In a backward feed multiple effect evaporator

For a cold dilute feed to produce thick viscous liquor, backward feeding as compared to forward feeding results in

Thickness of thermal boundary layer is more compared to that of hydrodynamic boundary layer, when the value of Prandtl number is

Heat transfer by natural convection is enhanced in system with

For small temperature difference, the heat transfer rate as per Newton's law of cooling is proportional to (where, Δt = excess temperature)

Pick out the wrong statement.

At what value of Prandtl number, the hydrodynamic and thermal boundary layers are identical ?

With increase in the distance between the heat source and the object receiving the heat, the radiation heat transfer

Heat transfer by radiation between two bodies at T₁ & T₂ and in an ambient temperature of T_a°C depends on

The ratio of momentum diffusivity to thermal diffusivity is the __________ number.

The equation, , corrosponds to __________ analogy.

For large heat transfer area requirement, shell and tube heat exchanger is preferred, because it

Economy of an evaporator is influenced by the

The critical radius of insulation for cylindrical pipe is (where, h_i = heat transfer coefficient at inside of the pipe )

A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because

For a perfectly transparent surface (like gases), the

Dropwise condensation occurs on __________ surfaces.

Radiation heat transfer rates does not depend upon the

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

Planck's distribution law is valid for __________ bodies.

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. )

Economy of an evaporator is influenced by the

The Graetz number is concerned with the

For hot feed, forward feeding as compared to backward feeding results in __________ economy.

Which area is used in case of heat flow by conduction through a cylinder ?

Temperature profile in steady state heat transfer is

Mechanical recompression evaporation is used in the production of

Solid angle subtended by the finite surface at the radiating element is

Radiation energy is emitted by all the substances, which are above

Among liquids, water has a comparatively high value of thermal conductivity, due to its

Heat transfer by conduction results due to the transfer of free electrons, kinetic energy & vibrational energy from one molecule to another. Conduction heat transfer can not take place

Evaporation of 1kg of water from a solution in a single effect evaporator requires about __________ kg of steam.

A measure of the extent to which viscous heating is important relative to the heat flow resulting from the impressed temperature difference is represented by the __________ number.

Pick out the wrong statement.

The dimensionless group in mass transfer that is equivalent to Prandtl number in heat transfer is

A metal wire of 0.m dia and thermal conductivityW/m.K is exposed to a fluid stream with a convective heat transfer coefficient ofW/m².K. The Biot number is

Analogy between mass and heat transfer is not applicable in case of

In case of a multipass shell and tube heat exchanger, providing a baffle on the shell side __________ the heat transfer rate.

Baffles are provided in heat exchangers to increase the

Out ofkcal/second of incident radiant energy on the surface of a thermally transparent body,kcal/second is reflected back. If the transmissivity of the body is 0.the emissivity of the surface will be

In forced convection, the heat transfer depends on

In a single effect evaporator, the economy is

The thermal radiative flux from a surface of emissivity = 0.4 is 22.kW/m². The approximate surface temperature (K) is
(Stefan-Boltzman constant = 5.67xl0^-8 W/m².K⁴)

For evaporation of viscous solution in a multiple effect evaporator, the prefered feeding scheme is

A 2-4 heat exchanger involves

'Fouling factor' used in the design of a multipass shell and tube heat exchanger is a

What is the steam economy in case of a single effect evaporator system ?

Choose the most important factor on which the heat conducted through a wall in a unit time will depend on ?

A __________ surface has the maximum thermal emissivity out of the following.

Temperature profile in steady state heat transfer is