The high pressure and low pressure cylinders in a Tandem type compound engine are regarded as having cranks
180° to each other
90° to each other
0° to each other
None of these
Correct Answer :
C. 0° to each other
Related Questions
Which is not correct statement about effect of sulphur in fuel?
It has heating value
It helps in electrostatic precipitation of ash in flue gases
It leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
It erodes furnace walls
The compounding of turbines is done in order to
Reduce speed of rotor
Improve efficiency
Reduce exit losses
All of these
The maximum heat loss is a boiler occurs due to
Moisture in fuel
Dry flue gases
Steam formation
Unburnt carbon
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)
Calorific value of coal is of the order of
200-400 kcal/ kg
800-1200 kcal/ kg
2000-4000 kcal/ kg
5000-8000 kcal/ kg
Fusible plug for boilers is made of fusible metal containing tin, lead, and
Bismuth
Copper
Aluminium
Nickel
Heating of dry steam above saturation temperature is known as
Enthalpy
Superheating
Super saturation
Latent heat
The draught (in mm of water), for maximum discharge of flue gases through the chimney, is given by (where H = Height of the chimney in metres, and T1 = Absolute temperature of air outside the chimney in K)
T1 /88.25H
88.25H/T1
T1 /176.5H
176.5H/T1
The process of draining steam from the turbine, at certain points during its expansion and using this steam for heating the feed water in feed water heaters and then supplying it to the boiler is known as
Regenerative heating
Reheating of steam
Bleeding
None of these
The length of Cornish boiler varies from
2 to 4.5 m
3 to 5 m
5 to 7.5 m
7 to 9 m
The natural draught is produced by
Steam jet
Centrifugal fan
Chimney
Both (A) and (B)
Which of the following statement is wrong?
The critical pressure gives the velocity of steam at the throat equal to the velocity of sound.
The flow in the convergent portion of the nozzle is subsonic.
The flow in the divergent portion of the nozzle is supersonic.
To increase the velocity of steam above sonic velocity (supersonic) by expanding steam below the critical pressure, the divergent portion for the nozzle is not necessary.
The cylindrical shell of a Lancashire boiler has diameter from
1 to 2 m
1.25 to 2.25 m
1.5 to 2.5 m
1.75 to 2.75 m
The velocity of steam leaving the nozzle (V) is given by (where K = Nozzle coefficient or nozzle efficiency, and hd = Enthalpy or heat drop during expansion of steam in a nozzle)
V = 44.72 hd K
V = 44.72 K hd
V = 44.72 K hd
V = 44.72 K hd
The function of a safety valve is
To blow off steam when the pressure of steam inside the boiler exceeds the working pressure
To indicate the water level inside the boiler to an observer
To measure pressure of steam inside the steam boiler
None of the above
A nozzle is said to be a divergent 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
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
Caking coals are those which
Form lumps or masses of coke
Burn freely
Show little or no fusing action
Burn completely
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
The flow of steam is supersonic
At the entrance to the nozzle
At the throat of the nozzle
In the convergent portion of the nozzle
In the divergent portion of the nozzle
The economiser is used in boilers to
Increase thermal efficiency of boiler
Economise on fuel
Extract heat from the exhaust flue gases
Increase flue gas temperature
De-Laval turbine is a
Simple impulse turbine
Simple reaction turbine
Impulse-reaction turbine
None of these
Lancashire boiler is a
Stationary fire tube boiler
Stationary water tube boiler
Water tube boiler with natural/forced circulation
Mobile fire tube boiler
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 number of flue tubes in Lancashire boiler is
Zero
One
Two
Four
The average operating pressure of Benson boiler is
100 bar
150 bar
200 bar
250 bar
The isentropic enthalpy drop in moving blade is two-third of the isentropic enthalpy drop in fixed blades of a turbine. The degree of reaction will be
0.4
0.56
0.67
1.67
Latent heat of dry steam at atmospheric pressure is equal to
539 kcal/ kg
539 BTU/ lb
427 kcal/ kg
100 kcal/ kg
Efficiency of Rankine cycle can be increased by
Decreasing initial steam pressure and temperature
Increasing exhaust pressure
Decreasing exhausts pressure
Increasing the expansion ratio
Alkaline pyrogallate is used in Orsat's apparatus for absorption of
CO₂
CO
O₂
N₂