Select the valid equation ?
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Answer: B. Nu = (Re) (Pr) (St)
Explanation
The Chilton-Colburn analogy relates the jH factor to the Stanton number and Prandtl number as jH = St * Pr^(2/3) = f/2. This empirical analogy successfully links fluid friction factor to convective heat transfer coefficients in turbulent flow. Exponent values on the Prandtl number in the Chilton-Colburn equation are established at two-thirds for gases and liquids. Analogy between momentum and heat transfer allows engineers to predict convective heat coefficients from friction data. Stanton number combines Nusselt, Reynolds, and Prandtl numbers into a single dimensionless heat transfer parameter. Fanning friction factor represents shear stress at solid boundaries relative to fluid kinetic energy head.
Chemical engineers use the Chilton-Colburn analogy to design shell-and-tube and finned-tube heat transfer equipment. Turbulent flow inside pipes and across tube bundles is modeled effectively using friction-heat transfer analogies. Optimizing thermal hydraulic performance in compact heat exchangers relies on accurate analogy equations. Alternative exponent placements on the Prandtl number violate established empirical Chilton-Colburn analogy correlations. Placing exponents on Stanton numbers rather than Prandtl numbers contradicts standard turbulent transport equations. Modifying friction factor scaling terms ruins the validated equality between momentum and thermal transport.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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