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thermodynamic-properties
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A novel correlation approach for viscosity prediction of water based nanofluids of Al2O3, TiO2, SiO2 and CuO
, Article Journal of the Taiwan Institute of Chemical Engineers ; Volume 58 , 2016 , Pages 19-27 ; 18761070 (ISSN) ; Daryasafar, A ; MoradiKoochi, M ; Moghadasi, J ; BabaeiMeybodi, R ; KhorramGhahfarokhi, A ; Sharif University of Technology
Taiwan Institute of Chemical Engineers
2016
Abstract
Nanofluids viscosity is one of the most important thermophysical properties in nanofluids usage especially in chemical and petroleum engineering applications. So it is highly desirable to predict the viscosity of nanofluids accurately. Experimental measurements are impossible in most situations and present models are not comprehensive and efficient especially for high temperature, high volume concentration and high viscosity values. In this study, a new correlation has been developed based on the comprehensive database of water based Al2O3, TiO2, SiO2 and CuO nanofluids viscosity data found in literature. The proposed correlation uses temperature, nanoparticle size, nanoparticle volumetric...
The effect of inlet turbulence intensity on nano-particulate soot formation in Kerosene-fueled combustors
, Article ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2016, 4 January 2016 through 6 January 2016 ; Volume 2 , 2016 ; 9780791849668 (ISBN) ; Ghafourizadeh, M ; Heat Transfer Division ; Sharif University of Technology
American Society of Mechanical Engineers
2016
Abstract
In this work, we numerically study the effects of turbulence intensity at the fuel and oxidizer stream inlets on the soot aerosol nano-particles formation in a kerosene fuel-based combustor. In this regard, we study the turbulence intensity effects specifically on the thermal performance and nanoparticulate soot aerosol emissions. To construct our computer model, we simulate the soot formation and oxidation using the Polycyclic Aromatic Hydrocarbons PAHs-inception and the hydroxyl concept, respectively. Additionally, the soot nucleation process is described using the phenyl route, in which the soot inception is described based on the formations of tworinged and three-ringed aromatics from...
Simulation and multi-objective optimization of a combined heat and power (CHP) system integrated with low-energy buildings
, Article Journal of Building Engineering ; Volume 5 , 2016 , Pages 13-23 ; 23527102 (ISSN) ; Jokar, M. A ; Sameti, M ; Kasaeian, A ; Kasaeian, F ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
One of the novel applications of gas turbine technology is the integration of combined heat and power (CHP) system with micro-gas turbine which is spreading widely in the field of distributed generation and low-energy buildings. It has a promising great potential to meet the electrical and heating demands of residential buildings. In this study, a MATLAB code was developed to simulate and optimize the thermoeconomic performance of a gas turbine based CHP cycle. Three design parameters of this cycle considered in this research are compressor pressure ratio, turbine inlet temperature, and air mass flow rate. Firstly, two objective functions including exergetic efficiency and net power output...
Thermodynamic Properties of Aqueous Electrolyte Solutions Containing Urea
, M.Sc. Thesis Sharif University of Technology ; Ghotbi, Siroos (Supervisor) ; Taghikhani, Vahid (Supervisor)
Abstract
The behavior of biomolecules in mixtures is affected by the presence of electrolytes. For instance, in the presence of an electrolyte, solubility of most biomolecules like proteins,peptids and amino acids can be increased or decreased. As a biomolecule, urea is a protein denaturant and influences protein folding and protein-DNA binding. The presence of ions can affect the interactions between urea and water In this thesis, experimental data of density and electrical conductance of aqueous solutions of urea-NaCl were obtained at different physical conditions. Density measurement experiments were carried out at different temperatures from 20-40 oC. Apparent and infinite dilution molar volumes...
The effect of mechanical and thermal properties of FRP bars on their tensile performance under elevated temperatures
, Article Construction and Building Materials ; Volume 157 , 2017 , Pages 1001-1010 ; 09500618 (ISSN) ; Bazli, M ; Najafabadi, E. P ; Vatani Oskouei, A ; Sharif University of Technology
Abstract
In this experimental study the effect of physical and thermal properties of various FRP bars on their performance under elevated temperatures are investigated. The parameters included the bars' diameter, type of fiber, type of resin, fiber to matrix ratio, and thermal properties were studied. Moreover, ANOVA (ANalysis Of VAriance) was performed in order to investigate the contribution of each variable on the obtained results. The results showed that in addition to the temperature, the bars' diameter, type of fiber, type of resin, and thermal properties (Tg and Td) of the FRP bars have contributions to the results, while the fiber to matrix ratio was found to be an ineffective factor. It was...
Investigating the effect of hybrid silica nanoparticles-copolymer on increasing oil recovery in a three dimensional porous media
, Article Scientia Iranica ; Volume 24, Issue 6 , 2017 , Pages 3466-3475 ; 10263098 (ISSN) ; Ramazani, A. S. A ; Hekmatzadeh, M ; Sharif University of Technology
Abstract
In this work, hybrid of silica nanoparticles (NPs) with sulfonated copolymer has been prepared in order to improve the copolymer properties for Enhanced Oil Recovery (EOR). Some tests are done to find the effectiveness of injecting fluid on Recovery Factor (RF), such as Contact Angle (CA), interfacial tension (IFT), inherent viscosity, and eventually Micro-Model (MM) flooding. In CA test, wettability alteration from Oil-Wet (OW) to Water-Wet (WW) is reached by sedimentation and adsorption of NPs on the rock slice. In addition, IFT reduction is obtained by increasing the NaCl concentration. The viscosity change is investigated for the hybrid and copolymer under simulated high-temperature oil...
Polyurethane/clay nanocomposites reinforced with carbon and glass fibres: study of mechanical and thermal properties, and the effect of electron beam irradiation
, Article Plastics, Rubber and Composites ; Volume 46, Issue 9 , 2017 , Pages 413-420 ; 14658011 (ISSN) ; Mousavian, S. M. A ; Razavi, S. M ; Ahmadi, S. J ; Izadipanah, M ; Sharif University of Technology
Abstract
Polyurethane (PU) nanocomposites with 0, 1, 3, 5, and 7 wt-% nanoclay contents were prepared. X-ray diffraction patterns, transmission electron microscopy images, tensile test, and thermogravimetric analysis were utilised to reveal the morphological, mechanical, and thermal-resistant properties of the prepared nanocomposites. The exfoliated structure was obtained for nanoclay contents up to 3 wt-%. Incorporation of nanoclay to the PU matrix prompted the thermal stability of the polymer. A nanocomposite filled with 3 wt-% nanoclay showed the best tensile strength in the prepared nanocomposites. Subsequently, the nanocomposite with the 3 wt-% nanoclay was reinforced with carbon and glass...
A comparative study on the performance of HFO-1234yf and HFC-134a as an alternative in automotive air conditioning systems
, Article Applied Thermal Engineering ; Volume 110 , 2017 , Pages 1091-1100 ; 13594311 (ISSN) ; Kasaeian, A ; Golzari, S ; Mahian, O ; Nasirivatan, S ; Wongwises, S ; Sharif University of Technology
Abstract
In this study, an automotive air conditioning system is simulated by considering HFO-1234yf (2,3,3,3-tetrafluoropropene) as the drop-in replacement of HFC-134a. The simulated air conditioning system consists of a multi-louvered fin and flat-plate type evaporator, a wobble-plate type compressor, a mini-channel parallel-flow type condenser and a thermostatic expansion valve. The thermodynamic properties of the refrigerants are extracted from the REFPROP 8.0 software, and a computer program is simulated for the thermodynamic analysis. Two different conditions have been considered in this program for the cycle analysis: for the first state, the cooling capacity is taken as constant, and for the...
The impact of morphology on thermal properties and aerobic biodegradation of physically compatibilized poly (lactic acid)/co-plasticized thermoplastic starch blends
, Article Polymers for Advanced Technologies ; Volume 29, Issue 12 , 2018 , Pages 2880-2889 ; 10427147 (ISSN) ; Pircheraghi, G ; Bagheri, R ; Altstädt, V ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
Recently, the use of biodegradable polymers became the applicable solution to reduce the environmental concerns, which are created by plastic wastes as well as restrictions of petroleum-based synthetic polymers. By this point of view, polylactic acid (PLA) as a biodegradable and bio-based polymer is resolving both aforementioned issues. While, the high cost of PLA and its slow biodegradation rate make researchers to blend it with a faster one, for instance, thermoplastic starch (TPS). Adding TPS into PLA can influence on the morphological structure, thermal stability, and biodegradability. In this study, the well-tuned co-plasticized TPS via sorbitol/glycerol mixture was melt mixed with PLA...
Experimental investigation of triton X-100 solution on pulsating heat pipe thermal performance
, Article Journal of Thermophysics and Heat Transfer ; Volume 32, Issue 3 , 2018 , Pages 806-812 ; 08878722 (ISSN) ; Ghasempour, R ; Shafii, M. B ; Ahmadi, M. H ; Sharif University of Technology
American Institute of Aeronautics and Astronautics Inc
2018
Abstract
Pulsating heat pipes are cooling devices that are partially filled with working fluid. Working fluid thermophysical properties affect the thermal performance of pulsating heat pipes. In this research, the effect of adding a Triton X-100 surfactant to pure water and using the mixture as a working fluid is investigated experimentally. The results indicate that adding surfactant leads to improvement in the thermal performance of the pulsating heat pipe. In particular, the maximum of the thermal resistance improvement is about 61%, which is attributed to 0.01% surfactant concentration. Higher heat transfer ability is attributed to lower surface tension and the contact angle of the mixture...
Influence of additives on the morphology of PVDF membranes based on phase diagram: thermodynamic and experimental study
, Article Journal of Applied Polymer Science ; Volume 135, Issue 21 , 2018 ; 00218995 (ISSN) ; Khosravanian, A ; Sharif University of Technology
John Wiley and Sons Inc
2018
Abstract
In the present study, the morphology of asymmetric poly(vinylidene fluoride) blend membranes which were prepared by the phase inversion method is rationalized by comparing two non-dimensional number represent thermodynamic and kinetic properties of the prepared membrane. These two parameters change phase diagram and demixing rate between solvent and nonsolvent. TiO2 nanoparticles and polyvinylpyrrolidone were used as additives. Hansen solubility parameters of the components are calculated by Van Krevelen method. Furthermore, kinetic and thermodynamic properties of the prepared solutions are determined by drawing phase diagrams and controlling mass transfer rate during precipitation of...
Application of a free volume model in correlating thermodynamic properties of β-lactam, tetracycline, fluoroquinolone and chloramphenicol antibiotic groups in associating fluids
, Article Chemical Engineering Research and Design ; Volume 87, Issue 3 , 2009 , Pages 335-342 ; 02638762 (ISSN) ; Taghikhani, V ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
2009
Abstract
In this work, an expression for the free volume Gibbs energy model based on the local composition concept (LCC) has been proposed in correlating the solubility, the partitioning and the surface tension of β-lactam, tetracycline, fluoroquinolone and chloramphenicol antibiotic groups in water, alcohol, ketone, trihalomethane, ether and ester solvent groups. Similar to the LCC models the proposed model has two combinatorial and residual terms. The extended Guggenheim model is used as combinatorial term and a new local composition-based model, which is the extended local area fraction NRTL-NRF model, is proposed for the residual term. The results obtained from the proposed model have been...
Effect of rare earth elements addition on thermal fatigue behaviors of AZ91 magnesium alloy
, Article Journal of Rare Earths ; Volume 27, Issue 2 , 2009 , Pages 255-258 ; 10020721 (ISSN) ; Saebnoori, E ; Sharif University of Technology
Chinese Society of Rare Earths
2009
Abstract
Influences of rare earth (RE) elements addition on thermal fatigue behaviors of AZ91 alloy were studied. Repeated heating and cooling cycles were applied on the samples at 170 and 210 °C to develop thermal fatigue cracks. Crack growth mechanisms and microstructural influences were investigated by optical and scanning electron microscopy (SEM) as well as energy dispersive X-ray spectroscopy (EDS). Thermal fatigue behaviors were observed to improve successively by addition of the RE up to 2wt.%. This improvement was attributed to the consummation of aluminum in melt by precipitation of the needle shaped Al11RE3 phases. This process was attributed to the reduction of Mg17Al12 phase volume...
Complexity of Density Dependencies of Thermal- and Internal- Pressure Compared to that of Total Pressure
, M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor) ; Goharshadi, Elaheh (Supervisor)
Abstract
A simple equation of state (EoS) has recently been introduced (J. Phys. Chem. B 2009, 113, 11977–11987) as (Z-1) v^2=e+f⁄ρ+gρ^2, where Z≡pv⁄RT is the compressibility factor, v=1⁄ρ is molar volume, and e, f, and g are temperature dependent parameters. This EoS has been found to be accurate for all types of nano- and bulk- solids and bulk fluids, in the entire temperature and pressure ranges for which experimental data are reported, except for the isotherms within the critical region.
The aim of this work is to investigate the validity of a 3-term expression similar to the mentioned EoS for both thermal and internal contributions to the compressibility factor, separately. Such...
The aim of this work is to investigate the validity of a 3-term expression similar to the mentioned EoS for both thermal and internal contributions to the compressibility factor, separately. Such...
Modeling of aqueous biomolecules using a new free-volume group contribution model
, Article Industrial and Engineering Chemistry Research ; Volume 48, Issue 8 , 2009 , Pages 4109-4118 ; 08885885 (ISSN) ; Taghikhani, V ; Vossoughi, M ; Sharif University of Technology
2009
Abstract
In this article, a new group contribution model is suggested for obtaining the thermodynamic properties of biomolecules in aqueous solutions. Accordingly, a Freed-FV model has been applied for the combinatorial free-volume term. The activity coefficients, solubilities, densities, and vapor pressures of amino acids and simple peptides in aqueous solutions were correlated, using the proposed group contribution model. Group interaction parameters of the proposed model were obtained by use of experimental data from amino acids available in the literature. The results demonstrate that the group contribution model can accurately correlate activity coefficient, solubility, density, and vapor...
Calculation of the Thermodynamical Properties of [BMIM][PF6] via Equation of State and Molecular Dynamic Simulations Data
, M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor) ; Tafazzoli, Mohsen (Supervisor) ; Shamkhali, Amir Naser (Co-Advisor)
Abstract
In this thesis, We have investigated the accuracy of general equation of state ( EoS III ) and linear isotherm regularity ( EoS I ), introduced on 2009 and 1993, respectively, and the Ghatee’s equation of state ( EoS II ) introduced on 2001, for the pvT data and thermodynamic properties of [BMIM][PF6] ionic liquid. We have carried out simulations at first in a narrow range of pressure, namely within 1-3400 atm and in temperature range from 398 K to 1000 K. The results of fitting of EoS I, EoS II and EoS III into the simulations results, leads to R2 > 0.9936, 0.9800 and 0.9949 respectively, for the pressure range of 1-3400 atm and for the temperature range of 398-1000 K. The results of...
Theoretical Investigation of Carbon Monoxide Adsorption on the Nickel Surface in the Macroscopic and Microscopic Scales
, Ph.D. Dissertation Sharif University of Technology ; Parsafar, Gholamabbas (Supervisor)
Abstract
In this work, CO interaction with macroscopic Ni(111) surface and microscopic Nin (n = 2-4) clusters were investigated. First, the CO interaction with various adsorption sites were studied by DFT methods on Ni(111) surface. On the basis of these calculations, hcp site has the strongest interaction with CO adsorbate. Then, the vibrational frequencies of C=O and adsorptive bond on the hcp site were calculated and the results show that anharmonicity of adsorptive bond is more important than C=O bond. Therefore, three potential models are considered for adsorptive bond and the effect of potential models on its thermodynamic properties was investigated. The results show that the effect of...
Spectroscopic and thermodynamic studies of interaction between dopamine and cobalt (III) schiff-base complexes
, Article Scientia Iranica ; Volume 16, Issue 2 C , 2009 , Pages 89-93 ; 10263098 (ISSN) ; Boghaei, D. M ; Sharif University of Technology
2009
Abstract
In this paper, the interactions of cobalt(III) tetradentate Schiff-base complexes, [Co(S-MeO-salophen)]ClO4, (1), [Co(5-NO 2-salophen)]ClO4, (2), and [Co(5-Br-salophen)]ClO 4, (3), with dopamine, an important neurotransmitter, have been investigated. The formation and kinetic constants for complex formation of [Co(3-MeO-salophen)]ClO4, (1), with dopamine were determined spectrophotometrically in H2O/EtOH solution (4:1) at 30°C by using the Benesi-Hildbrand and Guggenheim equations, respectively. The stoichiometry has been found to be 1:1. The rate and equilibrium constants for the coordination of dopamine to (Co(3-MeO-salophen)]ClO4 were found to be 0.0053 min-1 and 1600 dm3 mol-1,...
Numerical investigation of fluid flow and heat transfer characteristics in parallel flow single layer microchannels
, Article Scientia Iranica ; Volume 16, Issue 4 B , 2009 , Pages 313-331 ; 10263098 (ISSN) ; Saidi, M. H ; Sharif University of Technology
2009
Abstract
Heat generation from Very Large-Scale Integrated (VLSI) circuits increases with the development of high-density integrated circuit technology. One of the efficient techniques is liquid cooling by using a microchannel heat sink. Numerical simulations on the microchannel heat sink in the literature are mainly two dimensional. The purpose of the present study is to develop a three-dimensional procedure to investigate flow and conjugate heat transfer in the microchannel heat sink for electronic packaging applications. A finite volume numerical code with a multigrid technique, based on an additive correction multigrid (AC-MG) scheme, which is a high-performance solver, is developed to solve the...
Study of VLE phase behavior and correlating the thermophysical properties of polymer solutions using a local composition-based model
, Article Journal of Applied Polymer Science ; Volume 112, Issue 3 , 2009 , Pages 1356-1364 ; 00218995 (ISSN) ; Taghikhani, V ; Vossoughi, M ; Sharif University of Technology
2009
Abstract
In this study, the recently proposed model by Pazuki et al., based on the local composition concept (LCC), has been used in correlating the vapor-liquid phase behavior of polymer solutions. Similar to the LCC models available in the literature, the proposed model has two combinatorial and residual terms to account for both entropic as well as enthalpic effects in solution. The Flory-Huggins model has been considered as the combinatorial part of the proposed model, while the equation proposed by Pazuki et al. was considered as the residual term. The proposed model has been used in correlating the vapor-liquid phase behavior for a large number of polymer-solvent mixtures at different...