02093nas a2200229 4500008004100000022001400041245007300055210006900128260006800197300001200265490000700277520133900284653000801623653000901631653001801640653001501658653002401673100001901697700001901716700002901735856009901764 2005 eng d a0001-154100aComputational study of a single-phase flow in packed beds of spheres0 aComputational study of a singlephase flow in packed beds of sphe a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcFEB a365-3780 v513 a

Packed-bed reactors are widely used in petrochemical, fine chemical, and pharmaceutical industries. Detailed knowledge of interstitial flow in the void space of such packed-bed reactors is essential for understanding the heat and mass transfer characteristics. In this paper, fluid flow through the array of spheres was studied using the unit-cell approach, in which different periodically repeating arrangements of particles such as simple cubical, 1-D rhombohedral, 3-D rhombohedral, and face-centered cubical geometries were considered. Single-phase flow through these geometries was simulated using computational fluid dynamics (CFD). The model was first validated by comparing predicted results with published experimental and computational results. The validated model was further used to study the effect of particle arrangement/orientation on velocity distribution and heat transfer characteristics. The simulated results were also used to understand and to quantify, relative contributions of surface drag and form drag in overall resistance to the flow through packed-bed reactors. The model and the results presented here would be useful in elucidating the role of microscopic flow structure on mixing and other transport processes occurring in packed-bed reactors. (C) 2005 American Institute of Chemical Engineers.

10aCFD10adrag10aheat transfer10apacked bed10apacking arrangement1 aGunjal, P., R.1 aRanade, V., V.1 aChaudhari, Raghunath, V. uhttps://library.ncl.res.in/content/computational-study-single-phase-flow-packed-beds-spheres-002698nas a2200229 4500008004100000022001400041245008600055210006900141260009600210300001400306490000700320520189900327653002302226653001602249653000802265653001802273653001002291100001802301700001802319700001902337856011202356 2005 eng d a0009-250900aModeling of vaporization and cracking of liquid oil injected in a gas-solid riser0 aModeling of vaporization and cracking of liquid oil injected in  aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbChem Engn Grp NancycNOV a6049-60660 v603 a

Vaporization and cracking of liquid oil injected in a gas-solid riser (fluid catalytic cracking riser reactor) was computationally studied in this work. Evaporation of a single drop injected in a stream of gas-solid mixture was analyzed first. A model for simulating evaporation of a drop considering heat transfer from the gas phase as well as from the solid particles was developed. The model relates the evaporation rate of droplet with rate of collisions of solid particles, specific heat capacities of solid and liquid, latent heat of vaporization, relative velocity of gas and liquid and temperatures of three phases. The understanding gained from such a model was then extended to simulate evaporation of liquid drops injected in FCC risers. The Eulerian-Lagrangian approach was used to simulate simultaneous evaporation and cracking reactions occurring in FCC riser reactors. A commercial CFD code, FLUENT (of Fluent Inc., USA) was used. Four and ten lump models were used for simulating cracking reactions. Appropriate user defined functions were developed to implement heterogeneous kinetics and heat transfer models in FLUENT. A special algorithm was developed to calculate accumulated coke on catalyst particles. A boiling point range was considered for simulating realistic oil feedstock. The model was first evaluated by comparing predicted results with published industrial data. The simulations were then carried out to understand influence of key design and operating parameters on performance of FCC riser reactors. The parameters studied included; initial oil droplet distribution, catalyst inlet temperature, catalyst to oil ratio and thermal cracking. The approach, model and results presented here would be useful for optimization of FCC operation, cost to benefit analysis of new FCC nozzles and related decision-making. (c) 2005 Elsevier Ltd. All rights reserved.

10acracking reactions10aEvaporation10aFCC10aheat transfer10ariser1 aNayak, S., V.1 aJoshi, S., L.1 aRanade, V., V. uhttps://library.ncl.res.in/content/modeling-vaporization-and-cracking-liquid-oil-injected-gas-solid-riser-002576nas a2200325 4500008004100000022001400041245007800055210006900133260006900202300001200271490000700283520148100290653002001771653001801791653002801809653001401837653002501851653001601876100002901892700002701921700002601948700002001974700002301994700002502017700001902042700002602061700002702087700003402114856010202148 2008 eng d a1369-703X00aEffect of hydrodynamic cavitation on zooplankton: a tool for disinfection0 aEffect of hydrodynamic cavitation on zooplankton a tool for disi aPO BOX 564, 1001 LAUSANNE, SWITZERLANDbELSEVIER SCIENCE SAcDEC a320-3280 v423 a

Application of hydrodynamic cavitation for disinfection of water is gaining momentum, as it provides environmentally and economically sound options. In this effort, the effect of cavitating conditions created by differential pump valve opening and that created by flowing through a cavitating element (orifice plates) on the microbes (zooplankton in sea water) is described. The experimental results are compared with modelling of cavitating conditions that includes cavity dynamics, turbulence generated by individual oscillating cavity, cell wall strength and geometrical and operating parameters of cavitation device. Theoretical model for quantifying the cavitationally generated turbulent shear and extent of microbial disinfection has been developed. Experimental results indicated that cavitation and/or turbulent fluid shear dominantly originating from cavitation are effective tools for sea water disinfection as more than 80% of the zooplankton present in the sea water were killed. It was also observed that shock waves generated due to cavitation is not the sole cause for zooplankton disruption. A correct physical mechanism accounting fluid turbulence and shear, generated from stable oscillation of cavity, significantly contribute towards the disruption. Further refinement of the model presented will serve as a basis for higher degree of disinfection and provide a practical tool for sea water disinfection. (C) 2008 Elsevier B.V. All rights reserved.

10aCell disruption10aheat transfer10aHydrodynamic cavitation10aModelling10aWastewater treatment10aZooplankton1 aSawant, Subhash, Shivram1 aAnil, Arga, Chandrashe1 aKrishnamurthy, Venkat1 aGaonkar, Chetan1 aKolwalkar, Janhavi1 aKhandeparker, Lidita1 aDesai, Dattesh1 aMahulkar, Amit, Vinod1 aRanade, Vivek, Vinayak1 aPandit, Aniruddha, Balchandra uhttps://library.ncl.res.in/content/effect-hydrodynamic-cavitation-zooplankton-tool-disinfection-002144nas a2200217 4500008004100000022001400041245005000055210005000105260006700155300001400222490000700236520144400243653003301687653001801720653001801738653001501756100002601771700002301797700002201820856008401842 2013 eng d a0001-154100aFlow and heat transfer in serpentine channels0 aFlow and heat transfer in serpentine channels a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcMAY a1814-18270 v593 a

Serpentine channels are often used in microchannel reactors and heat exchangers. These channels offer better mixing, higher heat and mass-transfer coefficients than straight channels. In the present work, flow and heat transfer experiments were carried out with a serpentine channel plate comprising of 10 units (single unit dimensions: 1 x 1.5 mm(2) in cross section, length 46.28 mm, D-h 1.2 mm) in series. Pressure drop and heat-transfer coefficients were experimentally measured. Flow and heat transfer in the experimental set-up were simulated using computational fluid dynamics (CFD) models to understand the mechanisms responsible for performance enhancement. The CFD methodology, thus, developed was applied to understand the effect of various geometrical parameters on heat transfer enhancement. A criterion was defined for evaluation of heat transfer performance (heat transfer per unit pumping power), thus, ensuring due considerations to required pumping power. The effect of geometrical parameters and the corresponding mechanisms contributing for enhancement are discussed briefly. Based on the results, a design map comprising different serpentine channels showing heat transfer enhancement with pumping power was developed for Reynolds number of 200 which will be useful for further work on flow and heat transfer in serpentine channels. (C) 2012 American Institute of Chemical Engineers AIChE J, 59: 1814-1827, 2013

10acomputational fluid dynamics10aheat transfer10apressure drop10aserpentine1 aKarale, Chaitanya, M.1 aBhagwat, Sunil, S.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/flow-and-heat-transfer-serpentine-channels-002045nas a2200253 4500008004100000022001400041245008100055210006900136260007300205300001200278490000800290520113200298653002101430653002201451653001801473653002701491653003701518653002601555653002301581100002301604700002301627700003001650856011101680 2013 eng d a0927-775700aSynthesis of triangular gold nanoplates: role of bromide ion and temperature0 aSynthesis of triangular gold nanoplates role of bromide ion and  aPO BOX 211, 1000 AE AMSTERDAM, NETHERLANDSbELSEVIER SCIENCE BVcAPR a181-1900 v4223 a

Synthesis of noble metal triangular nanoplates is a kinetically controlled process in which temperature and packing defects play a major role. Nucleation and growth process of kinetically controlled reaction can be greatly influenced by temperature affecting the yield and edge length of the triangles. Through a conventional batch mode process, here we study the effect of temperature on nucleation and growth of gold triangular nanoplates and obtain some insight of the temperature effects on the final yield and edge length of triangles. The role of Br- ions in the synthesis of triangular nanoplates is studied by varying the amount of CAB and by replacing the CTAB with HBr. The results show that, while CTAB controls the edge length and yield of triangles, its use is not mandatory to attain plate like morphology. Finally we show that, while the initial temperature of the reaction mixture governs the nucleation rate and the rate of temperature rise governs the growth rate of particles, they along with the concentration of Br- ions control the edge length and yield. (C) 2013 Elsevier B.V. All rights reserved.

10aAu nanotriangles10aHalide ion effect10aheat transfer10aKinetically controlled10aNature of gold precursor complex10aNucleation and growth10aOptical properties1 aKumar, D., V. Ravi1 aKulkarni, Amol, A.1 aPrasad, Bhagavatula L. V. uhttps://library.ncl.res.in/content/synthesis-triangular-gold-nanoplates-role-bromide-ion-and-temperature-001922nas a2200229 4500008004100000022001400041245006100055210005900116260010200175300001400277490000700291520115300298653001201451653001201463653001801475653001801493653001801511653001901529100003001548700002201578856009201600 2013 eng d a0256-249900aTwo-phase flow boiling in small channels: a brief review0 aTwophase flow boiling in small channels a brief review aC V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIAbINDIAN ACAD SCIENCEScDEC a1083-11260 v383 a

Boiling flows are encountered in a wide range of industrial applications such as boilers, core and steam generators in nuclear reactors, petroleum transportation, electronic cooling and various types of chemical reactors. Many of these applications involve boiling flows in conventional channels (channel size >= 3 mm). The key design issues in two phase flow boiling are variation in flow regimes, occurrence of dry out condition, flow instabilities, and understanding of heat transfer coefficient and vapor quality. This paper briefly reviews published experimental and modeling work in these areas. An attempt is made to provide a perspective and to present available information on boiling in small channels in terms of channel size, flow regimes, heat transfer correlations, pressure drop, critical heat flux and film thickness. An attempt is also made to identify strengths and weaknesses of published approaches and computational models of boiling in small channels. The presented discussion and results will provide an update on the state-of-the-art and will be useful to identify and plan further research in this important area.

10aBoiling10adry-out10aheat transfer10ainstabilities10asmall channel10atwo-phase flow1 aSardeshpande, Madhavi, V.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/two-phase-flow-boiling-small-channels-brief-review-001596nas a2200229 4500008004100000022001400041245005800055210005800113260006700171300001400238490000700252520084100259653003901100653001801139653001101157653001701168653001801185100002501203700002401228700002201252856009201274 2015 eng d a0008-403400aHeat transfer and mixing in flow through pinched pipe0 aHeat transfer and mixing in flow through pinched pipe a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcOCT a1860-18680 v933 a

There is an increasing trend of using tubular reactors either with passive or active augmentation methods for process intensification. A new passive method with pinching of pipe' is proposed and investigated for its performance. In the present work, initially, flow in a pinched pipe was studied experimentally and the same was reproduced numerically. The computational model was then used to investigate influences of key geometrical parameters of pinched pipe configuration on pressure drop, heat transfer, and mixing. The simulated results obtained with the pinched pipe were compared with a straight pipe, and with a commonly-used passive augmentation method (twisted tape inserts). The pinched pipe configuration offers better performance and more flexibility in manipulating heat transfer and mixing in intensified devices.

10acomputational fluid dynamics (CFD)10aheat transfer10amixing10apinched pipe10apressure drop1 aHasabnis, Nilesh, S.1 aTotlani, Kartik, A.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/heat-transfer-and-mixing-flow-through-pinched-pipe-002393nas a2200241 4500008004100000022001400041245005900055210005700114260000800171300001200179490000700191520169000198653000801888653001801896653002401914653001801938653001101956100002301967700002401990700002602014700002202040856008902062 2019 eng d a0008-403400aFlow, mixing, and heat transfer in fluidic oscillators0 aFlow mixing and heat transfer in fluidic oscillators cFEB a542-5590 v973 a

There is an increasing emphasis on process intensification and development of compact, intensified reactors and separators in recent years. Significant efforts are being made to develop such intensified reactors and separators without any moving parts. Some of the recent research studies have proven that a liquid-liquid extractor based on the Coanda effect and feedback oscillations exhibit excellent mixing and liquid-liquid contacting. These fluidic oscillators can potentially be used for a variety of other multiphase reactions and systems demanding enhanced mixing and heat and mass transfer. In this work, we have computationally investigated flow, mixing, and heat transfer in fluidic oscillators based on the Coanda effect. Available information on flow and mixing in fluidic oscillators was critically reviewed and key gaps in the available knowledge with respect to the design and optimization of fluidic oscillators were identified. Computational flow models were developed to characterize key flow features like unsteady flows, secondary vortices, and internal recirculation over a range of Reynolds number (Re = 90-1538) for three different oscillator designs. Systematic numerical studies were carried out to quantify different flow regimes, oscillations, and the influence of key geometric parameters on flow, mixing, and heat transfer. Simulated results were critically analyzed and are presented in the form of dimensionless numbers. The approach and results presented in this work will provide useful insights and a systematic basis for extending the applications of the Coanda-based feedback oscillatory devices for a wide range of engineering applications.

10aCFD10aCoanda effect10afluidic oscillators10aheat transfer10amixing1 aKhalde, Chirag, M.1 aPandit, Ajinkya, V.1 aSangwai, Jitendra, S.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/flow-mixing-and-heat-transfer-fluidic-oscillators02037nas a2200229 4500008004100000022001400041245014900055210006900204260000800273300001100281490000700292520120300299653001601502653002501518653001801543653001901561653003201580100002801612700001601640700002301656856012801679 2022 eng d a0001-154100aEvaluating suitability of confined impinging jet reactor for exothermic reactions: hydrodynamics, residence time distribution, and heat transfer0 aEvaluating suitability of confined impinging jet reactor for exo cOCT ae177920 v683 a

Effect of confinement (wall proximity) of a confined impinging jet reactor (CIJR) on the flow field, residence time distribution and heat transfer are explored, through experiments and CFD simulations. Hydrodynamic characteristics are evaluated for different parameters namely confinement, impinging jet velocity, temperature gradient, and so on. For 2 mm confinement, highest values of dispersion number and overall heat transfer coefficient are observed due to interaction of turbulent eddies followed by the effect of reactor wall proximity. For the CIJR having confinements above 10 mm, jet velocity need to be greater than 3 m/s to achieve both, excellent mixing efficiency and high heat removal rate. Empirical correlations for Dispersion and Nusselt numbers as a function of Re-j and L/D are obtained, over a range of 500 <= Rej <= 3000\$\$ 500\textbackslashle {\textbackslashmathit{\textbackslashoperatorname{Re}}}_j\text backslashle 3000 \$\$ and 5 <= L/D <= 35\$\$ 5\textbackslashle L/D\textbackslashle 35 \$\$, which correspond to jet velocity of 0.5-3 m/s. The present study gives a basis for designing CIJR suitable for rapid, homogeneous, exothermic reactions.

10aconfinement10aexothermic reactions10aheat transfer10aimpinging jets10aresidence time distribution1 aKhan, Muzammilanwar, S.1 aMane, Mayur1 aKulkarni, Amol, A. uhttps://library.ncl.res.in/content/evaluating-suitability-confined-impinging-jet-reactor-exothermic-reactions-hydrodynamics