Nanoscale Heat Transfer Calculator

Effective thermal conductivity and Knudsen regime at nanoscale.

Feature Size (nm)

Phonon Mean Free Path (nm)

Bulk Conductivity (W/m·K)

Temperature Diff. (K)

Kapitza Resistance (m²K/W)

Tab to move between fields

Knudsen Number

Effective k (W/m·K)

49.33

Regime (1=Diff, 2=Trans, 3=Ball)2

Conductivity Reduction (%)66.7

Heat Flux (W/m²)24,670,000,000

Thermal Time Constant (ps)18.89

Kapitza Conductance (W/m²K)100,000,000

Mfp M0

How to Use This Calculator

Enter the feature size (nm) — the critical dimension governing heat transport.
Set the phonon mean free path (nm) for your material from bulk thermal property data.
Enter bulk thermal conductivity (W/m·K) and temperature difference across the feature (K).
Set Kapitza (interfacial thermal) resistance (m²K/W) at material boundaries if applicable.
Review Knudsen number, transport regime (diffusive, transitional, or ballistic), effective conductivity, and heat flux.

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