Faculty Publications
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Item Hydrodynamics characterization of a counter-current spray column for particulate scrubbing from flue gases(2008) Biswas, S.; Rajmohan, B.; Meikap, B.C.Growing environmental concern and tightening of the regulations for particulate emission from various sources force us to think of an alternative technology for their control, which is cost effective and of high performance. A spray column using a wet process to control the particulates offers design simplicity, and has various other advantages over other conventional equipment used in industry. This work presents the hydrodynamic study of the spray column for the removal of particulates from gaseous wastes. Experiments were carried out to quantify pressure drop (?P), for varied gas and liquid rates ranging from 3.084 × 10-3 to 5.584 × 10-3 Nm3/s and 8.35 × 10-6 to 33.34 × 10 -6 m3/s, respectively with QL/QG ratio ranging from 1.59 to 10.81 m3 per 1000 ACM (actual cubic meter). The maximum pressure drop incurred in the column is 327 N/m3, which is at a gas rate of 5.584 × 10-3 Nm3/s, liquid rate of 33.34 × 10-6 m3/s, and an inlet solid loading range of 0-2.5 kg/m3. This is quite low compared to other wet process-based equipment, thus making it a low power loss scrubber. These results have further demonstrated the impact of solid dust (particulates) on the pressuredrop-hydrodynamics. A correlation was put forward for prediction of the overall pressure drop in the column. The experimental values agreed well with the predicted values, with minimum percentage error and standard deviation. © 2008 Curtin University of Technology and John Wiley & Sons, Ltd.Item CARED: Cautious Adaptive RED gateways for TCP/IP networks(2012) Tahiliani, M.P.; Shet, K.C.; Basavaraju, T.G.Random Early Detection (RED) is a widely deployed active queue management algorithm that improves the overall performance of the network in terms of throughput and delay. The effectiveness of RED algorithm, however, highly depends on appropriate setting of its parameters. Moreover, the performance of RED is quite sensitive to abrupt changes in the traffic load. In this paper, we propose a Cautious Adaptive Random Early Detection (CARED) algorithm that dynamically varies maximum drop probability based on the level of traffic load to improve the overall performance of the network. Based on extensive simulations conducted using Network Simulator-2 (ns-2), we show that CARED algorithm reduces the packet drop rate and achieves high throughput as compared to RED, Adaptive RED and Refined Adaptive RED. Unlike other RED based algorithms, CARED algorithm does not introduce new parameters to achieve performance gain and hence can be deployed without any additional complexity. © 2011 Elsevier Ltd. All rights reserved.Item Production and characterization of biosurfactant produced by a novel Pseudomonas sp. 2B(2012) Aparna, A.; Srinikethan, G.; Smitha, H.Biosurfactant-producing bacteria were isolated from terrestrial samples collected in areas contaminated with petroleum compounds. Isolates were screened for biosurfactant production using Cetyl Tri Ammonium Bromide (CTAB)-Methylene blue agar selection medium and the qualitative drop-collapse test. An efficient bacterial strain was selected based on rapid drop collapse activity and highest biosurfactant production. The biochemical characteristics and partial sequenced 16S rRNA gene of isolate, 2B, identified the bacterium as Pseudomonas sp. Five different low cost carbon substrates were evaluated for their effect on biosurfactant production. The maximum biosurfactant synthesis (4.97g/L) occurred at 96h when the cells were grown on modified PPGAS medium containing 1% (v/v) molasses at 30°C and 150rpm. The cell free broth containing the biosurfactant could reduce the surface tension to 30.14mN/m. The surface active compound showed emulsifying activity against a variety of hydrocarbons and achieved a maximum emulsion index of 84% for sunflower oil. Compositional analysis of the biosurfactant reveals that the extracted biosurfactant was a glycolipid type, which was composed of high percentages of lipid (~65%, w/w) and carbohydrate (~32%, w/w). Fourier transform infrared (FT-IR) spectrum of extracted biosurfactant indicates the presence of carboxyl, hydroxyl and methoxyl functional groups. The mass spectra (MS) shows that dirhamnolipid (l-rhamnopyranosyl-l-rhamnopyranosyl-3-hydroxydecanoyl-3-hydroxydecanoate, Rha-Rha-C 10-C 10) was detected in abundance with the predominant congener monorhamnolipid (l-rhamnopyranosyl-?-hydroxydecanoyl-?-hydroxydecanoate, Rha-C 10-C 10). The crude oil recovery studies using the biosurfactant produced by Pseudomonas sp. 2B suggested its potential application in microbial enhanced oil recovery and bioremediation. © 2012 Elsevier B.V..Item Evaluating the performance of a turbulent wet scrubber for scrubbing particulate matter(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2013) Lee, B.-K.; Raj Mohan, B.; Byeon, S.-H.; Lim, K.-S.; Hong, E.-P.A turbulent wet scrubber was designed and developed to scrub particulate matter (PM) at micrometer and submicrometer levels from the effluent gas stream of an industrial coal furnace. Experiments were conducted to estimate the particle removal efficiency of the turbulent scrubber with different gas flow rates and liquid heads above the nozzle. Particles larger than 1 ?m were removed very efficiently, at nearly 100%, depending upon the flow rate, the concentration of the dust-laden air stream, and the water level in the reservoir. Particles smaller than 1 ?m were also removed to a greater extent at higher gas flow rates and for greater liquid heads. Pressure-drop studies were also carried out to estimate the energy consumed by the scrubber for the entire range of particle sizes distributed in the carrier gas. A maximum pressure drop of 217 mm H2O was observed for a liquid head of 36 cm and a gas flow rate of 7 m3/min. The number of transfer units (NTU) analysis for the efficiencies achieved by the turbulent scrubber over the range of particles also reveals that the contacting power achieved by the scrubber is better except for smaller particles. The turbulent scrubber is more competent for scrubbing particulate matter, in particular PM2.5, than other higher energy or conventional scrubbers, and is comparable to other wet scrubbers of its kind for the amount of energy spent. Copyright © 2013 A&WMA.Item Wetting kinematics and spreading behaviour of water based aluminium nanofluids during immersion quenching(2013) Ramesh, G.; Prabhu, K.In the present work, wetting kinematics of water based aluminium nanofluids having nanoparticle concentrations varying from 0.001 to 0.5 vol.-% during immersion quenching of Inconel 600 probe was investigated by measuring the contact resistance. The contact resistance between the quench probe and counter electrode during quenching indicated that the duration of the film of water vapour decreased with increasing nanoparticle concentration as well as absence of stable vapour film formation with 0.05, 0.1 and 0.5 vol.-% of nanoparticles. The phenomenon of a repeated wetting process was observed during quenching in nanofluids. Further, quenching in 0.1 and 0.5 vol.-% nanofluids indicated the formation of a nanoparticle porous layer and its deposition on the quench probe. The spreading behaviour was studied by measuring the dynamic contact angle of nanofluids droplets on Inconel 600 substrate. Contact angle measurement showed that the addition of aluminium nanoparticles did not have a significant effect on the relaxation of contact angle of water droplet. However, lower static contact angles were obtained for nanofluids indicating improved wetting. © 2013 IHTSE Partnership.Item Heat transfer and pressure drop characteristic of zinc–water nanofluid(Springer Verlag, 2015) Sonage, B.K.; Mohanan, P.Development of alternative working fluids with enhanced thermal properties is very much needed to replace conventional fluids. Colloidal solution of some base fluid with solid nanoparticles dispersed in it, which is called as nanofluid, is emerging as a promising alternative heat transfer fluid. Zinc, being ecofriendly material, is selected as dispersed phase in water to develop zinc–water (Zn–H2O) nanofluid. Zn–H2O nanofluid is synthesized by single step method and characterized. Thermophysical properties are estimated by available theoretical models. Estimated properties proved that nanofluid is having enhanced thermophysical properties compared to the base fluid due to which nanofluid can become potential working fluid for heat exchanging devices. Synthesized nanofluid is circulated through heat transfer loop to assess its performance in turbulent flow regime and at constant wall temperature condition. Heat transfer coefficient and pressure drop are estimated from experimental results and both are considered as performance evaluation criteria for heat transfer performance assessment. 83 % increase in Nusselt number with 9 % increase in pressure drop is observed for the nanofluid compared to water. © 2014, Springer-Verlag Berlin Heidelberg.Item Miniaturization of automobile radiator by using zinc-water and zinc oxide-water nanofluids(Korean Society of Mechanical Engineers, 2015) Sonage, B.K.; Mohanan, P.High performing fluids for energy conservation and energy efficiency replace conventional heat transfer fluids. This study relates to the development of an alternative heat transfer fluid called as nanofluid. Nanofluid is a dispersion of solid nanoparticles in a base fluid having enhanced thermal properties compared to base fluid. Zinc and Zinc oxide, being eco-friendly and having easy nanoparticle production processes, are considered for the synthesis of nanofluids of different volume fractions. In this experimental study related to heat transfer, the preparation of Zinc-water (Zn-H2O) nanofluid involves the single step method, while the preparation of Zinc oxide-water (ZnO-H2O) uses the two-step method. Six nanofluids comprising of three Zn-H2O and three ZnO-H2O in different volume fractions are tried for this study. Conduct an experimental study to calculate the enhancement of heat transfer coefficient and pressure drop compared to water. Apply the performance evaluation criterion to assess the heat transfer performance of the considered nanofluids. Amongst the six nanofluids, Zn-H2O nanofluid of 0.5% volume fraction proves to have the best heat transfer performance. Then, assess this high performing fluid theoretically in an automobile radiator to get benefits of its use. If by replacing the water with Zn-H2O nanofluid of 0.5% volume fraction it is estimated that the size of the radiator, inventory of the fluid, and pumping power is reduced, thus, making this nanofluid an energy efficient fluid for the engine cooling system. © 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.Item Vibration analysis of a tapered laminated thick composite plate with ply drop-offs(Springer Verlag service@springer.de, 2015) Edwin Sudhagar, P.; Arumugam, A.; Vasudevan, R.; Jeyaraj, J.In this study, vibration characteristics of a tapered laminated thick composite plate have been investigated using finite element method by including the shear deformation and rotary inertia effects. The governing differential equations of motion of a tapered laminated thick composite plate are presented in the finite element formulation based on first-order shear deformation theory for three types of taper configurations. The effectiveness of the developed finite element formulation in identifying the various dynamic properties of a tapered laminated thick composite plate is demonstrated by comparing natural frequencies evaluated using the present FEM with those obtained from the experimental measurements and presented in the available literature. Various parametric studies are also performed to investigate the effect of taper configurations, aspect ratio, taper angle, angle ply orientation and boundary conditions on free and forced vibration responses of the structures. The comparison of the transverse free vibration mode shapes of the uniform and tapered composite plates under various boundary conditions is also presented. The forced vibration response of a composite plate is investigated to study the dynamic response of tapered composite plate under the harmonic force excitation in various tapered configurations. It is concluded that the dynamic properties of laminated thick composite plates could be tailored by dropping off the plies to yield various tapered composite plate. © 2015, Springer-Verlag Berlin Heidelberg.Item Numerical Analyses of Single-Phase Pressure Drop and Forced Convective Heat Transfer Coefficient of Water–Ethanol Mixture: An Application in Cooling of HEV Battery Module(John Wiley and Sons Inc. P.O.Box 18667 Newark NJ 07191-8667, 2016) Suhas, B.G.; Sathyabhama, A.The present numerical analyses are related to the cooling of a hybrid electric vehicle (HEV) battery module by water–ethanol mixture. The fluid is passed through a cold plate consisting of two rectangular channels of 0.01 m depth, 0.015 m width, and 0.15 m length. The battery module is represented by a heater placed below the cold plate. The single-phase pressure drop and single-phase heat transfer coefficient for water, water–ethanol mixture of mass fraction of 25%, 50%, and 75%, and ethanol are determined numerically for different heat fluxes of 10, 15, 20, and 25 kW/m2 and different Reynolds numbers 500, 1000, 1500, 2000, and 2500. To solve the Navier–Stokes equation, the pressure correction method was used and to solve the energy equation, the Lax–Wendroff explicit method is used. Numerical results obtained for water are compared with the literature correlations. The friction factor for water deviated by an average of 8.02% from the Lewis and Robertson equation. The Nusselt number for water deviated by 7.35% from the Churchill and Ozoe equation at lower Reynolds number 500 and at higher Reynolds number 2500, Nusselt number deviated by 13.68% from the Stephan equation. The results showed that the heat transfer coefficient increased with an increase in Reynolds number and heat flux. The effect of the increase in Reynolds number is more significant than the increase in heat flux. At higher ethanol mass fraction and higher Reynolds number the heat transfer coefficient increased with heat flux when compared to water. There is no significant decrease in heat transfer coefficient with an increase in ethanol mass fraction. The pressure drop increased and the heat transfer coefficient decreased with an increase in ethanol mass fraction. © 2015 Wiley Periodicals, Inc.Item Condensation heat transfer and pressure drop of R-134a saturated vapour inside a brazed compact plate fin heat exchanger with serrated fin(Springer Verlag service@springer.de, 2017) Ramana Murthy, K.V.; Chennu, C.; Ashok Babu, T.P.This paper presents the experimental heat transfer coefficient and pressure drop measured during R-134a saturated vapour condensation inside a small brazed compact plate fin heat exchanger with serrated fin surface. The effects of saturation temperature (pressure), refrigerant mass flux, refrigerant heat flux, effect of fin surface characteristics and fluid properties are investigated. The average condensation heat transfer coefficients and frictional pressure drops were determined experimentally for refrigerant R-134a at five different saturated temperatures (34, 38, 40, 42 and 44 °C). A transition point between gravity controlled and forced convection condensation has been found for a refrigerant mass flux around 22 kg/m2s. In the forced convection condensation region, the heat transfer coefficients show a three times increase and 1.5 times increase in frictional pressure drop for a doubling of the refrigerant mass flux. The heat transfer coefficients show weak sensitivity to saturation temperature (Pressure) and great sensitivity to refrigerant mass flux and fluid properties. The frictional pressure drop shows a linear dependence on the kinetic energy per unit volume of the refrigerant flow. Correlations are provided for the measured heat transfer coefficients and frictional pressure drops. © 2016, Springer-Verlag Berlin Heidelberg.