A. 0.01 to 1
B. 1.5 to 2.5
C. 5 to 10
D. 10 to 20
Related Mcqs:
- Length to diameter ratio of most rotary driers is in the range of____________________?
A. 1 to 2
B. 4 to 10
C. 10 to 20
D. 20 to 30 - Normally, the length to diameter ratio of rotary dryers varies from 4 to 10 and for its economic operation; the number of transfer units (NTU) for such dryers varies from ?
A. 1.5-2.5
B. 3.5-5.5
C. 7.5-10.0
D. 10-15 - In a double pipe (concentric) heat exchanger, the hydraulic radius for heat transfer (for a fluid flowing through the annulus) would be_________________?
A. Same as that for fluid flow
B. Less than that for fluid flow
C. More than that for fluid flow
D. D2 – D1 (D1 and D2 are I.D. of inner and outer pipes respectively) - The thickness of heat transfer plates used in the plate type heat exchanger ranges from _____________ mm, pressed in a single piece provided with grooves & corrugations?
A. 0.3 to 0.8
B. 1.25 to 3.125
C. 3.5 to 7.0
D. 8 to12 - Which tube arrangement in a heat exchanger would facilitate highest heat transfer rate ?
A. Triangular pitch
B. Square pitch
C. Diagonal square pitch
D. Heat transfer rate is independent of tube arrangement - In case of a shell and tube heat exchanger, the effect of L/D on inside film heat transfer coefficient (hi) vanishes after a Reynold number of_____________?
A. 1000
B. 3000
C. 5000
D. 10000 - In a shell and tube heat exchanger for a given heat transfer surface area, smaller diameter tubes are favoured as compared to larger diameter ones; because the smaller diameter tubes ______________?
A. Are easier to clean
B. Are less prone to fouling
C. Can be fitted into a smaller shell diameter hence the cost of the heat exchanger would be less
D. None of these - In a shell and tube heat exchanger, the overall heat transfer co-efficient is proportional to the tube side (volumetric flow rate)0.8. This is valid, only when the ratio of the tube side film resistance to the total resistance is almost equal to____________________?
A. ∞
B. 1
C. 20.8
D. 2 - The operating velocity in the absorption tower is usually 40-50% of the flooding velocity. Packed absorption towers are normally designed for a pressure drop of about _________________ mm of water column per metre height of packing?
A. 1-5
B. 20-40
C. 100-150
D. 1000-1500 - Overall mass transfer co-efficient in case of absorption of __________ in water is based on the gas film co-efficient only, as the mass transfer process is gas film (phase) controlling ?
A. CO2
B. SO2
C. NH3
D. None of these
