张凯, 喻黎明, 刘凯硕, 曹东亮, 李娜, 仵峰. 网式过滤器拦截率计算及其影响因素分析[J]. 农业工程学报, 2021, 37(5): 123-130. DOI: 10.11975/j.issn.1002-6819.2021.05.014
    引用本文: 张凯, 喻黎明, 刘凯硕, 曹东亮, 李娜, 仵峰. 网式过滤器拦截率计算及其影响因素分析[J]. 农业工程学报, 2021, 37(5): 123-130. DOI: 10.11975/j.issn.1002-6819.2021.05.014
    Zhang Kai, Yu Liming, Liu Kaishuo, Cao Dongliang, Li Na, Wu Feng. Calculation of interception rate of mesh filter and analysis of its influencing factors[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(5): 123-130. DOI: 10.11975/j.issn.1002-6819.2021.05.014
    Citation: Zhang Kai, Yu Liming, Liu Kaishuo, Cao Dongliang, Li Na, Wu Feng. Calculation of interception rate of mesh filter and analysis of its influencing factors[J]. Transactions of the Chinese Society of Agricultural Engineering (Transactions of the CSAE), 2021, 37(5): 123-130. DOI: 10.11975/j.issn.1002-6819.2021.05.014

    网式过滤器拦截率计算及其影响因素分析

    Calculation of interception rate of mesh filter and analysis of its influencing factors

    • 摘要: 为了使网式过滤器在工程应用中既保持滤网良好渗透率又提高滤网拦截率,该研究通过试验,分析了5种不同入口压强(0.02、0.04、0.06、0.08、0.10 MPa)、7种滤网孔径(125、150、180、210、250、300和350 μm)及其与砂粒中值粒径的关系对过滤器拦截率的影响。结果表明:当滤网孔径与砂粒中值粒径的比值小于一个阈值C(C∈1.80,1.88)时,拦截率随着滤网孔径增大而增大,当该值大于此阈值时,拦截率随着滤网孔径的增大而减小;过滤器的入口压强越大,过滤器拦截率越大,入口压强对过滤器拦截率有显著影响,被拦截砂粒在出口侧分布越集中;入口压强从0.02 MPa提高到0.10 MPa,250 μm滤网拦截率提升38.49%,而125 μm滤网拦截率提升88.94%;250 μm滤网在0.10 MPa入口压强下15 min末出水砂粒粒径组成与180 μm、0.02 MPa下初始出水砂粒粒径组成相似,在短时间的灌溉应用上,可调整入口压强而不需要调整设备来满足灌溉要求,研究为实际灌溉工程中提高过滤器拦截率和过滤效果提供了参考。

       

      Abstract: This study analyzed effects of inlet pressure, filter screen aperture and median particle size of sand on interception rates of filters in order to maintain the good permeability of filter screens and improve the interception rate of the filter screen in the engineering application of the screen filter. A full test and a three-factors-and-three-level orthogonal test were conducted. Five different inlet pressures were designed including 0.02, 0.04, 0.06, 0.08, 0.10 MPa. Seven kinds of filter screen apertures were 125, 150, 180, 210, 250, 300 and 350 μm. The median particle size was from 60 to 300 μm. The results showed that the cake produced in the filtration process was the main reason of the interception phenomenon. The larger the inlet pressure of the filter tended to lead to more significant interception phenomenon and the higher interception rate. The inlet pressure had a very significant impact on the interception rate of the filter. The interception rate increased with the increase of the filter screen aperture when the ratio of the filter screen aperture to the median size of sand was less than a critical range from 1.80 to 1.88. However, the interception rate decreased with the increase of the filter screen aperture when the ratio was higher than the critical range. A model of intercept rate estimation was fitted with the determination of coefficient of 0.94, indicating that the model has a high accuracy. The larger inlet pressure of the filter could result in the more concentrated distribution of intercepted sand particles at the outlet. It indicated that filter performance could be improved by reducing the skeleton density of the filter element at the outlet and designing the filter outlet segment into a circular arc shape with a large front and a small rear to increase the water passing area at the outlet. When the inlet pressure increased from 0.02 MPa to 0.10 MPa, the interception rate of 250 μm filter increased by 38.49%, while that of 125 μm filter increased by 88.94%. At the 15 min of the experiment, the composition of the sand particle size in the outlet water from the 250 μm filter under the inlet pressure of 0.01 MPa was similar to that in the initial outlet from 180 μm filter under the inlet pressure of 0.02 MPa. The filtration accuracy of the filter after a period of operation was more than expected. Therefore, the inlet pressure rather than adjusting the whole equipment could be an option to obtain good performance of filtration during short-term irrigation processes. This study provides valuable information for improving the interception rates and filtration effects of filters in irrigation projects.

       

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