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Nusselt Number Formula:
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The Nusselt Number for a sphere with Prandtl number equal to 1 is a dimensionless parameter used in heat transfer calculations. It represents the ratio of convective to conductive heat transfer at the boundary of a spherical object in a fluid flow.
The calculator uses the Nusselt Number formula:
Where:
Explanation: This formula calculates the Nusselt number for a sphere in natural convection when the Prandtl number is approximately equal to 1, accounting for both buoyancy and viscous forces.
Details: The Nusselt number is crucial for determining the convective heat transfer coefficient in various engineering applications involving spherical objects, such as heat exchangers, chemical reactors, and environmental systems.
Tips: Enter the Grashof Number based on diameter and Prandtl Number. Both values must be positive numbers. The calculator will compute the corresponding Nusselt Number.
Q1: What is the physical significance of the Nusselt number?
A: The Nusselt number represents the enhancement of heat transfer through a fluid layer due to convection compared to conduction alone.
Q2: When is this specific formula applicable?
A: This formula is specifically designed for natural convection around spheres when the Prandtl number is approximately equal to 1.
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 from 0.7 for gases to higher values for liquids.
Q4: Are there limitations to this equation?
A: This equation is specifically valid for Pr ≈ 1 and may not be accurate for fluids with significantly different Prandtl numbers.
Q5: How does this relate to other Nusselt number correlations?
A: Different correlations exist for various geometries and flow conditions. This specific correlation is optimized for spherical geometries with Pr ≈ 1.