Study for Numerical Flow Field Near Porous Fence and its Influence on Particle Suspension

• Main Authors: Shiao-Ying Chang, 張曉英
• Other Authors: Cheng-Hsiung Huang
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/xv33dh

碩士 === 元培科技大學 === 環境工程衛生研究所 === 99 === The study applied numerical simulation to discuss the fluid velocity field, pressure field and turbulence intensity to the rear of the wind fences. In the study, porous wind fences of different porosity, with or without wind fences, sand pile of different heights, and the velocity field, pressure field and fluid distribution relationships at different distance to the rear of wind fences were discussed. The study deliberated the reentrainment of particle suspension to the rear of wind fence in relation to the velocity field, pressure field and turbulence intensity under different conditions. The results showed that the greater the porosity, when the air closed to the porous wind fences, and flew through the porous wind fences, the larger the flow rate, otherwise the smaller, and the air flow behind porous wind fences formed a return flow area. When the porosity was 30%, the wind deduction effect was better in the low velocity area, while the porosity was 50%, the wind deduction effect was less effective; the turbulence intensity was smaller behind porous wind fence structure than solid structures, wherein at 30% porosity reached less turbulence intensity. Deliberating the effect of the reentrainment of particle suspension, it was found that while porosity was ε=30% the particles behind porous wind fences presented return flow status such that the particles concentrated and effectively controlled, however while porosity was ε=50% the particles appeared not concentrated but spreading backward status, therefore, it was inferred that when porosity ε=30%, the particles could be more effectively controlled, avoiding the reentrainment of particle suspension owing to the air flow effect.