Search for: wetting
Total 291 records
The dynamics of wettability driven droplets in smooth and corrugated microchannels, Article Journal of Statistical Mechanics: Theory and Experiment ; Volume 2012, Issue 10 , 2012 ; 17425468 (ISSN) ; Moosavi, A ; Mazloomi, A ; Sharif University of Technology
A multi-component lattice Boltzmann scheme is used to investigate the dynamics of a wettability driven droplet within a microchannel. The driving force for the motion is created by a stepwise change in the wettability of the channel walls. Moreover, an analytical solution is developed for evaluation of the dynamics of the droplet inside the channel. The effects of various parameters such as the height of the channel, the wetting pattern of the channel walls, the viscosity and the density ratio on the dynamics are studied. Also, the effect of grooves of different sizes on the channel surfaces on the dynamics of the droplet is investigated for both hydrophilic and hydrophobic surfaces....
Modeling of Pull-In Instability of Nano/Micromirrors Under the Combined Effect of Capillary and Casimir Forces, Article International Journal of Optomechatronics ; Volume 5, Issue 4 , Dec , 2011 , Pages 378-392 ; 15599612 (ISSN) ; Darvishian, A ; Ahmaidan, M. T ; Sharif University of Technology
In the current article the effect of the Casimir force on the static behavior and pull-in characteristics of nano/micromirrors under capillary force is investigated. At the first, the dimensionless equation governing the static behavior of nano/micromirrors is obtained. The dependency of the critical tilting angle on the physical and geometrical parameters of the nano/micromirror and its supporting torsional beams is investigated. It is found that the Casimir effect can considerably reduce the pull-in instability limits of the nano/micromirror. It is also found that rotation angle of the mirror under capillary force highly depends on the Casimir force applied to the mirror. Finally the...
A mathematical and experimental analysis of role of ultrasonic wave radiation on relative permeabilties in gravity drain, Article 73rd European Association of Geoscientists and Engineers Conference and Exhibition 2011: Unconventional Resources and the Role of Technology. Incorporating SPE EUROPEC 2011 ; Volume 7 , May , 2011 , Pages 5104-5108 ; 9781617829666 (ISBN) ; Keshavarzi, B ; Ghazanfari, M ; Ghotbi, C ; Amani, M ; Sharif University of Technology
Society of Petroleum Engineers 2011
This work concerns with experimental and analytical investigation of role of ultrasonic wave radiation in relative permeability of both wetting and non-wetting phases in a free gravity drainage process in porous media under the influence of ultrasonic wave. Glass beads ranged from 70 to 100 mesh sizes were packed and used in the tests. The working fluids consist of distilled water, kerosene and Doroud and Paidar crude oils as wetting and air as non-wetting phase. The measured oil recovery data along with Hagoort (1984) backward methodology were used to determine and to compare the relative permeability of wetting phases in presence and absence of ultrasonic radiation. In addition, the...
Three-dimensional nanofiber scaffolds are superior to two-dimensional mats in micro-oriented extraction of chlorobenzenes, Article Microchimica Acta ; Volume 185, Issue 7 , 2018 ; 00263672 (ISSN) ; Manshaei, F ; Rezvani, O ; Sharif University of Technology
Springer-Verlag Wien 2018
Three-dimensional (3D) polyamide scaffolds were fabricated by applying a solvent bath as the collecting element. Electrospun nanofibers were immersed into the solvent bath to give a material with a laminated 3D texture. In parallel, 2D nanofibers were synthesized and utilized as microextractive phases in a needle trap device to compare the capabilities of 2D and 3D materials in terms of headspace extraction of various chlorobenzenes (chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene and 1,2,3,4-tetrachlorobenzene). The results demonstrate the superiority of 3D nanofibrous scaffolds over 2D mats. The porosity, morphology, and thermal stability of the 3D scaffolds...
Gas-liquid membrane contactors: Modeling study of non-uniform membrane wetting, Article Journal of Membrane Science ; Volume 555 , 2018 , Pages 463-472 ; 03767388 (ISSN) ; Mousavi, S. A ; Bozarjomehri, R. B ; Bakhtiari, F ; Sharif University of Technology
Elsevier B.V 2018
Current available models for simulation of the separation process in gas-liquid membrane contactor (MC) systems consider a uniform partial membrane wetting along the membrane length (Lmem). However, transmembrane pressure changes along the Lmem. Additionally, the available models usually consider a simplified uniform pore size to represent the micro-porous MC. Additionally, not all pores in a MC have the same size. In this study, a pore-scale network model is developed to simulate the physical separation of H2S using MCs by taking to account for (i) transmembrane pressure variation and (ii) pore size distribution of MC. The model results are compared with the experimental results of H2S...
Catalytic wet peroxide oxidation of phenol : H2O2 gradual addition study, Article 2008 AIChE Annual Meeting, AIChE 100, Philadelphia, PA, 16 November 2008 through 21 November 2008 ; November , 2008 ; 9780816910502 (ISBN) ; Ebrahimi, A. A ; Shahalami, S ; Sharif University of Technology
An investigation on the wetting of polycrystalline alumina by aluminium, Article Journal of Materials Processing Technology ; Volume 197, Issue 1-3 , 2008 , Pages 156-160 ; 09240136 (ISSN) ; Halali, M ; Sharif University of Technology
In this report, sessile drop technique was employed to study the wetting of alumina by pure aluminium. Contact angle of pure aluminium on the surface of polycrystalline alumina substrate was studied in the temperature range of 750-1100 °C. Electron microscopy and EDX analysis were employed to examine the possible reactions at the melt-substrate interface. It was found that at temperatures in excess of 1050 °C molten aluminium can wet alumina. No reaction layer was detected at the Al/Al2O3 interface. © 2007 Elsevier B.V. All rights reserved
Investigating the role of ultrasonic wave on two-phase relative permeability in a free gravity drainage process, Article Scientia Iranica ; Vol. 21, issue. 3 , 2014 , p. 763-771 ; Karimi, R ; Najafi, I ; Ghazanfari, M. H ; Ghotbi, C ; Sharif University of Technology
In this work, the process of free gravity drainage under the influence of ultrasonic waves was investigated. A glass bead pack porous medium was used to perform free fall gravity drainage experiments. The tests were performed in the presence and absence of ultrasonic waves, and the data of recovery were recorded versus time under both conditions. The wetting phase relative permeability curves were obtained using the data of recovery versus time, based on the Hagoort backward methodology. Subsequently, using the wetting phase relative permeability curve, the relative permeability of non-wetting phases were calculated by performing history matching to the experimental production data. The...
Static pull-in analysis of micro-cantilevers in wet etching fabrication process, Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 9 November 2012 through 15 November 2012 ; Volume 9, Issue PARTS A AND B , November , 2012 , Pages 347-350 ; 9780791845257 (ISBN) ; Moeenfard, H ; Ahmadian, M. T ; Sharif University of Technology
Parallel micro actuators are mostly fabricated using the wet etching process within which the presence of capillary force and the resulting pull-in instabilities can severely affect the success of the fabrication process. In the case the capillary force is large enough then the beam like structure of the micro actuators is collapsed. The current paper investigates; static behavior of microcantilevers under effect of capillary force. It is observed that with increasing the instability number defined in the paper, the deflection of the micro-cantilevers is increased. This study shows in the wet etching fabrication process, if the distance between the beam and substrate is small enough, the...
Relationship between wetting properties and macroscale hydrodynamics during forced gravity drainage and secondary waterflood, Article Petroleum Science and Technology ; Volume 28, Issue 8 , 2010 , Pages 804-815 ; 10916466 (ISSN) ; Kharrat, R ; Ghotbi, C ; Alipour Tabrizy, V ; Sharif University of Technology
In order to relate the wetting properties at the pore scale to the macroscale prevailing forces, a series of experiments was performed in vertical porous media under forced gas invasion at various wettability conditions with partially spreading oil. To describe the dynamics of oil recovery in a three-phase flow condition, the downward gas flood experiments were continued by water injection from the bottom. Experimental results obtained in situations where the magnitudes of viscous, capillary, and gravity forces are comparable. We study the transition from flow configurations where the interface is stable with respect to viscous instability to flow configurations where viscous fingering...
Electrowetting-induced droplet jumping over topographically structured surfaces, Article Materials Research Express ; Volume 6, Issue 8 , 2019 ; 20531591 (ISSN) ; Moosavi, A ; Shafii, M. B ; Sharif University of Technology
Institute of Physics Publishing 2019
We analyze the process of electrowetting-induced jumping of droplets away from a substrate with a geometric heterogeneity in the form of a cone and compare the results with those of a flat substrate in different wettabilities and hydrophobicities. Our results reveal that the droplet dynamics can be enhanced through applying a topographic heterogeneity. However, increasing the height of the cones does not always provide a better condition for the jumping and there is an optimum value for the height of the cones. The enhancement is due to the fact that more liquid flowing affects the pressure gradient within the droplet leading to a higher jumping velocity. It is shown that for the flat...
Sliding on wet sand, Article Granular Matter ; Volume 22, Issue 3 , May , 2020 ; Aliasgari, M ; Maleki Jirsaraei, N ; Rouhani, S ; Bonn, D ; Sharif University of Technology
We present sliding experiments of a sledge on wetted sand and describe that the frictional response is controlled by the penetration hardness of the granular medium. Adding a small amount of water to sand increases the hardness which results in a decrease of the sliding friction. Pouring even more water to sand results in a decrease of the hardness and a subsequent increase of the friction. This inverse correlation between hardness of a wetted granular material and its frictional response to sliding is found to be due to ploughing of the sledge. When the load of the sledge exceeds the penetration hardness of the water-sand mixture the granular material is irreversibly deformed, which is...
Using SiO2¬ Nano Particles in Enhanced Oil Recovery Process, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran ; Vossoughi, Manoochehr
After primary and secondary recovery processes more than 50 percent of oil remains in reservoirs. Therefore for more recovery from these reservoirs, methods of enhanced oil recovery should be applied.In this paper the effect of nanoparticles of SiO2 in size of 14 nm, on wettability is investigated. Using this nanoparticle, the wettability of carbonate rock in reservoirs could be changed and alter from oil-wet or mix-wet to water-wet. To assess this, hydrophilic changes of sandstone core and carbonate core are studied using the contact angle test. The same test is done on the carbonate core saturated with brine and oil that had received injection with brine and nanoparticles of SiO2 with two...
Effect of Packing Roughness on the Cooling Tower's Performance, M.Sc. Thesis Sharif University of Technology ; Bastani, Darush
The application of wet cooling towers is cooling the circulating water which in many processes extract the exess heat in the system. Any cooling tower involves different parts and one of these parts is packings. The effect of changing packing's charactorizations on the cooling tower's performance is significant and was studied in different researches. In this project the effect of packing roughness on the heat transfer, mass transfer and pressure drop in two arrays of packings and in different conditions of water flow rate, air flow rate and inlet water temperature was studied experimentally. For calculating and investigating the change of mass transfer coefitient, the Poppe model was ...
Immiscible Displacement of a Wetting Fluid by a Non-wetting One at High Capillary Number in a Micro-model Containing a Single Fracture, Article Transport in Porous Media ; Volume 94, Issue 1 , 2012 , Pages 289-301 ; 01693913 (ISSN) ; Rashtchian, D ; Shadizadeh, S. R ; Sharif University of Technology
Most reservoirs in Iran are heterogeneous fractured carbonate reservoirs. Heterogeneity causes an earlier breakthrough and an unstable front which leads to a lower recovery. A series of experiments were conducted whereby the distilled water displaced n-Decane in strongly oil-wet glass micro-models containing a single fracture. Experimental data from image analysis of immiscible displacement processes are used to modify the Buckley-Leverett and fractional flow equations by a heterogeneity factor. It is shown that the heterogeneity factor in the modified equations can be expressed as a function of fracture length and orientation
Incorporation of viscosity scaling group into analysis of MPMS index for laboratory characterization of wettability of reservoir rocks, Article Journal of Petroleum Exploration and Production Technology ; Volume 7, Issue 1 , 2017 , Pages 205-216 ; 21900558 (ISSN) ; Saboorian Jooybari, H ; Masihi, M ; Sharif University of Technology
Springer Verlag 2017
Wettability is a key parameter affecting petrophysical properties of reservoir rocks. Mirzaei-Paiaman et al. (Energy Fuels 27:7360–7368, 2013) presented an index (referred to as MPMS) for laboratory characterization of wettability of native- or restored-state reservoir rock samples. To use this index two counter-current spontaneous imbibition (COUCSI) experiments are needed, one on the native- or restored-state core sample and another on the strongly water-wet (SWW) reference system. Slope analysis of recovery data in these two systems gives inputs for determination of MPMS index. The two systems must have the same pore structure, initial water saturation, and viscosity ratio. The case of...
A comparative study of earthquake source models in high-order accurate tsunami simulations, Article Ocean Modelling ; Volume 141 , 2019 ; 14635003 (ISSN) ; Bonev, B ; Hesthaven, J. S ; Sharif University of Technology
Elsevier Ltd 2019
The discontinuous Galerkin method is used to solve the non-linear spherical shallow water equations with Coriolis force. The numerical method is well-balanced and takes wetting/drying into account. The two fold goal of this work is a comparative study of dynamic and static tsunami generation by seabed displacement and the careful validation of these source models. The numerical results show that the impact of the choice of seabed displacement model can be significant and that using a static approach may result in inaccurate results. For the validation of the studies, we consider measurements from satellites and buoy networks for the 2011 Tohoku event and the 2004 Sumatra–Andaman tsunami. The...
Investigation of the effect of water based nano-particles addition on hysteresis of oil and-water relative permeability curves, Article Society of Petroleum Engineers - SPE International Oilfield Nanotechnology Conference 2012 ; 2012 , Pages 267-277 ; 9781622761104 (ISBN) ; Masihi, M ; Ghazanfari, M. H ; Sherafati, M ; Mashayekhi, L ; Sharif University of Technology
It has been shown that one kind of poly silicon particles with sizes ranging from 10-500 nm, can be used in oilfields to enhance the oil recovery of water injection by 15-20%. The contributing mechanism might be reducing the interfacial tension which appears through improving relative permeability of the oil-phase. However, fundamental understanding of how hysteretic behavior of relative permeability curves affected by nanosilica particles remains a topic of debate in the literature. In this study, water as well as water dispersed nanosilica particles floods was performed on sandstone rock sample saturated by light crude oil supplied from one of Iranian oil reservoir, and the relative...
Wettability alteration and oil recovery by spontaneous imbibition of low salinity brine into carbonates: Impact of Mg2+, SO4 2− and cationic surfactant, Article Journal of Petroleum Science and Engineering ; Volume 147 , 2016 , Pages 560-569 ; 09204105 (ISSN) ; Al-Maamari, R. S ; Ayatollahi, S ; Mehranbod, N ; Sharif University of Technology
Elsevier B.V 2016
A large amount of the discovered oil reserves are reserved in carbonate formations, which are mostly naturally fractured oil-wet. Wettability alteration towards more water-wet state reduces the capillary barrier, hence improving the oil recovery efficiency in such reservoirs. In this study, wettability alteration towards favorable wetting state was investigated by combining modified low salinity brine with surfactant during water flooding. The diluted brine was modified by increasing the concentration of Mg2+ and SO4 2−, individually as well as both ions in combination. Different brine formulations were tested experimentally through the observations of contact angle measurements and...
Effect of magnesium addition on the wetting of alumina by aluminium, Article Applied Surface Science ; Volume 255, Issue 19 , 2009 , Pages 8202-8206 ; 01694332 (ISSN) ; Halali, M ; Sharif University of Technology
In this report the wetting behaviour between polycrystalline alumina substrates and molten aluminium doped with magnesium as a wetting agent has been studied using the sessile drop technique. The time required for equilibrium attainment is investigated. To explore the formation of possible phases at the interface, electron microscopic studies along with EDX analysis have been employed. It is found that magnesium reduces the time and temperature required for equilibrium in the Al/Al2O3 system. The Al-7 wt% Mg and Al-10 wt% Mg alloys can wet alumina at temperatures as low as 900 °C. It is also found that molten aluminium doped with magnesium can wet polycrystalline alumina at temperatures...