Numerical Study Of Flow Characteristics Behind Butterfly Porous Fences

Dust suppression engineering technology of porous fences, which is composed by porous metal plates or knitted, cohered, extrusion molded nonmetal mesh sheets, steel bracing structure, underground concrete foundation and corresponding auxiliary apparatus, is the effective measure to control dust re-entrainment in a large open-air stockyard. The core component of the technology is the porous fences, but the wake zone flow field characteristics behind porous fences directly affect the shelter effect of them.In this paper, numerical models of the butterfly porous fences were established by the Fluent based on the non-planar porous fences used in the engineering construction by our group recently. The numerical simulation of the influence about the porosity and bottom gap on the flow characteristics behind the butterfly porous fence were carried out, and the experimental data of the porosity and bottom gap on the flow characteristics obtained from the wind tunnel experiment were used to identify the feasibility and the correction of the numerical models, on these bases the numerical simulations of the porosity, hole diameter, opening forms of holes, hole matching and bottom gap on the flow characteristics behind the butterfly porous fences were conducted. And the conclusions are as follows:(1) The results of numerical simulation were in well agreement with the data of wind tunnel experiments, which indicated that the present numerical model can be used to study about the butterfly porous fences in this paper;(2) The butterfly porous fences, with porosity of0.301will have the best shelter effect and the biggest wind reduction rate of65.33%to wake zone as they have the same hole diameter of6mm;(3) The butterfly porous fences, with hole diameter of9mm will have the best shelter effect and the biggest wind reduction rate of69.274%to wake zone as they have the same porosity of0.301; (4) The butterfly porous fences, which the opening forms of holes are all circle will have the biggest wind reduction rate of69.274%to wake zone as they have the same porosity of0.301and cross-sectional area;(5) The butterfly porous fences with the same porosity of0.301and hole diameter of9mm are divided into two parts based on the middle plate will have the biggest wind reduction rate of71.35%to wake zone as the upper porosity is0.25and the lower is0.35, but the porosity of uniform distribution is69.27%. Considering the difficulty degree and costing of process, uniform distribution is the first engineering preferred;(6) The butterfly porous fences will have better wind reduction rate with more than60%when their bottom gap is among0-0.025H as they have the same porosity of0.273and hole diameter of6mm.