Q.1
Steam trap is used to
Q.2
Pick out the wrong statement:
Q.3
The Graetz number is concerned with the
Q.4
Vibrations in the tubes of a shell and tube heat exchanger is induced due to the
Q.5
Radiation heat losses from satisfactorily insulated high pressure boilar may be about __________ percent.
Q.6
Which of the following forced convection heat transfer equation accounts for the liquid viscosity effect for viscous liquids?
Q.7
Which of the following situations can be approximated to a steady state heat transfer system?
Q.8
While the total emissivity of a perfect black body is unity, the same for a real body is
Q.9
The ratio of momentum diffusivity to thermal diffusivity is the __________ number.
Q.10
The Nusselt number for fully developed (both thermally and hydrodynamically) laminar flow through a circular pipe, where the wall heat flux is constant, is
Q.11
Water always boils when its
Q.12
Which one gives the monochromatic emissive power for black body radiation?
Q.13
If heat transfer rate varies with the time, it is termed as
Q.14
A sphere of radius 'R₁' is enclosed in a sphere of radius 'R₂'. The view (or shape) factor for radiative heat transfer of the outer sphere with respect to the inner sphere is
Q.15
For hot feed, forward feeding as compared to backward feeding results in __________ economy.
Q.16
Reynold's analogy states that
Q.17
A perfect black body is a perfect __________ of radiation.
Q.18
Tubes are held between top and bottom tube sheets in Calenderia type evaporator by keeping
Q.19
Heat flux is the time rate of heat transfer per unit
Q.20
Radiation heat transfer rates does not depend upon the
Q.21
A multiple effect evaporator as compared to a single effect evaporator of the same capacity has
Q.22
If the thermal conductivity of a wall material is independent of temperature, the steady state temperature distribution in the very large thin plane wall having steady, uniform surface temperature follows __________ law.
Q.23
Nusselt number is the ratio of the temperature gradient at the wall to
Q.24
With the increase of temperature, the Col-burn jH factor
Q.25
For a liquid in laminar flow through a very long tube, when the exit fluid temperature approaches the wall temperature, the equation to be used is
Q.26
In case of a vertical tube evaporator, with increase in the liquor level, the
Q.27
For a perfectly transparent surface (like gases), the
Q.28
The inside heat transfer co-efficient in case of turbulent flow of liquid in the tube side in a 1-2 shell and tube heat exchanger is increased by __________ times, when the number of tube passes is increased to 8.
Q.29
The units of resistance to heat transfer is
Q.30
Electromagnetic radiations propagate in vacuum with a velocity of __________ metre/second.
Q.31
Which of the following is generally considered as opaque surface towards radiations?
Q.32
The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are
Q.33
Heat transfer by __________ may not necessarily require the presence of a medium.
Q.34
Electro-magnetic spectrum range, which is important for radiation varies from __________ microns.
Q.35
Which of the following has the lowest Prandtl number?
Q.36
Which has the lowest Prandtl number?
Q.37
In a heat exchanger, one transfer unit means
Q.38
When does the heat generated by fluid friction becomes appreciable compared to the heat transferred between the fluids?
Q.39
The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation.
Q.40
For a given ambient air temperature with increase in the thickness of insulation of a hot cylinderical pipe, the rate of heat loss from the surface would
Q.41
__________ chart is known as transient heat conduction chart.
Q.42
It is not preferable to use superheated steam in evaporators, because of its very
Q.43
Vent pipes are provided in a condenser to
Q.44
Economy of a multiple effect evaporator is not influenced much by the
Q.45
The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation.
Q.46
The driving potential for the crystal growth during crystallisation is the __________ of the solution.
Q.47
The thermal boundary layer at NPr > 1
Q.48
In a heat exchanger, the rate of heat transfer from the hot fluid to the cold fluid
Q.49
Latent heat absorbed by 1 lb of water at 212°F, when it is changed to steam at 212°F, may be around __________ BTU.
Q.50
h.D/K is called the __________ number.
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