Unit 16- Prime Movers And Engines Practise Flashcards
When deciding on the energy design of the plant, one of the following would not be of concern
- ) type of fuel being burned
- ) equipment costs
- ) who are the customers
- ) system efficiency
- ) the environment
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The cross head of a steam engine
Imparts linear motion to the piston rod
When checking bearings on running pieces of equipment it is wise to.
Get accustomed to normal operating temperature and vibration by touching equipment parts, such as bearings, lube oil, and cooling water returns
The reciprocating motion of a steam engine is converted to rotary motion:
At the crankshaft
A routine inspection of an operating steam engine should cover first and foremost.
Lubricators
A steam engine will have the steam supply to the cylinder shut off once the piston has travelled
25- 35% of its stroke
A steam engine piston
Moves fastest at the beginning of its stroke
One of the first ways to detect fault in a reciprocating engine is
Sound
A steam turbines exhaust can often supply a process with steam because
It is free of oil
Turbines often have segmental carbon ring sealing glands held in place by:
Garter springs
Turbine thrust bearings are fixed to the casing and prevent axial movement of the spindle by contracting a component on the shaft known as a
Collar
A large reaction turbine will have
Steam pressure dropping through moving and stationary sections
Turbine speed can be fine tuned with a device which will be limited to about 10% over the rated speed. The device is the
Hand speed control
The great majority of steam turbine governing systems utilize the
Mechanical centrifugal principle
A typical overspeed trip setting for a mechanical drive steam turbine will be
15% above normal speed
When the steam pressure drops occurs in only the stationary members or components of a turbine, the turbine is known as a/an:
Impulse unit
A steam turbine should trip or shutdown when normal operating speed is exceeded by
10-15%
Shaft sealing carbon glands are:
Self lubricating
Excessive wind velocity in a natural draft cooling towers may cause
High water drift or losses
A cooling tower which requires neither fan nor fill is the
Venturi unit
To prevent cooling tower basin water from freezing during cold weather many units are equipped with
Electric heating basins
Scaling is not as severe in cooling towers as it is in boilers because
Temperature is not as high
Natural draft cooling tower operate most efficiently in large open spaces and
Where wind is relatively constant
Water contained in the air stream at the discharge of a mechanical draft cooling tower is removed
With drift eliminators
Compared to a cross flow tower, a counter flow tower has
Less floor space
The average amount of water volume which evaporates from a cooling tower is
5%
A valve which prevents water flow over the fill of a tower during cold weather should not be closed until the temperature reaches
27 degrees celcius
You are replacing the cooling tower fan motor bearings because
The noise which sounded like a bad bearing was heard
The output of a gas turbine is directly related to the
Mass of gas passing through the turbine per second
The air enters a gas turbine regenerator from
Downstream the compressor
A combined steam and gas turbine arrangement could be termed
A co-generation system
Early gas turbines were handicapped by
Metals not being able to withstand the high temperatures of the working fluid
Many typical steam plant auxiliaries are eliminated with a gas turbine due to it’s
Simplicity
A gas turbine compressor
May be on the same shaft as the turbine or on a separate shaft
The temperature to which air can be raised at the turbine inlet is
An indication of the units efficiency
Gas turbines are very popular where
Water is scarce
A gas turbine performs most efficiently if
Ambient air temperature is low
In a compression ignition engine the fuel is ignited by
The compressed air temperature
Four stroke cycle engine valves are operated by
Cams
An example of an engine which gives high torque at low speeds would be a
Four stroke motor cross motorcycle
A major difficulty encountered with a two- stroke engine cycle is
Exhausting the spent gasses from the cylinder
The fuel for a compression ignition engine is
Injected in atomized liquid form
An engine which develops one power stroke with every two turns of the crankshaft is the
Four stroke natural gas engine
Pre-mixing lube Is typical of the average
Two- stroke spark ignition engine
Four cycle engine lubrication is ussually
By forced circulation
When using compressed air to each cylinder for starting an industrial type compression ignition, the air pressure used is ussually
2100 Kpa
Diesel engine governing is accomplished by
Varying the fuel quantity
A two cycle engine
Must always have lube oil premixed with the fuel
Using a compressed air starting motor is a common method of starting a
Large stationary Diesel engine
