Chemical Engineering - Heat Transfer
Exercise :: Heat Transfer - Section 11
| 1. |
Reason for operating an evaporator in multiple effect is to secure |
| A. |
increased steam economy. | | B. |
decreased steam consumption. | | C. |
both (a) and (b). | | D. |
increased capacity. |
Answer: Option C
Explanation:
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| 2. |
In a cooling tower, water becomes cool by |
| A. |
loosing sensible heat. | | B. |
heat transfer to surroundings. | | C. |
vaporisation due to heat loss to air. | | D. |
loosing latent heat. |
Answer: Option A
Explanation:
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| 3. |
In Fourier's law, the proportionality constant is called the |
| A. |
heat transfer co-efficient | | B. |
thermal diffusivity | | C. |
thermal conductivity | | D. |
Stefan-Boltzman constant |
Answer: Option C
Explanation:
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| 4. |
The heat transfer co-efficient in film type condensation is __________ that for dropwise condensation. |
| A. |
greater than | | B. |
lower than | | C. |
is same as | | D. |
half |
Answer: Option B
Explanation:
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| 5. |
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. |
Answer: Option B
Explanation:
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