Question

Which of the following is a dimensionless number related to heat conduction?

• A. Fourier Number
• B. Nusselt Number
• C. Prandtl Number
• D. Stanton Number

Hint:

The Fourier number is widely used in the study of transient heat conduction to measure the relative importance of thermal diffusion over time.

Answer 1

The Correct Option is A

The Fourier Number (\(Fo\)) is a dimensionless number that relates the rate of heat conduction to thermal energy storage in a system. It is particularly useful in transient heat conduction problems. The Fourier number is given by: \[ Fo = \frac{\alpha t}{L^2} \] where \( \alpha \) is the thermal diffusivity, \( t \) is the time, and \( L \) is the characteristic length. It indicates how quickly heat is diffused in a material compared to the time passed.
- The Nusselt Number (\(Nu\)) is a dimensionless number related to convective heat transfer, not conduction. It is defined as the ratio of convective to conductive heat transfer across a boundary.
- The Prandtl Number (\(Pr\)) is a dimensionless number that relates the viscous diffusion rate to the thermal diffusion rate, but it is not specifically related to heat conduction.
- The Stanton Number (\(St\)) is another dimensionless number used in heat transfer, but it relates to the convective heat transfer rate and not directly to heat conduction.
Thus, the correct answer is the Fourier Number as it is directly related to heat conduction.