The nozzle efficiency is the ratio of
Workdone on the blades to the energy supplied to the blades
Workdone on the blades per kg of steam to the total energy supplied per stage per kg of steam
Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
None of the above
Correct Answer :
C. Energy supplied to the blades per kg of steam to the total energy supplied per stage per kg of steam
Related Questions
Thermal equilibrium means that the flow of steam is
Isothermal
Isentropic
Hyperbolic
Polytropic
The increase in pressure
Lowers the boiling point of a liquid
Raises the boiling point of a liquid
Does not affects the boiling point of a liquid
Reduces its volume
The pressure of steam __________ while flowing through a nozzle.
Increases
Decreases
Remains constant
None of these
A compound steam engine in which piston rods of high pressure and low pressure cylinders ' are attached to two different cranks set at 180° to each other, is called
Receiver type compound engine
Tandem type compound engine
Woolf type compound engine
Both (A) and (B)
The impulse turbine rotor efficiency will have a maximum value of 0.5 cos 2α, where α is the nozzle exit flow angle, if the
Blades are equiangular
Blade velocity coefficient is unity
Blades are equiangular and frictionless
Blade solidity is 0.65
In forced circulation 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 amount of water evaporated in kg per kg of fuel burnt is called
Evaporative capacity of a boiler
Equivalent evaporation from and at 100° C
Boiler efficiency
None of these
The discharge is __________ at critical pressure.
Zero
Minimum
Maximum
None of these
When the nozzle operates with the maximum mass flow, the nozzle is said to be
Choked
Under-damping
Over-damping
None of these
The theoretical indicator diagram of a simple steam engine is based upon the assumption that
There is no pressure drop due to condensation
Steam is admitted at boiler pressure and exhausted at condenser pressure
The expansion (or compression) of the steam is hyperbolic
All of the above
The diagram factor is the ratio of the
Area of the actual indicator diagram to the area of theoretical indicator diagram
Actual workdone per stroke to the theoretical workdone per stroke
Actual mean effective pressure to the theoretical mean effective pressure
Any one of the above
Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
Increases
Decreases
Remain unaffected
First increases and then decreases
The ratio of brake power to the indicated power is known as
Mechanical efficiency
Overall efficiency
Indicated thermal efficiency
Brake thermal efficiency
Film boiling occurs at
Very low pressure
Atmospheric pressures
Medium pressures
Very high pressures
A device used to heat feed water by utilising the heat in me exhaust flue gases before leaving through the chimney, is known as
Economiser
Fusible plug
Superheater
Stop valve
Spontaneous combustion is a phenomenon in which
All the fuel burns instantaneously producing high energy release
Fuel burns with less air
Coal bursts into flame without any external ignition source but by itself due to gradual increase in temperature as a result of heat released by combination of oxygen with coal
Explosion in furnace
Which of the following boiler is best suited to meet the fluctuating demand of steam?
Locomotive boiler
Lancashire boiler
Cornish boiler
Babcock and Wilcox boiler
The diameter of internal flue tubes of a Lancashire boiler is about _________ that of its shell.
One-fourth
One-third
Two-fifth
One-half
The latent heat of steam with increase of pressure
Remain same
Increases
Decreases
Behaves unpredictably
If the critical pressure ratio for steam is 0.546, then the steam is initially
Wet steam
Dry saturated steam
Superheated steam
None of these
The friction in the nozzle __________ exit velocity of steam.
Has no effect on
Decreases
Increases
None of these
The steam temperature with increase in load in case of a boiler fitted with radiation superheater
Increases
Decreases
Remain unaffected
First increases and then decreases
The critical pressure at which latent heat of vaporisation is zero is
225.65 kgf/ cm²
273 kgf/ cm²
100 kgf/ cm²
1 kgf/ cm²
The function of injector used in small steam plants is to
Create vacuum in furnace
Create vacuum at turbine exhaust
Pump feed water
Dose chemicals in feed water
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
Gusset stays in a boiler are provided to
Prevent the bulging of flat surfaces
Avoid explosion in furnace
Prevent leakage of hot flue gases
Support furnace freely from top
One kg of steam sample contains 0.8 kg dry steam; Its dryness fraction is
0.2
0.8
1.0
0.6
The shell of the Cochran boiler is made hemispherical
To give maximum space and strength
To withstand the pressure of steam inside the boiler
Both (A) and (B)
None of the above
The pressure compounded impulse turbine as compared to velocity compounded turbine require __________ number of stages.
Same
Less
More
None of these
Size of boiler tubes is specified by
Mean diameter and thickness
Inside diameter and thickness
Outside diameter and thickness
Outside diameter and inside diameter