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考虑纳米颗粒吸附边界层对管径大小的影响和不同流态时的岩心渗透率的差异,建立了基于纳米颗粒吸附的均质多孔介质水流滑移数学模型(K-L MⅡ)。测试了油基和水基两种纳米流体的减阻效果,两组岩心水相渗透率的增幅平均分别为46.5%和76%。利用K-L MⅡ和K-L MⅠ计算了两组岩心中的水流滑移长度,大约在20–80 nm左右。结果显示,两者的差异较大,最大相差100%,表明不宜用K-L MⅠ计算具有吸附层厚度影响的滑移长度。利用K-L MⅡ解释了纳米颗粒吸附造成孔道减小而注水量增加的矛盾,为阐述纳米减阻机理提供了理论依据。K-L MⅡ也适用于吸附层厚度为0的水流滑移效应,具有普适性。
Considering the influence of nanoparticle adsorption boundary layer on tube diameter and the difference of core permeability in different fluid regimes, a mathematical model of homogeneous porous media flow slip (K-L MⅡ) based on nanoparticle adsorption was established. The drag reduction effect of two kinds of oil-based and water-based nanofluids was tested. The average increase of water-core permeability in both groups was 46.5% and 76% respectively. Using K-L M II and K-L M I, the slip length of water flow in two sets of cores was calculated, about 20-80 nm. The results show that the difference between the two is large, with a maximum difference of 100%, indicating that it is inappropriate to calculate the slip length with the influence of the thickness of the adsorption layer by K-L MⅠ. K-L M Ⅱ was used to explain the contradiction between the decrease of pore size and the increase of water injection due to the adsorption of nano-particles, which provided a theoretical basis for elucidating the mechanism of nano-scale drag reduction. K-L M II is also suitable for water slip effects with adsorbed layer thickness of 0 and is universal.