When the inlet pressure of steam is equal to the exit pressure, then
There is a pressure drop in the nozzle
Fluid flows through the nozzle
Pressure drops and fluid flows through the nozzle
There is no pressure drop and fluid does not flow through the nozzle
Correct Answer :
D. There is no pressure drop and fluid does not flow through the nozzle
Related Questions
Steam engine operates on
Carnot cycle
Joule cycle
Stirling cycle
Brayton cycle
Fire 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
Forced circulation takes place
Tubes are laid vertically
A safety valve mainly used with locomotive and marine boilers is
Lever safety valve
Dead weight safety valve
High steam and low water safety valve
Spring loaded safety valve
The efficiency of a pressure-velocity compounded impulse turbine is __________ as compared to pressure compounded impulse turbine.
Same
Less
More
None of these
In a velocity compounded impulse turbine, when steam flows through the second row of moving blades,
Velocity increases
Velocity decreases
Velocity remains constant
Pressure remains constant
The supersaturated flow of steam through a nozzle as compared to a stable flow, the available heat drop
Remains the same
Increases
Decreases
Is unpredictable
In forced recirculation type boiler,
Heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum
Water is supplied in drum and through down comers located in atmospheric condition it passes to the water wall and rises to drum in the form of mixture of water and steam
Feed pump is employed to supplement natural circulation in water wall type furnace
Water is converted into steam in one pass without any recirculation
The difference between Cornish boiler and Lancashire boiler is that
Former is fire tube type and latter is water tube type boiler
Former is water tube type and latter is fire tube type
Former contains one fire tube and latter contains two fire tubes
None/of the above
Which of the following statement is correct for steam turbines as compared to reciprocating steam engines?
A steam turbine develops higher speeds
The efficiency of steam turbine is higher
The steam consumption is less
All of these
The pressure of steam __________ while flowing through a nozzle.
Increases
Decreases
Remains constant
None of these
The bituminous coal is no caking if its carbon content is
78-81 %
81-85 %
85-90 %
90-95 %
The artificial draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
The mechanical draught _________ with the amount of smoke.
Increases
Decreases
Does not effect
None of these
The friction present between the steam and the nozzle surfaces reduces the heat drop by
10 to 15 %
15 to 25 %
25 to 40 %
40 to 60 %
Cut-off ratio is the ratio of
Swept volume to the volume at cut-off
Volume at cut-off to the clearance volume
Volume at cut-off to the swept volume
Clearance volume to the volume at cut-off
In case of non-condensing steam engines, the pressure of steam in the cylinder during exhaust stroke is _________ the condenser pressure.
Equal to
Lower than
Higher than
None of these
The blade friction in the impulse turbine reduces the velocity of steam by __________ while it passes over the blades.
10 to 15 %
15 to 20 %
20 to 30 %
30 to 40 %
In a throttling process
Steam temperature remains constant
Steam pressure remains constant
Steam enthalpy remains constant
Steam entropy remains constant
Alkaline pyrogallate is used in Orsat's apparatus for absorption of
CO₂
CO
O₂
N₂
For a Parson's reaction turbine, if α₁ and α₂ are fixed blade angles at inlet and exit respectively and β₁ and β₂ are the moving blade angles at entrance and exit respectively, then
α₁ = α₂ and β₁ = β₂
α₁ = β₁ and α₂= β₂
α₁ < β₁ and α₂ > β₂
α₁ = β₂ and β₁ = α₂
The coal requirement per kW hour generation in the thermal power plant is of the order of
0.1 to 0.2 kg
0.2 to 0.4 kg
0.6 to 0.8 kg
1.0 to 1.5 kg
Lancashire boiler is
Stationary fire tube boiler
Internally fired boiler
Horizontal boiler
All of these
The ratio of the isentropic heat drop to the heat supplied, is called
Reheat factor
Stage efficiency
Internal efficiency
Rankine efficiency
The critical pressure ratio for gases is
0.528
0.546
0.577
0.582
The efficiency of an impulse turbine is maximum when (where Vb = Blade speed, V = Absolute velocity of steam entering the blade, and α = Nozzle angle)
Vb = 0.5 V cosα
Vb = V cosα
Vb = 0.5 V² cosα
Vb = V² cosα
De-Laval turbine is a
Single rotor impulse turbine
Multi-rotor impulse turbine
Impulse reaction turbine
None of these
The maximum efficiency of a De-Laval turbine is (where α = Nozzle angle)
sin²α
cos²α
tan²α
cot²α
The principal function of a stop valve is to
Control the flow of steam from the boiler to the main pipe and to shut off the steam completely when required
Empty the boiler when required and to discharge the mud, scale or sediments which are accumulated at the bottom of the boiler
Put off fire in the furnace of the boiler when the level of water in the boiler falls to an unsafe limit
Increase the temperature of saturated steam without raising its pressure
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 piston rod is
To guide motion of the piston rod and to prevent it from bending
To transfer motion from the piston to the cross head
To convert heat energy of the steam into mechanical work
To exhaust steam from the cylinder at proper moment