Liquid phase axial mixing in solid–liquid circulating multistage fluidized bed: CFD modeling and RTD measurements

Kalaga, Dinesh V.; Reddy, Rupesh K.; Joshi, Jyeshtharaj B.; Dalvi, Sameer V.; Nandkumar, K.

doi:10.1016/j.cej.2012.02.091

Cited by 44 publications

(33 citation statements)

References 60 publications

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“…CFD has been used as a useful tool for hydrodynamic prediction, design, scale‐up, and optimization of several chemical engineering equipments. Some of the commonly used chemical engineering equipments, that have investigated using CFD so as to understand the underlying flow physics involved are: pipes and pipe bends, particulate flows, packed bed reactors, fluidized bed reactors, bubbly flows, and heat exchangers . CFD has gained a lot of importance in the previous three decades owing to the wide application and promising results, which it offers at a nominal cost.…”

Section: Introductionmentioning

confidence: 99%

Teaching turbulent flow through pipe fittings using computational fluid dynamics approach

Gajbhiye

Kulkarni

Tiwari

et al. 2020

Engineering Reports

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The largest network of fluid transportation in the world is through pipelines.During the transportation of fluids through pipes, several "fittings" are used in the piping system such as elbows, T-junctions, reducers, expanders, bends, couplings, valves, etc. The flow complexities in pipe fittings are accounted for the pressure drop in piping network design. The pressure drop is estimated using the loss coefficient or equivalent length method using standard charts. Computational fluid dynamics (CFD) is a reliable tool to estimate pressure drop and understand nonidealities in pipe fittings. The use of CFD in the advanced level course in transport phenomena/fluid flow for piping network design can help students to implement modern mathematical tools as well as evaluate standard protocols followed in the industries. In this article, an interactive teaching methodology has been implemented to investigate the hydrodynamics in various pipe fittings (elbow, bend, Tee, and reducer) by actually visualizing the flow. The three-dimensional flow visualization is used to demonstrate the nonidealities such as separation, swirling, dead zones, etc. The CFD simulations of pipe fittings provided a new learning experience to the students that would help them to predict the pressure drops in industrial piping network systems. The outcome from the students' survey showed that the proposed CFD methodology assisted them to gain a better understanding of conventional Chemical Engineering subjects of "Transport Phenomena" and "Fluid Dynamics" in an innovative way. K E Y W O R D Scomputational fluid dynamics, head loss coefficient, pipe fittings, turbulence models 1

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Section: Introductionmentioning

confidence: 99%

Teaching turbulent flow through pipe fittings using computational fluid dynamics approach

Gajbhiye

Kulkarni

Tiwari

et al. 2020

Engineering Reports

View full text Add to dashboard Cite

show abstract

“…Unfortunately, it is difficult to distinguish strictly and express precisely the volumetric ratio of circulation fluid caused by the preset riser and the imaged riser, respectively, because there is no way to obtain the boundary between them. It is probable that two‐dimensional computational fluid dynamics methodologies developed in recent years will present an effective pathway to solve this problem …”

Section: Resultsmentioning

confidence: 99%

Oxygen mass transfer characteristics in an internal‐loop airlift reactor with preset trumpet‐shaped riser

Huang

et al. 2014

Asia-Pacific J Chem Eng

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A size-adjustable trumpet-shaped riser was installed into a conventional airlift reactor to form a modified internal-loop airlift reactor (ILAR). The volumetric oxygen mass transfer coefficient (k L a) and gas holdup of the ILAR were heavily influenced by the height ratio of riser to static fluid level above the spargers (h/H), the cross-sectional area ratio of riser to downcomer (A r /A d ) and the superficial gas velocity in the riser (U g ) when deoxidized distilled water was used as the oxygen absorbent. An oxygen transfer rate of (2.17 ± 0.11) × 10 À5 kg m À3 s À1 , k L a of (27.88 ± 1.12) × 10 À3 s À1 and gas holdup of 0.031 were obtained with the ILAR of A r /A d = 1.09 and h/H = 0.73 at U g = 18 mm s À1 . As the well-constructed preset trumpet-shaped riser provided ideal conditions for complete circulation and blending of the fluid, enhanced oxygen transfer efficiency was achieved. The gas holdup and k L a were increased by 16.2% and 10.2% at 19°C, as compared with those of the conventional airlift reactor without this preset riser. The fluid rising velocity in the riser (V R ) and falling velocity in the downcomer (V D ) may be expressed by power-law functions of U g and A r /A d , respectively. These metrics indicate that the ILAR has better performance, as compared with a conventional airlift reaction, for oxygen transfer and microorganism culture for chemical engineering, biological fermentation and environmental protection.

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“…They proved that only a 3dimensional calculation would be able to resolve the flow phenomena required to establish circulation such as the entrainment and carryover of the solids and the liquid solid separation at the top are non axis symmetric. Liquid phase residence time distribution (RTD) in conventional solid-liquid fluidized bed (SLFB) and solid-liquid circulating multistage fluidized bed (SLCMFB) was studied by Kalaga [48]. The riser column was made up of 50 mm i.d.…”

Section: Advanced Measurement Techniquesmentioning

confidence: 99%

Hydrodynamics in a Liquid Solid Circulating Fluidized Bed–A Review

Gnanasundaram

Muruganandam

2019

J. Chem. Rev.

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In this study, the liquid-solid circulating fluidised bed and its performance at various operating conditions were critically reviewed. Hydrodynamic includes pressure drop across the bed, phase hold up distribution, flow regime, flow structure of each phase and solid circulation rate. Detailed analysis of the axial and radial solid distributions, average solid holdup, solid circulation rate, critical transitional velocity for solid at different densities and fluids at various viscosities was discussed. The effect of increasing the liquid viscosity during the heat and mass transfer phenomena in LSCFB has to be studied extensively as the industrial processing fluids are highly viscous. Solid Circulating Fluidized bed. Specialized in studies relating to hydrodynamics in a packed and circulating fluidized bed. Designed and fabricated column for two phases and three phase systems. Focusing on the application of LSCFB for biosorption of heavy metals, Phenol recovery, Industrial effluent bio degradation etc.L. Muruganandam, a chemical engineer working in the area of shock wave applications in Bio and Chemical engineering process. Specialized in membrane development, design and fabrication of Circulating Fluidized bed for environmental treatment like bio-sorption, physical separation of heavy metals, oil impurities from produced water. The research on biodegradation of perchlorate leads to isolation of several species had 9 GEN Publications.

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Liquid phase axial mixing in solid–liquid circulating multistage fluidized bed: CFD modeling and RTD measurements

Cited by 44 publications

References 60 publications

Teaching turbulent flow through pipe fittings using computational fluid dynamics approach

Teaching turbulent flow through pipe fittings using computational fluid dynamics approach

Oxygen mass transfer characteristics in an internal‐loop airlift reactor with preset trumpet‐shaped riser

Hydrodynamics in a Liquid Solid Circulating Fluidized Bed–A Review

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