1. What is the Nusselt Number for Horizontal Plate with Heated Surface Up?

The Nusselt Number for a horizontal plate with heated surface facing upward is a dimensionless parameter that characterizes the convective heat transfer from the plate surface to the surrounding fluid. It represents the ratio of convective to conductive heat transfer at the boundary.

2. How Does the Calculator Work?

The calculator uses the Nusselt Number formula:

Where:

• \( Nu \) — Nusselt Number (dimensionless)
• \( Gr_e \) — Grashof Number with properties evaluated at elevated temperature (dimensionless)
• \( Pr_e \) — Prandtl Number with properties evaluated at elevated temperature (dimensionless)

Explanation: This empirical correlation is specifically derived for horizontal plates with heated surface facing upward, where natural convection dominates the heat transfer process.

3. Importance of Nusselt Number Calculation

Details: Accurate Nusselt Number calculation is crucial for designing heat transfer systems involving horizontal heated surfaces, predicting heat transfer rates, and optimizing thermal performance in various engineering applications.

4. Using the Calculator

Tips: Enter the Grashof Number and Prandtl Number with properties evaluated at the elevated temperature. Both values must be positive numbers greater than zero.

5. Frequently Asked Questions (FAQ)

Q1: What is the range of validity for this correlation?
A: This correlation is typically valid for natural convection over horizontal plates with heated surface facing upward, particularly in the laminar flow regime.

Q2: How does surface orientation affect the Nusselt Number?
A: Surface orientation significantly affects natural convection patterns. For horizontal plates, the heated surface facing upward creates different flow patterns compared to downward-facing or vertical surfaces.

Q3: What are typical values for Grashof and Prandtl Numbers?
A: Grashof Numbers typically range from 10^4 to 10^9 for natural convection, while Prandtl Numbers vary with fluid type (0.7 for air, 5-7 for water, higher for oils).

Q4: When should this correlation be used?
A: This correlation is specifically designed for horizontal plates with heated surface facing upward under natural convection conditions.

Q5: Are there limitations to this correlation?
A: This correlation may have limitations at very high or low Rayleigh numbers, for different fluid types, or when forced convection effects become significant.