Coupled Effects of Biofilm Dynamics and Flow on Hydrogen Transport in a Hydrogen-Generating Fracture
Abstract
Biofilms alter fracture flow and consume hydrogen, affecting recovery from stimulated geologic hydrogen systems. High-fidelity simulations couple flow, biofilm evolution, and hydrogen transport in a rough fracture with reactive walls. Varying flow rate and biofilm permeability reveals reductions in apparent fracture permeability of up to 65%. Highly permeable biofilms produce a non-monotonic outlet hydrogen response as growing biofilms suppress roughness-induced vortices. For low-permeability biofilms, transport resistance and microbial consumption instead cause an approximately monotonic concentration decline. A Darcy-scale Reynolds number distinguishes these regimes, suggesting that temporal hydrogen concentration measurements may provide information about intrinsic biofilm permeability.
