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GATE 2021 CH – Question 16

Heat Transfer · Boiling, condensation and evaporation · 1 mark · Multiple choice

Heat transfer coefficient for a vapor condensing as a film on a vertical surface is given by

  1. Dittus-Boelter equation
  2. Nusselt theory
  3. Chilton-Colburn analogy
  4. Sieder-Tate equation

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Show answer and explanation

Correct answer: (B) Nusselt theory

Explanation

Nusselt’s film-condensation theory balances gravity and viscous resistance in the condensate film and treats heat conduction through that film. It predicts the heat-transfer coefficient for laminar film condensation on a vertical surface.

Dittus–Boelter and Sieder–Tate are primarily correlations for convective heat transfer in flowing fluids inside tubes. Chilton–Colburn is a heat/mass/momentum-transfer analogy. **Answer: B.**