Steam & Related Questions (Mechanical Engineering) 6 Online Test

Which aspect is not true in the context of draught produced by chimney?
Chimney needs no auxiliary power for its operation
Amount of draught produced increases with increase of outside air temperature
Lower the temperature of furnace gases, greater will be the chimney draught
No flexibility in creating more draft to take peak loads
Mollier diagram is a plot of
Temperature and entropy
Temperature and enthalpy
Pressure and enthalpy
Enthalpy and entropy
The ordinate of a Mollier diagram represents
Temperature
Pressure
Entropy
Specific enthalpy
Dryness fraction
The abscissa of a Mollier diagram represents
Temperature
Pressure
Entropy
Total heat
Dryness fraction
Identify the false statement:
During a constant volume process, the total heat absorbed equals the change in kinetic energy
The leakage of steam through a boiler fitting is identical to a throttling process
When steam gets throttled, the kinetic energy of steam gets converted into heat by friction
For adiabatic expansion of steam, the value of exponent n, in the relation pvn=c, for superheated steam equals 1.135
In a test using combined separting and throttling calorimeter, the test data gave dryness fraction of 0.9 in the separting unit and 0.98 in the throttling unit. The actual dryness fraction of steam sample was then

0.9+

0.9x0.98
In a separting and throttling calorimeter, x1 is the dryness fraction of steam in the separating unit and x2 is the dryness fraction in the throttling unit. The dryness fraction of the steam sample would be



x1x2
In a separting and throttling calorimeter, The steam will be at minimum pressure
After separating unit
Before throttling unit
After throttle valve
Pressure remains constant throughout
The amount of draught necessary for a certain boiler insallation is least dependent upon
Nature of fuel and its depth on the grate
Rate at which combustion is required to take place
Method of burning of fuel
Resistance in the flue gas circuit
A throttling calorimeter can be used for determining the dryness fraction of steam only if
Throttling process is accomplished quickly
Throttling process is accomplished slowly
Steam after throttling must become dry and saturated
Steam after throttling must become superheated
In an experiment to determine the dryness fraction of steam, 0.25 kg of water was retained by a separating calorimeter in 10 minutes and 2.25 kg of steam was passed out in the same time. The dryness fraction of steam sample would be about
0.9
0.85
0.8
0.66
Attempering is
Reduction of steam pressure
Reduction of steam temperature
Discharge of flue gases at certain height
Conditioning of disposable fluids for minimum pollution
A draught of 1 mm of water is equivalent to
1kgf/cm2
1 kgf/m2
10 kgf/m2
1 kgf/mm2
In a steam engine, the reciprocating motion to the slide valve is provided by
Cross head
Flywheel
Eccentric
Crankshaft
The function of D-slide valve in a steam engine is to
Throttle the steam and reduce its pressure
Act as a safety valve against high pressure of steam
Guide the motion of piston
Admit and exhaust the steam at proper timings
Description:

This is a 15-question test on ‘Steam: Generation, Engines and Turbines’ under a series of tests of Mechanical Engineering which is attributed to Competitive Examination Preparations e.g. IAS (Optional), GATE, IES etc.

Discussion

Mufassir

A mass 0.2 kg of steam initially at temperature of 165C. it expands reversibly at a constant pressure of 7 bar until the volume is double. if the initial dryness fraction of steam is 0.7 ,find
1. the final state of steam.
2. final temprature of steam
3. work transfer during the process
4. heat transfer during the process

pleaSee more

2312 days 57 minutes ago

Nikhil Deore

application of separating and throttling calorimeter

2392 days 22 hours 29 minutes ago

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