Investigation of Laminar Flow in a Porous Pipe with Variable Wall Suction

Abstract

An analytical model has been developed to provide an analogy for and predict flow property distributions in the condensing regions of a heat pipe. The model incorporates the phenomenon of incompressibl e, steady, laminar flow through a uniformly-poro us-wall pipe with a closed end-wall. A Karman-Pohlhau sen momentum integral technique was employed to reduce the axisymmetric Navier-Stokes equation to a nonlinear second-order ordinary differential equation. The axial pressure gradient, suction velocity at the porous wall, and wall friction coefficient were computed over a range of Reynolds numbers and wall permeabilities. These flow property distributions were not constrained a priori, but were allowed to vary in accordance with the conservation laws. The calculated flow property distributions for the condenser region of the heat pipe model are compared with published experimental data and several other theoretical models cited in the literature.