In condensers used in thermal power plants, steam is normally used in shell side and cooling water on the tube side, because of the reason that
Compared to the mass flow rate of cooling water, the rate of condensation of steam is invariably smaller
Maintaining vacuum on tube side is more difficult than that on the shell side
Water velocity can be increased conveniently to increase the overall heat transfer co-efficient because of its lower specific volume compared to steam
Condenser can act as a storage unit for condensed steam
Correct Answer :
C. Water velocity can be increased conveniently to increase the overall heat transfer co-efficient because of its lower specific volume compared to steam
Related Questions
Transition from laminar flow to turbulent flow in fluid flow through a pipe does not depend upon the
Length of the pipe
Diameter of the pipe
Density of the fluid
Velocity of the fluid
__________ of test specimens is not involved in any hardness testing method.
Fracture
Indentation
Wear
Scratch
Spheroidising of a material is a/an __________ process.
Normalising
Annealing
Tempering
Hardening
Which of the following represents the correct time-temperature curve when a block of metal is heated above room temperature & then left to cool in the room following Newton's law of cooling in which the rate of temperature drop will go on decreasing with the passage of time.
Work required for compression of a gas contained in a cylinder is 7000 kJ. During compression, heat interaction of 3000 kJ causes the surroundings to be heated. Internal energy change of the gas during the compression is __________ kJ.
+4000
-4000
10000
-10000
Corona discharge is related to the operation of a/an
Induction motor
Electrostatic precipitator
Fast breeder reactor
Magneto hydrodynamic generator (MHD)
The most important consideration, while designing the refrigeration system of an aircraft is that the refrigeration system
Is as light as possible
Has very high C.O.P.
Employs minimum quantity of refrigerant
Consumer minimum horse power
A compact estimate about the amount of materials handling between various work stations is obtained from the
Gantt chart
Bin chart
String diagram
Travel chart
Frother is added in the froth floatation cell used in ore beneficiation to stabilise the air bubbles (i.e., froth), which will hold the ore particles, but it does not affect the floatability of minerals. Which of the following is not used as a frother?
Cresylic acid
Xanthaies
Pine oil
All 'a' 'b' & 'c'
Softening of hardened steel is done by its
Normalising
Tempering
Annealing
Carburising
Earing is a defect found in steels after the following metal working operation.
Extrusion
Rolling
Deep drawing
Wire drawing
Lead is poured into the joint between two __________ pipes.
Mild steel
Concrete
Cast iron
Asbestos cement
Air intake for an air compressor should be preferably taken from
A site, where cooling towers are located nearby
A site, where open coal yard in located nearby
An air conditioned room maintained at a temperature of 18°C
An outside atmosphere at 10°C
Boiler draught of 10 mm water column is equivalent to
1 kgf/m2
10 kgf/m2
10 kgf/mm2
1 kgf/mm2
Nitriding of a steel part does not increase its
Grain size
Fatigue limit
Surface hardness
Wear resistance
Pick out the wrong statement.
A ferromagnetic material becomes paramagnetic above the 'Curie temperature'
Permanent magnets are made of hard materials, whereas electromagnets require soft magnetic materials
Soft magnetic materials (e.g., pure iron) have higher permeability and low hysterisis loss and coercive forces
Tungsten steel and alnico are not hard magnetic materials
In troposphere (the weather domain), the temperature 't' at height 'h' above the sea level in metres is given by (where, temperature at sea level is 15°C and t is in °C.)
t = 15 - 0.0065 h
t = 15 + 0.0065 h
t = 0.0035 h - 15
t = 15 - 0.0035 h
Addition of __________ to steel does not impart hardness.
Nickel
Copper
Chromium
Silicon
Square steel key is normally strong in failure by shear & crushing. Keys are normally made of __________ steel bars.
Hot rolled mild
Cold rolled mild
Forged
Machinable stainless
'Flare tower' used in industry is meant for
Venting off (after burning) the excess inflammable/toxic gases at high pressure
Absorbing the pollutant gases from the furnace exhaust
Cooling of furnace exhaust gases
None of these
Lead is poured into the joint between two- __________ pipes.
Mild steel
Concrete
Cast iron
Asbestos cement
Which of the following is an undesirable property of slag produced during the Pyrometallurgical method of metal extraction from its ore?
High fusibility & fluidity
High thermal conductivity
Low density
High chemical activity
Baffles provided on the shell side of a shell and tube heat exchanger are meant for
Providing support for the tubes
Improving heat transfer
Both 'a' & 'b'
Preventing the fouling of tubes & stagnation of shell side fluid
Boiler tube size is specified by its thickness and __________ diameter.
Outside
Inside
Mean
None of these
The diffusion co-efficient of Ni in Cu at 1000 K is 1.93 × 10-16 m2S-1 and it is 1.94 × 10-14 m2S- 1 at 1200 K. The activation energy (in k. J.mole-1) for the diffusion of Ni in Cu is
130
180
230
250
Austempering of steel requires it to be heated to 875°C followed by sudden cooling to 250-525°C, thereby changing austenite to
Sorbite
Bainite
Martensite
Troostite
There are one octahedral void and __________ tetrahedral void in the closest packing of atoms.
One
Two
Three
None of these
The maximum thickness of the metal which can be welded using ultrasonic welding is __________ mm.
0.5
3
10
25
While the bin cards are used in the effective stores management, the queuing theory is associated with the __________ time.
Waiting
Idle
Inspection
Tool replacement
Which of the following is the most suitable abrasive for grinding high tensile strength materials?
Silicon carbide
Corundum
Aluminium oxide
Boron carbide