02207nas a2200205 4500008004100000022001400041245011300055210006900168260006800237300001400305490000700319520140200326653000801728653003101736653002801767100003001795700002301825700002201848856013101870 2010 eng d a0001-154100aHysteresis in cloud heights during solid suspension in stirred tank reactor: experiments and CFD simulations0 aHysteresis in cloud heights during solid suspension in stirred t a111 RIVER ST, HOBOKEN, NJ 07030 USAbJOHN WILEY & SONS INCcNOV a2795-28040 v563 a

Solid suspension in stirred tank reactor is widely used in process industries for catalytic reactions, dissolution of solids, crystallization, and so on. Suspension quality is a key issue in design and operation of stirred reactor and its determination is not straight forward. Cloud height measurements of solid suspension provide a relatively simple way to quantify quality of suspension. In this work, experiments were carried out to quantify variation of cloud heights with impeller speed and particle characteristics. These measurements were carried out using visual observations, image analysis, and ultrasound velocity profiler techniques. The obtained data demonstrated the existence of hysteresis in cloud heights with respect to impeller speed. Apart from possible applications in reducing power required for achieving desired solid suspension quality, the existence of hysteresis also provides a new way to evaluate computational fluid dynamics (CFD) simulations of solid liquid flows in stirred vessels. An attempt was made to capture observed hysteresis in cloud heights in CFD simulations. The simulated results were compared with the experimental data. The presented models and results (experimental and computational) will he useful for simulating complex solid liquid flows in stirred reactors. (C) 2010 American Institute of Chemical Engineers AIChE J, 56: 2795-2804, 2010

10aCFD10ahysteresis in cloud height10asolid velocity profiles1 aSardeshpande, Madhavi, V.1 aJuvekar, Vinay, A.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/hysteresis-cloud-heights-during-solid-suspension-stirred-tank-reactor-experiments-and-cfd-001552nas a2200229 4500008004100000022001400041245007600055210006900131260007600200300001400276490000700290520075500297653000801052653002101060653002101081653002801102653000801130100003001138700002301168700002201191856010901213 2011 eng d a0008-403400aSolid suspension in stirred tanks: UVP measurements and CFD simulations0 aSolid suspension in stirred tanks UVP measurements and CFD simul aCOMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USAbWILEY-BLACKWELLcOCT a1112-11210 v893 a

Suspension of solids in stirred reactor is widely used for catalytic reactions, dissolution, etc. Quality of solid suspension is an important parameter required for the reliable design, optimum performance, and scale up of the system. Quality of suspension depends on local characteristics of solid velocity and hold up profiles. The present work was focused on investigating quality of solid suspension using ultrasound velocity profiler (UVP) measurements and CFD simulations. The slip velocity measurements carried out with UVP were used to evaluate different drag correlations used in CFD simulations. Results discussed in this work would be useful for extending the applications of CFD models for simulating large stirred slurry reactors.

10aCFD10adrag coefficient10asolid suspension10asolid-liquid velocities10aUVP1 aSardeshpande, Madhavi, V.1 aJuvekar, Vinay, A.1 aRanade, Vivek, V. uhttps://library.ncl.res.in/content/solid-suspension-stirred-tanks-uvp-measurements-and-cfd-simulations-002059nas 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