Fractal analysis of the heat and mass transfer limit of a novel PV/micro-channels-loop heat pipe

By treating the wicked surface of the micro-channel as a porous thin layer that is a combination of the random/tortuous pore spaces and water-containing skeletons, the fractal geometry and associated mathematic treatment equations are applied to compute the heat and mass transfer rates within the thin film layer. This paper reports a mathematical model established for the coupled heat and mass transfer within the porous thin layer of the PV/micro-channel evaporator based on the fractal theory, as well as the relevant computer simulation process for the fluid flow and heat/mass transfer. The simulation results are used to calculate the permeability and thermal conductivity of the porous thin film that can further implemented into an integrated model for PV/T heat pipe simulation. It is shown that (1) the permeability, thermal conductivity, boiling limit, all are function of fractal dimension, (2) the new model based on fractal theory for simulating is more ideal in reflecting the behaviour of the irregular porous thin film and thus can deliver a more approximate solution to the fluid flow and heat/mass transfer problems than the conventional modelling method.