Flow and heat transfer of liquefied natural gas in fiber-reinforced aerogel based on lattice Boltzmann method

Fiber-reinforced silica aerogel composite exhibits exceptional performance in mitigating cryogenic fracture and dispersion risks during liquefied natural gas leakage, primarily due to its intricate pore-scale porous structure. However, the underlying mechanisms remain poorly understood. To address this gap, a double distribution function lattice Boltzmann method integrating a multi-relaxation-time particle distribution function with single-relaxation-time temperature distribution function is implemented to directly simulate liquefied natural gas flow and heat transfer within the fiber-reinforced silica aerogel composite microstructure. Three-dimensional fiber-reinforced silica aerogel composite geometric models with fiber diameters of 1 μm, 2 μm, and 3 μm are reconstructed using stochastic generation algorithms. Through these simulations, key parameters including Darcy permeability ( K D ), the onset of non-Darcy flow, the Forchheimer coefficient ( β ), and local/average Nusselt numbers ( Nu and Nu a ) are quantified. Results reveal that reducing fiber diameter from 3 μm to 1 μm decreases K D by 72.8 % while simultaneously enhancing thermal insulation performance. This study provides new insights and a theoretical reference for the design of fiber-reinforced silica materials and their application in liquefied natural gas (LNG) leakage mitigation.