01967nas a2200169   4500008004100000245011600041210006900157260000800226300001200234490000800246520127700254653007501531100002201606700001701628700002301645856012901668       2016                        eng d00aEffect of number of branches on the performance of fractal impeller in a stirred tank: mixing and hydrodynamics0 aEffect of number of branches on the performance of fractal impel  cAPR  a164-1750 v1083 a<p>Number of blades of an impeller, impeller design and its positioning in a stirred tank is known to affect the mixing in a stirred tank reactor. The extent of non-uniformity in mixing from conventional impellers can be reduced significantly using a space-filling impeller like a fractal impeller. In this work, we report the effect of number of branches (and hence the number of blades) of fractal impeller on power consumption, mixing and hydrodynamics. Velocity measurements were carried out using ultrasonic velocity profiler (UVP). Measurements showed that the performance of fractal impeller with different configuration is equivalent, however, better than standard impellers in terms of mixing achieved per unit power consumption. No significant difference was observed in radial and axial mean velocity profiles for three different configurations. However, the tangential velocity was found higher for four branches than two and three branches FL Two distinct circulation loops were observed in upper as well as lower half of the vessel in r-z plane. Strong tangential flow throughout the baffled vessel helps to achieve good mixing even at low rotational speeds. (C) 2016 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.</p>10aFractal impeller; Number of branches; UVP; Tangential velocity; Mixing1 aMule, Gunwant, M.1 aLohia, Rajat1 aKulkarni, Amol, A.  uhttps://library.ncl.res.in/content/effect-number-branches-performance-fractal-impeller-stirred-tank-mixing-and-hydrodynamics01676nas a2200217   4500008004100000022001400041245007700055210006900132260000800201300001100209490000700220520098300227653001901210653002201229653002801251653001701279653001801296100002201314700002301336856009901359       2021                        eng d  a0169-598300aEffect of object shape on the flow past microstructures in small channel0 aEffect of object shape on the flow past microstructures in small  cFEB  a0155050 v533 a<p>Flow past objects in microfluidics and microscale devices are used to perturb the flow and thereby achieve effective mixing and heat transfer. This paper presents the observations on the flow past bluff (elliptical, rectangular and triangular) cylindrical micropillars (objects) having different cross-sectional area in a micro-channel through 2D simulations. The pertinent range of Re based on object dimension (0.1 Re 150) was chosen to understand the wake dynamics that would remain relevant for comparison with literature data. Drag coefficient, recirculation region, critical Reynolds number for flow oscillations and vortex strength in a channel were studied. The drag coefficient was found to increase with aspect ratio of the object. The critical Re for flow oscillations was found to increase with the cross-sectional area of the object. The vortex strength in a channel was seen highest for triangular cylinder compared to elliptical and rectangular cylinder.</p>
10a2D simulations10aflow past objects10amicro and mini-channels10amicropillars10awake dynamics1 aMule, Gunwant, M.1 aKulkarni, Amol, A.  uhttps://library.ncl.res.in/content/effect-object-shape-flow-past-microstructures-small-channel