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Preparation of Nanofluid by Using Hybrid Nanostructures and Investigation of Thermal and Rheological Properties and Using it in the Petroleum Fluids
, M.Sc. Thesis Sharif University of Technology ; Rashtchian , Davood (Supervisor) ; Rashidi, Alimorad (Supervisor) ; Lotfi, Roghayeh (Co-Advisor)
Abstract
In this study, thermal and rheological properties of nanofluids of water/carbon nanotubes, water/spherical silica nanoparticles and water/hybrid nanoparticles (hybrid of carbon nanotubes and spherical silica nanoparticles) have been investigated. To do so, carbon nanotubes have been synthesized by CCVD process and spherical silica nanoparticles and hybrid nanoparticles by wet chemical method. After synthesis of nanomaterials, nanofluids have been prepared by using SDBS as a dispersant with the concentration of 1.5 times of concentration of nanomaterials and then thermal conductivity, kinematic viscosity, dynamic viscosity and density of nanofluids have been investigated. As the results show,...
Investigating the rheological properties of nanofluids of water/hybrid nanostructure of spherical silica/MWCNT
, Article Thermochimica Acta ; Volume 578 , 20 February , 2014 , Pages 53-58 ; ISSN: 00406031 ; Rashidi, A ; Soleimanisalim, A. H ; Rashtchian, D ; Sharif University of Technology
Abstract
Regarding the importance of rheological properties of water based drilling fluids, the effects of silica nanospheres, multiwall carbon nanotubes (MWCNTs) and two types of their hybrid, i.e. H1 (80 wt.% silica nanosphere/20 wt.% MWCNT) and H2 (50 wt.% silica nanosphere/50 wt.% MWCNT) on the viscosity and density of distilled water were investigated. According to the results, viscosity and density of the nanofluids increased with the concentration, while they were reduced by increasing the temperature. At high concentrations, the least increase in the viscosity of distilled water by adding the nanomaterials is related to H2 (8.2% increase at 1.0 wt.%). Likewise, the optimum operating...
Synthesis of spherical silica/multiwall carbon nanotubes hybrid nanostructures and investigation of thermal conductivity of related nanofluids
, Article Thermochimica Acta ; Volume 549 , 2012 , Pages 87-94 ; 00406031 (ISSN) ; Rashidi, A ; Rashtchian, D ; Lotfi, R ; Amrollahi, A ; Sharif University of Technology
2012
Abstract
In this study, a hybrid of silica nanosphere/multiwall carbon nanotube (MWCNT) has been synthesized by wet chemical method at room temperature. The effect of MWCNTs, silica nanospheres and hybrid nanostructures (80% silica nanosphere/20% MWCNT and 50% silica nanosphere/50% MWCNT) on the thermal conductivity of distilled water has been investigated. SDBS was used as the dispersant to stabilize nanomaterials in the aqueous suspension and its concentration was 1.5 times of the concentration of nanomaterials. As results show, by increasing the concentration of nanomaterials, effective thermal conductivity of nanofluids increased. The most and the least enhancement in the effective thermal...