For condensation of pure vapors, if the heat transfer co-efficients in filmwise and drop-wise condensation are respectively hf and hd, then__________________?
Correct answer: C. hf < hd
- A. hf = hd
- B. hf > hd
- C. hf < hd
- D. hf could be greater or smaller than hd
Explanation
Dropwise condensation exposes much more of the cold surface directly to fresh condensate and avoids the insulating liquid film. Consequently, its heat-transfer coefficient is much higher than that for filmwise condensation, so hf < hd.
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