Formula Used:
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Thermal Conductivity is the rate at which heat passes through a specified material, expressed as the amount of heat flows per unit time through a unit area with a temperature gradient of one degree per unit distance. It is a fundamental property in heat transfer analysis.
The calculator uses the formula:
Where:
Explanation: This formula relates thermal conductivity to dynamic viscosity, specific heat capacity, and Prandtl number, which is the ratio of momentum diffusivity to thermal diffusivity.
Details: Thermal conductivity is crucial for designing heat exchangers, insulation systems, and various thermal management applications. It helps in predicting how quickly heat will transfer through materials.
Tips: Enter dynamic viscosity in Pa·s, specific heat capacity in J/kg·K, and Prandtl number (dimensionless). All values must be positive numbers.
Q1: What is the typical range of thermal conductivity values?
A: Thermal conductivity values vary widely: metals (50-400 W/m·K), water (0.6 W/m·K), air (0.025 W/m·K), and insulation materials (0.02-0.1 W/m·K).
Q2: How does temperature affect thermal conductivity?
A: For metals, conductivity decreases with temperature; for gases and insulation materials, it generally increases with temperature.
Q3: What is the significance of Prandtl number?
A: Prandtl number represents the ratio of momentum diffusivity to thermal diffusivity, indicating the relative thickness of velocity and thermal boundary layers.
Q4: Are there limitations to this calculation method?
A: This formula is most accurate for ideal gases and may require adjustments for complex fluids or extreme conditions.
Q5: How is thermal conductivity measured experimentally?
A: Common methods include guarded hot plate, heat flow meter, and laser flash techniques, depending on the material and temperature range.