Loading...
Search for:
convection-coefficient
0.005 seconds
Preparation of Nano Fluid from Carbon Nanostructures to Enhance Heat Transfer in Cooling Towers
, M.Sc. Thesis Sharif University of Technology ; Syfkordi, Ali Akbar (Supervisor) ; Lotfi, Roghayeh (Supervisor)
Abstract
In this paper, carbon structures such as multi wall carbon nano tubes, graphene and hybrid graphene-iron oxide, for utilisation in wet cooling towers in order to improve heat transfer are being discussed. All synthesized nanoparticles are prepared by chemical vapour deposition and wet chemical methods. Nature and structure of the created particles is also being examined by using X-Ray diffraction, transmission electron microscope and scanning electron microscope. The water used in this research is a kind of brine water, currently being used in industrial cooling towers at oil-rich regions of southern Iran. Performing the ICP test on the available water and by exact determination of its...
Analysis and modeling of building thermal response to investigate the effect of boundary conditions
, Article Scientia Iranica ; Vol. 20, Issue. 4 , 2014 , pp. 1269-1277 ; ISSN: 10263098 ; Azimi, A ; Hannani, S. K ; Sharif University of Technology
Abstract
Thermal load simulation and sensitivity analysis are performed for a building in Tehran by numerical means. A heat conduction equation of the walls, together with appropriate convection and radiation boundary conditions, is simulated numerically to compute temperature distributions in the walls. This research proposes a heat balance method, coupled with a bulk model, to calculate the building thermal load. In the first step, the results of the building thermal load for weather data of Tehran are compared and validated with those of Carrier HAP software, and a good agreement is found between them. The building thermal load depends on the boundary conditions of the building. The influence of...
Air pressure dependence of natural-convection heat transfer
, Article World Congress on Engineering 2010, WCE 2010, London, 30 June 2010 through 2 July 2010 ; Volume 2 , 2010 , Pages 1444-1447 ; 9789881821072 (ISBN) ; Abardeh, R. H ; Sharif University of Technology
2010
Abstract
Heat transfer is one of the prevalent concepts with many usages in different fields of science, industry and so on. In different applications we need more or less to know about this phenomenon. Control of this phenomenon is too important in some cases and we should be aware how to control it. The importance of heat transfer rate and effect of various parameters on it, is a reason of performing this research. Because of changes of air pressure in different applications, we need to know how heat transfer affected by air pressure. In different places air pressure is higher or lower than atmospheric pressure and we can't use more of experimental equations (e.g. Morgan or Churchill-Chu for a...
Simplified Modeling of Integral Abutment Bridges for Seismic Analysis and Prediction of Target Displacement Using Displacement Coefficient Method
, M.Sc. Thesis Sharif University of Technology ; Maleki, Shervin (Supervisor)
Abstract
Performance-based design (PBD) has been accepted as one of the most reliable design methods in the past few decades. PBD can overcome inherent deficiencies associated with force-based design (FBD) and has advantages over this traditional method. Various PBD methods have been developed, which Displacement-based design (DBD) has been considered as one of the effective design approaches of the PBD method. In this study, the Displacement coefficient method (DCM) is developed for stub-type integral abutment bridges (IABs). For this purpose, two coefficients are proposed to determine the target displacement of these types of bridges. Validation of this method by nonlinear time-history analysis...
Unsteady solute dispersion by electrokinetic flow in a polyelectrolyte layer-grafted rectangular microchannel with wall absorption
, Article Journal of Fluid Mechanics ; Volume 887 , 2020 ; Saidi, M. H ; Moosavi, A ; Sadeghi, A ; Sharif University of Technology
Cambridge University Press
2020
Abstract
The dispersion of a neutral solute band by electrokinetic flow in polyelectrolyte layer (PEL)-grafted rectangular/slit microchannels is theoretically studied. The flow is assumed to be both steady and fully developed and a first-order irreversible reaction is considered at the wall to account for probable surface adsorption of solutes. Considering low electric potentials, analytical solutions are obtained for electric potential, fluid velocity and solute concentration. Special solutions are also obtained for the case without wall adsorption. To track the dispersion properties of the solute band, the generalized dispersion model is adopted by considering the exchange, the convection and the...