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Colburn's j-factor is a non-dimensional parameter that arises in convective heat transfer analysis. It relates the heat transfer coefficient to fluid properties and flow conditions, providing a useful correlation for heat exchanger design and analysis.
The calculator uses the simple relationship:
Where:
Explanation: This relationship shows that Colburn's j-factor is exactly half of the Fanning friction factor, providing a direct correlation between heat transfer and fluid friction characteristics.
Details: Colburn's j-factor is crucial in heat exchanger design as it helps predict heat transfer performance based on fluid flow characteristics. It's particularly useful in the analogy between heat and momentum transfer in turbulent flow.
Tips: Enter the Fanning friction factor value (must be greater than 0). The calculator will compute the corresponding Colburn's j-factor.
Q1: What is the typical range of values for Colburn's j-factor?
A: j-factor values typically range from 0.001 to 0.05 depending on the flow regime and surface characteristics.
Q2: How does Colburn's j-factor relate to Nusselt number?
A: j-factor is related to Stanton number (St) as j = St·Pr2/3, and Stanton number relates to Nusselt number as St = Nu/(Re·Pr).
Q3: Is this relationship valid for all flow conditions?
A: The j = f/2 relationship is most accurate for turbulent flow in smooth tubes and represents the Reynolds analogy between heat and momentum transfer.
Q4: What's the difference between Fanning and Darcy friction factors?
A: The Fanning friction factor is one-fourth of the Darcy friction factor (fFanning = fDarcy/4).
Q5: When should this correlation be used with caution?
A: This simple relationship may not hold for rough surfaces, very low Reynolds numbers, or complex geometries where additional factors influence the heat transfer process.