02114nas a2200217 4500008004100000022001400041245007900055210006900134260006800203300001400271490000700285520133200292653003901624653001701663653002801680653002001708653001901728100002001747700001901767856011001786 2006 eng d a0001-154100aCFD simulation of gas-liquid stirred vessel: VC, S33, and L33 flow regimes0 aCFD simulation of gasliquid stirred vessel VC S33 and L33 flow r a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcMAY a1654-16720 v523 a

A comprehensive computational model based on the Eulerian-Eulerian approach was developed to simulate gas-liquid flows in a stirred vessel. A separate submodel was developed to quantitatively understand the influence of turbulence and presence of neighboring bubbles on drag acting on bubbles. This submodel was used to identify an appropriate correlation for estimating the interphase drag force. The standard k-epsilon turbulence model was used to simulate turbulent gas-liquid flows in a stirred vessel. A computational snapshot approach was used to simulate motion of the standard Rushton turbine in a fully baffled vessel. The computational model was mapped onto FLUENT4.5, a commercial CFD solver. The model predictions were compared with the previously published experimental data of Bombac and co-workers. The model was used to simulate three distinct flow regimes in gas-liquid stirred vessels: vortex clinging (VC), alternating small cavities (S33), and alternating large cavities (L33). The predicted results show reasonably good agreement with the experimental data for all three regimes. The computational model and results discussed in this work would be useful for understanding and simulating gas holdup distribution and flow regimes in stirred vessels. (c) 2006 American Institute of Chemical Engineers.

10acomputational fluid dynamics (CFD)10aFlow regimes10agas holdup distribution10aRushton turbine10astirred vessel1 aKhopkar, A., R.1 aRanade, V., V. uhttps://library.ncl.res.in/content/cfd-simulation-gas-liquid-stirred-vessel-vc-s33-and-l33-flow-regimes-002393nas a2200241 4500008004100000022001400041245009200055210006900147260010600216300001400322490000700336520152900343653000801872653001701880653001101897653002601908653001901934100002001953700002101973700001901994700001902013856011902032 2006 eng d a0009-250900aCFD simulation of mixing in tall gas-liquid stirred vessel: role of local flow patterns0 aCFD simulation of mixing in tall gasliquid stirred vessel role o aTHE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLANDbPERGAMON-ELSEVIER SCIENCE LTDcMAY a2921-29290 v613 a

In this work, we have used the computational fluid dynamics (CFD)-based models to investigate the gas-liquid flows generated by three down-pumping pitched blade turbines. A two-fluid model along with the standard k-epsilon turbulence model was used to simulate the dispersed gas-liquid flow in a stirred vessel. Appropriate drag corrections to account for bulk turbulence [Khopkar and Ranade, 2005. CFD simulation of gas-liquid flow in a stirred vessel: VC, S33 and L33 flow regimes. A.I.Ch.E. Journal, accepted for publication] were developed to correctly simulate different flow regimes. The computational snapshot approach was used to simulate impeller rotation and was implemented in the commercial CFD code, FLUENT4.5 (of Fluent. Inc., USA). The computational model has successfully captured the flow regimes as observed during experiments. The particle trajectory simulations were then carried out to examine the influence of the different flow regimes on the circulation time distribution. The model predictions were verified by comparing the predicted results with the experimental data of [Shewale and Pandit, 2006. Studies in multiple impeller agitated gas-liquid contactors. Chemical Engineering Science 61, 489-504]. The computational model and results discussed in this study would be useful for explaining the implications local flow patterns on the mixing process and extending the applications of CFD models for Simulating large multiphase stirred reactors. (c) 2005 Elsevier Ltd. All rights reserved.

10aCFD10aFlow regimes10amixing10apitched blade turbine10astirred vessel1 aKhopkar, A., R.1 aKasat, Gopal, R.1 aPandit, A., B.1 aRanade, V., V. uhttps://library.ncl.res.in/content/cfd-simulation-mixing-tall-gas-liquid-stirred-vessel-role-local-flow-patterns-101938nas a2200229 4500008004100000022001400041245008500055210006900140260009100209300002000300490000600320520108100326653003301407653002501440653001701465653002901482653002001511100002101531700002601552700001901578856011101597 2008 eng d a1542-658000aCFD simulation of gas-liquid flows in a reactor stirred by dual rushton turbines0 aCFD simulation of gasliquid flows in a reactor stirred by dual r a2809 TELEGRAPH AVENUE, STE 202, BERKELEY, CA 94705 USAbBERKELEY ELECTRONIC PRESScJAN aArticle No. A600 v63 a

In the present work, we have simulated gas-liquid flows in a tall stirred reactor equipped with dual Rushton turbines. A two fluid model along with the standard k-epsilon turbulence model and modified drag coefficient, (proposed by Khopkar & Ranade, 2006) accounting for the effect of bulk turbulence, was used to simulate the dispersed gas-liquid flow in a stirred reactor. The multiple reference frames (MRF) approach was used to simulate impeller rotation in a fully baffled reactor. The computational model was mapped on to a commercial solver FLUENT 6.2 (of Fluent Inc. USA). The model was used to simulate three distinct flow regimes in a gas-liquid stirred reactor: L33-VC (lower impeller-upper impeller), S33-VC and VC-VC. The model predictions were compared with the published experimental data of Bombac & Zun (2000). The predicted results show good agreement with the experimental data for all the three flow regimes. The computational model presented in this work would be useful for simulating different flow regimes in a gas-liquid stirred vessel.

10acomputational fluid dynamics10adual Rushton turbine10aFlow regimes10agas hold-up distribution10astirred reactor1 aKasat, Gopal, R.1 aPandit, Aniruddha, B.1 aRanade, V., V. uhttps://library.ncl.res.in/content/cfd-simulation-gas-liquid-flows-reactor-stirred-dual-rushton-turbines-002033nas a2200217 4500008004100000022001400041245009700055210006900152260009500221300000900316490000700325520122400332653000801556653001701564653001901581653001801600100003001618700002301648700002201671856012201693 2015 eng d a0263-876200aVoid fraction measurement using electrical capacitance tomography and high speed photography0 aVoid fraction measurement using electrical capacitance tomograph a165-189 RAILWAY TERRACE, DAVIS BLDG, RUGBY CV21 3HQ, ENGLANDbINST CHEMICAL ENGINEERScFEB a1-110 v943 a

Gas-liquid flows are encountered in variety of industrial applications including boilers, distillation towers, chemical reactors, oil pipelines, nuclear reactors etc. The measurement of two-phase flow parameters such as flow regime and void fraction is considerably important and play an important role in characterization of the hydrodynamic behavior of such gas-liquid two phase systems. The void fraction is a dimensionless quantity and is often termed as ``holdup or fraction'' in two-phase flows. According to industrial applications; it is essential to develop measurement technique for void fraction measurement which can work in hot and opaque systems. Therefore, an attempt was made here to establish electrical capacitance tomography (ECT) facility for measuring void fraction and flow regimes as well as develop suitable data processing methodologies. In the present work, focus was to measure void fraction using ECT technique and compares it with conventional and high speed photography technique. Therefore, that will give guidelines of using ECT technique for hot and opaque systems like boiling flows. (C) 2014 The Institution of Chemical Engineers. Published by Elsevier BM. All rights reserved.

10aECT10aFlow regimes10aTwo phase flow10aVoid fraction1 aSardeshpande, Madhavi, V.1 aHarinarayan, Sagar1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/void-fraction-measurement-using-electrical-capacitance-tomography-and-high-speed-102059nas a2200217 4500008004100000022001400041245007100055210006900126260006700195300001200262490000700274520131500281653000801596653001701604653002701621653001901648100003001667700002001697700002201717856010201739 2016 eng d a0008-403400aTwo-phase flow boiling in 19mm tube: experiments and CFD modelling0 aTwophase flow boiling in 19mm tube experiments and CFD modelling a111 RIVER ST, HOBOKEN 07030-5774, NJ USAbWILEY-BLACKWELLcMAY a872-8850 v943 a

Boiling flows are encountered in a wide range of industrial applications such as boilers, nuclear reactors, electronic cooling, and various types of chemical reactors. Heat transfer coefficients, flow boiling regimes, flow instabilities, pressure drops, and conditions like dry-out are some of the key issues in every boiling flow study. It is observed that a limited experimental database is available for the 19mm ID channel diameter, i.e. a typical tube diameter of steam generator. Therefore, in the present work, the experimental setup was designed for studying boiling flows in a 19mm ID tube in such a way that different flow regimes occurring in a steam generator tube (from pre-heating of sub-cooled water to dry-out) could be investigated by varying inlet conditions. The reported results cover a reasonable range: 8-27kW/m(2) and 2.9-5.9kg/m(2)s heat and mass flux conditions, respectively. A basic computational flow model was also developed to facilitate interpretation of the obtained data. The presented design of the experimental setup and the approach of mimicking different types of steam generator tubes as well as presented experimental and simulated results are useful for gaining insight into complex boiling flows in tubes, and provide a sound basis for further work in this area.

10aCFD10aFlow regimes10atwo-phase flow boiling10avapour quality1 aSardeshpande, Madhavi, V.1 aRaymond, Barlev1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/two-phase-flow-boiling-19mm-tube-experiments-and-cfd-modelling