A general correlation for the volumetric heat transfer coefficient between stream of air and open- cellular porous materials was developed utilizing experimental data obtained by Hamaguchi et al., Younis- Viskanta and Kamiuto et al.

The developed correlation is written in form of h_v = (A/D_s^2-n) uⁿ. Here, h_v denotes the volumetric heat transfer coefficient, A is the constant, n is the velocity exponent, u is the mean air velocity and D_s is the equivalent strut diameter of Dulnev`s unit cell for open-cell foam. The parameters, A and n, were determined by a least- square fit of the expression to the above-mentioned experimental data to give A= 12.44 and n= 0.792. Moreover, from the h_v -u correlation thus determined, the following Nusselt vs Reynolds number heat transfer correlation was obtained: Nu_s = 0.105 (Re_sPr)^0.792, where Nu_s represents the Nusselt number defined by h_v D_s² / k_f , Re_s denotes the Reynolds number defined by uD_s /V_f, Pr is the Prandtl number, k_f is the thermal conductivity of fluid and V_f is the kinematic viscosity of fluid. It is found that this correlation approximates 76.6% of the available experimental data with an error of less than ±40%.