A. Superheated steam is preferably not used for process heating because of its low heat transfer film co-efficient
B. In a shell and tube heat exchanger, the shell pressure drop is maximum for orifice baffles
C. S.I. unit of fouling factor is Watt/m2.°K
D. Longitudinal fins are used in extended surface heat exchangers, when the direction of fluid flow is parallel to the axis of the tube
Related Mcqs:
- Pick out the wrong statement?
A. Fluid movement under the influence of buoyant forces resulting from change in density takes place in case of natural convection
B. The ratio NNu/NRe . Npr is called the Stanton number
C. The Peclet number is a measure of the ratio of energy transport by convection to that by conduction
D. The Colburn jH factor for heat transfer is given by Nst Npr - Pick out the wrong statement?
A. Bubble size increases with the dynamic viscosity of the liquid in case of nucleate pool boiling
B. Thermal conductivity of a dry material is more than that of the damp material
C. Ratio of its capacity to economy equals the steam consumption in kg/hr in an evaporator
D. Vaporisation of organic substances in evaporator mostly causes foam formation - Pick out the wrong statement ?
A. In drying a solid containing moisture above the critical moisture content the number of degrees of freedom is 2
B. Sherwood number in mass transfer corresponds to Nusselt number in heat transfer and Schmidt number to Prandtl number
C. Forced convection is relatively more effective in increasing the rate of mass transfer, if Schmidt number is larger
D. Hot gases at moderate pressure are usually in the shell side of shell and tube heat exchangers. At higher pressure, however, it is customary to put gas in the tube side - Pick out the wrong statement ?
A. Economy of a multiple effect evaporator is not influenced by the boiling point elevation
B. Two identical cubes of iron and copper will have the same heat content under the same
conditions of temperature
C. Double pipe heat exchangers are mostly used in the field of refrigeration
D. Finned tube heat exchangers are suitable for heating air by steam - Pick out the wrong statement ?
A. ‘Solvates’ are chemical compounds formed by solute with their solvents. When water is the
solvent, then it is called a ‘hydrate’
B. In heat exchanger calculations (Δt) weighted is used in place of Δt, when it involves more
than one sequence of heating or cooling i.e., desuperheating & condensation or condensation
& sub-cooling
C. Heat transfer co-efficient during nucleate boiling is not influenced by the agitation imparted
D. In case of short tube vertical evaporators, area of central downtake is about 50 to 100% of the
total tube cross-sectional area - Pick out the wrong statement ?
A. The controlling resistance in case of heating of air by condensing steam is in the air fil
B. The log mean temperature difference (LMTD) for counter flow and parallel flow can be theoretically same when any one of the fluids (hot or cold fluid) passes through the heat exchanger at constant temperature
C. In case of a 1 – 2 shell and tube heat exchanger, the LMTD correction factor value increases
sharply, when a temperature cross occurs
D. Phase change in case of a pure fluid at a given pressure from liquid to vapor or vice-versa occurs at saturation temperature - Pick out the wrong statement?
A. Orifice baffles are never used in a shell and tube heat exchanger
B. Pressure drop on the shell side of a heat exchanger depends upon tube pitch also
C. In a horizontal tube evaporator, surface blanketing by air is avoided
D. Split ring type and pull through type floating heads are two commonly used floating heads is
heat exchangers - Pick out the wrong statement?
A. Swenson-Walker crystalliser is a batch crystalliser
B. Super saturation of the solution is the driving potential for a crystal growth
C. The liquor left after the removal of crystals from a solution is called mother liquor
D. The first stage of crystal formation is called nucleation - Pick out the wrong statement ?
A. Heat transfer by radiation cannot occur across an absolute volume
B. In case of a shell and tube heat exchanger, the pressure drop through the shell is proportional to the number of times the fluid crosses the bundle between baffles
C. Propagation velocity for travel of heat radiation through vacuum is equal to the velocity of the light
D. The amount of heat involved in the condensation or vaporisation of 1 kg of a fluid is the same - 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
