Radiation Heat Transfer Formula:
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Definition: This calculator computes the thermal radiation energy transfer between two surfaces based on the Stefan-Boltzmann law.
Purpose: It helps engineers and physicists determine the radiant heat exchange between objects at different temperatures.
The calculator uses the formula:
Where:
Explanation: The formula calculates the net radiant energy exchange between two surfaces based on their temperatures and material properties.
Details: Accurate calculation is crucial for thermal system design, energy efficiency analysis, and temperature control in various applications.
Tips: Enter the emissivity (0-1), surface area in m², and both temperatures in Kelvin. All values must be positive numbers.
Q1: What is typical emissivity for common materials?
A: Black body = 1, polished metals ≈ 0.05-0.2, oxidized metals ≈ 0.3-0.7, most non-metals ≈ 0.7-0.95.
Q2: Why must temperatures be in Kelvin?
A: The Stefan-Boltzmann law requires absolute temperature (Kelvin) because radiation depends on T⁴.
Q3: What if T₂ > T₁?
A: The result will be negative, indicating heat flows in the opposite direction (from T₂ to T₁).
Q4: Does this account for view factors?
A: No, this is for direct radiation between surfaces. For complex geometries, view factors must be considered.
Q5: What's the Stefan-Boltzmann constant?
A: It's a fundamental physical constant (5.67×10⁻⁸ W/m²K⁴) that appears in the law of thermal radiation.