InterPore2026

A coupled pore-network modeling and experimental validation framework for freeze-drying: fluid–solid–thermal interactions in porous media under rarefied-gas conditions

22 May 2026, 10:05

15m

Oral Presentation (MS16) Complex fluid and Fluid-Solid-Thermal coupled process in porous media: Modeling and Experiment MS16

Speaker

Mr Shalong Xiong (Technical University of Munich)

Description

Freeze-drying involves strongly coupled heat and mass transfer in evolving porous structures, where the interplay between rarefied gas flow, solid conduction, and phase-change kinetics governs the sublimation front dynamics and overall drying rate. In this work, we present a physics-based pore-network modeling framework for freeze-drying and validate it against controlled laboratory experiments designed to access Knudsen-transition transport regimes. The model resolves conservation of mass and energy at the pore/throat scale, incorporating temperature-gradient-driven transpiration flow, pressure-driven transport, and solid-phase heat conduction, with an interfacial sublimation source term that couples local temperature and vapor removal capacity. Gas transport is formulated via a regime-aware conductance law that uses an effective Knudsen number and an accommodation-dependent correction, enabling continuous predictions from slip to transition regimes. The evolving saturation field is updated by linking local sublimation rates to pore-scale mass removal, allowing the model to predict front propagation and spatiotemporal heterogeneity.

For validation, we conduct freeze-drying experiments in porous bead packs confined in a well-defined container geometry and operated at low pressures (order of 10 Pa) and subzero temperatures (around 253 K), yielding effective Knudsen numbers in the range 0.5–1. Model predictions are compared with experimental observables including mass-loss rate and front position, demonstrating that the proposed framework captures both the global drying kinetics and the transition between transport-limited and heat-limited regimes. The combined modeling–experiment approach provides a quantitative path to upscale pore-scale mechanisms to macroscale freeze-drying operation, and offers a transferable methodology for fluid–solid–thermal coupled processes in porous media under non-continuum flow conditions.