Question

The Fourier number (\(N_{Fo}\)) is defined as (α is thermal diffusivity, L is characteristic length and t is time)

• A. \( \frac{h k}{L} \)
• B. \( \frac{h L}{k} \)
• C. \( \frac{t L^2}{\alpha} \)
• D. \( \frac{\alpha t}{L^2} \)

Hint:

Higher Fourier number indicates deeper heat penetration in transient conduction.

Answer 1

The Correct Option is D

Fourier number represents dimensionless time and is given by:
\[ N_{Fo} = \frac{\alpha t}{L^2} \]
It is used in transient heat conduction to describe heat penetration over time.