Practice Test: Question Set - 34
1. The type of liquor circulation system to be ' employed in evaporators (viz. natural or forced circulation) is determined mainly by the __________ of the liquid.
- (A) Viscosity
- (B) Density
- (C) Thermal
conductivity
- (D) Corrosive
nature
2. Nusselt number (for forced convection heat transfer) is a function of the __________ number.
- (A) Prandtl
- (B) Reynolds
- (C) Both (a) & (b)
- (D) Neither (a) nor (b)
3. In case of __________ boiling, the bubbles formed on a submerged hot surface get absorbed in the mass of the liquid.
- (A) Nucleate
- (B) Pool
- (C) Low pressure
- (D) None of these
4. The separation of liquid droplets from the vapor is done by a/an __________, in the evaporators.
- (A) Steam ejector
- (B) Entrainment separator
- (C) Compressor
- (D) Vacuum pump
5. For the same heat transfer area and the terminal conditions, the ratio of the capacities of a single effect evaporator to a triple effect evaporator is
- (A) 3
- (B) 0.33
- (C) 1
- (D) 1.33
6. A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because
- (A) Total
heat transfer area of all the effects is -less than that in a single effect
evaporator system
- (B) Total amount of vapor
produced per Kg of feed steam in a multiple effect system is much higher than
in a single effect
- (C) Boiling
point elevation in a single effect system is much higher than that in any
effect in a multi-effect system
- (D) Heat transfer
co-efficient in a single effect is much lower than that in any effect in a
multi-effect system
7. In a boiling curve, the peak heat flux is called the __________ point.
- (A) Nusselt
- (B) Leidenfrost
- (C) Boiling
- (D) Burnout
8. Film condensation is promoted on a/an __________ surface.
- (A) Oily
- (B) Coated
- (C) Clean & smooth
- (D) Dirty
9. The equivalent diameter for the annulus of a double pipe heat exchanger, whose inner pipe has fins on the outside is __________ compared to the same size pipes without fins.
- (A) More
- (B) Less
- (C) Same
- (D) Unpredictable
10. The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body).
- (A) αT
- (B) α × 1/T
- (C) α T4
- (D) Independent of T
11. In a 1-1 concurrent heat exchanger, if the tube side fluid outlet temperature is equal to the shell side fluid outlet temperature, then the LMTD is
- (A) ∞
- (B) 0
- (C) Equal to the
difference between hot and cold fluids inlet temperature
- (D) Equal
to the difference between hot fluid inlet temperature and cold fluid outlet
temperature
12. According to Reynolds analogy, Stanton number is equal to (where, f = Fanning friction factor)
- (A) 2f
- (B) f
- (C) f/2
- (D) f/4
13. Grashoff number, which is defined as g . β (Ts - T∞) ρ2. L3/μ2, is proportional to the ratio of buoyancy force to __________ force.
- (A) Viscous
- (B) Elastic
- (C) Inertial
- (D) None of these
14. In forced circulation, the heating element is injected
- (A) Internally
- (B) Externally
- (C) Both (a) and (a)
- (D) Neither (a) nor (b)
15. 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 temperature follows __________ law.
- (A) Hyperbolic
- (B) Parabolic
- (C) Linear
- (D) Logarithmic
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