About rheology of nanofluids

The rheological properties of several tens of nanofluids based on water, ethylene glycol, and engine oil with nanoparticles of various oxides and diamond is studied experimentally. Particle concentrations and their sizes were varied within quite wide range. Tested nanofluids did not contain any dispersants, while the base fluid was Newtonian liquid. It is revealed that in some cases, nanofluids are characterized by non-Newtonian rheological behavior. In the last part of the paper the effect of the nanoparticles on the properties of drilling fluids is discussed

Numerical simulation of the oil displacement process from a porous medium by nanofluid

Numerical simulation of the oil displacement process from a porous medium by nanofluid was carried out. To describe this process a flow model of two immiscible fluids taking into account the surface tension forces and the wetting angle was used. The simulation results of the penetration of fluid with nanoparticles into a porous medium are obtained using the example of the oil displacement. The nanoparticles addition to the displacing fluid affects the process of oil displacement from porous medium significantly. SiO2 particles with a size of 5 nm were used as nanoparticles. The concentration of nanoparticles ranged from 0 to 1 wt.%. The main reason for the increase in ORF (oil recovery factor) during oil displacement by nanofluid is the improvement of rock wetting

MAGNETIC SURFACE-MODIFIED NANOSIZED SORBENT FOR MSPE-HPLC-UV DETERMINATION IN NATURAL WATERS

In order to develop a more simple and efficient procedure of preconcentration and determination of the organic pollutants in waters it has been proposed to apply a static mode of magnetic solid-phase extraction using a novel surface-modified nanosized sorbent. The synthesis procedure of the sorbent consisted of: 1) synthesis of magnetite nanoparticles by co-precipitation method; 2) subsequent surface modification with tetraethoxysilane (TEOS) and cetyltrimethylammonium bromide (CTAB). Both stages were performed using microwave heating. The formation of nanoparticles was confirmed by SEM and dynamic light scattering method. The possible structure of the surface adsorption layer of the sorbent particles was characterized by comparing experimental and literature data on the CTAB adsorption. Sorption properties of the material have been investigated using 4-nonylphenol (4-NF) as an example. The extraction of 4-NF from aqueous solutions and surface waters with typical salt and dissolved organic matter content was shown to be quantitative. The technique based on the magnetic solid-phase extraction and HPLC determination of 4-NF has been developed.  The duration of a single analysis was about 35-40 min, detection limit – 2 µg/L of 4-NF.Keywords: magnetic nanoparticles, microwave synthesis, magnetic separation, 4-nonylphenol, HPLC, natural waters(Russian)DOI: http://dx.doi.org/10.15826/analitika.2015.19.3.006D.V. Pryazhnikov, M.S. Kiseleva, I.V. Kubrakova V.I. Vernadsky Institute of Geochemistry and Anaytical Chemistry, Russian Academy of Sciences, Moscow, Russian FederationIn order to develop a more simple and efficient procedure of preconcentration and determination of the organic pollutants in waters it has been proposed to apply a static mode of magnetic solid-phase extraction using a novel surface-modified nanosized sorbent. The synthesis procedure of the sorbent consisted of: 1) synthesis of magnetite nanoparticles by co-precipitation method; 2) subsequent surface modification with tetraethoxysilane (TEOS) and cetyltrimethylammonium bromide (CTAB). Both stages were performed using microwave heating. The formation of nanoparticles was confirmed by SEM and dynamic light scattering method. The possible structure of the surface adsorption layer of the sorbent particles was characterized by comparing experimental and literature data on the CTAB adsorption. Sorption properties of the material have been investigated using 4-nonylphenol (4-NF) as an example. The extraction of 4-NF from aqueous solutions and surface waters with typical salt and dissolved organic matter content was shown to be quantitative. The technique based on the magnetic solid-phase extraction and HPLC determination of 4-NF has been developed.  The duration of a single analysis was about 35-40 min, detection limit – 2 µg/L of 4-NF.Keywords: magnetic nanoparticles, microwave synthesis, magnetic separation, 4-nonylphenol, HPLC, natural waters DOI: http://dx.doi.org/10.15826/analitika.2015.19.3.00

Experimental investigation of laminar forced convection of nanofluid in heat exchange equipment

The laminar forced convection in a recuperative heat exchanger operating with nanofluids with MgO nanoparticles was investigated experimentally. In the experiments, nanoparticle concentration varied in the range from 2.5 to 12 wt. %. The nanoparticle size equalled 50 nm. The viscosity and thermal conductivity coefficients of the nanosuspensions were experimentally determined. The dependence of the average heat transfer coefficient and pressure drop on the Reynolds number for nanofluids was obtained

Investigation of temperature dependence of drilling mud viscosity with silica nanoparticles addition

An experimental study on the effect of silica nanoparticles addition on the viscosity of water-based mud at different temperatures was carried out. The mass concentration of clay was 5%, and the nanoparticles concentration varied from 0.5wt% to 3wt%. The nanoparticle size was 10 nm. Viscosity coefficient measurements were carried out in a wide temperature range

Experimental study of temperature dependence of drilling fluids viscosity with nanoparticles

This research is focused on the dependence of viscosity of water-based drilling fluid modified by nanoparticles on temperature. Silicon oxide of 10 nm size was used as nanoparticles. The nanosuspensions were prepared for nanoparticle concentrations from 0.25 to 3 wt%. An aqueous solution of bentonite with a mass fraction of 5 % was used as a base drilling fluid. Rheological studies were conducted at varying temperatures (25, 40, 55 and 80 °C). The dependences of the effective viscosity of these suspensions on the concentration of nanoparticles and temperature have been obtained

Numerical study of the cuttings transport by drilling mud in horizontal directional well

The results of numerical simulation of cutting by mud are providing in this article. The influence of flow rate on the values of pressure drop and cutting removal was studied