A backward feed multiple effect evaporator is better than forward feed for concentrating cold feed, because it provides __________?
For evaporation of viscous solution in a multiple effect evaporator, the preferred feeding scheme is __________?
1000 Kg of liquid at 30°C in a well stirred vessel has to be heated to 120°C, using immersed coils carrying condensing steam at 150°C. The area of the steam coils is 1.2 m2 and the overall heat transfer co-efficient to the liquid is 1500 W/m2.°C. Assuming negligible heat loss to the surrounding and specific heat capacity of the liquid to be 4 kJ/kg.°C, the time taken for the liquid to reach desired temperature will be__________?
Heat waves__________?
If air (a non-condensing gas) is present in a condensing vapor stream, it will __________ the condensation rate of vapor?
For a perfectly transparent surface (like gases), the__________?
A fluid is flowing inside the inner tube of a double pipe heat exchanger with diameter ‘d’. For a fixed mass flow rate, the tube side heat transfer co-efficient for turbulent flow conditions is proportional to__________?
Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by h = 0.023 (K/D) (DVρ/μ)0.8 (CP.μ/k)0.4. This is valid for the value of NRe equal to__________?
The ratio of kinematic viscosity to thermal diffusivity is called the __________ number?
Vibrations in the tubes of a shell and tube heat exchanger is induced due to the __________?
What is the steam economy in case of a single effect evaporator system ?
For turbulent flow in a tube, the heat transfer co-efficient is obtained from the Dittus- Boelter correlation. If the tube diameter is halved and the flow rate is doubled, then the heat transfer co-efficient will change by a factor of__________?
Baffles in the shell side of a shell and tube heat exchanger ?
__________ chart is known as transient heat conduction chart?
Controlling heat transfer film co-efficient is the one, which offers __________ resistance to heat transfer?
Which of the following is concerned with both heat and mass transfer ?
Duhring‟s rule is important in solving problems on__________?
Heat transfer by radiation between two bodies at T1 & T2 and in an ambient temperature of Ta°C depends on__________?
The film thickness for laminar film condensation on vertical surface __________ from top to bottom?
__________ paint has the minimum absorption co-efficient?
For shell and tube heat exchanger, with increasing heat transfer area, the purchased cost per unit heat transfer area__________?
Mode of heat transfer in which the fluid moves under the influence of changes in fluid pressure produced by external work is called__________?
Steam traps are provided in steam carrying pipelines to__________?
Kirchoff‟s law applies to __________ radiation?
Log mean temperature difference (LMTD) cannot be used, if __________?
In a parallel flow heat exchanger, if the outlet temperature of hot and cold fluids are the same, then the log mean temperature difference (LMTD) is__________?
Bulk of the convective heat transfer resistance from a hot tube surface to the fluid flowing in it, is __________?
If Prandtl number is greater than the Schmidt number, then the__________?
Thermal diffusivity is the most important in heat transfer by__________?
LMTD correction factor which is to be applied for a cross-flow heat exchanger increases with increase in the number of shell passes. Its value for a single pass cross flow heat exchanger is __________?
The statement that “maximum wavelength of radiation is inversely proportional to the temperature” is __________ law?
Among liquids, water has a comparatively high value of thermal conductivity, due to its__________?
In which mode of heat transfer, the Biot number is important ?
A diathermanous substance __________ the thermal radiation completely?
Boiling point elevation of a solution of NaOH __________?
Radiant energy received by a body is proportional to (where, d = the distance between the object emitting radiation and that receiving it.) ?
Overall thermal resistance for conductive heat transfer through a series of flat resistances is equal to the__________?
Prandtl and Reynolds analogy are same, when Prandtl number is__________?
Arithmetic mean area can be used in heat transfer problem to calculate the heat flow by conduction through a cylinder which is __________?
jH factor for heat transfer is not a function of the __________ number?
In a heat exchanger, one transfer unit means__________?
A 2-4 heat exchanger involves__________?
In a shell and tube heat exchanger, the height of 25 percent cut baffles is equal to (where, D = inside diameter of shell) ?
Latent heat absorbed by 1 lb of water at 212°F, when it is changed to steam at 212°F, may be around __________ BTU?
Baffle spacing __________?
The local surface conductance for laminar film condensation on vertical surface is (where, t = film thickness) __________?
The purpose of floating head in a heat exchanger is to__________?
Mechanical recompression evaporation is used in the production of__________?
The outlet temperature of cooling water in a heat exchanger is generally not allowed to exceed above 50°C in industrial practice mainly to avoid__________?
The Fourier number (defined as a.t/L2) is used in the analysis of problem involving heat transfer by__________?
Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil each attaining the bath temperature eventually. The time required for 90% change in temperature is the smallest for__________?

Pick out the wrong statement?

A. The capacity of an evaporator is reduced by the boiling point elevation
B. Corrosive liquid is normally passed through the tubes in a shell and tube heat exchanger
C. Steam jet ejector is used for vapor compression in a thermal recompression evaporator
D. Heat sensitive materials should be concentrated in high pressure evaporators

Correct Answer: Heat sensitive materials should be concentrated in high pressure evaporators ✔

Last Updated: March 03, 2019