BITS Faculty Publications

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Author: search.filters.author.Sande, Priya ChristinaSubject: search.filters.subject.Chemical Engineering

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    PIV investigation on the effect of gas distributor design for fluidization of Geldart A spherical particles
    (Elsevier, 2024-06) Sande, Priya Christina; Sharma, Arvind Kumar; Mohanta, Hare Krishna
    This is a hydrodynamics study on gas distribution during fluidization of the industrially relevant Geldart A type particles. The impact of 10 different distributor designs comprising perforated distributors (pitch and orifice arrangement pattern varied) and nozzle distributors (nozzle size varied) were studied experimentally on a bench-scale unit. Particle flow homogeneity in air was determined by a novel Particle Image Velocimetry (PIV) analysis of the freeboard velocity field. Over 50 PIV particle phase vector field images are presented and analysed. Bed expansion, Particle attrition with and without fines, velocity profiles with and without fines and effect of fines on bed expansion were ascertained. Best distributor design for a unit such as Fluid Catalytic Cracking (FCC) regenerator and FCC riser were found to be 0.8 cm and 0.6 cm nozzle plates distributors respectively. Confirmation with previous study revealed a correlation between homogeneous distribution of particulate flow and lower number of turbulence zones.
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    Reinterpretation of the Geldart A powder classification based on Eulerian–Eulerian CFD simulation
    (De Gruyter, 2022-07) Sande, Priya Christina
    Geldart classified powders into four categories and assigned each category its own unique characteristic. Geldart A particles, being easily aeratable, show a unique feature of ‘Homogenous expansion’ before bubbling. In this work, an additional feature for the Geldart chart is proposed which adds significant utility for the processing of Geldart A particles. CFD was used to characterize the entire Geldart A region of the Geldart chart based on detailed fluidization behavior. For this, Eulerian–Eulerian Two-fluid model (TFM) simulations were conducted for 25 particle systems across the entire span of the Geldart A region. The simulations (Solid volume fraction (SVF) contours) of bed evolution, taken before the appearance of multiple bubbles, were analyzed in detail. The particle systems were then sub-categorized into Red (5% average bed expansion), Orange (12.5% average bed expansion), and Green (30% average bed expansion) sub-types. The sub-types were plotted on Geldart chart, and for the first time a continuum heat map was generated, from which the ‘level of fluidizability’ of all Geldart A powders can be conveniently gaged. The map can be used for a more informed choice of powder for various industrial applications. Also, the A/B boundary proposed by Verloop was found to be a better fit for our proposed continuum when compared to the original Geldart A/B boundary. The 2D Simulation results performed in this work, found adequate validation against experimental findings in literature. Further, fine mesh 2D simulation results compared well with 3D simulations for dense bed, and were thereby deemed adequate for revealing dense bed behavior before onset of multiple bubbles.
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    Particle image velocimetry investigations on multiphase flow in fluidized beds: A review
    (Elsevier, 2023-03) Mohanta, Hare Krishna; Sande, Priya Christina
    Fluidized Beds (FBs) are widely employed in the petroleum and coal energy sector because they offer excellent contact, both in terms of high surface area and long times. The last two decades has seen measurement on multiphase flows shift from conventional pressure sensors to direct flow image acquisition and processing. Particle Image Velocimetry or PIV, and PIV coupled with Digital Image Analysis or DIA, are used to directly and instantaneously acquire flow field data to make hidden flow patterns and flow structures discoverable. Research abounds on Gas-Solid FB hydrodynamics using PIV, but Liquid-Solid and Gas-Liquid-Solid systems are only slowly catching up. Similarly, the use of Geldart B and D particles for such studies is very common, whereas A and C type particle hydrodynamics is as yet largely unexplored by using imaging. Turbulence, high temperature, particle clusters, particle agglomeration and dense particle flows pose particular challenges to using PIV in FB. The two-zone FB and micro-FB warrant further attention. Small sized A & C type particles of rod-like, plate-like and angular shape provide huge scope for PIV investigations on FBs in the future. This review provides a concise account of several PIV studies on all types of FBs with focus on the past two decades, and also details the limitations of PIV measurements with future scope of work.
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    Improving Classroom Delivery of Engineering Education Through Design Thinking
    (Springer, 2020-07) Sharma, Sangeeta; Sande, Priya Christina
    Teaching is an art which requires systematic exploration in manifestations, be it curriculum design, pedagogical strategies and theories, teaching material and practices, and technological interventions. Due to the interface of technology and the mitigating attention span of the students, teachers have realized that the old method of teaching is not relevant anymore. As a result in the different courses offered at the Engineering institute, the teachers are adopting divergent thinking, synectics and design thinking for better understanding of the concepts. Design thinking offers better solutions to the problems and includes analogies and synectics to clarify the concepts. Design thinking aids better student participation and fosters teacher-student relationship. The students are encouraged for team based learning, which make them more attentive. This paper discusses how design thinking has been applied in two popular courses at Birla Institute of Technology and Sciences, BITS Pilani namely General Biology and Computational Fluid Dynamics. The feedback suggests that through analogies and design thinking the profound concepts are made easy to grasp.
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