Subsurface drip irrigation (SDI) is a highly efficient and safe method for water reuse, particularly with biogas slurry. However, emitter clogging risks are high and it was hard to visualize the process. This study developed a high-precision numerical simulation method using 3D industrial computed tomography scanning, inverse modeling, and numerical simulation. We investigated the spatial distribution of clogging substances at various clogging levels. A new simulation method based on a porous media boundary was compared with the traditional fixed boundary method, showing improved accuracy. The results indicated that the cumulative growth of clogging substances on different walls of emitter increased with larger clogging degree, which also resulted in significantly different distributions. As the clogging degree increased to 50 %, the maximum and minimum values of the average volume of clogging substances appeared at the upstream face (2.36 mm3) and the downstream face (1.38 mm3), respectively. Compared to the traditional fixed-boundary simulation method, the method based on permeable porous media boundary improved the relative accuracy of the flow rate by 3.41 %-6.86 %. Furthermore, for the hydrodynamic parameters of emitter flow channel cross-section, the average velocity, average shear force, and average turbulent kinetic energy were 3.54 %-5.75 %, 14.93 %-16.26 %, and 11.16 %-30.46 % lower than those predicted by the fixed boundary module, respectively. The traditional fixed-boundary numerical simulation method tends to underestimate the clogging degree of the emitter and the influence of the clogging substances on the internal hydrodynamic characteristics to a certain extent. In summary, the results of this study can contribute to the development of anti-clogging emitter and facilitate the implementation of SDI system using biogas slurry.

中文翻译：

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使用多孔介质模型表征沼液地下滴灌中的发射器堵塞物质边界


地下滴灌 （SDI） 是一种高效且安全的水再利用方法，尤其是沼液回用。然而，发射器堵塞的风险很高，并且很难可视化该过程。本研究开发了一种使用 3D 工业计算机断层扫描、逆向建模和数值模拟的高精度数值模拟方法。我们研究了不同堵塞水平的堵塞物质的空间分布。将基于多孔介质边界的新模拟方法与传统的固定边界方法进行了比较，显示出更高的精度。结果表明：随着堵塞程度的增大，发射器不同壁面上堵塞物质的累积增长增加，这也导致了显著不同的分布。当堵塞程度增加到 50 % 时，堵塞物质平均体积的最大值和最小值分别出现在上游表面 （2.36 mm3） 和下游表面 （1.38 mm3）。与传统的固定边界模拟方法相比，基于渗透多孔介质边界的方法将流速的相对精度提高了 3.41 %—6.86 %。此外，对于发射器流道截面的水动力参数，平均速度、平均剪切力和平均湍流动能分别比固定边界模块预测的低 3.54 %-5.75 %、14.93 %-16.26 % 和 11.16 %-30.46 %。传统的固定边界数值模拟方法往往在一定程度上低估了发射器的堵塞程度以及堵塞物质对内部流体动力学特性的影响。 综上所述，本研究结果有助于防堵塞发射器的开发，并促进使用沼液的 SDI 系统的实施。