Faculty Publications

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    Validation of an analytical model for spiral wound reverse osmosis membrane module using experimental data on the removal of dimethylphenol
    (2011) Srinivasan, G.; Sundaramoorthy, S.; Murthy, D.V.R.
    A new analytical model for spiral wound RO module has been recently proposed by Sundaramoorthy et al. [1] and the same has been validated [2] with experimental data obtained on a laboratory scale RO unit used for the removal of chlorophenol. In this paper, the need to check the validity of this model with solutes other than chlorophenol is addressed by conducting suitable experiments with dimethylphenol as solute and validating this experimental data with the model. The four model parameters namely solvent transport coefficient Aw, solute transport coefficient Bs, feed channel friction parameter b and the mass transfer coefficient k were estimated. The results show that the mass transfer coefficient is influenced not only by fluid velocity but also by the solvent flux and solute concentration. A new correlation for mass transfer coefficient k, proposed by Sundaramoorthy et al. [2] for experimental data taken with chlorophenol as solute is also shown to be consistent with the experimental readings recorded in this study taking dimethylphenol as solute. Comparison of model predictions with the experimental observations demonstrated the capability of the model in predicting permeate concentration within 12% error, retentate flow within 5% error and rejection coefficient within 2% error. © 2011 Elsevier B.V.
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    An analytical model for spiral wound Reverse Osmosis membrane modules: Part I - Model development and parameter estimation
    (2011) Sundaramoorthy, S.; Srinivasan, G.; Murthy, D.V.R.
    A mathematical model for spiral wound Reverse Osmosis membrane module is presented in this work. The model incorporates spatial variations of pressure, flow and solute concentration in the feed channel and uniform conditions of pressure in the permeate channel. Assuming solution-diffusion model to be valid, explicit analytical equations were derived for spatial variations of pressure, flow, solvent flux and solute concentration on the feed channel side of the module. Analytical procedures for estimation of model parameters were presented. Graphical linear fit methods were developed for estimation of parameters Aw (solvent transport coefficient), Bs (solute transport coefficient) and b (feed channel friction parameter). The mass transfer coefficient k was assumed to vary along the length of the feed channel with varying conditions of flow, solute concentration and pressure. Explicit analytical equations for estimation of mass transfer coefficient were presented. In this paper (Part I), theoretical studies on development of mathematical model and methods for estimation of model parameters are presented. In Part II of this paper series [1], Studies on validation of this model with experimental data are presented. The studies cover experimental work on a spiral wound RO module with an organic compound namely chlorophenol as a solute. © 2011 Elsevier B.V.
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    Full scale experiment and finite element modeling of support structures of substation equipment for evaluation of ground motion amplification
    (2012) Nandam, S.; Ramesh Babu, R.; Venkataramana, K.
    Post earthquake performance of porcelain insulators installed for high voltage substation equipment, in general, revealed their vulnerability to failure, not due to any quality deficiency, but due to failure of their supporting structures. Most of the equipment in standalone state, withstood to tests of induced vibrations conforming to International standards. The same tested equipment, when erected in position over its supporting structure failed to sustain earthquake ground accelerations, as the supporting structure adversely contributed to amplification of the ground seismic motions while traversing to the top of the structure or the base of the insulator. This paper critically examines salutary effects of damping of vibrations on a typical instrument- transformer, using a rubber based elastic damper, with particular reference to the connected porcelain insulators, in partial containment of amplification of earthquake acceleration or in minimizing attendant distress on them. The analytical study carried out is based on experimental studies conducted on the equipment using shake table and then correlating the results obtained using finite element analysis, on the full scale model to draw meaningful conclusions. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.