Browsing by Author "Mishra, G."

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Advances in Computational Fluid Dynamics Modeling for Biomass Pyrolysis: A Review
(Multidisciplinary Digital Publishing Institute (MDPI), 2023) Kulkarni, A.; Mishra, G.; Palla, S.; Ramesh, P.; Surya, D.V.; Basak, T.
Pyrolysis, a process for extracting valuable chemicals from waste materials, leverages computational fluid dynamics (CFD) to optimize reactor parameters, thereby enhancing product quality and process efficiency. This review aims to understand the application of CFD in pyrolysis. Initially, the need for pyrolysis and its role in biomass valorization are discussed, and this is followed by an elaboration of the fundamentals of CFD studies in terms of their application to the pyrolysis process. The various CFD simulations and models used to understand product formation are also explained. Pyrolysis is conducted using both conventional and microwave-assisted pyrolysis platforms. Hence, the reaction kinetics, governing model equations, and laws are discussed in the conventional pyrolysis section. In the microwave-assisted pyrolysis section, the importance of wavelength, penetration depth, and microwave conversion efficiencies on the CFD are discussed. This review provides valuable insights to academic researchers on the application of CFD in pyrolysis systems. The modeling of pyrolysis by computational fluid dynamics (CFD) is a complex process due to the implementation of multiple reaction kinetics and physics, high computational cost, and reactor design. These challenges in the modeling of the pyrolysis process are discussed in this paper. Significant solutions that have been used to overcome the challenges are also provided with potential areas of research and development in the future of CFD in pyrolysis. © 2023 by the authors.
Giant dipole resonance studies in Ba isotopes at E/A?5 MeV
(2017) Ghosh, C.; Kumar, A.K.R.; Dey, B.; Nanal, V.; Pillay, R.G.; Arumugam, P.; Anoop, K.V.; Dokania, N.; Garai, A.; Gupta, G.; Mirgule, E.T.; Mishra, G.; Mondal, D.; Pal, S.; Pose, M.S.; Rout, P.C.
Exclusive measurements of high-energy ? rays have been performed in Ba124 and Ba136 at the same excitation energy (?49MeV) to study the properties of the giant dipole resonance (GDR) over a wide N/Z range. The high-energy ? rays are measured in coincidence with the multiplicity of low-energy ? rays to disentangle the effect of temperature (T) and angular momentum (J). The GDR parameters are extracted employing a simulated Monte Carlo statistical model analysis. The observed ?-ray spectra of Ba124 can be explained with prolate deformation, whereas a single-component Lorentzian function which corresponds to a spherical shape could explain the ?-ray spectra of Ba136. The observed GDR width in Ba136 is narrower compared to that of Ba124. The statistical model best-fit GDR cross sections are found to be in reasonable agreement with the thermal shape fluctuation model (TSFM) calculations. Further, it is shown that the variation of GDR width with T is well reproduced by the TSFM calculations over the temperature range of 1.1-1.7 MeV. 2017 American Physical Society.
Giant dipole resonance studies in Ba isotopes at E/A?5 MeV
(American Physical Society revtex@aps.org, 2017) Ghosh, C.; Rhine Kumar, A.K.R.; Dey, B.; Nanal, V.; Pillay, R.G.; Arumugam, P.; Anoop, K.V.; Dokania, N.; Garai, A.; Gupta, G.; Mirgule, E.T.; Mishra, G.; Mondal, D.; Pal, S.; Pose, M.S.; Rout, P.C.
Exclusive measurements of high-energy ? rays have been performed in Ba124 and Ba136 at the same excitation energy (?49MeV) to study the properties of the giant dipole resonance (GDR) over a wide N/Z range. The high-energy ? rays are measured in coincidence with the multiplicity of low-energy ? rays to disentangle the effect of temperature (T) and angular momentum (J). The GDR parameters are extracted employing a simulated Monte Carlo statistical model analysis. The observed ?-ray spectra of Ba124 can be explained with prolate deformation, whereas a single-component Lorentzian function which corresponds to a spherical shape could explain the ?-ray spectra of Ba136. The observed GDR width in Ba136 is narrower compared to that of Ba124. The statistical model best-fit GDR cross sections are found to be in reasonable agreement with the thermal shape fluctuation model (TSFM) calculations. Further, it is shown that the variation of GDR width with T is well reproduced by the TSFM calculations over the temperature range of 1.1-1.7 MeV. © 2017 American Physical Society.
Recent advancements of CFD and heat transfer studies in pyrolysis: A review
(Elsevier B.V., 2023) Dadi, V.S.; Sridevi, V.; Tanneru, H.K.; Busigari, R.R.; Ramesh, P.; Kulkarni, A.; Mishra, G.; Basak, T.
There is a pressing need to process the solid waste by using pyrolysis technology due to its uniqueness to produce various solid, liquid and gaseous products. However, further understanding of pyrolysis process is needed. Most importantly, the role of computational fluid dynamics (CFD) in pyrolysis is to be thoroughly investigated. In recent times, there has been significant progress in the research works aligned with evaluating the role of CFD in biomass pyrolysis. Hence, the current review manuscript focusses the current state of the art in the application of CFD tools to multi-scale biomass pyrolysis systems. Modeling of fluid and heat transport in conventional pyrolysis reactors, microwave-assisted pyrolysis reactors, and solar-assisted pyrolysis reactors for the conversion of biomass have been critically analyzed. The theoretical basis and the practical applicability of the CFD models to efficiently emulate and predict the overall complexity of pyrolysis process for the multi-scale and multi-phase nature of biomass have been discussed. However, the validity and accuracy of the CFD models needs to be enhanced. In the future directions, the steps for expanding the applicability of these theoretical and computational models have been outlined. This review would provide detailed understanding of CFD role in pyrolysis process conducted in various reactor systems. © 2023 Elsevier B.V.