The pressure of steam in the engine cylinder at the beginning of the stroke is ________ the boiler pressure.
Equal to
Less than
Higher than
None of these
Correct Answer :
B. Less than
Related Questions
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
A boiler in India should conform to safety regulations of
DIN
BS
ASTM
IBR
Hard coke is used in
Cement industry
Thermal power plant
Blast furnace
Domestic use
When the total heat of steam is h kJ/kg and the sensible heat of feed water is hf1 kJ/kg, then the factor of evaporation is given by
(h - hf1)/2257
(h + hf1)/2257
(h × hf1)/2257
None of these
The pressure of feed water has to be raised before its entry into the boiler. The pressure is raised by a device known as
Feed pump
Injector
Feed check valve
Pressure gauge
In a nozzle, the effect of super-saturation is to
Decrease dryness fraction of steam
Decrease specific volume of steam
Increase the entropy
Increase the heat drop
The critical pressure ratio for initially dry saturated steam is
0.546
0.577
0.582
0.601
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 boiler is best suited to meet the fluctuating demand of steam?
Locomotive boiler
Lancashire boiler
Cornish boiler
Babcock and Wilcox boiler
Which of the following statement indicates the difference between Cornish boiler and Lancashire boiler?
Cornish boiler is a water tube boiler whereas Lancashire boiler is a fire tube boiler
Cornish boiler is a fire tube boiler whereas Lancashire boiler is a water tube boiler
Cornish boiler has one flue tube whereas Lancashire boiler has two flue tubes
Cornish boiler has two flue tubes whereas Lancashire boiler has one flue tube
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
Caking coals are those which
Form lumps or masses of coke
Burn freely
Show little or no fusing action
Burn completely
Lancashire boiler is used where working pressure and power required are
Low
Moderate
High
None of these
Which of the following coals has the highest calorific value?
Anthracite coal
Bituminous coal
Lignite
Peat
The function of injector used in small capacity boilers is to
Create vacuum
Inject chemical solution in feed pump
Pump water, similar to boiler feed pump
Add make up water in the system
Pour point of fuel oil is the
Lowest temperature at which oil will flow under set condition
Storage temperature
Temperature at which fuel is pumped through burners
Temperature at which oil is transported
By compounding the expansion of steam in two or more cylinders, the length of stroke
Does not change
Increases
Decreases
None of these
The rate of steam produced in Benson boiler is
100 tonnes/h
135 tonnes/h
175 tonnes/h
250 tonnes/h
A throttle governed steam engine develops 15 kW with 280 kg per hour of steam and 35 kW with 520 kg per hour of steam. The steam consumption in kg per hour when developing 20 kW will be nearly
150 kg/h
210 kg/h
280 kg/h
340 kg/h
The ratio of the temperature rise of cooling water to the vacuum temperature minus inlet cooling water temperature is called
Condenser efficiency
Vacuum efficiency
Nozzle efficiency
Boiler efficiency
Which of the following statement is correct?
The efficiency of steam turbines is greater than steam engines
A flywheel is a must for steam turbine
The turbine blades do not change the direction of steam issuing from the nozzle
The pressure of steam, in reaction turbines, is increased in fixed blades as well as in moving blades
The critical pressure gives the velocity of steam at the throat
Equal to the velocity of sound
Less than the velocity of sound
More than the velocity of sound
None of these
In a nozzle, whole frictional loss is assumed to occur between
Inlet and throat
Inlet and outlet
Throat and exit
All of these
Fire tube boilers are
Internally fired
Externally fired
Internally as well as externally fired
None of these
The purpose of governing in steam turbines is to
Maintain the speed of the turbine
Reduce the effective heat drop
Reheat the steam and improve its quality
Completely balance against end thrust
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
The relative efficiency is defined as the
Ratio of thermal efficiency to Rankine efficiency
Ratio of brake power to the indicated power
Ratio of heat equivalent to indicated power to the energy supplied in steam
Product of thermal efficiency and Rankine efficiency
The numbers of fire tubes in a Cochran boiler are
75
115
165
225
Equivalent evaporation is the amount of water evaporated in a boiler from and at
0°C
100°C
Saturation temperature at given pressure
Room temperature
In an impulse turbine, steam expands
Wholly in blades
Wholly in nozzle
Partly in the nozzle and partly in blades
None of these