In a throttling process
Steam temperature remains constant
Steam pressure remains constant
Steam enthalpy remains constant
Steam entropy remains constant
Correct Answer :
C. Steam enthalpy remains constant
Related Questions
The number of drums in Benson steam generator is
One
Two
One steam drum and one water drum
No drum
The Parsons' reaction turbine has
Only moving blades
Only fixed blades
Identical fixed and moving blades
Fixed and moving blades of different shape
A compound steam engine in which piston rods of high pressure and low pressure cylinders are attached to two different cranks set at 90° to each other, is called
Receiver type compound engine
Tandem type compound engine
Woolf type compound engine
Both (A) and (B)
Ultimate analysis of fuel is determination of percentage of
Carbon, hydrogen, nitrogen, sulphur, moisture
Fixed carbon, ash, volatile matter, moisture
Higher calorific value
Lower calorific value
The function of a flywheel is
To convert reciprocating motion of the piston into rotary motion
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To prevent fluctuation of speed
To keep the engine speed uniform at all load conditions
The fusible plug in small boilers is located
In the drum
In the fire tubes
Above steam dome
Over the combustion chamber
On Mollier chart, flow through turbine is represented by
Horizontal straight line
Vertical straight line
Straight inclined line
Curved line
Thermal efficiency of well maintained boiler will be of the order
40 %
50 %
75 %
90 %
The high pressure boiler is one, which produces steam at a pressure more than
Atmospheric pressure
5 kg/cm²
10 kg/cm²
7580 kg/cm²
Relative percentage of heat absorbed through the heat transfer of (i) Furnace water wall (ii) Boiler tank (iii) Superheater (iv) Economiser (v) Air-heater of a typical boiler of 200 MW capacity would be of the order of
48 : 20 : 15 : 7 : 10
10 : 7 : 15 : 20 : 48
20 : 48 : 7 : 15 : 10
7 : 15 : 20 : 10 : 48
Sublimation region is the region where
Solid and vapour phases are in equilibrium
Solid and liquid phases are in equilibrium
Liquid and vapour phases are in equilibrium
Solid, liquid and vapour phases are in equilibrium
The safety valve at superheater as compared to drum safety valve setting is set at
Higher value
Lower value
Same value
Any value
Benson boiler requires
No drum
One drum
Two drums
Three drums
Which of the following gases has the highest calorific value?
Producer gas
Coal gas
Water gas
Blast furnace gas
In reaction turbines, the axial thrust is due to
Pressure drop across the rotor
Change in axial velocity
Both (A) and (B)
None of these
An economiser is generally placed between
Last superheater or reheater and air preheater
Induced draft fan and forced draft fan
Air preheater and chimney
None of the above
Water tube boilers are those in which
Flue gases pass through tubes and water around it
Water passes through the tubes and flue gases around it
Work is done during adiabatic expansion
Change in enthalpy
Which of the following statement is correct for a compound steam engine?
The cost of the engine, for the same power and economy, is more than that of a simple steam engine.
The forces in the working parts are increased as the forces are distributed over more parts.
The ratio of expansion is reduced, thus reducing the length of stroke.
The temperature range per cylinder is increased, with corresponding increase in condensation.
A binary vapour plant consists of
Steam turbine
Steam condenser
Mercury boiler
All of these
In an impulse reaction turbine, the pressure drops gradually and continuously over
Fixed blades
Moving blades
Both fixed and moving blades
None of these
The actual power generated in the engine cylinder is called
Indicated power
Brake power
Frictional power
None of these
Which of the following is a water tube boiler?
Lancashire boiler
Babcock and Wilcox boiler
Locomotive boiler
Cochran boiler
Equivalent evaporation of water is the evaporation for a feed water supply at 100°C
And its corresponding conversion into dry saturated steam at 100°C and 1.033 kg/cm²
And its corresponding conversion into dry steam at desired boiler pressure
Conversion into steam at atmospheric condition
Conversion into steam at the same pressure at which feed water is supplied
In a compound steam engine, the first stage of expansion is carried out in a high pressure cylinder whereas the last expansion is completed in low pressure cylinder. The diameter of high pressure cylinder is _________ the low pressure cylinder.
Equal to
Less than
More than
None of these
Maximum energy loss in a boiler occurs due to
Unburnt carbon in ash
Incomplete combustion
Ash content
Flue gases
The diameter of a cylindrical shell of a Scotch marine boiler varies from
1.5 to 2 m
2.5 to 3.5 m
3.5 to 4.5 m
None of these
Which device is used in thermal power plants to reduce level of pollution?
Induced draft fan
Smoke meter
Chimney
Precipitator
The condition of steam in boiler drum is always
Dry
Wet
Saturated
Supersaturated
A steam nozzle converts
Heat energy of steam into kinetic energy
Kinetic energy into heat energy of steam
Heat energy of steam into potential energy
Potential energy into heat energy of steam
O₂ content in atmospheric air on weight basis is
21 %
23 %
30 %
40 %