Papers by Keyword: Viscosity

Abstract: Catalytic aquathermolysis is proposed as one of the potential methods which functions to reduce the viscosity of heavy oil for ease of extraction. In this research, we have developed a solution dispersed catalyst of Fe₃O₄ nanoparticles through a co-precipitation method. FeCl₃·6H₂O and FeCl₂·4H₂O were used to serve as an Fe source, with NaOH as a co-precipitator. The as-synthesized nanoparticles were characterized by X-ray diffraction (XRD) to verify materials. In order to be able to be used in the reservoir, the prepared powder was further dispersed into a base fluid with the addition of a dispersant by an ultrasonication for 2 hours. The stable nanofluid was achieved using the ratio of ethylene glycol/water mixture of 20%:80%. Dynamic light scattering (DLS) characterization results showed that the average size of the particle was about 309 nm, which is small enough to ensure its ability to pass through rock pores. Catalytic aquathermolysis of heavy oil in laboratory scale was employed under the addition of stable nanofluid at 200°C for 6 hours. The viscosity of heavy oil after the reaction could be reduced up to 71.3%.

Abstract: This paper presents the preparation, characterisation and thermal behavior of TiO₂/water Nanofluids with different concentration. The presence of Nanosized particles in the conventional heat transfer fluids enhances its thermo physical character. In the present work, TiO₂/water Nanofluids with various volume concentrations were prepared by dispersing a specified amount of spherical sized TiO₂ Nanoparticles in distilled water without any surfactant. To get a uniform dispersion and stable suspension, the Nanofluids were kept under ultrasonic vibration continuously for 3 hours. Zeta potential measurement brought detailed insight into the causes of dispersion, aggregation of Nanofluids. The KD2 Pro, fully portable thermal properties analyser, was used to measure thermal conductivity of nanofluids. The viscosity of the nanofluid was measured using a Brookfield Viscometer. The experimental results show that the thermal conductivity increases with an increase of particle volume fraction and the enhancement was observed to be 9.22% over the base fluid for volume concentration of 0.75%. From the experimental observations, enhancement in thermal conductivity is larger than the enhancement in viscosity.

Abstract: An investigation on the liquid holdup, wave velocity, and wave frequency in horizontal annular flow has been experimentally conducted through the measurement of liquid holdup using constant electric current method (CECM) sensors. To investigate the effect of viscosity, water and glycerin were used as working liquid, using superficial liquid velocity and superficial gas velocity of 0.05 to 0.2 m/s and 12 to 40 m/s, respectively. Liquids with higher viscosity give the higher liquid holdup, lower wave velocity, and lower wave frequency. Correlations for liquid holdup and mean film thickness, wave velocity, and wave frequency have been developed with mean average errors (MAE) of 13.5%, 9.2%, and 8.6%, respectively.

Abstract: Boron nitride/ethylene alcohol (BN/EG) nanofluid was synthesized by two-step method. The effect of dispersant on stability, viscosity and thermal conductivity enhancement was investigated. The experimental results indicated that the addition of anionic dispersant (SHMP) and catioic dispersant (CTAB) will induce the severe deterioration of stability of BN/EG nanofluids. PVP, which belonging to non-ionic dispersant, can improve the stability and fluidity obviously besides keeping the enhancement of thermal conductivity.

Abstract: Two different nanofluids (SiO₂ – EG/DW and SiO₂ – DW) with various volume fractions are prepared by dispersing SiO₂ nanoparticles (< 20 nm) into two different types of base fluid: distilled water and ethylene glycol/distilled water mixture. The effective thermal conductivity and viscosity of nanofluids are characterized and compared over a temperature range of 25^oC - 50^oC. It is found that the effective thermal conductivity and viscosity of nanofluid are influenced by the nanoparticle volume fraction and the operating temperature. The thermal conductivity of the SiO₂ nanofluids with different volume concentrations increases as temperature increases while the viscosity decreases with the increasing temperature. The base fluid alters the characteristics of both the thermal conductivity and viscosity of nanofluid. Over the same range of operating temperature, the effective thermal conductivity and viscosity of SiO₂ – EG/DW nanofluid manifest stronger dependency on the nanoparticle concentration compared to those of water-base-fluid nanofluid.

Abstract: The properties of heat resistance and manufacturability of epoxy resin system are contradictory to each other. In order to maintain the balance of both properties, this article studied the heat resistance (testing the glass-transition temperature using differential scanning calorimetry) and the manufacturability (characterizing the variation trend of viscosity at molding temperature using AR2000EX rotational rheometer) of two kinds of epoxy resin systems by means of designing orthogonal table. Studies show that when the mass ratio of hydantoin epoxy resin, MF-4101 epoxy resin, anhydride and accelerant is 100:20:150:1.5, the glass transition temperature of the epoxy resin system can reach over 180°C. What’s more, the initial viscosity of the epoxy resin at 40°C is about 230mPa•s, and the viscosity can maintain no more than 800mPa•s in approximately 3 hours, which meets the requirements of liquid composite molding.

Abstract: Natural rubber (SMR L grade), epoxidized natural rubber (ENR) 25 and 50 were loaded with hybrid tackifiers consisting of a mixture of coumarone-indene and gum rosin. The coumarone-indene was fixed at 40 parts per hundred of rubber (phr) while the concentration of gum rosin was varied from 20 to 80 phr. The viscosity, peel and shear strength of the adhesives prepared from the elastomers was studied. Results show that peel strength exhibits a maximum value at 60 phr gum rosin for SMR L-based adhesive while for ENR 25 and ENR 50 based adhesives a maximum value is observed at 40 phr gum rosin which was attributed to the occurrence of optimum wettability and compatibility at this tackifier loading. Meanwhile, viscosity and shear strength decreases with increasing gum rosin concentration. SMR L-based adhesive consistently exhibits higher viscosity and shear strength whereas ENR 25-based adhesive steadily shows higher value for all modes of peel tests.

Abstract: Knowledge of fluid rheology and flow characteristics is important when studying nanofluid flow in porous media. In this study, an experimental investigation is presented to determine the nanofluid viscosity, the permeability and the inertial (non-Darcy) parameter of a porous cylinder made of several capillary tubes. The applicability of the Darcy-Forchheimer equation for power-law fluids to estimate pressure drop through the porous material is discussed. The occurrence of particle losses from the base fluid (deposition) is also verified.Experiments are completed in two steps. In the first step, physical properties of nanofluids consisting of deionized water and different volume concentrations of Al₂O₃ nanoparticles is measured. In the second step, Al₂O₃-deionized water nanofluids are pumped through a porous cylinder (porosity 0.249) to evaluate hydraulic and intrinsic permeabilities, and the inertial parameter. The effect of Al₂O₃ volume fraction on these flow properties is studied, and the void morphology changes within the porous cylinder via deposition of nanoparticles are analyzed.

Abstract: The water-based nanoTiN fluids were prepared by nanoTiN particles, dispersion medium and dispersant using a two-step method. The dispersion and rheology of nanoparticles in water-based fluid were studied under different preparation conditions. The dispersion and rheology of prepared nanoTiN fluids were evaluated and analyzed from the mass fraction of nanoparticles, mass fraction of dispersant and type of dispersion medium respectively by using the analysis of sedimentation stability and rheological properties. The results show that the above-mentioned factors all have different degree of influence on nanofluids’ dispersion and rheology. The viscosity of nanofluids increases with mass fraction of nanoparticles. A balance amount of mass fraction of dispersant will improve nanofluids’ dispersity and fluidity. The dispersion effect of deionized water is the best when the nanoparticles dispersed in different dispersion medium.

Abstract: The direct fibrillation of blast furnace slag can solve these problems, such as having not been recycled of sensible heat, the consumption of water resources, environmental pollution and the low additional value of product, which are caused by the traditional water quenching method. The modification is the key problem of fiber forming. The thesis mainly aims at the study of viscosity of slag, the ability of crystallization and mineral phase structure after the modified process of blast furnace slag and confined the relevance of the three to optimize the appropriate texturizer and adding ratio. The results are as following: Iron ore waste rock, fly-ash and compounded texturizer can improve the high temperature viscosity of the slag respectively, while it has different effect on landing gradient of viscosity and temperature (Fly-ash occupies first place, compounded texturizer comes second and iron ore and waste rock comes the minimum). By analyzing the crystallization behavior of the slag in the solidification process, when the proportion of iron ore waste rock is more than 9%, the fly-ash is equal or greater than 8% and the compounded texturizer is more than 9%, the solidification slag will appear amorphous. The mineral composition of the slag transforms gradually from melilite to vitreous body, which will make the air hole of the vitreous body increased and aperture decreased. When the iron ore waste rock is added, the homogeneity of the air hole will deteriorate, while adding the fly-ash and compounded texturizer will strengthen the homogeneity of the air hole and make the mineral structure intensive gradually.