Rate Of Heat Transfer By Conduction Formula

Fourier's Law of Heat Conduction:

\[ Q = \frac{k A \Delta T}{L} \]

Thermal Conductivity (k):

W/m·K

Cross-sectional Area (A):

m²

Temperature Difference (ΔT):

Thickness (L):

Heat Transfer Rate (Q):

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1. What is Fourier's Law of Heat Conduction?

Fourier's Law describes the rate of heat transfer through a material by conduction. It states that the heat transfer rate is proportional to the temperature gradient and the cross-sectional area, and inversely proportional to the material thickness.

2. How Does the Calculator Work?

The calculator uses Fourier's Law equation:

\[ Q = \frac{k A \Delta T}{L} \]

Where:

\( Q \) — Heat transfer rate (W)
\( k \) — Thermal conductivity (W/m·K)
\( A \) — Cross-sectional area (m²)
\( \Delta T \) — Temperature difference (K)
\( L \) — Thickness of material (m)

Explanation: The equation quantifies how quickly heat energy flows through a material due to temperature differences across it.

3. Importance of Heat Transfer Calculation

Details: Accurate heat transfer calculations are essential for designing thermal insulation systems, heat exchangers, electronic cooling systems, and building energy efficiency analysis.

4. Using the Calculator

Tips: Enter thermal conductivity in W/m·K, cross-sectional area in m², temperature difference in Kelvin, and material thickness in meters. All values must be positive numbers.

5. Frequently Asked Questions (FAQ)

Q1: What is thermal conductivity?
A: Thermal conductivity (k) is a material property that indicates its ability to conduct heat. Higher values mean better heat conduction.

Q2: Why use Kelvin for temperature difference?
A: Kelvin is used because temperature differences are the same in Celsius and Kelvin scales, and it avoids negative values in calculations.

Q3: What are typical thermal conductivity values?
A: Copper: ~400 W/m·K, Steel: ~50 W/m·K, Glass: ~1 W/m·K, Wood: ~0.1 W/m·K, Air: ~0.026 W/m·K.

Q4: When is Fourier's Law applicable?
A: It applies to steady-state heat conduction through homogeneous materials with constant thermal properties.

Q5: What are the limitations of this equation?
A: It assumes one-dimensional heat flow, constant thermal conductivity, and steady-state conditions. Not suitable for transient heat transfer or complex geometries.