An instrument requires mercury to be cooled from 418.15 K to 278.15 using an iced-water bath kept at 273.15 K. The flow rate of mercury is 0.4 kg/s. Assume the inner surface of the tube carrying mercury is at the same temperature of the bath. There are three types of tubing available: (A) thin tube with a circular cross-section of 0.25 m diameter, (B) thin tube with a square cross-section of 0.3 m sides, or (C) thin tube with a rectangular cross-section of 0.15 mx0.30 m. Which tube will provide the highest convection coefficient if the flow is fully- developed? (b) Can one assume that the flow is thermally fully-developed in any of the above tubes?

An instrument requires mercury to be cooled from 418.15 K to 278.15 using an iced-water bath kept at 273.15 K. The flow rate of mercury is 0.4 kg/s. Assume the inner surface of the tube carrying mercury is at the same temperature of the bath. There are three types of tubing available: (A) thin tube with a circular cross-section of 0.25 m diameter, (B) thin tube with a square cross-section of 0.3 m sides, or (C) thin tube with a rectangular cross-section of 0.15 mx0.30 m. Which tube will provide the highest convection coefficient if the flow is fully- developed? (b) Can one assume that the flow is thermally fully-developed in any of the above tubes?

Principles of Heat Transfer (Activate Learning with these NEW titles from Engineering!)

8th Edition

ISBN:9781305387102

Author:Kreith, Frank; Manglik, Raj M.

Publisher:Kreith, Frank; Manglik, Raj M.

Chapter9: Heat Transfer With Phase Change

Section: Chapter Questions

Problem 9.21P

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