Different models are proposed to evaluate the stagnant thermal conductivity of some 2D and 3D spatially periodic porous media. Based on a lumped-parameter model, algebraic expressions of the proposed geometries are obtained. The geometries under consideration include arrays of touching and non-touching in-line square, elliptic cylinders (2D), the touching and non- touching in-line cubes (3D) as well as in-line ellipsoids (3D) with connecting bars. A comparison of results based on these algebraic expressions with existing numerical solutions and experimental results shows that they are in excellent agreement....[ Read more ]

Different models are proposed to evaluate the stagnant thermal conductivity of some 2D and 3D spatially periodic porous media. Based on a lumped-parameter model, algebraic expressions of the proposed geometries are obtained. The geometries under consideration include arrays of touching and non-touching in-line square, elliptic cylinders (2D), the touching and non- touching in-line cubes (3D) as well as in-line ellipsoids (3D) with connecting bars. A comparison of results based on these algebraic expressions with existing numerical solutions and experimental results shows that they are in excellent agreement.

A modified Zehner-Schlunder model is proposed for calculation of the stagnant thermal conductivity of porous medium with spatially periodic structures. The modified model takes into consideration of finite contact area between spheres in a packed-sphere bed. It is shown that results based on the modified model is in better agreement with experimental data than those based on the original Zehner- SchIunder model, especially at high solid/fluid thermal conductivity ratios.

By applying the lumped parameter model, algebraic expression of the stagnant thermal conductivity of a network of waived porous fibers are obtained. The geometry of the network includes parallel straight porous fibers aligning perpendicularly in different layers with small connecting bars. The results show good agreement with experimental data.