1. What is Heat Flux?

Heat flux (q) is the rate of heat energy transfer through a given surface per unit area. According to Fourier's Law, heat flux is proportional to the negative temperature gradient and the material's thermal conductivity.

2. How Does the Calculator Work?

The calculator uses Fourier's Law:

Where:

• \( q \) — Heat flux (W/m²)
• \( k \) — Thermal conductivity (W/m·K)
• \( \nabla T \) — Temperature gradient (K/m)

Explanation: The negative sign indicates that heat flows from higher to lower temperatures. The greater the temperature difference and the higher the material's conductivity, the greater the heat flux.

3. Importance of Heat Flux Calculation

Details: Heat flux calculations are essential in thermal engineering, building design, electronics cooling, and materials science. They help determine insulation requirements, heat dissipation needs, and thermal management solutions.

4. Using the Calculator

Tips: Enter thermal conductivity in W/m·K and temperature gradient in K/m. The temperature gradient can be positive or negative, representing the direction of temperature change.

5. Frequently Asked Questions (FAQ)

Q1: What are typical thermal conductivity values?
A: Copper: ~400 W/m·K, Aluminum: ~200 W/m·K, Water: ~0.6 W/m·K, Air: ~0.025 W/m·K.

Q2: What does negative heat flux mean?
A: Negative values indicate heat flow in the opposite direction of the coordinate system being used (but still from hot to cold).

Q3: How is temperature gradient measured?
A: It's the temperature difference divided by the distance over which the change occurs (ΔT/Δx).

Q4: Does this apply to all materials?
A: Fourier's Law applies to isotropic materials. Anisotropic materials require tensor analysis.

Q5: What about transient heat transfer?
A: This calculator is for steady-state conditions. Transient analysis requires solving the heat equation.