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基于CFD-DEM耦合的網(wǎng)式過濾器水沙運動數(shù)值模擬
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國家自然科學基金項目(51379024、51769009)和石河子大學高層次人才科研啟動資金專項(RCZX201434)


Numerical Simulation of Water and Sediment Movement in Screen FilterBased on Coupled CFD-DEM
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    摘要:

    過濾器內(nèi)部的水沙運動復雜且多變,初始狀態(tài)下沙粒分布的不均導致濾芯產(chǎn)生局部堵塞,改變了水流流態(tài)并進一步影響后續(xù)沙粒運動和分布。本文以CFD-DEM(Computational fluid dynamics, CFD;Discrete element method,DEM)耦合模擬Y型網(wǎng)式過濾器內(nèi)部流場變化與沙粒運動及分布,直觀地反映了濾芯對水流的流動阻力特性與對沙粒運動分布影響。結(jié)果表明,過濾器內(nèi)部存在明顯的回流區(qū)、旋渦區(qū)及滯流區(qū),導致各過濾面流速不均,出口一側(cè)流速大,進口一側(cè)流速小,兩者相差39%;隨著時間的變化,過濾器內(nèi)流場變化明顯,沙粒堆積依次出現(xiàn)在出口側(cè)下端面、出口側(cè)上端面、進口側(cè)下端面、進口側(cè)上端面上,最終布滿整個濾芯;在濾芯的4個過濾面中,出口側(cè)上端面流速大而沙粒堆積最少,進口側(cè)上端面流速小而沙粒堆積最多,由此可見出口側(cè)上端面具有更好的過濾性能,可適當提高該處過水面積,以提高過濾器過濾效率。

    Abstract:

    Water and sediment movement in filter is complex and changeable. In the beginning, local blockage on filter element caused by non-uniform distribution of sediment affects flow distribution which will change tracks of follow-up sediment. Using CFD-DEM(computational fluid dynamics, CFD;discrete element method,DEM) method to simulate flow field and sediment distribution in Y-type screen filter, the resistance characteristics of filter and its influence on the movement and distribution of sediment were directly reflected. Results showed that the obvious backflow, vortex and viscous flow in the whole flow field led the uneven flow rate which was higher in outlet area and lower in inlet area, with a difference of 39%. Filter element was responsible for 90% of the total pressure loss. Flow condition was changed significantly with time, while sediment deposition appeared in the order of outlet under area, outlet upper area, inlet under area, inlet upper area and finally blocked the whole filter element. Among the four face areas in the filter element, sediment deposition was the least in outlet upper area which was at high flow rate while most in inlet upper area which was at low flow rate. So appropriately raising the flow section of outlet upper area with a better performance can improve the filtration efficiency.

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喻黎明,徐洲,楊具瑞,范文波,李娜,龍俊.基于CFD-DEM耦合的網(wǎng)式過濾器水沙運動數(shù)值模擬[J].農(nóng)業(yè)機械學報,2018,49(3):303-308. YU Liming, XU Zhou, YANG Jurui, FAN Wenbo, LI Na, LONG Jun. Numerical Simulation of Water and Sediment Movement in Screen FilterBased on Coupled CFD-DEM[J]. Transactions of the Chinese Society for Agricultural Machinery,2018,49(3):303-308.

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  • 收稿日期:2017-08-31
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  • 在線發(fā)布日期: 2018-03-10
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