Question 1

What does this tool calculate?

Accepted Answer

The tool performs 1D melting analysis of a phase change material, computing melt front position s(t), melt fraction, stored thermal energy (kJ/m²), and half-domain melt time in real time. It simultaneously displays the Stefan analytical solution alongside the enthalpy-method numerical result, with animated temperature T(x) and enthalpy H(x) profiles.

Question 2

How do I use this tool?

Accepted Answer

Select a material preset (ice, paraffin, or nitrate salt) from the left panel, or enter custom values for melting point, latent heat, density, and thermal conductivity. Press the Animation button to watch the melt front advance in real time. Changing parameters instantly updates the half-domain melt time.

Question 3

What is the Stefan problem?

Accepted Answer

The Stefan problem is a heat conduction problem with phase change, where the solid-liquid interface (melt front) moves over time — a moving boundary value problem. For a 1D semi-infinite body, the analytical solution gives melt front position s(t) = 2λ√(α_l·t), where λ satisfies λ·exp(λ²)·erf(λ) = k_l(T_s − T_m) / (L_f·ρ·√(π·α_l)).

Question 4

What are practical design tips for PCM thermal storage systems?

Accepted Answer

Key design considerations for PCM systems: (1) choose materials with high latent heat L_f (water at 334 kJ/kg is among the best); (2) for materials with low thermal conductivity, add extended surfaces such as fins or metal foams; (3) account for supercooling by using nucleating agents; (4) design the container to accommodate the volumetric expansion during melting (typically ~10%).

Phase Change Material (PCM) Thermal Analysis Tool