Heat Transfer

311. Rate of heat transfer by vaporisation from pools of water is affected by the

1. Nature of heating surface and distribution of bubbles
2. Surface tension of water
3. Viscosity of water
4. All (A), (B) and (C)

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312. Reason for operating an evaporator in multiple effects is to secure

1. Increased steam economy
2. Decreased steam consumption
3. Both (A) and (B)
4. Increased capacity

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313. Removal of _________ heat is involved in the condensation of a vapor under saturated conditions.

1. Super
2. Sensible
3. Latent
4. Both (B) & (C)

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314. Resistance to heat flow by conduction is proportional to (where, t & ρ are thickness & density of the material respectively and A = area normal to the direction of heat flow.)

1. t
2. 1/ρ
3. 1/A
4. All (A), (B) & (C)

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315. Reynold's analogy states that

1. Nst αƒ
2. Nst α NRe
3. NNu αƒ
4. NRe αƒ

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316. Reynold's analogy states that (where, St = Stanton number f = friction factor)

1. St = f/2
2. St = f/4
3. St = 4f
4. St = f^1/2

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317. Sensible heat absorbed by 1 lb of water when it is heated from 32 to 212°F may be around _________ BTU.

1. 180
2. 970
3. 3.97
4. Data insufficient, can't be predicted

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318. Sensible heat of hot industrial flue gases cannot be recovered by a/an

1. Economiser
2. Regenerator
3. Ceramic recuperator
4. None of these

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319. Shell side pressure drop in a shell and tube heat exchanger does not depend upon the

1. Baffle spacing & shell diameter
2. Tube diameter & pitch
3. Viscosity, density & mass velocity of shell side fluid
4. None of these

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320. Small scale evaporation is done in a

1. Heat exchanger
2. Condenser
3. Multiple effect evaporator
4. Steam jacketed kettle

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