Freeze-drying of structurally heterogeneous biomaterials such as porcine aorta presents considerable modeling challenges due to their inherent multilayer composition and moving sublimation interfaces.Conventional mode...Freeze-drying of structurally heterogeneous biomaterials such as porcine aorta presents considerable modeling challenges due to their inherent multilayer composition and moving sublimation interfaces.Conventional models often overlook structural anisotropy and dynamic boundary progression,while experimental determination of key parameters under cryogenic conditions remains difficult.To address these,this study develops a heat and mass transfer model incorporating a dynamic node strategy for the sublimation interface,which effectively handles continuous computational domain deformation.Additionally,specialized fixed nodes were incorporated to adapt to the multilayer structure and its spatially varying thermophysical properties.A novel non-contact gravimetric system was introduced to monitor mass loss in real time without disrupting vacuum,enabling accurate experimental validation.Combined with dehydration data,the model quantified critical parameters including effective thermal conductivity of the dried layer,vapor diffusivity,and sublimation mass transfer resistance.The results show that the migration of the sublimation fronts from both the inner and outer tunics toward the tunica media significantly alters the drying kinetics and heat-mass transfer characteristics.The proposed approach provides an adaptable and predictive framework for simulating freeze-drying processes in structurally heterogeneous systems with spatially varying thermophysical properties.展开更多
基金funded by the Scientific and Technological Research Projects in Henan Province(No.252102310425)the Key Scientific Research Projects of Higher Education Institutions in Henan Province(No.23A560018).
文摘Freeze-drying of structurally heterogeneous biomaterials such as porcine aorta presents considerable modeling challenges due to their inherent multilayer composition and moving sublimation interfaces.Conventional models often overlook structural anisotropy and dynamic boundary progression,while experimental determination of key parameters under cryogenic conditions remains difficult.To address these,this study develops a heat and mass transfer model incorporating a dynamic node strategy for the sublimation interface,which effectively handles continuous computational domain deformation.Additionally,specialized fixed nodes were incorporated to adapt to the multilayer structure and its spatially varying thermophysical properties.A novel non-contact gravimetric system was introduced to monitor mass loss in real time without disrupting vacuum,enabling accurate experimental validation.Combined with dehydration data,the model quantified critical parameters including effective thermal conductivity of the dried layer,vapor diffusivity,and sublimation mass transfer resistance.The results show that the migration of the sublimation fronts from both the inner and outer tunics toward the tunica media significantly alters the drying kinetics and heat-mass transfer characteristics.The proposed approach provides an adaptable and predictive framework for simulating freeze-drying processes in structurally heterogeneous systems with spatially varying thermophysical properties.
