Effects of fractal network channel on heat and mass transfer in methanol steam reforming

Abstract

Hydrogen production by methanol steam reforming is one of the best choices for portable proton exchange membrane fuel cells (PEMFC). The channel is a dominant role in hydrogen production performance as the main reaction site. In this study, a fractal network channel architecture was designed and a three-dimensional (3D) numerical simulation was conducted in accordance with the Uniform Latin Hypercube design simulation scheme to explore the influence mechanism of branch grade (m), branch angle (θ), branch length ratio (α) and branch width ratio (β) on hydrogen production performance. Furthermore, four factors (m, θ, α, β) for the hydrogen production performance of fractal network channel were optimized by combining response surface method and non dominated sorting genetic algorithm II. The results showed that the hydrogen production performance is most sensitive to changes in β with the growth of the fractal network, followed by m, α, and θ. And the optimum parameter combination in terms of yield hydrogen is m of 3, θ of 134°, α of 0.88, and β of 0.85. The mechanism of the influence of fractal network structure parameters on the methanol reforming reaction as revealed in this study may provide a workable guideline for effective heat and mass transfer in new fractal reaction channel.