136 research outputs found
Unpredictable Nature of Nanofluid Flow: A Study on Effects of Uncertainties in Effective Viscosity
No full textAbstractA numerical analysis of steady, laminar and 2-D nanofluid flow around a circular cylinder has been carried out to showcase the effects of variable viscosity on flow characteristics. The governing equations of flow are solved using a finite-volume method based on SIMPLE algorithm. Three cases of simulations in which the effective viscosity of the nanofluid is calculated using (a) Classical Brinkman model, (b) Recent correlation from literature and (c) Experimental data from literature are performed. A comparative analysis of the three cases shows that the flow characteristics of nanofluids become unpredictable due to the uncertainties in effective viscosity. In the first case, nanofluids show an accelerated flow with earlier flow separation and longer wake bubbles. Whereas, in other two cases, a decelerated flow with delayed flow separation is noted. This is the first time; a decelerated flow of nanofluids has been reported in literature. It is understood that, flow characteristics of nanofluid vary both qualitatively and quantitatively due to the variations in effective viscosity. This work showcases the importance of precise effective viscosity models to clearly understand the flow features of nanofluids
Towards a critique of Maharashtra's political economy: Conceptual cobwebs and policy puzzles
No full textBased on P.R. Dubhashi Public Lecture delivered at Gokhale Institute of Politics and Economics, Pune on Friday, December 18, 2009. Jayant Lele, Professor Emeritus, Departments of Political Studies, Sociology and Global Development Studies, Queen's University at Kingston, Canada, email: [email protected]. Author is grateful to Dr. Dubhashi, Dr. Parchure, Dr. Deepak Shah, Dr. Nagarajan, Dr. Rath and Dr. Tripathy for making this possible
Heat transfer and particle migration in nanofluid flow around a circular bluff body using a two-way coupled Eulerian-Lagrangian approach
No full text
Set Based Design: An explorative research into the possible improvements in design quality in Process plants by use of Set Based Design.
No full textCivil Engineering | Construction Management and Engineerin
A technique to calibrate spatial light modulator for varying phase response over its spatial regions
No full textNumerical investigation of injection-induced electro-convection in a dielectric liquid between two eccentric cylinders
No full textInternational audienceNumerical analysis of the 2D radial and azimuth electro-convection (EC) flow of dielectric liquid between two eccentric cylindrical electrodes driven by unipolar injection of ions is presented. The finite volume method is used to resolve the spatiotemporal distributions of the flow field, electric field, and charge density. The flow instability is studied in various scenarios where the radius ratio Gamma = R-i/R-o ranges between 0.1 and 0.7 and the eccentricity eta between 0.1 and 0.5. The bifurcation of the flow patterns depends on the electric Rayleigh number T, a ratio of the electric force to viscous force, and the two geometric parameters Gamma and eta. For an increasing T, the EC system develops from a weak steady convective state to chaos via different intermediate states experiencing pitchfork and Hopf bifurcations. The influence of Gamma and eta on the bifurcation behavior is also investigated. When Gamma lies between 0.1 and 0.3, a novel periodic oscillation of the flow patterns has been observed
Low Temperature de-NOx Technology-a Challenge for Vehicular Exhaust and its Remedation: An Overview
No full textAbstractOver the past few decades, nitrogen oxides (NOx) from mobile and stationary sources have become a major environmental concern. Environmental regulations about NOx reduction are forced to become more stringent due to escalating global issues like respiratory diseases, photochemical smog, acid rain and stratospheric ozone depletion. Worldwide stringent legislations Euro 6/VI has been implemented recently in September 2014 to control the NOx emission from light and heavy duty vehicles respectively. Selective catalytic reduction (SCR) technology acquires its wide acceptance in mobile and stationary sources in catalytic NOx reduction with aqueous urea/ammonia. Most of the NOx abatement catalysts are able to reduce NOx under intermediate and high temperature ranges. At the low temperature (<523K), during the engine start-up, active NOx abatement catalysts are the challenging area in this regard due to the presence of excess H2O and SO2. A low temperature noble metal free SCR catalyst has the benefit of lesser energy expenditure and low cost advantage. The aim of the present paper is to compile the various parameters like choice of precursor, oxidation states of active components, effect of different dopants, and structural stability affects. The catalyst efficiency verified by various surface characterization studies in structure-activity relationship is also reviewed. A low temperature SCR catalyst with broad operating temperature range in engine exhausts are the viable solutions to the current situation
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