A spherical shell of 40 cm diameter contains saturated steam and water at 300oC. if their volumes are equal, the mass of steam would be
6.4 kg
25.6 kg
47.5 kg
95 kg
At 300oC, the specific volumes of water and vapour are 0.0014m3/kg and 0.021m3/kg respectively
Clapeyron’s equation is used for finding out the
Dryness fraction of steam
Entropy of superheated vapour
Specific volume at any temperature and pressure
Total heat of saturated steam
The thermodynamic parameters are
temperature
specific volume
pressure
enthalpy
entropy
The clapeyron equation of state provides relationship between
1 and 2
2, 3 and 4
3, 4 and 2
1, 2, 3 and 4
Choose the incorrect statement
The saturation temperature increases with increase in temperature
The wet vapour can be completely specified by its pressure and temperature
Specific heat at constant pressure for superheated steam lies between 0.5-0.6 kcal/kgoK
The values of enthalpy and entropy tabulated in steam tables have been reckoned from 0oC
The pressure of leakage of steam through a narrow or slightly open valve constitutes an
Isobaric process
Isochoric process
Isothermal process
Isentropic process
Constant enthalpy process
When steam flows through a throttle valve and remains wet at exit
Its temperature and quality increase
Its temperature decreases but quality increases
Its temperature increases but quality decreases
Its temperature and quality decrease
Which of the following aspects is not true in the context of a throttling process?
No change in pressure of expanding steam
No work is done by the expanding steam
Enthalpy after expansion equals the enthalpy before expansion
Dryness fraction of steam increases
Which of the following device is used for pumping water into the boiler and also for heating the feed water?
Economizer
Feed pump
Injector
Duplex pump
Which is not true in respect of injector when compared with other feed water equipment?
Occupies minimum space
Comparatively cheap in first cost and ever-day-maintenance
More steam consumption
Thermally less efficient
Consider the following statements:
boiler mountings are mainly protective devices
steam stop valve is an accessory
feed water pump is an accessorty
Which of these statements are correct?
1, 2 and 3
1 and 2
2 and 3
3 and 1
Which of the following form part(s) of boiler mountings?
economizer
feed check valve
steam trap
superheater
Select the correct answer using the codes given below:
2 alone
1 and 3
2, 3 and 4
1, 2, 3 and 4
The term priming in a boiler is associated with
Removal of air from the boiler shell
Water particles being carried by steam
Firing of boilers
Control of the rate of fuel consumption
Blow down is necessary on boilers, because
the boiler water level is lowered rapidly in case it accidentally rises too high
the precipitated sediment or sludge is removed while the boiler is in service
the concentration of suspended solids in the boiler is controlled
Which of these statements are correct?
1, 2 and 3
1 and 2
3 alone
1 and 3
The term heating surface in a boiler means
Area of grate
Volume of furnace
Outer surface area of boiler shell
Surface area which is in contact with flue gases
Calculations for the mean effective pressure from the hypothetical indicator diagram of a steam engine area made by using the relation
(1+loger)-Pb
(1-loger)+Pb
(1+loger)+Pb