Heat transfer co-efficient (h) for a fluid flowing inside a clean pipe is given by h = 0.023 (K/D) (DVρ/μ)0.8 (CP.μ/k)0.4. This is valid for the value of NRe equal to_______________?
Correct answer: A. > 10000
- A. > 10000
- B. 4000
Explanation
This correlation is the Dittus-Boelter equation, which applies to fully developed turbulent flow in a smooth pipe, normally for Reynolds numbers above about 10,000. Lower values may lie in the transition region, where the correlation is unreliable.
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