Pick out the wrong statement.
If heat transfer rate varies with the time, it is termed as
Terminal point temperature differences between fluids in case of a heat exchanger is termed as
The rate of emission of radiation by a body does not depend upon the
According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor)
The absorptivity of a body is equal to its emissivity
All analogy equations connecting friction factor and heat transfer co-efficient apply only to
__________ paint has the minimum absorption co-efficient.
Asymptotic conditions is reached, when for a fluid flowing in laminar flow through a long tube
Unsteady state heat conduction occurs, when
The advantage of backward feed multiple effect evaporators over forward feed units is that
Film condensation is promoted on a/an __________ surface.
A BTU/hr.ft.2 °F is equal to
The overall resistance for heat transfer through a series of flat resistance, is the __________ of the resistances.
If the baffle spacing in a shell and tube heat exchanger increases, then the Reynolds number of the shell side fluid
The capacity of double-effect evaporator is less than half of the capacity of two single effects, each of which is operating over same terminal temperature difference, when the
Forced circulation evaporators are useful for the concentration of viscous, salting and scale forming liquors. Which of the following is a forced circulation evaporator?
Agitated film evaporator is suitable for concentrating __________ liquids.
Pick out the wrong statement.
LMTD can't be used as such without a correction factor for the
Which of the following has maximum thermal conductivity at the same temperature?
Absorptivity and refletivity of a perfect black body are respectively
In thermal radiation for a black body (where, ε is emissivity and α is absorptivity)
At what value of Prandtl number, the hydrodynamic and thermal boundary layers of a fluid flowing over a heated plate will be identical ?
Fourier's law of heat conduction applies to __________ surfaces.
Electro-magnetic spectrum range, which is important for radiation varies from __________ microns.
kg of wet solids are to be dried fromtomoisture (by weight). The mass of moisture removed in kg is
What is the absorptivity of a black body ?
Which characteristic of a fluid is not important in deciding its route in a shell and tube heat exchanger ?
Dietus-Boelter equation cannot be used for molten metals mainly due to its very low
Which of the following has the lowest Prandtl number ?
At what value of Prandtl number, conduction is negligible in the turbulent core of a fluid flowing through a heated pipe ?
The heat transfer by radiation from a mild steel surface is to be reduced by reducing the emissivity of the surface. This can be best achieved by
Peclet number (Pe) is given by
"The ratio of the total emissive power to the absorptivity for all bodies is same at ther-mal equilibrium". This is __________ law.
The thickness of condensate layer in filmwise condensation depends on the
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 tempeature follows __________ law.
Overall heat transfer co-efficient for cooling of hydrocarbons by water is about
A dephlegmator is a
Fqra cold viscous feed, backward feed gives __________ than forward feed.
Maximum heat transfer rate is obtained in __________ flow.
__________ chart is known as transient heat conduction chart.
Which is the most suitable for the con-certration of highly concentrated solution?
Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called
Baffle spacing
Thermal conductivities of most of the liquids __________ with rise in temperature.
__________ paint has the maximum absorption coefficient.
Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer co-efficient is 3k/l. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade ?
In case of __________ boiling, the liquid temperature is below the saturation temperature and the boiling takes place in the vicinity of the heated surface.
Boiling point elevation of a solution of NaOH