02143nas a2200217 4500008004100000022001400041245005000055210005000105260006700155300001400222490000700236520144400243653003301687653001801720653001801738653001501756100002601771700002301797700002201820856008301842 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. uhttp://library.ncl.res.in/content/flow-and-heat-transfer-serpentine-channels-001921nas a2200229 4500008004100000022001400041245006100055210005900116260010200175300001400277490000700291520115300298653001201451653001201463653001801475653001801493653001801511653001901529100003001548700002201578856009101600 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. uhttp://library.ncl.res.in/content/two-phase-flow-boiling-small-channels-brief-review-001595nas a2200229 4500008004100000022001400041245005800055210005800113260006700171300001400238490000700252520084100259653003901100653001801139653001101157653001701168653001801185100002501203700002401228700002201252856009101274 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. uhttp://library.ncl.res.in/content/heat-transfer-and-mixing-flow-through-pinched-pipe-002392nas a2200241 4500008004100000022001400041245005900055210005700114260000800171300001200179490000700191520169000198653000801888653001801896653002401914653001801938653001101956100002301967700002401990700002602014700002202040856008802062 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. uhttp://library.ncl.res.in/content/flow-mixing-and-heat-transfer-fluidic-oscillators