Nusselt Number For Constant Wall Temperature Calculator

Nusselt Number Formula:

\[ Nu = 0.332 \times (Re^{0.5}) \times (Pr^{0.333}) \]

Nusselt Number (Nu):

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1. What is the Nusselt Number?

The Nusselt Number is the ratio of convective to conductive heat transfer at a boundary in a fluid. Convection includes both advection and diffusion. It is a dimensionless number used in heat transfer calculations.

2. How Does the Calculator Work?

The calculator uses the Nusselt Number formula for constant wall temperature:

\[ Nu = 0.332 \times (Re^{0.5}) \times (Pr^{0.333}) \]

Where:

\( Nu \) — Nusselt Number
\( Re \) — Reynolds Number (ratio of inertial forces to viscous forces)
\( Pr \) — Prandtl Number (ratio of momentum diffusivity to thermal diffusivity)

Explanation: This formula calculates the Nusselt number for laminar flow over a flat plate with constant wall temperature boundary condition.

3. Importance of Nusselt Number Calculation

Details: The Nusselt number is crucial for determining convective heat transfer coefficients in various engineering applications, including heat exchanger design, cooling systems, and thermal analysis of fluid flows.

4. Using the Calculator

Tips: Enter Reynolds Number and Prandtl Number. Both values must be positive numbers. The calculator will compute the Nusselt Number using the specified formula.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for this formula?
A: This formula is valid for laminar flow (Re < 5×10⁵) over a flat plate with constant wall temperature.

Q2: How does the Nusselt number relate to heat transfer?
A: Higher Nusselt numbers indicate more efficient convective heat transfer compared to conductive heat transfer.

Q3: What are typical values for Reynolds and Prandtl numbers?
A: Reynolds numbers can range from 10 to 10⁷ depending on flow conditions. Prandtl numbers typically range from 0.7 for gases to 50-100 for oils.

Q4: Are there other formulas for different boundary conditions?
A: Yes, different formulas exist for constant heat flux boundary conditions and for turbulent flow regimes.

Q5: What are the limitations of this calculation?
A: This calculation is specific to laminar flow over flat plates and may not be accurate for other geometries or flow conditions.