@article { ISI:000251763600057, title = {Hydrodynamics and liquid phase residence time distribution in mesh microreactor}, journal = {Chemical Engineering Science}, volume = {62}, number = {24, SI}, year = {2007}, note = {8th International Conference on Gas-Liquid and Gas-Liquid-Solid Reactor Engineering, Indian Inst Technol Delhi, New Delhi, INDIA, DEC 16-19, 2007}, month = {DEC}, pages = {7484-7493}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

This paper is focused on the experimental analysis of residence time distribution and phase hold-up in a mesh microreactor. A microreactor, where a finely weaved mesh is sandwiched between two flat plates with specific inlets for gas and liquid, is proposed. The microvolumes formed upon sandwiching the mesh are totally connected and thus it yields a view of several interconnected microvolumes. This system is easy to build and does not need precision micromachining. A high-speed photographic analysis yielded the phase distribution for different mesh types over a wide range of operating gas and liquid flow rates. The RTD was studied by measuring the liquid phase conductivity at the outlet of the reactor. Channeling prevailed for mesh with smaller open area. The ADEM was used for fitting the tracer curves with tailing ends. The RTD and the image analysis for all the mesh types showed hysteresis when the gas flow rate was maintained constant and the liquid flow rate was gradually increased and then decreased. (c) 2007 Elsevier Ltd. All rights reserved.

}, keywords = {hydrodynamics, hysteresis, image analysis, microreactor, residence time distribution}, issn = {0009-2509}, doi = {10.1016/j.ces.2007.08.063}, author = {Kulkarni, A. A. and Gorasia, A. K. and Ranade, V. V.} } @article { ISI:000305766800017, title = {Computational fluid dynamics modelling of solid suspension in stirred tanks}, journal = {Current Science}, volume = {102}, number = {11}, year = {2012}, month = {JUN}, pages = {1539-1551}, publisher = {INDIAN ACAD SCIENCES}, address = {C V RAMAN AVENUE, SADASHIVANAGAR, P B \#8005, BANGALORE 560 080, INDIA}, abstract = {

Solid suspension and mixing are crucial in many important processes, including multiphase catalytic reactions, crystallization, precipitation, etc. In recent years, various efforts have been made to numerically simulate solid-liquid flows in stirred vessels using computational fluid dynamics (CFD). In this article, we present a brief account of our group{\textquoteright}s efforts at developing and using CFD models for simulating solid suspension in stirred tanks. Computational models were developed and evaluated by comparing model predictions with our data as well as published experimental data. A variety of experimental techniques ranging from torque and wall pressure fluctuations to ultrasound velocity profiler were used. Efforts were made to develop appropriate sub-models for capturing influence of the prevailing turbulence and solid volume fraction on effective inter-phase coupling terms. A hysteresis in variation of the height of the cloud of suspended solid with impeller rotational speed was observed. The hysteresis, besides having applications in realizing better suspension at lower effective power consumption, also offers an attractive evaluation test for CFD models. A new way to carry out dynamic settling of solid cloud by sudden impeller stoppage has been developed. The approach, models and results presented here will be useful for extending applications of CFD models for simulating industrial stirred slurry reactors as well as further research in the field.

}, keywords = {computational fluid dynamics, hysteresis, solid suspension, stirred tanks}, issn = {0011-3891}, author = {Sardeshpande, Madhavi V. and Ranade, Vivek V.} } @article {47342, title = {MoSx surface-modified, hybrid core-shell structured LiFePO4 cathode for superior Li-ion battery applications}, journal = {Journal of Alloys and Compounds}, volume = {872}, year = {2021}, month = {AUG}, pages = {159718}, type = {Article}, abstract = {

A hybrid core-shell cathode, composed of MoSx shell and carbon-coated lithium iron phosphate core (MoSx@cLiFePO(4) or MoSx@c-LFP) is obtained by the post-annealing of a thermally decomposable ammonium thiomolybdate and commercial carbon-coated LiFePO4 (c-LFP) powder. The specific capacity of the commercially available amorphous carbon-coated LFP (c-LFP) is typically around 120-160 mAhg(-1), which is usually lower than the theoretical values similar to 170 mAhg(-1) due to the limited Li+ phase-boundary diffusion and low electrical conductivity. In the present investigation, we report that the specific capacity of surfacemodified (similar to 1.2 wt\% of layered MoSx) c-LFP (MoSx@c-LFP) material can reach as high as similar to 228 mAhg(-1) delivering high gravimetric energy density similar to 750-770 Whkg(-1). The excess capacity can be attributed to the partial Li-ions intercalated/de-intercalated through the MoSx layers within a specific potential range (2.0-3.8 V). MoSx coating helps increase the c-LFP surface{\textquoteright}s stability by forming strong covalent bonding and is believed to enhance the electronic conduction by reducing the interparticle contact. During charge and discharge the hysteresis is substantially reduced by MoSx coating. The approach may open up a universal route to increase the cathode capacity, potentially attractive for further Li-ion battery research and industrial applications. (C) 2021 Elsevier B.V. All rights reserved.

}, keywords = {Ammonium thiomolybdate, Coulombic efficiency, Hybrid core-shell cathode, hysteresis, MoSx}, issn = {0925-8388}, doi = {10.1016/j.jallcom.2021.159718}, author = {Hu, Lung-Hao and Kumar, Pushpendra} }