V-CPL-05 — TGA-to-gasification consistency ladder (1D → 0D thin limit)

Tags: kinetics, consistency_ladder, thin_limit, bc_coupling

References:

• MaCFP condensed-phase guidelines (2020) — TGA target simulations
• Verification Suite Plan 2026-07-06, V-CPL-05

Problem statement

MaCFP-style internal-consistency chain: the same first-order kinetics run (a) 0D isothermal — covered exactly by the V-RX cases; (b) 0D constant heating rate — exact reference ξ(t) = ξ₀e^(−(A/β)I(T)) with the temperature integral I computed to high precision (exact/tga.jl, self-tested against the asymptotic expansion); (c) 1D slabs driven by a Dirichlet ramp T = T₀ + βt on BOTH faces, with a thickness ladder L → 0: the volume-mean solid mass must converge to the 0D TGA curve at second order in L (the interior lags the faces by the quasi-steady parabola ΔT ≈ β(L/2)²/2α ∝ L², which maps onto the mass curve through dξ/dT). Catches BC/volume-coupling contamination of the kinetics that no pure 0D test can.

The depletion limiter is disabled: its tanh roll-off below ~1 kg/m³ holds a residual tail of order 0.1% of ξ₀ — the size of the thinnest rung's entire error — which would corrupt both the error metric and the observed order. h = 0 keeps the ramp exact (no reaction self-heating), everything is impermeable and Eulerian (held gas, no volume change), so temperature is the ONLY coupling between the 1D solve and the kinetics.

Quantities of interest (n = 16)

Solver configuration