V-BO-01 — PMMA-on-Kaowool burnout under ALE (parked depletion)

Tags: ale, burnout, depletion, beer_lambert, coupled, performance

References:

MaCFP-2 PMMA gasification case (NIST), 50 kW/m²
Gpyro V2 PMMA deck property fits

Problem statement

A 5.9 mm PMMA slab on 12 mm Kaowool under 50 kW/m² burns out completely: every PMMA cell shrinks to the depletion threshold and is parked, the exposed boundary walks down the stack, and the run ends on the bare substrate. The deck is the MaCFP PMMA gasification case with the Gpyro V2 property fits (power-law k(T), c(T) above 394 K — positive on the whole property bracket) and in-depth (Beer–Lambert) absorption.

The run must burn out completely, lose exactly the mass of the PMMA layer, match the reference peak mass loss rate, its time and the burnout time, close the mass ledger, and converge the surface temperature at every evaluation, within a wall-time budget at 0.098 mm cells.

Quantities of interest (n = 120)

QoI	value	exact	error	tolerance	within tol	provenance
complete burnout: live thickness at t_end is the substrate	0.012	0.012	3.333e-06	1e-05	yes	every PMMA cell parked; 12.00 ± 0.01 mm
mass loss of the gasified PMMA layer	69.92	69.91	0.005843	0.3	yes	percent of the initial mass; exact = ρPMMA LPMMA / m₀
peak MLR	32.47	32.39	0.002449	0.03	yes	g m⁻² s⁻¹, gas generation rate
mass ledger closure	0.002557	0	0.002557	0.001	no	total-mass drop vs ∫ ṁ″ dt over the run
surface-Newton warnings	0	0	0	0.5	yes	boundary temperature solve converged at every evaluation
time of peak MLR	335.5	335	0.001493	0.03	yes	s
burnout time (live thickness < 12.02 mm)	363.5	363.5	0	0.01	yes	s

V-BO-01 mlr_history

V-BO-01 thickness_history

Solver configuration

setting	value
integrator	KenCarp4 (default)
use_ale	true
handle_depletion	true
depletion_threshold	0.05
min_cells	2
min_thickness	0.001
radiation_model	BEER_LAMBERT
abstol	1.0e-8
reltol	1.0e-6