Browsing by Author "Kulkarni, A."

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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.
Exergy analysis of a LPG fuelled, MPFI multi-cylinder engine with vaporized water methanol induction
(2013) Patil, B.; Kulkarni, A.; Mohanan, P.
The influence of vaporized water methanol induction on a MPFI multi-cylinder engine performance and thermal balance has been experimentally investigated. A four stroke, four cylinder MPFI gasoline engine was used with LPG as fuel and vaporized water methanol. For the generation of vaporized water methanol, heat from the exhaust gas has been used. Different percentages of water methanol by mass basis were used with variable engine speed ranging from 2000 to 4500 rpm. The results showed that as the percentage water methanol induction level to the engine increased, there is slight increase in percentage of useful work, while the losses decreased except unaccounted losses. Additionally, the engine brake thermal efficiency increases. The average increase in the brake thermal efficiency for a 20% water methanol with LPG is approximately 1.5% over the use of LPG without water methanol induction.
Exergy analysis of a LPG fuelled, MPFI multi-cylinder engine with vaporized water methanol induction
(Korean Society of Combustion, 2013) Patil, B.; Kulkarni, A.; Mohanan, P.
The influence of vaporized water methanol induction on a MPFI multi-cylinder engine performance and thermal balance has been experimentally investigated. A four stroke, four cylinder MPFI gasoline engine was used with LPG as fuel and vaporized water methanol. For the generation of vaporized water methanol, heat from the exhaust gas has been used. Different percentages of water methanol by mass basis were used with variable engine speed ranging from 2000 to 4500 rpm. The results showed that as the percentage water methanol induction level to the engine increased, there is slight increase in percentage of useful work, while the losses decreased except unaccounted losses. Additionally, the engine brake thermal efficiency increases. The average increase in the brake thermal efficiency for a 20% water methanol with LPG is approximately 1.5% over the use of LPG without water methanol induction.
Experimental investigations of performance and emission characteristics of single cylinder CI engine fueled with different blends of jatropha biodiesel with Metal based additive.
(Korean Society of Combustion, 2013) Kulkarni, A.; Patil, B.; Vijaykumara, M.; Kumar, G.N.
The present investigation is focused on effect of CoCl2 as metal based additives on four stroke, single cylinder, air cooled direct injection diesel engine fuelled with various blends of jatropha biodiesel. Experiments were conducted to study performance and emission characteristics of CI engine operated at a constant speed of 1500 rpm at variable load from no load to full load in step of 25%. The Metal based additive (CoCl2) was added at a dosage of 50 Î¼mol/L of biodiesel in a jatropha biodiesel-diesel blend. Experimental results revealed that, when compared with blends without additive, significant improvement in brake thermal efficiency was observed by 1.24% for B20 and 1.52% for B40. From emissions profile, HC was lowered such as 18.18% reduction was observed for B40 with additive at 50% load condition also, other blends showed reductions in the range of 10% to 16% at various load conditions.NOx found to be lowered in the range of 10-12% for blends with additive compared to plain blends. Hence, CoCl2 added at a dosage of 50 Î¼mol/L is efficient in improving the performance and emission characteristics of jatropha biodiesel particularly for B20 and for B40. And they can be used as a suitable alternative to diesel fuel.
Modelling and analysis of lower metal on-chip interconnects using physical fabrication parameters
(Institute of Electrical and Electronics Engineers Inc., 2019) Kulkarni, A.; Iteesh, V.A.; Sahith, S.R.
This paper looks into the modelling and analysis of on-chip interconnects in the lower metal region of an Integrated Circuit (IC). A proposed Ï€-interconnect model is quantitatively modelled and analysed and the delay time, td is used as a metric to measure performance change from ideal circuit simulations for varying interconnect lengths using a driver-load inverter pair. The Ï€-model delay time performance is also compared with that of a layout of an driver-load inverter pair circuit and a 3-stage ring-oscillator circuit. The layout is generated using MOSIS SCMOS technology using ON Semiconductor C5 600nm device model with VDD = 5V. All modelling and analysis is done using open-source EDA tools and technology. Â© 2019 IEEE.
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.
TestQuBE: A Testbench Enhancement Methodology for Universal Serial Interfaces in Complex SoCs
(IEEE Computer Society, 2021) Kulkarni, A.; Singh, A.; Waje, S.A.; Kashide, S.S.; Choi, S.B.
With the increasing computational requirements of complex Systems on Chips (SoCs), the number of Universal Serial Interface (USI) instances have been scaled up, for handling data from ever greater number of peripheral components. This has increased the testbench (TB) complexity during verification, requiring numerous test vectors across multiple iterations to validate the design logic, negatively affecting turn-around-time. In this paper, we propose the TestQuBE (Testbench Quality Benchmark Enhancement) methodology which targets four TB quality benchmarking metrics: total TB development time, resource utilization, functional coverage development efficiency. TestQuBE generates an enhanced testbench with automated components that target the aforementioned TB quality metrics. Simulation results for a real-time use-case scenario show 76.2% improvement in functional coverage for up to 75% faster TB development time, resulting in a 91.6% reduction in resource utilization and approximately 50x greater development efficiency, compared to deployed solutions. Â© 2021 IEEE.
The Second DISPLACE Challenge: DIarization of SPeaker and LAnguage in Conversational Environments
(International Speech Communication Association, 2024) Kalluri, S.B.; Singh, P.; Roy Chowdhuri, P.; Kulkarni, A.; Baghel, S.; Hegde, P.; Sontakke, S.; Deepak, K.T.; Mahadeva Prasanna, S.R.; Vijayasenan, D.; Ganapathy, S.
The DIarization of SPeaker and LAnguage in Conversational Environments (DISPLACE) 2024 challenge is the second in the series of DISPLACE challenges, which involves tasks of speaker diarization (SD) and language diarization (LD) on a challenging multilingual conversational speech dataset. In the DISPLACE 2024 challenge, we also introduced the task of automatic speech recognition (ASR) on this dataset. The dataset containing 158 hours of speech, consisting of both supervised and unsupervised mono-channel far-field recordings, was released for LD and SD tracks. Further, 12 hours of close-field mono-channel recordings were provided for the ASR track conducted on 5 Indian languages. The details of the dataset, baseline systems and the leader board results are highlighted in this paper. We have also compared our baseline models and the team's performances on evaluation data of DISPLACE-2023 to emphasize the advancements made in this second version of the challenge. Â© 2024 International Speech Communication Association. All rights reserved.
Two-step synthesis of biochar using torrefaction and microwave-assisted pyrolysis: Understanding the effects of torrefaction temperature and catalyst loading
(Elsevier B.V., 2023) Ramesh, P.; Sankar Rao, C.S.; Surya, D.V.; Sridevi, V.; Kulkarni, A.
The study focused on synthesizing the biochar from sawdust using torrefaction followed by pyrolysis. Sawdust was torrefied at different temperatures (125 °C, 150 °C, and 175 °C) using a conventional hot air oven. The obtained torrefied biochar was subjected to Microwave-assisted pyrolysis at a power of 300 W for 10 min. Graphite was used as a susceptor, and KOH was used as a catalyst. The maximum biochar product yield varied from 24 to 48 wt% and increased with torrefaction temperature. The average heating rates ranged from 54.5 to 74.6 °C/min. At 10 g of KOH, higher heating rates were obtained. The pyrolysis index analyzed varied between 97.5 and 111.5 and decreased with the increase in torrefaction temperature. The obtained biochar was analyzed using SEM, BET, XRD, FTIR, ICP-OES, and Raman spectroscopy. Porous structure formation enhanced, and the concentrations of Ca, Al, and Fe decreased with the increase in torrefaction temperature. © 2023 Elsevier B.V.