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| 1 | 纳米流体在平板上的湍流边界层和流体流动分析显示文摘对分别浸入3种纳米流体(ZnO-水,SiO_(2)-水,TiO_(2)-水)的平板近壁面流动的湍流边界层的对数规律进行数值分析。采用CFD程序对边界层和流体动力流动进行数值模拟。使用已发表的测量点对数值模型进行验证,结果表明一致性较好。对流速0.04 m/s,0.4 m/s,4 m/s以及纳米颗粒浓度0.1%和5%的情况进行模拟。研究了纳米颗粒浓度对速度、温度分布、壁面剪切应力和湍流强度的影响。结果表明:沿势流层的黏性亚层、缓冲层和对数律层可以基于具有单壁距离区域的弯曲质量进行分析。可见,与其他区域相比,黏性亚层面积最大。另一方面,温度变化与热边界层厚度有关的区域在流速减小时也减小,热边界层离前缘越来越深,而纳米颗粒体积分数的增加对壁面剪切应力的影响较小。在所有情况下,边界层的厚度都随着流速的增加而减小,而纳米颗粒浓度的增加会使边界层的厚度增加。更准确地说,对数层在Y^(+)=50和Y^(+)=95之间最小。在所研究的纳米流体中,φ=5%时的边界层温度高于φ=0.1%时的边界层温度。而Y^(+)=1时,结果正好相反,φ=0.1%时的温度比φ=5%的更高。当流速分别为v=4,0.4,0.04 m/s时,湍流强度峰值分别出现在Y^(+)=100,Y^(+)=10和Y^(+)=8时。 | AOUINET Hana DHAHRI Maher SAFAEI Mohammad Reza SAMMOUDA Habib ANQI Ali E. | 2021 | Journal of Central South University2021，28，11： | 2 |
| 2 | Effects of Cationic Surfactant on Fresh and Hardened Properties of Cement-Based Mortar显示文摘The objective of this study is to analyze the effects of using surfactant(CTAB)and cellulose nanofibers(NFC)as an admixture in cement mortars.We examined composite properties as porosity,compression energy,thermal conductivity and hydration.The results showed that with the addition of 0.7%by weight of NFC per emulsion in the presence of a cationic surfactant(CTAB).The new material produced presented a dry porosity between 4.7%and 4.4%,compressive strength between 9.8 and 22.9 MPa,and thermal conductivity between 0.95 and 2.25 W·m^(−1)·K^(−1).Thus we show better mechanical and thermal performance than that traditional Portland cement mortar with a density similar.In addition,the mortar made by emulsion of ordinary portland cement,cellulose nanofiber and organophilic clay(OC)treated with cetyltrimethylammonium bromide(CTAB)obtained has good resistance under high temperature and water,as well as excellent thermal insulation performance under high temperature and humidity conditions.This study verified that the presence of NFC promotes hydration,leading to the production of more calcium silicate and portlandite gel. | Soumaya Zormati Fadhel Aloulou Habib Sammouda | 2023 | Journal of Renewable Materials2023，11，5： | 0 |
| 3 | Influence and Dispersion of Nanofiber of Wood Modified on Properties of Cement Based Mortars显示文摘Wood nanofibers from industrial waste have been used as polymeric material to reinforce the cement paste to a content of up to 2%by weight of cement.The effect of the wood nanofibre content on the porosity,the compressive strength and the degree of hydration of the cement was studied.The results showed an improvement in compressive strength of over 50%with 1%of added fiberwood.Chemical modification of nanofiber wood by grafting alkyl chains to their surface can reduce the amount of water absorbed by the sample.Addition of an anionic additive(SDBS)to the mixing water improves the surface of the samples more and more by minimizing the pore size by emulsion effect,hence the water absorption decreases.The degree of hydration of the cement increased with the cellulose content containing nanofibrils.The analysis revealed that the presence of nanofibers favored the hydration of the cement by producing more calcium silicate gel and portlandite,probably the main reason for this improvement in compressive strength. | Fadhel Aloulou Alila Sabrine Habib Sammouda | 2019 | Journal of Renewable Materials2019，7，7： | 0 |
| 4 | Stabilization and Evaluation of Modified Nanofiber Flour Wood on the Properties of Cement-Baszd Mortar显示文摘The influence of nanofiberwood on the properties of the fresh condition of cement based mortars is not known in detail,despite recent advances in nanocellulose technology and it is related composite materials.Nanofiber wood from industrial waste,produced by high-pressure homogenization,was used as cement partial replacement for cement paste at a content ranging from 0%to 2%by weight of cement.The effect of the nanofiber wood content on the porosity,the compressive strength and the degree of hydration of the cement was investigated.Results have shown an improvement in the compressive strength by more than 50%with 1%of added fiber wood.The chemical modification of nanofibers wood by grafting of chains alkyls in their surfaces can reduce the quantity of water absorbed by the sample.The addition of an anionic additive(SDBS)in the water of mixing improves of more the surface of samples by minimizing the size of pores by emulsion effect,from where the absorption of water reduces.The degree of hydration of the cement has increased with the cellulose content containing nanofibrils.The analyze revealed that the presence of nanofiber wood favored the hydration of the cement by producing more calcium silicate gel and portlandite,probably the main reason for this improvement in compressive strength. | Fadhel Aloulou Sabrine Alila Habib Sammouda | 2019 | Journal of Renewable Materials2019，7，8： | 0 |
| 5 | Some Advances in Applications of Lattice Boltzmann Method for Complex Thermal Flows显示文摘Over the past two decades,there have been enormous advances in lattice Boltzmann(LB)numerical simulation and modelling.The lattice Boltzmann method has become a practical and promising tool for many fluid problems.A majority of recent studies have relied on numerical computations of isothermal flows.However,much less efforts have been devoted to complex thermal flows,such as flows in porous media subjected to external magnetic force,flows with temperature-dependent properties.In this paper,an overview is made based on some accomplishments in these numerical endeavours.Along with the paper’s sections,the state-of-the-art trend and the LBM advances in modelling and in computational aspects for specific classes of problems of major interest will be fully touched on.Concluding remarks are given and the axis of our future studies will be traced. | Ridha Djebali Habib Sammouda Mohammed El Ganaoui | 2010 | Advances in Applied Mathematics and Mechanics2010，2，5： | 0 |
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