A theoretical octet-truss lattice unit cell model for effective thermal conductivity of consolidated porous materials saturated with fluid

A theoretical octet-truss lattice unit cell model for the effective thermal conductivity of consolidated porous materials saturated with fluid was proposed. Onedimensional heat conduction analysis was conducted to derive the explicit expression of effective thermal heat conductivity with isotropic assumption and negligible natural convection inside the solid matrix. By introducing the morphological parameter defined as the ratio of the intersection node radius to the fiber diameter, the effective thermal conductivity was expressed as a function of porosity, thermal conductivity of solids and fluids, and the defined morphological parameter. The limitations in range of the defined morphology parameter were obtained on the basis of the model constraints and implementation examples were formulated. The feasibility of the model was evaluated using the experimental data from previous literature and those obtained in the present study. The effective thermal conductivities of nine sintered metal fiber felts with different morphological parameters were tested in the manner of heating on the top and cooling at the bottom of sample simultaneously to suppress internal natural convection. The validation of applicable porosity range was extended from ε>0:9, used in previous literature, to ε>0:8 applied in the present model.