Experimental study on non-Darcian flow in two kinds of media with different diameters
Experimental study on non-Darcian flow in two kinds of media with different diameters
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DOI：
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发表时间：
2008
影响因子：
2.4
通讯作者：
Li Jian;Huang Guan-hua;Wen Zhang;Zhang Hong-bing
中科院分区：
文献类型：
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作者：
Li Jian;Huang Guan-hua;Wen Zhang;Zhang Hong-bing
当比流量足够大时，达西定律中的水力梯度与比流量之间的线性关系不再成立，这意味着出现非达西流。利用不同水力梯度的一维砂柱进行实验，建立了分别通过直径为0.5mm～0.63mm和0.63mm～1.25mm的两种多孔介质时的水力梯度与比流量之间的关系。结果表明，Forcheimer方程和lzbash方程都能很好地描述流动。分别代表惯性力和粘性力引起的能量耗散的水力梯度线性项和非线性项都随着比流量的增加而增加，同时水力梯度中非线性项的比例不断增加。水力梯度非线性项为40%和50%，临界雷诺数为22～27和两种介质分别为52～104。发生非达西流动的临界雷诺数随颗粒直径的增加而增大。
The linear relationship between the hydraulic gradient and specific discharge for Darcy's law is no longer valid when the specific discharge is large enough.This means that non-Darcian flow occurs.An experiment was conducted by using 1-D sand columns with various hydraulic gradients to establish the relationship between the hydraulic gradient and specific discharge passing through two kinds of porous media with diameters of 0.5mm～0.63mm and 0.63mm～1.25mm respectively.The hydraulic resistivity and Reynolds number were used to identify the occurrence of non-Darcian flow.The results indicate that both the Forcheimer and lzbash equations can well describe the flow.Both the linear term and nonlinear term of hydraulic gradient representing the energy dissipation due to inertia force and viscous force respectively are increasing with the increase of specific discharge.At the same time,the portion of nonlinear term in hydraulic gradient increases continuously.The nonlinear term of hydraulic gradient is 40% and 50%,and the critical Reynolds number is 22～27 and 52～104 for two kinds of media respectively.The critical Reynolds number for occurring of non-Darcian flow increases with grain diameter.