same size and speed.
A gas turbine which has been in service for 5000 hours will see its power output drop by approximately how much? A) 1.5 % B) 2 % C) 1 % D) 0.5 % E) 2.5 %
E) 2.5 % about 0.5 % per 1000 hours
A bypass valve, which prevents water flow over the fill of a tower during cold weather, should not be closed until the water temp reaches: A) -1°C B) 1°C C) 5°C D) 21°C E) 27°C
E) 27°C Find source ?????
A major difficulty encountered with a two-stroke cycle engine is: A) the high torque at low speeds. B) maintenance of many moving parts. C) the difficulty in cold weather starting. D) the high speeds compared to an equivalent four stroke engine. E) exhausting the spent gases from the cylinder.
E) exhausting the spent gases from the cylinder.
Microorganisms require carbon to develop. where would they get this carbon from in a cooling tower? A) from the carbon steel in the structure. B) from the carbon filters which are used to remove odours from the water. C) from carbonic acid in the form of acid rains. D) from entrained carbon dioxide in the cooling water. E) from the cellulose in the wood.
E) from the cellulose in the wood.
A turbines speed can be "fine tuned", while operating, with a device which is known as a: A) over-speed trip B) governor valve C) sentinel valve D) over-speed governor E) hand speed control
E) hand speed control or "speeder"
Reaction turbines: A) have a pressure drop in the moving blades only. B) are used for high pressures only. C) have bucket shaped blades. D) have little axial thrust. E) have a pressure drop through the moving and stationary blades.
E) have a pressure drop through the moving and stationary blades.
Dirty air filters on a gas turbine could lead to what alarm? A) high stator vibration. B) over-speed. C) high pressure. D) high output temperature. E) high differential pressure air intake.
E) high differential pressure air intake.
Cylinder scavenging: A) is more efficient in a 2 stroke engine than a 4 stroke. B) is scoring the cylinder by a broken piston ring. C) is the removal of intake gases from the cylinder. D) is the recycling of combusted gases. E) is the removal of exhaust gases from the cylinder.
E) is the removal of exhaust gases from the cylinder.
Early gas turbines were handicapped by: A) their inadequate power capability. B) their high operation speed. C) metal not being able to withstand high speed centrifugal forces. D) the inability to get get enough air into the combustion chamber. E) metals not standing the high temperature involved.
E) metals not standing the high temperature involved.
In a typical 4-stroke diesel engine, what houses the fuel nozzle and the valves? A) the frame. B) the liner. C) the bedplate. D) the manifold. E) the cylinder head.
E) the cylinder head.
Larger, high output machines use a shaft seal with many complex winding restrictions to the steam flow by fitting rings into the casing and shaft that form narrow passages for the steam to pass through. These are called ___________________________ glands.
Labrynth
A routine inspection of an operating steam engine should start with: A) Lubricators B) Drive belts C) Engine speed D) Steam temperature E) Steam quality
a
A two shaft gas turbine: A) Has the load turbine downstream from the compressor turbine B) Uses the first turbine to drive the propeller of a turboprop engine C) Is always an open cycle D) Is always a closed cycle E) Does not require a starting motor
a
__________________ is used for the removal of any water caused by condensation of steam? A) Slide valve B) Flywheel C) Crosshead D) Drain cocks
d
Connecting rods on a steam engine: A) Convert reciprocating motion to rotary motion B) Are used to move the slide valve C) Are only needed on vertical engines D) Are used to connect the piston to the slide valve E) Connects the inlet valve to the discharge valve
a
Four-stroke cycle engine valves are A) operated by cams B) of the pressure differential variety C) a number of ports in the cylinder wall D) often termed reed or channel valves E) always open as the piston travels upwards
a
In a simple gas turbine, air is first drawn into the compressor and compressed. It is then discharged from the compressor to the: A) Combustor B) Turbine C) Reciprocating piston D) Heat recovery steam generator
a
One complete movement of the piston in one direction through the cylinder requires ______________ revolution(s) of the engine crankshaft: A) One-half B) One C) Two D) Four E) Eight
a
One of the first ways to detect a fault in a reciprocating steam engine is by: A) monitoring changes in its sound B) observing temperature indication C) determining its performance efficiency D) monitoring its oil consumption E) monitoring changes in smell
a
Pre-mixing lube oil and fuel or having a special lube oil injection system is typical of the average A) snowmobile engine B) automobile engine C) aircraft engine D) tractor engine E) heavy equipment engine
a
Steam turbine lubrication oil: A) Can be used to operate the turbine governor B) must be water soluble C) Lubricates the dummy piston D) Contaminates the condensate of condensing turbines E) Lubricates the labyrinth gland
a
The compressor on the gas turbine A) can be driven by the load turbine B) is always of the axial type C) is always a multi-stage compressor D) is always independently driven E) is always a reciprocating type
a
The feature of an impulse turbine that prevents a drop in pressure as the steam passes through the blades is? A) The shape of the steam passages between adjacent blades B) The lower shaft speed C) The back torque on the driver D) The higher temperature of the inlet steam E) The momentum of the load
a
The turbine overspeed trip: A) Prevents the turbine exceeding the maximum rated speed B) Prevents the turbine from vibrating C) Prevents turbine bearing damage D) Opens the sentinel valve E) Alerts the operator of excessive turbine RPM
a
Using a compressed air starting motor is a popular method of starting: A) A large stationary diesel engine B) A small two-stroke engine C) A gasoline engine D) An aircraft engine E) A propane engine
a
With this type of governor the oil pump is driven from the: A) Turbine shaft. B) Emergency trip mechanism. C) Hand speed changer. D) Pump shaft.
a
A gas turbine: A) Expands hot gases through the compressor B) Output increases when using air of maximum density C) Operates the best when the inlet air is hot D) Output increases at higher altitude E) Output increases when equipped with an air preheater
b
A steam engine's crosshead: A) Imparts angular motion to the piston rod B) Converts linear motion of the piston rod into angular motion C) Imparts linear motion to the connecting rod D) Does not require any lubrication E) Is often called the "gudgeon".
b
A turbine overspeed trip: A) Trips the turbine if it is overloaded B) Is installed on all turbines C) Can be adjusted according to the load demand D) Is regulated by exhaust pressure E) Disconnects the turbine load if the turbine overspeeds
b
An arrangement of a steam system and a gas turbine is commonly referred to as A) A complex-cycle system B) A cogeneration system C) A once-through system D) A 2-stage system E) A high capacity system
b
Calcium sulphate scaling increases with: A) Rise in pH and decrease in temperature. B) Decrease in pH and increase in temperature. C) Rise in pH and temperature. D) Decrease in pH and temperature.
b
Compression ignition engines: A) Need suction and discharge valves B) Will compress air only on the compression stroke C) Need a carburetor to mix the fuel with the air D) Will compress air only on the power stroke E) Require a spark timing device
b
Condensing turbines A) are always impulse turbines B) will have a vacuum in the last row of rotating blades C) will use the condensate for heating D) are very small units E) cannot have counterflow stages
b
Gas turbines are ideal where: A) Noise is undesirable B) Water is scarce C) Industrial sites are small and in populated areas D) Thermal pollution is of major concern E) There is an abundance of qualified Power Engineers to operate them.
b
High discharge water temperature from the cooling tower could be caused by: A) Low wet bulb air temperature. B) High wet bulb air temperature. C) Low dry bulb air temperature. D) Fine water spray in the tower. E) Low concentration of solids in the water.
b
In a reaction turbine the steam pressure __________________ in passing through moving blades, as well as through stationary nozzles or blades. A) Increases B) decreases C) Remains constant D) Accelerates E) Fluctuates
b
In an impulse turbine, the: A) Steam flow is reduced through the nozzles B) Steam pressure is reduced in the nozzles C) Steam pressure decreases across the rotating blades D) Steam velocity is increased through the rotating blades E) Exhaust steam re-enters the same row of blades
b
Organic growths also called _________ can reduce the flow rates in heat exchanger tubes and channels. A) Algae B) Slime C) Fungi D) Spores E) Silt
b
Reaction turbines: A) have all of the steam pressure drop take place. in the stationary nozzle. B) have a velocity increase in the fixed blading. C) are used for higher speed only. D) have a velocity decrease through the fixed blading. E) require little blade sealing.
b
The purpose of a regenerator is to: A) Re-circulate the exhaust gases back through the compressor B) Improve the efficiency of the turbine C) Increase the temperature in the combustion chamber D) Decrease the temperature in the combustion chamber E) Remove the exhaust gas impurities
b
The purpose of the hand speed changer on this type of governor is to: A) Provide overspeed protection. B) Allow the operating speed to be varied. C) Open or close the steam shutoff valve. D) Control oil pump speed.
b
The term "prime mover" refers to: A) All heat engines B) A device that uses a source of energy to produce mechanical motion C) Electric motors only D) Steam and gas turbines only E) thermal generating stations
b
To prevent cooling tower basin water from freezing during cold weather, many units: A) are equipped with ethylene glycol antifreeze systems B) are equipped with electric basin heaters C) are equipped with propane burners D) are equipped with ice defrosters E) have salt added to the water
b
When starting a steam turbine it is customary practice to: A) Stop the auxiliary oil pump as soon as steam begins to turn the unit. B) Turn on all cooling water systems first. C) Place the speed control system in service once the unit is rolling. D) Test the overspeed trip as soon as running speed is attained. E) Analyze the oil for water prior to rolling.
b
When the steam pressure drop occurs only in the stationary steam passages, the turbine is known as: A) A single stage unit B) An impulse unit C) A reaction unit D) A Parsons unit E) A simple turbine
b
Which of the following is a prime mover ? A) An electric generator B) A gas turbine C) A centrifugal pump D) An air compressor E) A boiler
b
Which turbine uses a condenser? A) back pressure turbine B) a turbine exhausting to a vacuum C) a bleeder turbine exhausting at atmospheric pressure D) a non-condensing extraction turbine E) a turbine exhausting to atmosphere
b
__________________ is used to dampen or even-out changes of speed caused by varying steam pressure A) Slide valve B) Flywheel C) Crosshead D) Packing box
b
A gas turbine must be rotated at _____ of its maximum speed before fuel is turned on. A) 10% to 30% B) 15% to 30% C) 20% to 30% D) 25% to 30% E) 25% to 50%
c
An engine which develops one power stroke with every second rotation of the crankshaft is the: A) Two stroke diesel engine B) Type that requires pre-mixed lube oil and fuel C) Four stroke natural gas engine D) V type engine E) External combustion engine
c
Cylinder scavenging: A) Is more efficient in a two-cycle engine than a four-cycle type B) Is scoring the cylinder by a broken piston ring C) Is the removal of exhaust gases from the cylinder D) Prevents the air from entering the cylinder E) Removes excessive oil from the cylinder walls
c
Natural draft cooling towers are divided into: A) Dry and wet types B) Closed and semi closed types C) Atmospheric towers and chimney towers D) Filled and unfilled types E) Open and filled types
c
Reduction in sealing qualities between the piston rings and the cylinder wall by oil may be the result of: A) Low cooling water temperature B) High oil viscosity C) High cooling water temperature D) High carbon residue in the oil E) Improper fuel selection.
c
Shaft sealing of small steam turbines is done with: A) O-rings B) compressed air C) Carbon rings D) Labyrinth glands E) mechanical seals
c
Some of the characteristics that make the gas turbine a better choice over other prime movers are: A) Low power-to-weight ratio B) High thermal efficiency C) Rapid startup and loading D) Low fuel consumption E) Low NOx emissions
c
The combustion chamber of a gas turbine: A) Increases the pressure of the compressed air B) Is located between the load turbine and the compression turbine C) Burns fuel with excess air D) Is water-cooled E) Rotates at shaft speed
c
The fuel for a diesel engine is: A) Light fuel oil B) Vaporized by a carburetor C) Mechanically atomized by high pressure D) Atomized before the cylinder E) Mixed with air in the intake manifold
c
The great majority of steam turbine governing systems utilize the: A) hydraulic system principle B) pneumatic system principle C) mechanical centrifugal principle D) lever principle E) bimetal expansion principle
c
The hot air from the gas turbine combustor is expanded through the: A) The compressor B) A reciprocating piston chamber C) The turbine blading D) The intercooler
c
The principal cause of steel corrosion in cooling towers is: A) Dissolved carbon dioxide B) High pH C) Dissolved oxygen D) Low pH E) Dissolved hydrogen
c
The purpose of turbine glands is to prevent: A) Water from entering the turbine B) Steam from entering the turbine C) Steam escaping from the turbine D) Steam from entering the lubrication system E) Oil from entering the turbine
c
The rate of calcium bicarbonate breakdown and calcium carbonate scaling increases with: A) Rise in pH and decrease in temperature. B) Decrease in pH and increase in temperature. C) Rise in pH and temperature. D) Decrease in pH and temperature.
c
The rotor passages of a steam turbine consist of blades or buckets which are attached to: A) The turbine casing. B) The turbine nozzle. C) The turbine rotors. D) The turbine governor.
c
__________________ is used to prevent steam from leaking past the piston rod and valve rod. A) Slide valve B) Flywheel C) Crosshead D) Packing box
d
With all other factors being equal, a counter-flow cooling tower _____________ as a cross-flow cooling tower. A) Is not as tall B) Has much less cooling capacity C) Requires less floor space D) Requires less fan power E) Has a lower pressure drop
c
_______________ causes the fuel to ignite in a diesel engine. A) A precisely timed glow plug B) The pressure of the injected fuel C) The high temperature compressed air in the engine cylinder. D) The fuel injector nozzle E) A spark plug
c
An example of an engine which gives high torque at low speeds would be that of a A) chain saw B) two cycle snowmobile C) four stroke motocross motorcycle D) two cycle lawnmower E) two cycle transit bus
c ?????????
Large power production plants tend to be of the thermal type because they can burn solid fuels and: A) They are the least expensive to build B) The noise level is much less than internal combustion engines C) The heat cycle they use is the most efficient D) Solid fuels are the most plentiful and the cheapest E) They require the least amount of manpower
c ????????? find source
Incorporating a steam boiler and a gas turbine together is commonly called a _______________________________________________ system known for its thermodynamically efficient use of ________________________________________________________.
combined cycle of cogeneration the exhaust heat from the gas turbine.
The cylinder walls of a four-stroke engine are often lubricated by the splashed from the _________________________. The oil is kept out of the combustion chamber by the ___________________________.
crank case, piston rings
Since a steam turbine requires no __________________________________, the exhaust steam contains no oil and can be used as a steam supply to low pressure systems or condensed for reuse as boiler feedwater.
cylinder lubrication
A disadvantage of the gas turbine is? A) High cost B) High maintenance C) Requires a lot of cooling water D) Low thermal efficiency
d
A gas turbine performs most effectively if the: A) Lubricating oil is of low viscosity B) Cooling water temperature is kept low C) Compressor inlet air temperature is high D) Ambient air temperature is low E) Load is added immediately after starting
d
A steam engine piston: A) Moves fastest at the end of its stroke B) Produces the most force at the end of its stroke C) Is lubricated with crankcase oil by the splash method D) Moves fastest at the mid point of its stroke E) Needs no lubrication
d
A steam turbine should trip or shut down when normal operating speed is exceeded by: A) 250 RPM B) 3 to 5% C) 50 RPM D) 10 to 15% E) 25 RPM
d
A two cycle engine A) must always have lube oil premixed with the fuel B) can never have a crankcase lubrication system C) can never be operated in an inverted position D) "pops" twice as often as an equivalent cylinder four stroke engine E) gives one power stroke every other crankshaft revolution
d
Air flow in a natural draft cooling tower is dependent upon the: A) Speed of the cooling fan B) Volume of water flowing through C) Partial pressure exerted above the surface of the sump. D) Differences in the temperature of the air leaving and entering the cooling tower E) Wind direction
d
Large heavy industrial diesel engines should be operated with a cooling water temperature of: A) 30 to 45C B) 35 to 50C C) 45 to 55C D) 50 to 65C
d
Many typical steam plant auxiliaries are eliminated with a gas turbine due to its: A) Small size B) High speed C) High power to weight ratio D) Simplicity E) Low oil consumption
d
Shaft sealing carbon glands are: A) Lubricated by the main oil pump B) Limited to a temperature of 250°C C) Replaced monthly due to erosion D) Self-lubricating E) Sprayed with Monel
d
The average amount of water volume that evaporates from a cooling tower is __________. A) 2% B) 10% C) 15% D) 5% E) 3.5%
d
The main scale forming substance in cooling water towers is: A) Calcium bicarbonate B) Sodium sulphite C) Potassium hydroxide D) Calcium carbonate E) Sodium Phosphate
d
The slide valve of a steam engine is designed to: A) Allow the piston to slide more freely B) Drain the condensate from the cylinder during warm-up C) Provide lubrication for the steam engine D) Allow steam to enter and leave the cylinder at the proper time. E) Prevent the engine from over speeding
d
The stationary passages of a reaction turbine are called the: A) Shaft B) Rotor C) Shroud ring D) Fixed blades E) Diaphragms
d
The temperature to which the air can be raised at the turbine inlet is: A) an indication of a unit's power B) directly related to the unit's size C) a function of the air compressor input D) an indication of the unit's efficiency E) important for proper compressor performance
d
Turbine speed can be "fine tuned" with a device which will be limited to about 10% over the rated speed. This device is the: A) governor valve B) overspeed governor C) sentinel valve D) hand speed control E) overspeed trip
d
Turbines often have segmental carbon ring sealing glands which are held in place by A) labyrinths B) shrouding C) drive screws D) garter springs E) thrust runners
d
What is a disadvantage of the four cycle engine? A) Poor fuel economy B) Poor control at all speeds C) Low torque at low speeds D) Complicated and heavy
d
When using compressed air to start a diesel engine, the pressure is approximately: A) 520 kPa B) 255 kPa C) 3030 kPa D) 2100 kPa E) 435 kPa
d
Your cooling tower fan motor is running hot and is noisy; after examining the motor, you discover that the bearings need replacement. The evidence you discovered was: A) The motor was running on a single phase B) The motor windings were faulty C) You heard a noise that sounded like a bad bearing D) The rotor was rubbing the stator E) The gear reducer pinion shaft was misaligned
d
Crossflow towers: A) have low pressure drop in relation to its capacity. B) have high pressure drop in relation to its capacity. C) have lower fan power requirement leading to lower energy costs. D) have high fan power requirements. E) A and C
e
Despite their size and complexity, steam plants are widely used because: A) of their low emissions of pollutants B) they are easily located in an urban environment C) they can be run by untrained personnel D) they require minimal amounts of water E) they can burn solid fuels such as coal and wood
e
Impulse turbines: A) are only used with low pressure steam B) require large thrust bearings C) were invented by Parsons D) have large pressure drops across the huckets E) have blades with the same steam inlet and outlet angles
e
The component of wood that is leached away reducing the ability of the wood to resist decay is the: A) Bark B) Creosote C) Lignin D) Cellulose E) Natural extractives
e
The exhaust steam from a condensing steam turbine ____________ than the exhaust from a steam engine: A) is drier B) has more vapour C) is more contaminated D) is hotter E) has more moisture
e
The injection pump of a diesel engine is driven by: A) Piston action B) The governor C) The wrist pin D) The gudgeon pin E) A camshaft
e
The low installation cost of a gas turbine is: A) Due to cheap materials in the blades B) Due to short fuel lines C) Because no fuel pump is required D) Because no electrical wiring is required E) Because less auxiliary equipment is needed
e
The principle of an impulse turbine is that: A) kinetic energy is converted to mechanical energy B) a thrust force causes the rotating blades to move C) The steam leaves the blades with high velocity D) Steam exerts a high pressure on the nozzles E) high velocity steam exerts force upon the rotating blades
e
The shafts of high output, high temperature steam turbines are usually sealed by using: A) Compressed air seals B) Carbon rings C) Packing rings D) Oil sealed glands E) Labyrinth glands
e
The steam turbine that has a pressure drop across every set of blades is the _______________________ turbine. A) double-stage impulse B) single-stage impulse C) topping D) back pressure E) reaction
e
Water contained in the air stream at the discharge of a cooling tower is removed: A) With centrifugal separators B) With a desiccant C) Using mechanical refrigeration D) By a series of baffles E) With drift eliminators
e
The slide valve of a steam engine is designed to provide for the steam to enter and leave the ____________________.
engine cylinder.
This engine delivers one power stroke for every two full rotations of the crank shaft. It uses compression to ignite a fuel/air mixture in a cylinder. The fuel is injected shortly before the end of the compression stroke. What is this engine type?
four stroke diesel engine
Cooling towers are divided into two classes according to the method of air circulation. These classes are ________________________________ and __________________________________.
natural circulation mechanical circulation