The variation of steam pressure in the nozzle depends upon
Velocity of steam
Specific volume of steam
Dryness fraction of steam
All of these
Correct Answer :
D. All of these
Related Questions
In recuperative air preheaters, the heat is transferred
From a metal wall from one medium to another
From heating an intermediate material and then heating the air from this material
By direct mixing,
Heat is transferred by bleeding some gases from furnace
A boiler in India should conform to safety regulations of
DIN
BS
ASTM
IBR
Natural water circulation, by convection in water tube boilers, with increase in pressure of boiler
Increases
Decreases
Remain unaffected
First increases and then decreases
Reheating of steam under ideal conditions takes place at constant
Entropy
Enthalpy
Pressure
Temperature
Primary air is the air used to
Provide air around burners for obtaining optimum combustion
Transport and dry the coal
Convert CO (formed in lower zone of furnace) into CO₂ at higher zone
Air delivered by forced draft fan
Steam turbines are used for
Large marine propulsion
Electric power generation
Direct drive of fans, compressors, pumps
All of these
The density of supersaturated steam is about __________ that of the ordinary saturated vapour at the corresponding pressure.
Same as
2 times
4 times
8 times
Boiler parameters are expressed by
Tonnes/hr. of steam
Pressure of steam in kg/cm²
Temperature of steam in °C
All of the above
Water boils when its vapour pressure
Equals that of the surroundings
Equals 760 mm of mercury
Equals to atmospheric pressure
Equals the pressure of water in the container
Proximate 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 ratio of the volume at cut-off to the swept volume is called
Cut-off ratio
Expansion ratio
Clearance ratio
None of these
Locomotive boiler is of the following type
Multi tubular
Horizontal
Internally fired
All of the above
In a reaction turbine
The steam is allowed to expand in the nozzle, where it gives a high velocity before it enters the moving blades
The expansion of steam takes place partly in the fixed blades and partly in the moving blades
The steam is expanded from a high pressure to a condenser pressure in one or more nozzles
The pressure and temperature of steam remains constant
Steam turbines may be classified according to
Direction of steam flow
Number of stages
Mode of steam action
All of these
Besides mean effective pressure, the data required to determine the indicated power of an engine include
Piston diameter, length of stroke and calorific value of fuel
Piston diameter, specific fuel consumption and Calorific value of fuel
Piston diameter, length of stroke and speed of rotation
Specific fuel consumption, speed of rotation and torque
The discharge is __________ at critical pressure.
Zero
Minimum
Maximum
None of these
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 best suited coal for chain or travelling grate stoker boiler is
Coking coal
Non-coking or free burning coal
Pulverised coal
High sulphur coal
The condition of steam in boiler drum is always
Dry
Wet
Saturated
Supersaturated
The function of a valve rod is
To provide reciprocating motion to the slide valve
To convert reciprocating motion of the piston into rotary motion of the crank
To convert rotary motion of the crankshaft into to and fro motion of the valve rod
To provide simple harmonic motion to the D-slide valve
The high pressure and low pressure cylinders in a Woolf type compound engine are regarded as having cranks
180° to each other
90° to each other
0° to each other
None of these
The numbers of fire tubes in a Cochran boiler are
75
115
165
225
A nozzle is said to be a convergent nozzle
When the cross-section of the nozzle increases continuously from entrance to exit
When the cross-section of the nozzle decreases continuously from entrance to exit
When the cross-section of the nozzle first decreases from entrance to throat and then increases from its throat to exit
None of the above
In a reaction turbine when the degree of reaction is zero, then there is
No heat drop in moving blades
No heat drop in fixed blades
Maximum heat drop in moving blades
Maximum heat drop in fixed blades
Which of the following statement is wrong?
The factor of evaporation for all boilers is always greater than unity.
The amount of water evaporated in kg per kg of fuel burnt is called equivalent evaporation from and at 100° C.
The ratio of heat actually used in producing the steam to the heat liberated in the furnace is called boiler efficiency.
None of the above
The diameter of cylindrical shell of the Lancashire boiler is of the order of
1 to 1.25m
1 to 1.75 m
2 to 4 m
1.75 to 2.75 m.
The maximum steam pressure in a Locomotive boiler is limited to
0.18 MN/m²
1.8 MN/m²
18 MN/m²
180 MN/m²
The actual power supplied by the engine crankshaft is called
Indicated power
Brake power
Frictional power
None of these
The critical pressure ratio (p₂/p₁) is given by
(p₂/p₁) = [2/(n - 1)] n/(n + 1)
(p₂/p₁) = [2/(n + 1)] n/(n-1)
(p₂/p₁) = [(n - 1)/2] n + (1/n)
(p₂/p₁) = [(n + 1)/2] n - (1/n)
During polytropic process
Heat transfer takes place across cylinder walls
Work is done
Steam may be wet, dry or superheated after expansion
All of the above