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基于CFD-DEM耦合的迷宮流道水沙運動數(shù)值模擬
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國家自然科學(xué)基金項目(51379024)、長沙理工大學(xué)研究生科研創(chuàng)新基金項目(CX2015SS05)和石河子大學(xué)高層次人才科研啟動資金專項(RCZX201434)


Numerical Simulation of Water and Sediment Flow in Labyrinth Channel Based on Coupled CFD-DEM
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    摘要:

    基于顆粒動力學(xué)理論的歐拉-拉格朗日固液多相湍流模型,針對灌水器迷宮流道內(nèi)水沙運動進(jìn)行了CFD-DEM耦合數(shù)值模擬研究,分析了迷宮流道內(nèi)流體流場、單個沙粒的軌跡線、速度和沙粒群的運動規(guī)律、分布特性等。結(jié)果表明:沙粒在流道深度中心面附近分布較多,靠近邊壁較少,隨著流道深度減小,流道內(nèi)沙粒的體積濃度成倍上升。流道深度越小,流道深度(Z方向上)水流運動速度越小,隨著沙粒Z方向上運動速度增大,沙粒群穿過中心面次數(shù)越多,撞擊邊壁的次數(shù)越多,流道深度0.6mm的撞擊邊壁次數(shù)是1.4mm的7.01倍,邊壁撞擊次數(shù)的增加使沙粒高頻率改變原有運動方向,增加了沙粒之間,沙粒與壁面之間的碰撞,該運動情況降低了沙粒運動速度,減少了動能,不利于沙粒通過迷宮流道,增加了堵塞幾率。該方法可分析大量沙粒個體和群體運動,以及群體分布情況,從微觀角度了解迷宮流道內(nèi)沙粒運動,是迷宮流道結(jié)構(gòu)設(shè)計的有效手段之一。

    Abstract:

    The depth of flow path of drip irrigation emitter is important geometrical parameter to anti-clogging performance. An Eulerian-Lagrange liquid-solid multiphase turbulence model combined with the kinetic theory of granular flow was used to carry out simulation based on coupled CFD-DEM water-sand two-phase flow in drip irrigation emitter with labyrinth channel. The trajectories and speed of single sediment, speed of sediment group, moving pattern and distribution of sediment group were analyzed. Simulation result indicated that the quantity of sand near the central plane of depth was more than that near the wall. The volume concentration of sediment in channel was increased several times with the decrease of depth. The depth was small;the speed of waterflow in depth direction was descended, but the speed of sediment in depth direction was risen. The average number of hit of each sediment was 14.31 when the depth was 0.6mm, but the number was 2.04 when the depth was 1.4 mm. The increase of impact frequency to wall changed original movement direction of sediment, augmented the number of times of collision between sands and between sand on the wall, which decreased velocity and kinetic energy, and it was difficult for sand to go through labyrinth channel, which caused clogging easily. This method was applied to analyze movement and distribution of sand individuality and group, learn the movement regular from micro-view perspective, and it had become an efficient technique in structure design of labyrinth channel.

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喻黎明,譚弘,鄒小艷,常留紅,陳立志,范文波.基于CFD-DEM耦合的迷宮流道水沙運動數(shù)值模擬[J].農(nóng)業(yè)機(jī)械學(xué)報,2016,47(8):65-71. Yu Liming, Tan Hong, Zou Xiaoyan, Chang Liuhong, Chen Lizhi, Fan Wenbo. Numerical Simulation of Water and Sediment Flow in Labyrinth Channel Based on Coupled CFD-DEM[J]. Transactions of the Chinese Society for Agricultural Machinery,2016,47(8):65-71.

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  • 收稿日期:2016-01-19
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  • 在線發(fā)布日期: 2016-08-10
  • 出版日期: 2016-08-10