Faculty Publications
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Item Asymptotic approach to obtain nusselt number correlation for laminar mixed convection in a vertical channel(Dalian University of Technology, 2018) Nakate, P.; Kotresha, B.; Gnanasekaran, N.In this paper, a general methodology is proposed for treating mixed convection problems in a vertical channel by the concept of asymptotic computational fluid dynamics (ACFD). Average Nusselt number is developed based on the limiting solutions of natural and forced convection.These correlations are then blended to find a unified composite correlation that work very well for extreme limits of mixed convection. For the purpose of demonstration, the problem of 2-D laminar, mixed convection in a vertical channel that comprises of a heater sandwiched between two aluminum plates has been used. Numerical simulations are performed with ANSYS-FLUENT to generate the required correlation. The study proposed in this work reveals that with minimum CFD solutions one can obtain a reasonably good composite correlation for the Nusselt number. © 2018 by the authors of the abstracts.Item 6BTA 5.9 G2-1 Cummins engine performance and emission tests using methyl ester mahua (Madhuca indica) oil/diesel blends(2009) Godiganur, S.; Suryanarayana Murthy, C.H.; Reddy, R.P.Neat mahua oil poses some problems when subjected to prolonged usage in CI engine. The transesterification of mahua oil can reduce these problems. The use of biodiesel fuel as substitute for conventional petroleum fuel in heavy-duty diesel engine is receiving an increasing amount of attention. This interest is based on the properties of bio-diesel including the fact that it is produced from a renewable resource, its biodegradability and potential to exhaust emissions. A Cummins 6BTA 5.9 G2- 1, 158 HP rated power, turbocharged, DI, water cooled diesel engine was run on diesel, methyl ester of mahua oil and its blends at constant speed of 1500 rpm under variable load conditions. The volumetric blending ratios of biodiesel with conventional diesel fuel were set at 0, 20, 40, 60, and 100. Engine performance (brake specific fuel consumption, brake specific energy consumption, thermal efficiency and exhaust gas temperature) and emissions (CO, HC and NOx) were measured to evaluate and compute the behavior of the diesel engine running on biodiesel. The results indicate that with the increase of biodiesel in the blends CO, HC reduces significantly, fuel consumption and NOx emission of biodiesel increases slightly compared with diesel. Brake specific energy consumption decreases and thermal efficiency of engine slightly increases when operating on 20% biodiesel than that operating on diesel. © 2008 Elsevier Ltd. All rights reserved.Item Experimental analysis of SI engine performance and emission characteristics with gasoline-denatured spirit blends as alternative fuels(2010) Hubballi, P.A.; Ashok Babu, T.P.The experimental study focused on investigating benefits of unleaded gasoline (P100) - denatured spirit [DNS (ethanol 93.3% v/v + water 6.7% v/v)] blends as fuel in a four cylinder four stroke SI engine. Performance tests were conducted to study volumetric efficiency (VolE), brake thermal efficiency (BThE), brake power (BP), engine torque (torque), brake specific fuel consumption (BSFC). Engine exhaust emissions were investigated for carbon monoxide (CO), hydrocarbons (HC), oxides of nitrogen (NOx) and carbon dioxide (CO2). Experiments were conducted at different engine speeds between 2500 - 4500 rpm maintaining throttle position of 50% throughout the experiments. The fuel blends used include DNS30P70 (ethanol 28 % + water 2% + gasoline 70 %), DNS50P50 (ethanol 46.65 % + water 3.35 % + gasoline 50 %) and DNS85P15 (ethanol 79.3 % + water 5.7 % + gasoline 15 %) which were compared with base fuel P100. The investigations revealed that blending DNS with P100 increases BThE, VolE, BP, torque and BSFC. The CO, HC, NOx and CO2 emissions in the exhaust decrease when compared to P100 operation. The DNS85P15 blend produced encouraging results in improved engine performance and decreased engine exhaust emission.Item Geotechnical characteristics of lithomargic clay blended with marine clay as landfill liner material(CAFET INNOVA Technical Society cafetinnova@gmail.com 1-2-18/103, Mohini Mansion, Gagan Mahal Road, Domalguda, Hyderabad 500029, 2012) Allamaprabhu, K.; Sunil, B.M.; Nayak, S.; Fernandes, S.; Zafar, M.This paper reports a series of laboratory tests conducted on lithomargic clay (shedi soil), which is widespread over part of southwest coast of India, to assess whether it could be used as compacted clay liner for hydraulic barriers in engineered landfill. In order to assess the suitability of lithomarge as a barrier material, following tests such as index properties, compaction characteristics, hydraulic conductivity and unconfined compressive strength of the soil were conducted in the laboratory. From the studies, it is found that lithomargic soil is near to the recommended specifications for soils to be used as liner material. Suitable materials for soil liners are then obtained by blending different types of locally available soils to achieve the required low hydraulic conductivity and good strength. To achieve specifications for the liner material lithomargic clay is blended with 15% and 20% marine clay by weight of lithomargic clay. From standard compaction control, the blended soil shows hydraulic conductivity lower than the 1x10-7 cm/s. Acceptable zones (AZ) are constructed on the compaction plane to meet design objectives for hydraulic conductivity. It's strength properties show that the soil possesses higher strength than the recommended minimum strength of 200kPa, to support the overburden pressure imposed by the waste body. From the laboratory test results, it can be concluded that lithomargic clay blended with marine clay satisfies the requirements for a good soil liner material. © 2012 CAFET-INNOVA TECHNICAL SOCIETY.Item Synthesis, characterization and desalination study of composite NF membranes of novel Poly[(4-aminophenyl)sulfonyl]butanediamide (PASB) and methyalated Poly[(4-aminophenyl)sulfonyl]butanediamide (mPASB) with Polysulfone (PSf)(2013) Padaki, M.; Isloor, A.M.; Kumar, R.; A.F., A.F.; Matsuura, T.In the present investigation, Poly [(4-aminophenyl)sulfonyl]butanediamide (PASB) and methylated Poly[(4-aminophenyl)sulfonyl] butanediamide (mPASB) polymers were synthesized, using succinyl chloride and substituted 4-amino-1-benzenesulphonamide. Polysulfone composite membranes were prepared by blending these novel polymers by Diffusion Induced Phase Separation (DIPS) method. The performance of the membrane was studied in terms of salt rejection, water flux and molecular weight cutoff. The prepared membranes were hydrophilic in nature, which was confirmed by water uptake studies and contact angle measurement. All the membranes showed 1000. Da molecular weight cutoff. A maximum NaCl rejection of 52% was observed in some of the membranes. The effect of feed NaCl concentration on the NaCl rejection was also studied. The resistance of the membranes in a wide pH range was studied by water uptake measurement. Antifouling properties of the membranes were also performed using Bovine Serum Albumin (BSA) solution. © 2012 Elsevier B.V.Item Permeation, Antifouling and desalination performance of TiO2 nanotube incorporated PSf/CS blend membranes(2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Abdul Rashid, S.A.; Ahmed, A.A.Polysulfone (PSf) and chitosan (CS) blend membranes were prepared by incorporating titanium dioxide nanotubes (TiO2NT) in different compositions. The proper blending of PSf and CS in the PSf/CS/TiO2 membranes was confirmed by ATR-IR spectroscopy. The influence of nanotubes on morphology of membranes was investigated by Field Emission Scanning Electron Microscopy (FESEM). The effect of nanotubes on hydrophilicity of the membranes was studied by water swelling and contact angle measurements. The distribution of TiO2NT on the membrane surface was determined by Transmission Electron Microscope (TEM) analysis. The permeation property of PSf/CS/TiO2NT membranes was carried out by measuring the time dependent pure water flux (PWF). Bovine serum albumin (BSA) protein rejection studies were performed to know the antifouling properties. The rheological percolation threshold of PSf/CS/TiO2NT solutions was measured by viscosity studies. The nanotubes incorporated PSf/CS membranes showed enhanced permeation and antifouling properties compared to PSf/CS and nascent PSf ultrafiltration membranes. Membranes prepared well above rheological percolation threshold showed drastic reduction in pore size and acted as nanofiltration (NF) membranes. © 2013 Elsevier B.V.Item Modification of PSf/PIAM membrane for improved desalination applications using Chitosan coagulation media(2013) Kumar, R.; A.F., A.F.; Kassim, M.A.; Isloor, A.M.Polysulfone (PSf)/poly (isobutylene-alt-maleic anhydride) (PIAM) nanofiltration membranes were modified by changing the coagulation bath with various concentrations of glutaraldehyde cross-linked Chitosan solutions. Further the membranes were treated with 0.1N NaOH solution in order to achieve the hydrolysis of PIAM. The morphological changes of the membranes were determined using scanning electron microscope. The blending of PSf/PIAM membrane, the incorporation of Chitosan (CS) molecules in membrane matrix and the hydrolysis of PIAM in the membrane upon alkali treatment were studied by Attenuated Total Reflectance Infra Red (ATR-IR) spectroscopy. The hydrophilicity of modified membranes was measured using the contact angle analyzer. The pressure and time dependent pure water flux of modified PSf/PIAM/CS membranes were measured and compared with PSf/PIAM membranes (after alkali treatment). The antifouling property of membranes was determined using Bovine Serum Albumin (BSA) protein rejection studies. The modified membranes showed improved hydrophilicity and reduced pore size. The order of rejection of membranes for various electrolytes was Na2SO4>MgSO4>NaCl at minimum pressure of 0.2MPa TMP. The antifouling property of modified membranes increased with an increase in the composition of Chitosan in coagulation bath and membrane M-0.8 showed a maximum fouling resistance ratio of 74%. © 2013 Elsevier B.V.Item Performance improvement of polysulfone ultrafiltration membrane using N-succinyl chitosan as additive(2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Matsuura, T.A water soluble chitosan derivative, N-succinyl chitosan (NSCS), was blended with polysulfone (PSf) in three different compositions to fabricate PSf/NSCS blend membranes. The blending of polymers was confirmed by Attenuated Total Reflectance Infra-Red (ATR-IR) spectroscopy. The membranes were characterized by Scanning Electron Microscopy (SEM) images for their cross-sectional morphology. Pure water flux, water uptake and contact angle of the PSf/NSCS blend membranes were measured and compared with the pristine polysulfone membrane. The PSf/NSCS blend membranes showed enhanced hydrophilicity and permeation fluxes compared to the pristine polysulfone membrane. The membrane antifouling property was determined by filtering the bovine serum albumin (BSA) solution. The maximum flux recovery ratio (FRR) of 70% was observed by the PSf/NSCS blend membrane with 20% NSCS content. The PSf/NSCS membranes with the PSf:NSCS ratios of 80:20 and 90:10 showed nearly the same fluxes as those of polysulfone/polyethylene glycol (PSf/PEG) blend membranes with the same compositions. The hydrophilic derivative of chitosan NSCS acted as an excellent additive in improving PSf ultrafiltration properties. © 2013 Elsevier B.V.Item Polysulfone-Chitosan blend ultrafiltration membranes: Preparation, characterization, permeation and antifouling properties(2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Abdul Rashid, S.A.; Matsuura, T.Biocompatible and naturally occurring chitosan was used as an additive for the preparation of a polysulfone ultrafiltration membrane. Two different compositions of polysulfone in N-methylpyrrolidone (NMP) and chitosan in 1% acetic acid were blended to prepare PSf-CS ultrafiltration membranes by the diffusion induced phase separation (DIPS) method. The proper blending of polysulfone and chitosan in PSf-CS membranes was confirmed by ATR-IR analysis. The surface and cross-sectional morphology of the membranes was studied by scanning electron microscopy (SEM). The membrane hydrophilicity was determined by water uptake and contact angle measurements. The PSf-CS membrane showed an enhanced hydrophilicity compared to a PSf ultrafiltration membrane. The time dependent permeation studies revealed the improved flux of PSf-CS membranes. PSf-CS membranes were subjected to bovine serum albumin (BSA) protein rejection studies. An improved antifouling property was observed for PSf-CS blend membranes as compared to pristine PSf ultrafiltration membranes. Both the permeation and antifouling properties of PSf-CS membranes increased with an increase in chitosan composition. © 2013 The Royal Society of Chemistry.Item Synthesis and characterization of novel water soluble derivative of Chitosan as an additive for polysulfone ultrafiltration membrane(2013) Kumar, R.; Isloor, A.M.; A.F., A.F.; Matsuura, T.A novel water soluble Chitosan derivative N-propylphosphonic Chitosan (NPPCS) having a terminal phosphonic acid group was synthesized by reacting Chitosan with Hydroxybenzotriazole (HOBt) and propylphosphonic anhydride (T3P)® via one pot reaction. The novel derivative was characterized by 1H NMR, Attenuated Total Reflectance Infra Red (ATR-IR) spectroscopy and XRD. Due to insolubility of NPPCS in organic solvents, a new process was demonstrated for blending of NPPCS with Polysulfone. The proper blending of NPPCS with Polysulfone was confirmed by ATR-IR spectroscopy. The improved hydrophilicity of PSf/NPPCS membranes was confirmed by contact angle measurement. The permeation studies showed increased flux of PSf/NPPCS membranes as compared to the pristine Polysulfone membrane. The antifouling property of PSf/NPPCS membrane was determined by Bovine Serum Albumin (BSA) protein rejection studies. The membranes showed the enhanced antifouling property as compared to pristine Polysulfone membranes with a maximum of 74% flux recovery ratio (FRR) value. © 2013 Elsevier B.V.