Permeability and Thermal Transport in Compressed Open-Celled Foams
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چکیده
A computational methodology is proposed to describe the fluid transport in compressed opencelled metallic foams. Various unit-cell foam geometries are numerically deformed under uniaxial loads using a finite element method. An algorithm is developed and implemented to deform the fluid domain mesh inside the unit-cell foam based on the deformed solid unit-cell geometry. Direct simulations of the fluid transport in these deformed meshes are then performed over a range of Reynolds numbers used in practical applications. The model is validated against available experimental results and correlations. A corrected model is proposed for the permeability of compressed foams as a function of strain for flows transverse to the direction of compression. The thermal conductivity of fluid-saturated foams is also computed. Compression of foams increases the conductivity transverse to the direction of compression and decreases the conductivity parallel to it. * Submitted for possible publication in Numerical Heat Transfer, March 2008 † Corresponding author, Email: [email protected], Tel: 765-494-5646, Fax: 765-494-0539 2 NOMENCLATURE a edge length of the unit cell, m A area, m CP specific heat, J g −1 K D diameter of the pore, m Da Darcy number E Young’s modulus, Nm f friction factor J diffusion flux vector, ms K permeability, m k thermal conductivity, WmK L length of the periodic module, m Nu Nusselt number q” heat flux, Wm P pressure, Nm Pr Prandtl number Pe Peclet number R radius of the pore, m Re Reynolds number s center-to-center distance, m T temperature, K t time, s u,v,w velocities along x,y,z directions, ms V volume, m x,y,z Cartesian coordinates Greek α thermal diffusivity, ms δ displacement, m ε strain λ Lame’s constant μ dynamic viscosity, kg ms ρ density, kg m Φ porosity Superscripts
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تاریخ انتشار 2016