Blast Freezer Slab: 1D Conduction Freezing Front & Plank-Time Check (2D)

This 2D companion to the 3D blast-freezer tunnel zooms into a single product and asks a question the tunnel's lumped-temperature model cannot answer: what does the temperature look like inside the item while it freezes? Instead of one core-temperature number, this simulator solves real transient heat conduction across the product's half-thickness with a finite-volume, energy-conservative scheme, carrying the latent heat of fusion through an apparent-heat-capacity band around the freezing point so a genuine phase-change front appears and advances from the surface toward the center. The Biot number readout tells you when the 3D tunnel's simpler lumped assumption is reasonable (thin items, low Biot) and when it would be misleading (thick cuts, high Biot) — and the whole simulation is cross-checked live against Plank's classical freezing-time equation, the same textbook formula real refrigeration engineers use to size blast tunnels.