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The equation, Nst = (f/2)/[1 + 5 (Npr – 1) √(f/2)], corresponds to ______________ analogy?
Related MCQs
Open pan evaporators are preferred to be used, when the solution to be concentrated is__________?
When warm and cold liquids are mixed, the heat transfer is mainly by__________?
At constant temperature, the thermal conductivities of gases __________ with rise in pressure?
A single pass air heater is connected to a two pass unit. For the air flow rate and other conditions remaining the same, the film heat transfer co-efficient for air will vary in the ratio of__________?
It is not preferable to use superheated steam in evaporators, because of its very__________?
__________ heat exchanger is used for chilling oil to be dewaxed?
If heat transfer rate varies with the time, it is termed as__________?
The inner wall of a furnace is at a temperature of 700°C. The composite wall is made of two substances, 10 and 20 cm thick with thermal conductivities of 0.05 and 0.1 W.m-1.°C- 1 respectively. The ambient air is at 30°C and the heat transfer co-efficient between the outer surface of wall and air is 20 W.m-2.°C-1. The rate of heat loss from the outer surface in W.m-2is__________?
The absorptivity of a body is equal to its emissivity __________?
A perfect black body is a perfect __________ of radiation?
jH factor for heat transfer depends upon the __________ number?
The actual temperature drop across the heating surface of an evaporator depends on the__________?
Heat transfer by conduction in the turbulent core of a fluid flowing through a heated pipe is negligible, if the value of Prandtl number is__________?
Indirect contact heat exchangers are preferred over direct contact heat exchangers, because__________?
Which of the following has the lowest overall heat transfer co-efficient ?
Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator ?
The absorptivity of a grey body at a given temperature __________ with increasing wavelength of radiation?
In case of heat transfer by conduction in a hollow cylinder, __________ mean area is used to calculate the heat transfer rate?
The characteristic dimensionless groups for heat transfer to a fluid flowing through a pipe in laminar flow are__________?
One kilogram of water at 0°C is changed to superheated steam of one atm pressure and 300° C. The major heat consumption in the process will be to__________?
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 __________?
Solid angle subtended by the finite surface at the radiating element is__________?
Corrosiveness of steam condensate is due to the presence of__________?
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, D = shell diameter)?
Tube expansion allowances exist in __________ heat exchanger?
Multiple effect evaporation accounts for__________?
A black body does not __________ radiation?
An equipment which converts the latent or sensible heat of one fluid into the latent heat of vaporisation of another, is called a__________?
Fresh orange juice contains 12% (by weight) solids and the rest water 90% of the fresh juice is sent to an evaporator to remove water and subsequently mixed with the remaining 10% of fresh juice. The resultant product contains 40% solids. The kg of water removed from 1 kg fresh juice is__________?
Sensible heat absorbed by 1 lb of water when it is heated from 32 to 212°F may be around __________ BTU?
Stefan’s block body radiation law can also be derived from __________ law?
What is the geometric mean of two heat transfer areas A1 and A2 ?
The ratio of velocity head to tube side return loss in case of a multipass shell and tube heat exchanger is __________?
Which has the lowest Prandtl number ?
In case of heat flow by conduction for a cylindrical body with an internal heat source, the nature of temperature distribution is__________?
Heat flux increases with temperature drop beyond the Leiden frost point in the plot of heat flux vs. temperature drop for a boiling liquid, because__________?
‘Duhring’s plot’ is of use in__________?
View factor is important in heat transfer by__________?
Forced circulation evaporators are normally used for concentrating liquids having __________?
The equation, Nst = f/2, is the __________ analogy?
Which of the following is directly concerned with the heat transfer ?
The thermal boundary layer at NPr > 1 ?
Nucleate boiling is promoted __________?
At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe ?
The overall heat transfer co-efficient for a shell and tube heat exchanger for clean surfaces is U0 = 400 W/m2.K. The fouling factor after one year of operation is found to be hd0 = 2000 W/m2.K. The overall heat transfer co-efficient at this time is __________?
Cpμ/K is termed as the __________ number?
In a single evaporator system, the steam economy __________ by creating vacuum in the evaporator?
In case of a super-cooled solution, which is on the verge of crystallisation, the free energy of the solution as compared to that of the solid is __________?
Maximum heat transfer rate is obtained in __________ flow?
Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow.) ?
In a shell and tube heat exchanger, floating head is used for __________?
The equation, Nst = (f/2)/[1 + 5 (Npr – 1) √(f/2)], corresponds to ______________ analogy?
A. Von-Karman
B. Reynolds
C. Colburn
D. Prandtl
Correct Answer:
Prandtl
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Last Updated:
March 03, 2019