Author/Authors :
Y. Mahmoudi Abhar branch, Islamic Azad University, Abhar , M. Marefat Department of Mechanical Engineering, Tarbiat Modares University, Tehran , A. Mohammadi
چكيده لاتين :
This paper investigates numerically, the effect of porous inserts on forced convection in a circular
pipe. Two different configurations are considered (i) porous material is inserted at the core of the
pipe and (ii) an annulus porous material is attached to the inner wall. The flow inside the porous
material is modeled using the Darcy-Brinkman-Forchheimer model. The effect of several
parameters mainly, porous layer thickness (Rr), Darcy number (Da) and thermal conductivity (ke),
on the Nusselt number (Nu) and pressure drop are investigated. In the first configuration, the value
of Rr which maximizes Nu varies linearly from 0.8 to 0.95 as the value of Da decreases from 10-3
to 10-6, While previous investigation reported a fixed value of 0.8 for Rr. In the second
configuration, for low value of ke, increasing Rr decreases Nusselt number, and the porous
thickness to achieve lowest Nu, varies linearly from 0.6 to 0.85 as the value of Da decreases from
10-3 to 10-6 and the fully porous pipe configuration, yields the maximum Nu. But for high value of
ke, increasing Rr increases Nu. At the expense of reasonable pressure drop, the optimum thickness
of porous material is Rr=0.6, maximizes Nu in first configuration and minimizes it in second
configuration.
