【摘要】：土壤孔隙結(jié)構(gòu)復(fù)雜多變,揭示其內(nèi)部流場特性對于描述和預(yù)測土壤中水分傳輸、溶質(zhì)遷移等現(xiàn)象至關(guān)重要.基于規(guī)則性的土壤孔隙網(wǎng)絡(luò)模型,采用Micro-PIV(Micro-scale Particle Image Velocimetry,顯微粒子成像測速系統(tǒng))技術(shù)分析不同雷諾數(shù)下孔隙結(jié)構(gòu)中流體運(yùn)動(dòng)的特征,通過LBM方法(Lattice Boltzmann Method,晶格玻爾茲曼方法)對孔隙結(jié)構(gòu)中流場分布進(jìn)行數(shù)值模擬研究.結(jié)果表明:微觀尺度下孔隙網(wǎng)絡(luò)模型中不同孔隙區(qū)域流速分布差異明顯,中線區(qū)域流場呈規(guī)律性分布,孔喉處為高速區(qū),流速達(dá)到0.001 4 m/s,水平方向相鄰兩圓柱靠近邊界處存在低速區(qū),速度不高于0.000 2 m/s,在垂直于流向方向上速度場具有良好的對稱性;靠近上下邊界的大孔隙區(qū)域流體優(yōu)先通過,流體的速度可達(dá)到0.003 0 m/s.LBM方法模擬的孔隙網(wǎng)絡(luò)模型中流場分布結(jié)果與試驗(yàn)獲得的流場分布吻合,其平均均方根誤差為0.009 4 m/s,表明土壤孔隙網(wǎng)絡(luò)模型能有效模擬土壤孔隙,捕捉微觀尺度上的流體運(yùn)動(dòng)特征,為應(yīng)用孔隙網(wǎng)絡(luò)模型研究土壤孔隙中溶質(zhì)運(yùn)移和反應(yīng)等問題提供了微觀尺度的度量工具.
[Abstract]:The pore structure of soil is complex and changeable. It is very important to reveal the characteristics of internal flow field for describing and predicting the phenomena such as water transport solute transport and so on. Based on the regular soil pore network model, Micro-PIV (Micro-scale Particle Image Velocimetry, microscopic Particle Imaging velocimetry) technique was used to analyze the characteristics of fluid movement in pore structure under different Reynolds numbers. LBM method (Lattice Boltzmann Method, was used to analyze the characteristics of fluid movement in pore structure. Lattice Boltzmann method (lattice Boltzmann method) is used to simulate the flow field distribution in pore structure. The results show that the velocity distribution of different pore areas in the micro-scale pore network model is obviously different, the flow field in the midline area is regular distribution, the pore throat is high-speed area, and the velocity of flow is 0.001 mm2. There is a low velocity region near the boundary between two adjacent cylinders in the horizontal direction, and the velocity is less than 0.000 mm2. The velocity field has good symmetry in the direction perpendicular to the direction of the flow direction. In the macroporous region near the upper and lower boundary, the velocity of the fluid can reach 0.003 m/s.LBM. The results of the flow field distribution in the pore network model are in good agreement with the experimental results. The mean root mean square error (RMS) is 0.009 mm2, which indicates that the soil pore network model can effectively simulate soil pores and capture the characteristics of fluid movement on micro-scale. It provides a micro-scale measurement tool for the study of solute transport and reaction in soil pores by using pore network model.
【作者單位】： 河海大學(xué)力學(xué)與材料學(xué)院;中國環(huán)境科學(xué)研究院;北京師范大學(xué)水科學(xué)研究院;華南理工大學(xué)土木與交通學(xué)院;
【基金】：國家自然科學(xué)基金項(xiàng)目(41571311)
【分類號】：X53
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本文編號：2444250