1. What is the Nusselt Number For Liquids For External Flow?

The Nusselt Number is a dimensionless number that represents the ratio of convective to conductive heat transfer at a boundary in a fluid. For external flow of liquids, this specific correlation provides an accurate estimation of heat transfer characteristics.

2. How Does the Calculator Work?

The calculator uses the Nusselt Number formula:

Where:

• \( Nu \) — Nusselt Number
• \( Re \) — Reynolds Number
• \( Pr \) — Prandtl Number

Explanation: This correlation accounts for both the flow characteristics (through Reynolds number) and the fluid properties (through Prandtl number) to estimate the convective heat transfer coefficient.

3. Importance of Nusselt Number Calculation

Details: Accurate Nusselt Number estimation is crucial for designing heat exchangers, predicting heat transfer rates, and optimizing thermal systems involving external flow of liquids.

4. Using the Calculator

Tips: Enter Reynolds Number and Prandtl Number. Both values must be positive numbers representing the appropriate dimensionless parameters for your fluid flow scenario.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for this correlation?
A: This correlation is typically valid for external flow of liquids with moderate Reynolds numbers and typical Prandtl numbers for common liquids.

Q2: How does Reynolds Number affect the Nusselt Number?
A: Higher Reynolds numbers (indicating more turbulent flow) generally result in higher Nusselt numbers, meaning better convective heat transfer.

Q3: What does the Prandtl Number represent?
A: The Prandtl Number represents the ratio of momentum diffusivity to thermal diffusivity, indicating the relative thickness of the momentum and thermal boundary layers.

Q4: When should this correlation be used?
A: This correlation is specifically designed for external flow of liquids over surfaces, such as flow over flat plates, cylinders, or other external geometries.

Q5: Are there limitations to this equation?
A: This correlation may have limitations at very high or very low Reynolds numbers, for non-Newtonian fluids, or in cases with significant property variations.